# La Crosse BC-900 Charger Test



## nikiwind (Sep 1, 2005)

I'm analysing it with scope and plotter (it takes time) and I'll post later scope and plotter screens with some conclusions.
May be I'll find the way for modifications to make it even better and I'll post it as well.


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## nikiwind (Sep 6, 2005)

I have a glitch and I think I now why.
I'll try to do some modification on a next few days and I'll post suggestions pictures and a scope screens.


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## Archangel (Sep 7, 2005)

I for one am looking forward to it.


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## nikiwind (Sep 7, 2005)

I did the modification and now power (3V on the board) looks much better. 
Now I have to run a few tests to make sure everything fine and then I'll post results.
Just one problem. It will be board pictures with modification and scope screens but looks like I can't upload it to the forum and I have no idea how to include it


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## jtr1962 (Sep 7, 2005)

Interestingly, my two chargers (the original and the replacement LaCrosse sent me) seem to be doing fine on a different power supply which can be obtained here. The chargers don't seem to mind 3.3V instead of 3V. Apparently the original supply is very glitchy which comes as no surprise given its small size (no room for large filter capacitors).

I also noticed that some components on the PC boards get very hot when running above 500 mA so I always have a small fan blowing on the chargers when running either 700 mA or 1000 mA. At first I thought this might be due to the higher voltage power supply but the chargers get just as hot on the stock supply.

I'm very interested in seeing what you came up with. If you have a place to host your pictures you can include them by using img and /img tags around the url of the image.


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## Flash_Gordon (Sep 7, 2005)

jtr1962 said:


> Interestingly, my two chargers (the original and the replacement LaCrosse sent me) seem to be doing fine on a different power supply which can be obtained here. The chargers don't seem to mind 3.3V instead of 3V. Apparently the original supply is very glitchy which comes as no surprise given its small size (no room for large filter capacitors).



Good find. Regulated switching power supply at over 4.5 amps ought to do the trick.

Is the connector the same size or did you have to change it?

Mark


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## jtr1962 (Sep 7, 2005)

Flash_Gordon said:


> Is the connector the same size or did you have to change it?


Same size and polarity. The only drawback is that the new power supply is physically larger than the charger and needs to sit on a flat surface. On the plus side since the plug is normal size you don't take up an extra space on a power strip as you would with the stock supply.


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## Archangel (Sep 7, 2005)

jtr -
What issues were you having that you decided to try a different adapter?


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## nikiwind (Sep 7, 2005)

I have a lot scope screens (TEK3000) and a voltage plots (FLUKE 196C) which will illustrate what's going on and how to fix it plus actual board before and after modification.
And I don't think another power supply can completely eliminate the problem. It is some PCB design problem.
But unfortunately I don't have a place to host all these pictures.
Any idea how I can post them?


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## balazer (Sep 7, 2005)

imageshack.us? Or your ISP?


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## Archangel (Sep 7, 2005)

Many people use ImageStation for a free site, but i'm not one of them, so can't give you any specifics.


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## jtr1962 (Sep 8, 2005)

Archangel said:


> jtr -
> What issues were you having that you decided to try a different adapter?


The units were doing a hard reset when in refresh mode once two or more cells finished their refresh cycles. So far, so good in that both chargers haven't yet done this with the new power supplies.


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## jtr1962 (Sep 8, 2005)

nikiwind said:


> But unfortunately I don't have a place to host all these pictures.
> Any idea how I can post them?


You might have a look at this thread. A lot of people, myself included, are very interested in your results.


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## N162E (Sep 8, 2005)

nikiwind said:


> I have a lot scope screens (TEK3000) and a voltage plots (FLUKE 196C) which will illustrate what's going on and how to fix it plus actual board before and after modification.
> 
> But unfortunately I don't have a place to host all these pictures.
> Any idea how I can post them?



http://www.pbase.com Its a few dollars a year to be able to post a lot of pictures.


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## nikiwind (Sep 8, 2005)

Test post for the image.

This is a scope screen of the power before modification:

http://www.pbase.com/nikiwind/image/48935233


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## nikiwind (Sep 8, 2005)

OK it works

This is the power after mod.

http://www.pbase.com/nikiwind/image/48935242

As you can see there is no glitches any more.
And these glitches were responsible for the "selfreset" and other funny behaviour when you have to charge more then one battery.

Within next few days I'll upload detailed picturestory with test results and explanation what should be done.


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## SilverFox (Sep 8, 2005)

Hello Nikiwind,

Very interesting...

Tom


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## nikiwind (Sep 8, 2005)

This is the first part of the story:

Test setup.

http://www.pbase.com/nikiwind/image/48944448

http://www.pbase.com/nikiwind/image/48944420

http://www.pbase.com/nikiwind/image/48944422


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## nikiwind (Sep 8, 2005)

This is what happened.

When one battery was fully discharged and goes to the charge mode second one almost on the same time before actual full discharge occurs switch to the charge mode too.

http://www.pbase.com/nikiwind/image/48944375


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## nikiwind (Sep 8, 2005)

Board (bottom view) before modifications

http://www.pbase.com/nikiwind/image/48944378

Board (top view) before modifications

http://www.pbase.com/nikiwind/image/48944382

Board (bottom view) after modifications

http://www.pbase.com/nikiwind/image/48944389

http://www.pbase.com/nikiwind/image/48944390 

http://www.pbase.com/nikiwind/image/48944392 

http://www.pbase.com/nikiwind/image/48944394

I think unit has this problem because of bad design.
No high volume low ESR (impedance) capacitors on the board, relatively long wires with some inductance from power supply and PW supply limited reaction time for the step load (overshot and undershot). All of it especially glitches (overshot and undershot) make the measurement system not reliable and this is the reason to selfreseting behaviour and other "glitches".


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## balazer (Sep 8, 2005)

How common are these glitches? Are all BC-900s affected? Can the problem be reported to the manufacturer?


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## nikiwind (Sep 8, 2005)

Three 470 uF capacitors are not really necessary. It could be just one tantalum cap > 100 uF rated for voltage higher then 6.3V.
Ceramic caps (very low ESR) are not necessary too but put them close to the switching MOSFETs for sure not make it worse.

For illustration a scope screens before and after modification.
As you can see after modification glitches completely gone.

Before (one battery):

http://www.pbase.com/nikiwind/image/48935233 

http://www.pbase.com/nikiwind/image/48943369

http://www.pbase.com/nikiwind/image/48943370 

http://www.pbase.com/nikiwind/image/48943373

Before (four batteries):

http://www.pbase.com/nikiwind/image/48943390

http://www.pbase.com/nikiwind/image/48943401 

http://www.pbase.com/nikiwind/image/48943403

http://www.pbase.com/nikiwind/image/48943404

After:

http://www.pbase.com/nikiwind/image/48935242

http://www.pbase.com/nikiwind/image/48943408

http://www.pbase.com/nikiwind/image/48943409

Now it is under continuous test to prove it but what I've seen so fare it works.

Your comments are appreciated


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## nikiwind (Sep 8, 2005)

balazer said:


> How common are these glitches? Are all BC-900s affected? Can the problem be reported to the manufacturer?



I have just one unit but I believe it is common problem for all of them.
At least my 20+ years like an electronics Eng. tell me about it


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## Archangel (Sep 8, 2005)

Not that i'm not clutching at straws here, but what version number is yours?


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## jtr1962 (Sep 8, 2005)

Very interesting results. I also thought that they skimped on bypassing which is why I added a bypass cap at the power supply input. Right now my units have three 4.7 uF caps in parallel at the input plus the new power supply and seem to be doing OK. However, this mod was ineffective with the stock power supply.

I will try your mod also. You said only 1 470 uF cap was needed. Would you put it at the power supply input or elsewhere? Perhaps the 2.2 uF caps at the MOSFETs will work provided you have a lot of bypassing right at the power supply input. I plan to try 4.7 uF at the MOSFETs because I have a lot of them handy and something much larger at the power supply input. Are those 470 uF, 10V caps tantalum?

Another thing to help make the charger completely bullet-proof might be to put a few uF right on the supply lines for the microprocessor, assuming that you can find them.

Thanks for the testing and for sharing your results. You might want to report this to LaCrosse engineering. Maybe they'll send you a few free chargers.


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## nikiwind (Sep 8, 2005)

Archangel said:


> Not that i'm not clutching at straws here, but what version number is yours?



32 like the everybody.


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## nikiwind (Sep 8, 2005)

jtr1962 said:


> Very interesting results. I also thought that they skimped on bypassing which is why I added a bypass cap at the power supply input. Right now my units have three 4.7 uF caps in parallel at the input plus the new power supply and seem to be doing OK. However, this mod was ineffective with the stock power supply.
> 
> I will try your mod also. You said only 1 470 uF cap was needed. Would you put it at the power supply input or elsewhere? Perhaps the 2.2 uF caps at the MOSFETs will work provided you have a lot of bypassing right at the power supply input. I plan to try 4.7 uF at the MOSFETs because I have a lot of them handy and something much larger at the power supply input. Are those 470 uF, 10V caps tantalum?
> 
> ...




I think even 100-200 uF tantalum cap will be sufficient.

I'd like to have schematic of this unit. In this case I definitely can make it perfect

It is almost impossible to catch it unless you sitting and looking on it for a few hours or using some plotting device like I did


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## balazer (Sep 8, 2005)

This is all very good. It would be nice if you could give a dummie's guide to the simplest fix that would be good enough for most people.


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## nikiwind (Sep 8, 2005)

balazer said:


> This is all very good. It would be nice if you could give a dummie's guide to the simplest fix that would be good enough for most people.





Open it from the bottom and solder one tantalum capacitor (>100 uF and > 6.3V) like shown on the pictures. It should be enough.

Go to the 

http://www.digikey.com

type "tantalum capacitor"

then choose "Tantalum" under the "Capacitors"

then choose "Voltage-Rated" - 6.3V, "Packaging" - Cut Tape, "Features" - Low ESR, and "Capacitance" - > then 100 uF (for instance 330 uF)

Then "Apply Filters"

Then choose anyone. For example:

B45197A1337K509

Digi-Key P.N. 495-1516-1-ND


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## balazer (Sep 8, 2005)

In your pictures I see capacitors added in three positions. Adding a single capacitor to any of those three positions will work?


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## nikiwind (Sep 8, 2005)

balazer said:


> In your pictures I see capacitors added in three positions. Adding a single capacitor to any of those three positions will work?



Yes it will work in any of these positions.


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## balazer (Sep 8, 2005)

If the solution is basically a capacitor between the GND and 3V lines, is that something that could be just as well fixed by a different kind of power supply?


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## balazer (Sep 8, 2005)

The Germans are reporting a newer board revision (G216D1V06) and newer firmware (33). The only physical change they note is a change in the temperature sensors that puts them closer to the batteries.

http://www.google.com/search?hl=en&q=g216d1v05&btnG=Google+Search


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## nikiwind (Sep 8, 2005)

balazer said:


> If the solution is basically a capacitor between the GND and 3V lines, is that something that could be just as well fixed by a different kind of power supply?



Different PW supply can make it better but I don't think so it will completely cure it. It MUST be enough capacitance present on the PC board close to the switching transistors. Otherwise the glitches still will be present.


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## nikiwind (Sep 8, 2005)

balazer said:


> The Germans are reporting a newer board revision (G216D1V06) and newer firmware (33). The only physical change they note is a change in the temperature sensors that puts them closer to the batteries.
> 
> http://www.google.com/search?hl=en&q=g216d1v05&btnG=Google+Search



I've add thermocompaund (regular white) before reasseble it and I think it's OK.

And unfortunately I don't understand German. Only English and Russian


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## Brock (Sep 8, 2005)

Actually wouldn't the simplest thing to fix it would be getting the better power supply that jtr1962 linked to above? Or is the problem after the power hits the charger?


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## balazer (Sep 8, 2005)

I linked the Google search results so you could click "translate".


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## nikiwind (Sep 8, 2005)

One more thing which I've noticed.
For discharge cycle this unit using four 0805 size 7.5 Ohm resistors in parallel.
Common surface mount 0805 resistor has 1/8W (0.125W) maximum power dissipation.

For discharge current 500 mA total power dissipation will be ~ 0.65W.
So each resistor will dissipate about 0.16W.
It is unacceptable.
In other word I not recommend using discharge current more then 350 ma or at least use 500 mA options only for two batteries separated with one or two empty slots.


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## nikiwind (Sep 8, 2005)

Brock said:


> Actually wouldn't the simplest thing to fix it would be getting the better power supply that jtr1962 linked to above? Or is the problem after the power hits the charger?



Like I've sad better power supply can make it better but it MUST be capacitor(s) on the board.


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## nikiwind (Sep 8, 2005)

balazer said:


> I linked the Google search results so you could click "translate".



Can you post link to our discussion to these German sites. May be they can add some interesting and useful info.


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## jtr1962 (Sep 8, 2005)

nikiwind said:


> One more thing which I've noticed.
> For discharge cycle this unit using four 0805 size 7.5 Ohm resistors in parallel.
> Common surface mount 0805 resistor has 1/8W (0.125W) maximum power dissipation.
> 
> ...


Actually, four 7.5 ohm resistors in parallel is 1.875 ohms, and 500 mA through 1.875 ohms dissipates 0.469W, or 0.117W per resistor-right on the bleeding edge but still within limits. I think the charger uses the MOSFET to regulate the discharge current through the resistors. As a result, the MOSFET is what will absorb the remainder of the power. I noticed that when the cell voltage falls under about 1 volt the discharge current falls under 500 mA. The MOSFET is probably full on at that point.

I always use a fan when running the charger at either 700 mA or 1000 mA. Without it the batteries just get too hot near the end of their charge cycle.


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## balazer (Sep 8, 2005)

I posted message with a link to this thread in the German forum. In English...


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## nikiwind (Sep 8, 2005)

jtr1962 said:


> Actually, four 7.5 ohm resistors in parallel is 1.875 ohms, and 500 mA through 1.875 ohms dissipates 0.469W, or 0.117W per resistor-right on the bleeding edge but still within limits. I think the charger uses the MOSFET to regulate the discharge current through the resistors. As a result, the MOSFET is what will absorb the remainder of the power. I noticed that when the cell voltage falls under about 1 volt the discharge current falls under 500 mA. The MOSFET is probably full on at that point.
> 
> I always use a fan when running the charger at either 700 mA or 1000 mA. Without it the batteries just get too hot near the end of their charge cycle.



0.5A * 1.875 Ohm = 0.9375V. On the fresh battery we have ~ 1.4V

I did the measurements and on the MOSFET voltage dropout is very small. So most of the energy dissipates on the resistors.
Fan will help to lower the battery temperature but not the bottom side of the PCB.


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## nikiwind (Sep 8, 2005)

balazer said:


> I posted message with a link to this thread in the German forum. In English...



Thanks.


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## Archangel (Sep 9, 2005)

So is this charger pretty much screwed the whole way around?


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## jtr1962 (Sep 9, 2005)

nikiwind said:


> 0.5A * 1.875 Ohm = 0.9375V. On the fresh battery we have ~ 1.4V
> 
> I did the measurements and on the MOSFET voltage dropout is very small. So most of the energy dissipates on the resistors.
> Fan will help to lower the battery temperature but not the bottom side of the PCB.


The rest of the voltage has to dissipate somewhere else then. Just do the math. You have 0.9375 V across the resistor and 0.5 A. That gives you 0.469 watts. By definition you _can't_ have any more power being dissipated across the resistors. It is being dissipated elsewhere.


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## nikiwind (Sep 9, 2005)

jtr1962 said:


> The rest of the voltage has to dissipate somewhere else then. Just do the math. You have 0.9375 V across the resistor and 0.5 A. That gives you 0.469 watts. By definition you _can't_ have any more power being dissipated across the resistors. It is being dissipated elsewhere.



Probably you are right. I'll check it with scope.

One more thing.
Before modification voltage readings on the charger display and FLUKE true RMS voltage measurements have difference about 100 mV (0.1V) as you can see it on the pictures. Now it is about 10 to 20 mV.


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## nikiwind (Sep 9, 2005)

Archangel said:


> So is this charger pretty much screwed the whole way around?



It's still much better then 99% off the others.
But nothing is perfect
Much better if you know it better. You can use it correctly and more efficient.


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## N162E (Sep 9, 2005)

Archangel said:


> So is this charger pretty much screwed the whole way around?



Thank you SOOOOOOOOOOO much for telling me what a piece of junk this charger is. For almost the last year I have been SOOOOOOOOO happy with this charger. I never thought I was having any of the problems other members reported, most of which seemed to be related to improper use or interpretation. I actually thought my batteries were operating better than ever because I thought I was matching them capacity wise. I also apparantly was living a false security thinking that refresh cycle was useful. I Was also (obviously) falsely liking the idle charge of about c/100 which I thought was great because I could leave the batteries on the charger until I was ready to use them. I guess fully topped NIMH's available at all times is bad. Oh!! I almost forgot that horrible horrible switching power supply that generates almost no heat. Heat sensors that are actually potted in with thermal grease!! What were they thinking. How could anybody put out such a bad FIRST generation product.

BTW Archangel, "What are you replacing YOUR La Crosse chargers with that isn't "Pretty much screwed the whole way around"?"


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## N162E (Sep 9, 2005)

nikiwind said:


> It's still much better then 99% off the others.
> But nothing is perfect
> Much better if you know it better. You can use it correctly and more efficient.



Nikiwind, Thank you so much (Really). Your time and effort is appreciated. I certainly welcome the opportunity to make an excellent product even better. Add to this effort pictures and explanation to the extent that we can do the mod ourselves is a service to us all.


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## nikiwind (Sep 9, 2005)

N162E said:


> Nikiwind, Thank you so much (Really). Your time and effort is appreciated. I certainly welcome the opportunity to make an excellent product even better. Add to this effort pictures and explanation to the extent that we can do the mod ourselves is a service to us all.



Thanks!

You just have to remove four screw on the bottom and place one small capacitor on the board (you have to know how to solder
In case I have schematic I can do it even better
By the way I've sent description of the problem to the La Crosse and they suggest to send the unit back.
It doesn't make sense for now


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## balazer (Sep 9, 2005)

If you would, write La Crosse again and try to make it clear that they have a design flaw that causes a malfunction, and it's easily corrected!

It would be great if this problem could be corrected for future buyers, at some point.


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## nikiwind (Sep 9, 2005)

I'll try but to be honest I don't think they will listen


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## jtr1962 (Sep 9, 2005)

Why not send a link to this thread to LaCrosse engineering?

BTW, I put 4.7 uF caps near the MOSFETs instead of the 2.2 uF you used, and I used 3 220 uF, 10V caps where you had the 470 uF caps. Those were the parts I happened to have handy. Hopefully I won't have any more problems, even running on the stock power supply. Thanks again for all the work. Now if only I could get my hands on a schematic...


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## Archangel (Sep 9, 2005)

No, thank *you*, N162E, for going completely overboard. Forgive me for not knowing anything about electronics, but when someone who obviously knows starts picking things apart, i begin to think maybe it wasn't such a good buy. My main charger is still a Maha, but instead of getting my brother one i bought both of us LaCrosses because of the screen, which i imagine is the reason most everyone bought them. You could just have said something like nikiwind did, which is basically "no, but there's definite room for improvement."


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## nikiwind (Sep 9, 2005)

jtr1962 said:


> Why not send a link to this thread to LaCrosse engineering?
> 
> BTW, I put 4.7 uF caps near the MOSFETs instead of the 2.2 uF you used, and I used 3 220 uF, 10V caps where you had the 470 uF caps. Those were the parts I happened to have handy. Hopefully I won't have any more problems, even running on the stock power supply. Thanks again for all the work. Now if only I could get my hands on a schematic...



I don't think it will work (sending link to LaCrosse).

Since I did modification (about 3 days) I'm doing non stop test of it and so far so good
I'd like to have schematic as well
I know I can do the better charger but I don't want spend time for it


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## nikiwind (Sep 9, 2005)

Archangel said:


> No, thank *you*, N162E, for going completely overboard. Forgive me for not knowing anything about electronics, but when someone who obviously knows starts picking things apart, i begin to think maybe it wasn't such a good buy. My main charger is still a Maha, but instead of getting my brother one i bought both of us LaCrosses because of the screen, which i imagine is the reason most everyone bought them. You could just have said something like nikiwind did, which is basically "no, but there's definite room for improvement."



Archangel - even without modification it is still very good unit. Like I'm already sad much better then 99% and usually it works fine.


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## Archangel (Sep 9, 2005)

Yeah, that's the way i understood it. nikiwind. Looks like i read too much into all the mods you did.


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## zespectre (Sep 9, 2005)

Okay, so for someone who isn't especially technical please give a simple plain-english answer. Is this charger worth buying or should one hold off for something else?

I ask because I was just planning on buying two of them.


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## nikiwind (Sep 9, 2005)

zespectre said:


> Okay, so for someone who isn't especially technical please give a simple plain-english answer. Is this charger worth buying or should one hold off for something else?
> 
> I ask because I was just planning on buying two of them.



Buy it it. It will do the job


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## nikiwind (Sep 9, 2005)

Archangel said:


> Yeah, that's the way i understood it. nikiwind. Looks like i read too much into all the mods you did.


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## SilverFox (Sep 9, 2005)

OK, in plane language I believe the following can be stated...

The LaCrosse BC-900 is a very good charger with lots of features that are very useful, however there have been reports of some problems with some units.

JTR discovered that the charger would reset in the middle of the refresh mode. He change power supplies and the problem seems to have gone away.

Nikiwind discovered "gliches" with his unit and added a capacitor to filter those away.

LaCrosse suggests that those units are faulty and should be returned for replacement.

Many people, including myself, have had no problems at all.

I believe it is still a good charger, but after seeing Nikiwind's observations, I may check mine out on the scope as well. At any rate, as I understand it, adding a capacitor does not take away from the ability of the charger to function, so the decision on doing this modification should depend on how many problems you encounter using the charger.

Tom


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## zespectre (Sep 9, 2005)

nice summary, thanks!


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## pocketpepe (Sep 10, 2005)

Hi @All,

fist of all, sorry for my bad english. My reading is much better :laughing:. I've a BC-900 too, and after reading all the posts about this charger i've got one question.

What's the different between version "29" and "33"?

Many thanks for your answer!

Kind regards,
Pepe


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## AdamThirnis (Sep 10, 2005)

zespectre said:


> nice summary, thanks!



I agree. Thanks for this informative test.


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## SilverFox (Sep 10, 2005)

Hello Pepe,

Welcome to CPF.

You must have an early version. I believe most of ours are version 32. I do not know what the differences are.

Tom


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## pocketpepe (Sep 10, 2005)

SilverFox said:


> Welcome to CPF.



Thank you .



> You must have an early version. I believe most of ours are version 32. I do not know what the differences are.



In a german forum they said that there are only some internal changes with the layout. About software changes i could get no answer.

Regards,
Pepe


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## glire (Sep 16, 2005)

Thanks to all the job done here.

I never bought a perfect piece of hardware. Either being a car, hifi sound, display device, etc, there is always something flawed.
Sometimes, those flaws seem so easy to be avoided at design time that I'm wondering if they're not there on purpose...

Anyway, enjoy your chargers. I just got mine 2 days ago. In case of problems, now I informed and know the wordkarounds.

Thanks CPF


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## jtr1962 (Sep 20, 2005)

I've been testing the charger with the _original_ power supply and the modifications. No glitches or false resets in almost a week of testing! I guess it's safe to say that the problem is solved.


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## nikiwind (Sep 20, 2005)

Did you have glitches or false resets before modification?


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## jtr1962 (Sep 20, 2005)

nikiwind said:


> Did you have glitches or false resets before modification?


Yes, I had them on both my chargers (the original and the replacement which LaCrosse sent me). The replacement was actually worse than the original, and reset even when just charging at anything other than 200 mA. Both chargers where fine on the replacement power supplies with 3 x 4.7 uF caps at the power supply plug (that mod didn't work with the original supply). After I modified both units the way you described, I tested the worst unit (the replacement) with the original power supply. No glitches so far when using the refresh mode or test mode or any other mode. As mentioned earlier, my mods were similar to yours except that I used 4.7 uF caps by the MOSFETs and three 220 uF tantalums instead of the 470 uF ones you used. I don't think the values are too important so long as you have enough bypassing.


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## wquiles (Sep 20, 2005)

nikiwind - thanks much for your time and effort to get this work done 

Will


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## nikiwind (Sep 20, 2005)

You are welcome


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## greenlight (Sep 28, 2005)

I just bought my charger at amazon with 30$ back from signing up for their Card. I hope the charger is good, otherwise I'll have to read this post more carefully.


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## Wingerr (Sep 29, 2005)

jtr1962 said:


> The rest of the voltage has to dissipate somewhere else then. Just do the math. You have 0.9375 V across the resistor and 0.5 A. That gives you 0.469 watts. By definition you _can't_ have any more power being dissipated across the resistors. It is being dissipated elsewhere.



Not sure if the four resistors mentioned are actually wired in series with the discharge current, but if so, and set up with four resistors in parallel handling all four banks, then the 469mW is with only one battery installed and discharging at the 500mA rate. If you happen to have four batteries going at once, then effectively the current going through the paralleled set is 2000mA. That'd give you 7.5W through the four resistors, or a smokey 1.875W each.

If they're just SMD resistors, they're probably not wired in series, since they don't come in 2W sizes-


By the way, anyone look into the function of the 47k ohm resistors used in each bank? I suspect it's used for the sensing circuit, and the one in my second bay is apparently open. Don't think there's enough voltage in this thing to overpower a 47k resistor, so I'm assuming it's a fluke failure. Bought another one, thanks for the Amazon lead..


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## balazer (Sep 29, 2005)

I sure don't know what you mean.

The most the BC-900 will dissipate in discharge per cell is 0.5 A * ~1.4 V = 0.7 W.

Most of the operations of this charger are time multiplexed.


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## greenlight (Sep 29, 2005)

Wingerr said:


> Bought another one, thanks for the Amazon lead..



I had been searching amazon's site for a month to find a battery/charger to spend my 30$ coupon on. Finally this shows up, and I had to buy it immediately. Now I have an amazon card to use when I shop there, which adds up to more discounts. Buy.com has a similar deal, where you can stock up on batteries.


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## Wingerr (Sep 29, 2005)

balazer said:


> I sure don't know what you mean.
> 
> The most the BC-900 will dissipate in discharge per cell is 0.5 A * ~1.4 V = 0.7 W.
> 
> As for the number of resistors, there might be only one. Most of the operations of this charger are time multiplexed.



This refers to an old post up in the thread, nikiwind mentioned there are four resistors wired in parallel, and used in the discharge circuit- there was some discussion about the power handling of the resistors.
If they have a current source drawing 500mA per cell, that would be the power dissipated through each resistor, if it were actually wired that way. That's why I suspect they're not in series, and the current is passing through the MOSFET, possibly in parallel to the resistors.
I haven't actually looked at the board, so haven't confirmed either way.


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## balazer (Sep 29, 2005)

The only way you'd get 7.5 W through those resistors is if the batteries were wired in series. I think that's very unlikely, since the discharge currents are independently selectable per cell. It seems much more likely to me that there are other components dissipating additional power. It doesn't matter if those additional components are in series or parallel with the resistors. Either way would reduce the power dissipated by the resistors.

In any case the charger will not let you dissipate 7.5 W. I have no idea where you got that number.


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## Wingerr (Sep 29, 2005)

Here's the 7.5W:
Power = I squared x resistance

It was said there are four resistors in parallel, 7.5 ohms each (up in the thread, back awhile-).
Parallelled combination is 1.875 ohms

2A total current (from four banks discharging at 500mA)

2A x 2A x 1.875 ohms = 7.5W

That's why it's not likely wired in series, cause 7.5W ain't happenin' through four SMD resistors..


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## balazer (Sep 29, 2005)

I don't know why you even bring that up. 7.5 W ain't happenin', period.


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## jtr1962 (Sep 29, 2005)

Wingerr said:


> Here's the 7.5W:
> Power = I squared x resistance
> 
> It was said there are four resistors in parallel, 7.5 ohms each (up in the thread, back awhile-).
> ...


_Each_ charging station has 4 7.5 ohm resistors in parallel, so actually there are 16 7.5 ohm resistors altogether on the board, and the cells aren't wired in series. That would require either a power supply of at least 7 or so volts for charging or a step-up regulator on the board. The power supply is 3V and there is no step-up regulator.

Maximum power dissipation at 500 mA discharge current is roughly 0.7 watts per cell, or 2.8 watts total. Since the 1.875 ohm resistor (i.e. the combination of four 7.5 ohm resistors in parallel) can only have a voltage drop of 0.9375 volts at 500 mA by definition then the remainder of the cell voltage is probably taken up by an active component. My guess is the MOSFET.


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## balazer (Sep 29, 2005)

jtr1962 said:


> Since the 1.875 ohm resistor (i.e. the combination of four 7.5 ohm resistors in parallel) can only have a voltage drop of 0.9375 volts at 500 mA by definition then the remainder of the cell voltage is probably taken up by an active component.


You'd need a _minimum_ voltage of 0.9375 to maintain 500 mA across a 1.875 Ohm resistor. It's quite possible to have a higher voltage and maintain that (average) current by adjusting the duty cycle of a switch.

The charger has a low voltage cut-off of 0.90. So it's possible that all of the power is being dissipated in the resistors, and that the current will fall slightly below 500 mA at the end of the discharge cycle (when the battery voltage is between 0.9375 and 0.9, which is a very brief period).


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## TomBrown (Sep 29, 2005)

I just ordered a BC-900 based on positive comments in a lot of places.

I had read this thread before ordering the charger and will probably do the mod, even if I don't notice any problems.

Thank you for your time and expertise, nikiwind.


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## Wingerr (Sep 29, 2005)

_For discharge cycle this unit using four 0805 size 7.5 Ohm resistors in parallel.
Common surface mount 0805 resistor has 1/8W (0.125W) maximum power dissipation.

For discharge current 500 mA total power dissipation will be ~ 0.65W.
So each resistor will dissipate about 0.16W.
It is unacceptable.
In other word I not recommend using discharge current more then 350 ma or at least use 500 mA options only for two batteries separated with one or two empty slots._

I didn't look at the charger circuit, and just assumed from this description that it was four total, rather than 16. 
Anyway, what I was trying to say, unsuccessfully, was that the resistors are not being used for dissipating the power.
I agree they're more likely using the MOSFETs for regulating the discharge current, and if they haven't got those resistors in series, they can easily draw the specified current all the way to the cutoff threshold voltage. 

So what about the 47k resistors? That's mainly what I was interested in; I'm considering replacing the bad one I have in bank two myself rather than send it back to LaCrosse. Anyone trace out the circuit?


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## jtr1962 (Sep 29, 2005)

Wingerr said:


> So what about the 47k resistors? That's mainly what I was interested in; I'm considering replacing the bad one I have in bank two myself rather than send it back to LaCrosse. Anyone trace out the circuit?


I'd say they're probably used to sense battery voltage or maybe voltage across one of the current sense resistors. Regardless of its function, if you have the part and ability to change it yourself you might as well do so rather than send it back. I know I would change it myself. If it's open then it's not detecting the battery properly.


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## Wingerr (Sep 29, 2005)

I'd be inclined to do that, but only thing stopping me is that I've got a few more months warranty left, and I don't know how they feel about someone going in there. I've already gotten a RA number from them, and I don't happen to have any 47k SMD resistors on hand, so I'd have to wait until I need to order other stuff.

I do have a heap of regular ones, maybe I'll try that in the interim, and if in the future have to send it in for some other problem, put the original one back in- 
The other bays are still working, so I may just hold off on sending it back until I get the new one.


ed: Found the problem with the unit, apparently a battery leaked in the bay, causing some electrolyte gunk to conduct from the positive terminal to another trace on the PCB. This caused the phantom battery problem, where the empty bay didn't show 'null' as it should have, because the leakage current was enough to trigger its sense circuit. Doesn't take much, putting just a 47k resistor on the battery contacts will cause the bay to read Full, and read 1.52V. After I cleaned it up, the problem disappeared. All is well again- 
I'll have to keep an eye out for leaky batteries in the future.


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## TomBrown (Oct 13, 2005)

My BC-900 has done several resets. In each case, it was when I was removing a freshly charged battery. That's not very nice when you have cells running through a multi-day conditioning cycle in other slots.

Also, it didn't seem to be working properly, with regard to adding batteries and setting the mode/current. It wouldn't always recognize a battery was present and sometimes wouldn't let me set anything until I unplugged it and re-plugged it.

... so I took a power supply from a Cisco PIX 501 (almost the identical model number to the unit jtr posted) and it has been working perfectly, including extracting cells.

It's kind of a bummer that it seems so buggy out of the box but it has been working great with the Cisco supply. I've had two days of no resets.

Mine is a 341-0008-02. jtr posted a link to model 341-0008-01. Both have the same specs.


- Tom


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## nikiwind (Oct 14, 2005)

Where did you get this Power Supply?
I can't find the link.

Thanks


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## TomBrown (Oct 14, 2005)

Hi Niki.

Here's the link jtr1962 posted.

http://www.allelectronics.com/cgi-bin/category.cgi?category=480&item=PS-334&type=store


The charger has been working well with the new supply. I haven't modded it 
with tantalum capacitors, as I'm still waiting on them to arrive, but I will 
mod the charger according to your instructions ASAP. Thank 
you very much for the work you did on this mod.


Regards,

Tom


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## tacoal (Nov 4, 2005)

Just some comments and observations.

I have got the BC-900 for a few months and it became my major charger at once. 
The problem with it is when it changes the Panasonic 2300mA AA battery on 200mA, 
it will stop charging at about 1.40V frequently. When changing is on 500mA or 
above, the problem is gone.

The glitch should be caused mainly by the long power cord. Adding a capacitor 
from the gate of power MOSFET to ground will surely remedy the glitch. The 
glitch itself in the power switch era is common as some reply point out.

The worst part of design, I think, is that there is no any isolation between the 
power to change the battery and the power to the MCU. Either JTR’s reset case or 
Nikiwind’s starting changing before discharging complete could be from this bad 
design.

The reference voltage for ADC in MCU is 2.2V. If the glitch makes the power too 
low so that it cannot be maintained, the ADC’s result will be incorrect to make 
MCU fuzzy. I don’t know what kind type of this MCU is, it will reset surely if 
its power is too low by the glitch.

Those five 1 ohm sampling register for charging are used as a part of 
discharging load. So for 500mA discharging, the equivalent load is about 
1/5+7.5/4=2.075 ohm.

For 3V power supply, the maximum charging current is 2A although the charging 
current could be 200mA, 500mA…, which is average one. Higher than 3 V power 
supply will causing the maximum changing current increase. Will this damage the 
battery? Just have some worry.

tacoal


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## greenlight (Nov 4, 2005)

tacoal said:


> Just some comments and observations.
> 
> I have got the BC-900 for a few months and it became my major charger at once.
> The problem with it is when it changes the Panasonic 2300mA AA battery on 200mA,
> ...


Did I get that right? Do I need a new power supply unit?


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## Wingerr (Nov 4, 2005)

greenlight said:


> Did I get that right? Do I need a new power supply unit?



If you're having problems you might, but it doesn't seem to be a universal problem, some have reported strange things happening and others haven't.
I did have strange things happen on one of mine, with the phantom battery symptoms, but that was due to leakage from a cell dripping onto some traces on the PC board, which I cleaned off successfully. Other than that, I haven't noticed any problems with either of the two unmodified units I have.
Looks like some sample to sample variation going on.


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## tc17 (Nov 5, 2005)

Considering how much this charger costs, you would think it wouldn't have this problem. I was debating on whether to get this charger, as it has some nice features for displaying battery stats/info.

I currently own a Sony charger which also has an LCD display, but doesn't give detailed stats like this one does. (although it does let me know when a battery is bad by flashing the display icon).

PS: I won't be buying Lenmar nimh batteries again, they are the only ones I have owned that have gone bad on me. I've read similar posts from some other people.


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## NoixPecan (Nov 5, 2005)

I've owned a BC-900 for 4 months, and have not seen any problem yet.

I don't know if it is related or not, but when a battery is full, if I want to remove it without disturbing other slots (which may still be charging or refreshing) I always set the done slot to discharge mode before removing the battery. Why ? Because the first time I used the charger, I noticed that removing a battery while in charge mode (even when full and trickle charging) always produces a slight low-pitched buzz sound. I thought it may be caused by the charger desperately trying to maintain the charge current while the impedance of battery connectors is raising (because of me pulling the battery). Call me stupid, but I feared this could harm the charger, so I always set a slot to discharge mode before removing a battery : no more buzz sound.

Could it be possible than doing so helped keeping reset glitches out of my way ?


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## lepa71 (Dec 29, 2005)

How can I find out what version I have?

Thanks


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## mastabog (Dec 31, 2005)

lepa71 said:


> How can I find out what version I have?


right after you plug in the charger, it displays the version number on the far right lcd cell ... the wide spread version is 32


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## Freedom1955 (Dec 31, 2005)

I received a new BC-900 charger a couple days ago and I'm not happy with it. I could be wrong but I don't think it's working right. I had 4 Energizer 2500 battery's in the Test mode for about 16 hrs. I went and pushed the display button to check some readouts and it must have had a reset because it started the test all over again from scratch according to the LCD screen.

Mine is a version 33.

What do you guys think? Should I send it back?

Thanks


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## lepa71 (Jan 1, 2006)

Freedom1955 said:


> I received a new BC-900 charger a couple days ago and I'm not happy with it. I could be wrong but I don't think it's working right. I had 4 Energizer 2500 battery's in the Test mode for about 16 hrs. I went and pushed the display button to check some readouts and it must have had a reset because it started the test all over again from scratch according to the LCD screen.
> 
> Mine is a version 33.
> 
> ...



How do you know that it has been reset? May be I have the same issue. I started the test for 4 batteries. After couple of hours LCD shows over 2 hours for 3 battery and 20 something minuites for another one.


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## yeba (Jan 17, 2006)

Would any regulated 3.3v power supply work with this charger? I have plenty of PC power supplies and I can use the 3.3V line to power the charger. I dont want to spend money to buy the cisco supply.

Thanks.


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## jtr1962 (Jan 17, 2006)

yeba said:


> Would any regulated 3.3v power supply work with this charger? I have plenty of PC power supplies and I can use the 3.3V line to power the charger. I dont want to spend money to buy the cisco supply.
> 
> Thanks.


The problem with that idea is that under light loads many PC supplies don't regulate. Of course, if you put a dummy load on the 12V or 5V lines you should be OK. Just check to make sure that the 3.3V line really is 3.3V. Also, ideally 3V is better since the charger seems to get a little hotter than normal with a 3.3V supply at high charge currents. Not a problem for me since I always use it with a fan over 500mA but just a word of warning. You can put a Schottky diode in series with the 3.3V supply to drop the voltage down to around 3V.


----------



## yeba (Jan 17, 2006)

Thanks for the feedback. I have modded my antec trupower supply so I can drop the voltage to 3 V using the one potentiometer. I am more concerned on the regulation. I was hoping that these power supplies have better regulation circuits than any other power supply especially the antec trupower series because they have voltage feedback.

I'll do some testing. Any ideas on how to test the regulation. I only have a multimeter.




jtr1962 said:


> The problem with that idea is that under light loads many PC supplies don't regulate. Of course, if you put a dummy load on the 12V or 5V lines you should be OK. Just check to make sure that the 3.3V line really is 3.3V. Also, ideally 3V is better since the charger seems to get a little hotter than normal with a 3.3V supply at high charge currents. Not a problem for me since I always use it with a fan over 500mA but just a word of warning. You can put a Schottky diode in series with the 3.3V supply to drop the voltage down to around 3V.


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## jtr1962 (Jan 17, 2006)

yeba said:


> I'll do some testing. Any ideas on how to test the regulation. I only have a multimeter.


Just watch the readings to see if they fluctuate much. It's not as good as using a scope to check for glitches, but it can tell you if you have a poorly regulating supply.


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## yeba (Jan 17, 2006)

Thanks again. I wish I had an oscilloscope. Last time i used one was when I was in college. I probably dont know how to use it now. Even though I have degree in Electronics Engineering, I pursued IT.




jtr1962 said:


> Just watch the readings to see if they fluctuate much. It's not as good as using a scope to check for glitches, but it can tell you if you have a poorly regulating supply.


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## Vipero00 (Jun 1, 2006)

I just purchased two of the BC-900U. One for home and other for work. I'm wondering if the U is an updated version?


Just plugged in the 1st one to charge the supplied batteries at 200mA. Slot two says Full already at :22 1.35v 70mAh wonder if its a bad battery or charger glitch?

The 2nd I put two pair of old AAs on test mode. Seems to be charging just fine. 

Will update any malfunctions.


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## wptski (Jun 1, 2006)

Vipero00 said:


> I just purchased two of the BC-900U. One for home and other for work. I'm wondering if the U is an updated version?
> 
> 
> Just plugged in the 1st one to charge the supplied batteries at 200mA. Slot two says Full already at :22 1.35v 70mAh wonder if its a bad battery or charger glitch?
> ...


The "U" has always been part of the model number just never mentioned.


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## AZLight (Jun 1, 2006)

Vipero00 said:


> Just plugged in the 1st one to charge the supplied batteries at 200mA. Slot two says Full already at :22 1.35v 70mAh wonder if its a bad battery or charger glitch?



Same thing happened to my second unit with V33 software. I sent it in for repair and it is on its way back to me as we speak.


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## Handlobraesing (Jun 2, 2006)

Mine's a v33 and it quite frequently goes into "cool off" mode due to thermal cut off. The timer read "5:35" while charging 2650mAh batteries at 1,000 mAh. It must have repeatedly charged the battery everytime the thermal cut off resets, but failed to detect -dV.

Very nice feature, very lousy charge termination method.


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## wptski (Jun 2, 2006)

Handlobraesing said:


> Mine's a v33 and it quite frequently goes into "cool off" mode due to thermal cut off. The timer read "5:35" while charging 2650mAh batteries at 1,000 mAh. It must have repeatedly charged the battery everytime the thermal cut off resets, but failed to detect -dV.
> 
> Very nice feature, very lousy charge termination method.


Why do you think that it failed to detect -DeltaV? I've had mine stop for high temperature several times during a cycle but still terminate. What did you do, pull them instead of letting then finish?


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## jayflash (Jun 2, 2006)

When charging, all four displays will briefly change to the same reading, every 15 seconds, and then return to whatever they were originally indicating.

I'm wondering if the 2450 mAh Lenmar cells I got from Thomas Distributing, with the BC-900, were cheap because they're, well...CHEAP? After five charge/discharge cycles, six of them indicate about 600 mah capacity and the other two about 1600. This hasn't increased much from the original reading. My CCrane wouldn't stop charging them but the LaCrosse will.


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## Vipero00 (Jun 8, 2006)

Last friday I put some old batteries in for test just to see what shape their in. When I came in Monday channels 1, 2, 3, were blank and there is a blinking 32 in channel 4. So I quickly sent a email to support and this is what they sent back.

_Dear Mr. Nelson,_



_We are currently backordered on the BC 900 Battery charger until November 2006._

_If your charger needs warranty work, we will extend your warranty to cover the gap._

_Sorry for the inconvenience,_

_La Crosse Technology Customer Support_
_2817 Losey Blvd S_
_La Crosse, WI 54601_
_1-888-211-1923_
_www.lacrossetechnology.com_

Wonder what that means?


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## wptski (Jun 9, 2006)

Vipero00 said:


> Last friday I put some old batteries in for test just to see what shape their in. When I came in Monday channels 1, 2, 3, were blank and there is a blinking 32 in channel 4. So I quickly sent a email to support and this is what they sent back.
> 
> _Dear Mr. Nelson,_
> 
> ...


It means if your warranty expires while your waiting for them to get new BC900's they will extend your warranty. So, if anyone smokes one, they'll have to wait till 11/06 too! Wow!!!


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## Vipero00 (Jun 9, 2006)

wptski said:


> It means if your warranty expires while your waiting for them to get new BC900's they will extend your warranty. So, if anyone smokes one, they'll have to wait till 11/06 too! Wow!!!


 
My take on it is that their warranty dept has last priority.  All stock is going out to distributers to supply new customers rather than taking care of old customers.

Meanwhile I have a non-working unit.


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## wptski (Jun 9, 2006)

I think that their out of stock, period! Maybe changes are being made? Last time they were first released elsewhere first.


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## Sonic2171 (Jun 14, 2006)

Although I haven't had any problems with my BC-900 I bought some 330uF 10v capacitors and fitted 3, as described in Nikiwind's post on page 1 of this thread, just to play safe.
Checking with a scope this has definately cleaned up the supply lines on the PCB! I have a feeling the long lead between PSU and BC-900 does not help!

Unfortunately I had to purchase a batch of 25, to get the small, low ESR types required (at a sensible price). To get 3 would cost about 5 GBP each, here in the UK. So if anybody is interested I have 22 to spare?

Thanks for all the Info


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## danlsmith (Jun 15, 2006)

:huh2:
I do not see that what you have done actually real world makes any bit of difference. Yeah, you have a scope so you look at things with it. But the output voltage is the same, and the frequency of the switching has been changed but the off time is a bit longer after your mods. That "glitch" that you saw and seem to worry about is of absolutely no inpact to the charger circutry. After the 3 volts from your original or modified power supply is connected to the charger, its main board has plenty of power supply filtering, which you have drawn attention to in some of your photos.

Sorry, but there was nothing wrong with the power supply before and there is virtually no difference operationally with it after your soldering and making changes. Its a switching regulator, for gods sake. It will make no diference what power supply you put on it, as long as it is at least the 3 volts and has the current capacity. The regulator 'switches' the voltage output OFF when the output voltage reaches the set voltage. You could plug a 4, 5, even 6 volt power supply to the charger and the switching regulator is simply going to cut off the output when it has reached 3 volts. 
:touche:
35 years electronics training and experience is telling you this, its real world stuff. All you have done is played with the circuit and made a change to its operation very slightly in so far as to have a slightly different image on the scope. That's all. Hey, I like to tinker too, but this imaginary 'glitch' problem, is simply no problem at all, not really. 
Operation same before and after.


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## stjohnh (Jun 15, 2006)

danlsmith

Welcome to CPF, 

Glad to have your input, I was wondering about this also.

Holland


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## N162E (Jun 15, 2006)

Sonic2171 said:


> Although I haven't had any problems with my BC-900 I bought some 330uF 10v capacitors and fitted 3, as described in Nikiwind's post on page 1 of this thread, just to play safe.
> Thanks for all the Info


I tried this mod back in September 05. I had no problems either until, I installed the caps. I have 2 BC-900 chargers bought together both V32. The one I installed the caps to had problems with cutting off using 200 ma, batteries got hot. I removed the caps and all was well again. Modding these units when there is nothing wrong seems to be a good way to have problems. If it ain't broke don't fix it.


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## Sonic2171 (Jun 15, 2006)

N162E I don't see why fitting the caps would cause you any problems!? Which ones did you fit?

My BC-900 is V33 and I only fitted the ones to the 3v supply rails, not the ones to the Mosfets, so it should only (and it does!) clean up the supply.

danlsmith
It is to cure the reset problem that sometimes happens when refreshing 4 cells and they switch between charge/discharge or discharge/charge at different times, causing spikes to reset the processor (in the charger not the power unit).


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## tacoal (Jun 21, 2006)

danlsmith said:


> :huh2:
> I do not see that what you have done actually real world makes any bit of difference. Yeah, you have a scope so you look at things with it. But the output voltage is the same, and the frequency of the switching has been changed but the off time is a bit longer after your mods. That "glitch" that you saw and seem to worry about is of absolutely no inpact to the charger circutry. After the 3 volts from your original or modified power supply is connected to the charger, its main board has plenty of power supply filtering, which you have drawn attention to in some of your photos.
> 
> Sorry, but there was nothing wrong with the power supply before and there is virtually no difference operationally with it after your soldering and making changes. Its a switching regulator, for gods sake. It will make no diference what power supply you put on it, as long as it is at least the 3 volts and has the current capacity. The regulator 'switches' the voltage output OFF when the output voltage reaches the set voltage. You could plug a 4, 5, even 6 volt power supply to the charger and the switching regulator is simply going to cut off the output when it has reached 3 volts.
> ...


Did you evey try a 6 volt PS for BC-900? If you did, you would know well what you had said here.


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## lefty2446 (Dec 28, 2006)

Bump, Bump. Could someone please fix the pictures? I live in Australia and as such don't have a warranty. Purchased from thomas-distributing. My charger resets when i remove or insert batteries. Even allows me to change the mode on already charging batteries after inserting subsequent batteries in the spare slots.

Alternativley could you please email them to me?

Adrian


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## moldyoldy (Dec 28, 2006)

FYI: The dubious BC-900 power supply problem was extensively reported on a German website. The solution was the same as yours - to either replace the power supply with a better one of your choice, or to solder some tantalum capacitors on the mother board to try to smooth out the glitches.

There is also some speculation that the reason for "cooking" the batteries on a 200ma charge rate is because of the glitchy power supply, possibly that a power line transient made it thru to the mother board. Why a higher percentage of difficulties with the 200ma and not higher rates? Because of the difficult power supply design - it is expensive to design a good regulation system in a switcher to cover the range from 200ma to 4+Amps and with a pulse charging system. Really messes up the voltage control.

Tim


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## moldyoldy (Dec 28, 2006)

One other thought for a check - how many of the failed BC-900 systems were running straight from the mains? ie: the power supply was plugged directly into a wall outlet. I always use a good surge suppressor with high noise reduction for any electronics, both at home and at my daughters' apartments. I know that when I did not use noise reduction surge suppressors, I lost several electronic devices that were not cheap! ie: my APC Network surge suppressor has 70dB of noise reduction - somewhat uncommon.

Tim


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## wptski (Dec 28, 2006)

lefty2446 said:


> Bump, Bump. Could someone please fix the pictures? I live in Australia and as such don't have a warranty. Purchased from thomas-distributing. My charger resets when i remove or insert batteries. Even allows me to change the mode on already charging batteries after inserting subsequent batteries in the spare slots.
> 
> Alternativley could you please email them to me?
> 
> Adrian


Adrian:

As far as the pictures go, I'm seeing the infamous X-Boxes in this thread too along with other places like in the Ni-MH Shootout thread. Not sure if it's just EI7 or what??


----------



## moldyoldy (Dec 28, 2006)

Hi again Bill,

Not to dump on Microsoft, but Internet Explorer 7 is incompatible with a record number of applications at our engineering site of a thousand engineers or so. IE6 was reasonably compatible. This is reflected by at least one other strong recommendation from another major company that we work with to NOT upgrade to IE7 - it breaks too many commonly used applications.

What is worse is that MS started inserting an upgrade to IE7 in its critical patch list - bad for users who have the MS patches on automatic. Gotta read and uncheck what you don't want. For now at least, avoid Internet Explorer 7!

!Use Firefox!

http://www.mozilla.com/en-US/firefox/

Tim


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## moldyoldy (Dec 28, 2006)

I was reading back in this thread a bit and noticed some comments on an arbitrary reset. The Winter season in colder climates normally represents a problem with static electricity. Always remember to ground yourself to something metal before you touch an electronic device! You don't have to hear a "snap" when you touch something to have a problem.

Static electricity has plagued electronic device manufacturers for many years. Way back when the HP-41C programmable calculator was new, HP in Corvallis started receiving a rather large number of devices coming in for repair, yet when they were turned on, nothing was wrong with them. The static charge drained to zero during transit back to HP Service. That is when HP first realized the extent of static electricity problem. In Corvallis Oregon, it is normally rather humid and static discharge is not normally a problem, even in the winter. BTW, profits from the HP-41 built a major building on the HP campus in Corvallis Oregon.

Tim


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## moldyoldy (Dec 28, 2006)

I forgot to mention that I am using Firefox 2.0.0.1 and I see the photos just fine. 

Tim


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## Alex 007 (Dec 29, 2006)

moldyoldy said:


> Hi again Bill,
> 
> Not to dump on Microsoft, but Internet Explorer 7 is incompatible with a record number of applications at our engineering site of a thousand engineers or so. IE6 was reasonably compatible. This is reflected by at least one other strong recommendation from another major company that we work with to NOT upgrade to IE7 - it breaks too many commonly used applications.
> 
> ...



Hello Tim!

I use Firefox 2.0 here some photos of my last week acquired from "T-D" BC-900U till today since was plug in & refreshing...all my ample batteries collection NO whole problem!:thumbsdow

http://mail.google.com/mail/?disp=imgs&view=att&th=10f960d959b17661

Peace,

Alex 007


----------



## Alex 007 (Dec 29, 2006)

Handlobraesing said:


> Mine's a v33 and it quite frequently goes into "cool off" mode due to thermal cut off. The timer read "5:35" while charging 2650mAh batteries at 1,000 mAh. It must have repeatedly charged the battery everytime the thermal cut off resets, but failed to detect -dV.
> 
> Very nice feature, very lousy charge termination method.



May ask you WHY...you are so in "HURRY"???

I since was received a week ago here in Israel we have 230v.ac I add an a adapter from US flat prongs to the European rounded ones...I yet don't finish to "Refresh" my whole batteries collection. works as intended...failures free!:goodjob:

Look my photos of my received unit & how I cope for better ventilation!!!

http://mail.google.com/mail/?disp=imgs&view=att&th=10f960d959b17661

Peace,

Alex 007


----------



## moldyoldy (Dec 29, 2006)

Hi Alex, 

Thanks for the link to your photos, but I get a "server error" before or after after I sign in to Google mail. ??

Tim


----------



## lefty2446 (Jan 6, 2007)

moldyoldy said:


> I forgot to mention that I am using Firefox 2.0.0.1 and I see the photos just fine.
> 
> Tim



I too use Firefox 2.0.0.1 and can see all scope traces except the 3 images on post #20 that show the location of the mod capacitors.

I can place caps on the input ok but also wanted to put caps across the mosfets.

Can anyone help me?

Adrian


----------



## Turbo DV8 (Feb 15, 2007)

OK, I can't stand my BC-900's intermittent resets during charging anymore! And also not being able to set certain currents and modes under circumstances where I should be able to do so. So I picked up some tantalum SMT caps today. I read here that anything over 100 uF and 6.3 volts should suffice. Here are my choices, so tell me which I should use. They only had two values: 150 uF, but only 6 volts, and 680 uF/10 volts. Is 680 uF too high, or does it matter? If the 6 volt rating of the 150 uF cap is not a problem, I could stack two to get 300 uF, but not sure how much clearance I have between the bottom of the circuit board and case. So, knowing my choices, which should I go with, and in which configuration? I don't want to keep sending these back to TD, because the v33 they sent me does the same thing. If possible, I would rather take care of it once and for all with a little effort. Thanks


----------



## SilverFox (Feb 15, 2007)

Hello Turbo DV8,

Perhaps you should wait for the revised C9000...  

Another thing to check out. When I first got my BC-900, I had some problems with it resetting on me. I would pick the unit up to add additional cells, because the buttons are a bit "strange," then set the unit back down. Sometimes everything would revert back to the default 200 mA charge.

I found I could reproduce this by wiggling the power connector. I cleaned the connections, then noticed that the negative connector seemed loose inside the BC-900. Loose is not correct, it seemed to be bent back a little and did not seem to make good contact with the plug.

I took a dental probe and added a little extra tension to it and the problem went away. 

You may want to check this out.

Tom


----------



## N162E (Feb 15, 2007)

Turbo DV8 said:


> OK,
> I picked up some tantalum SMT caps today. I don't want to keep sending these back to TD, because the v33 they sent me does the same thing. If possible, I would rather take care of it once and for all with a little effort. Thanks


I did this about a year ago to a perfectly good operating V32, it took care of the problem, once and for all. By the time I smelled the burning the batteries were reading almost 400f. Take a good look at your connections first before you attempt to "Improve" this charger by "Hacking" it.


----------



## Turbo DV8 (Feb 16, 2007)

SilverFox said:


> Hello Turbo DV8,
> 
> Perhaps you should wait for the revised C9000...  I cleaned the connections, then noticed that the negative connector seemed loose inside the BC-900. Loose is not correct, it seemed to be bent back a little and did not seem to make good contact with the plug.


 
Thanks for the suggestion. I will look at this area when it is apart, although I don't believe this is my likely problem. I don't move the unit at all, and I can actually watch the unit reset after the fourth and final cell terminates, without even touching the unit!


----------



## Turbo DV8 (Feb 16, 2007)

N162E said:


> I did this about a year ago to a perfectly good operating V32, it took care of the problem, once and for all. By the time I smelled the burning the batteries were reading almost 400f. Take a good look at your connections first before you attempt to "Improve" this charger by "Hacking" it.


 

Are you suggesting that adding a filter capacitor across the positive and negative supply rail caused your charger to self-destruct? If you did the mod correctly, I think it far more likely that you happend to suffer the infamous BC-900 meltdown, irrelevant to adding a filter cap. Adding a filter cap won't keep your BC-900 from melting down, if that is what is in the stars for your particular unit and all the planets are aligned just so.

Anybody still around from the early days of this thread who might shed some light on my original question?


----------



## N162E (Feb 16, 2007)

Turbo DV8 said:


> Are you suggesting that adding a filter capacitor across the positive and negative supply rail caused your charger to self-destruct?
> Anybody still around from the early days of this thread who might shed some light on my original question?


No I am not saying that it caused it but I know for sure that it did not prevent it. For the last year or so I have plugged my chargers into a UPS/Conditioner. While I don't have stats on current operation I have had no problems since including the UPS/conditioner. I live in an older neighborhood with underground wireing and for the past several years my AC has been getting "Dirtier" I also added a Power conditioner to my 40" Sony LCD TV, the picture is better. My C-9000s were unreliable terminating at 700ma after plugging into power conditioner they never miss at 500ma. I used 680 uF/10 volts caps and when the case was reassembled there was pressure on the board. Early on some users tried other DC supplies with less than favorable results.


----------



## Turbo DV8 (Feb 16, 2007)

I would not be installing the caps to prevent a meltdown, but to prevent power supply glitches from interefering with the uprocessor, causing the resets. I guess my 680uF SM caps won't fit, per your experience. Two 150 uF caps piggybacked won't be any thinner. I'll just have to wing it.


----------



## FlashCrazy (Feb 24, 2007)

On the Thomas Distributing website they're selling what they call the updated version of this charger. Are the updates just feature updates, or have they corrected some of these issues such as non-termination at 200 mA, and the glitchy power supplies?


----------



## Turbo DV8 (Feb 24, 2007)

I know the microprocessor resetting hasn't been addressed. I had TD exchange a v32 that would sporadically reset. They sent me a v33, and it did the same thing. Good news (so far) is that the 680uF surface mount tantalum caps did fit fine between the board and cover without any interference, and after several test/refresh cycles on both a modified v32 and modified v33, no resetting has been encountered.


----------



## DrLex (Jun 3, 2007)

I'm bumping this old thread because I ordered a BC-900 (to be exact, the European version which is called 'Voltcraft IPC-1'), and had the same problem of the charger resetting during 'test' mode. It's a v33 by the way.

Actually, I knew this could happen because I had read some reviews, including this thread, before I bought the IPC-1. I was quite sure to bump into the problem, because Murphy hates me and always makes me buy devices with defects, even if there's only one in a million. So despite the obvious glitches this charger has, I ordered it anyway because it's the kind of charger I have wanted since I first learned about rechargeable batteries. And of course, the price is nice. Plus, I knew the glitches could be fixed with the 'patch' nikiwind proposed, and I have a soldering iron and I'm not afraid to use it!

I soldered a big fat 1500µF 6.3V low ESR capacitor from an old PC motherboard straight onto the adaptor jack. This required some voodoo because of the battery contacts standing in the way, and there's only just enough space in the housing to accomodate that little tin can. I also soldered two 100µF 10V tantalum caps close to the MOSFETs, as shown on nikiwind's pictures. Since then, I have run refresh and test cycles in all 4 slots simultaneously without problems :twothumbs Murphy still hates me, however, because I just had a totally unrelated power outage in the entire house, aborting some nearly-finished test cycles... 

My conclusion is the same as nikiwind's: the mains adaptor either has inadequate regulation, the leads are too long, and/or there's insufficient decoupling inside the charger itself. I guess this explains the low price tag, but the bottom line is that if you have a bit of experience with electronics, you can still get an awesome charger for a very reasonable price.


----------



## jayflash (Jun 4, 2007)

Still...if I'm correctly judging from correspondence on the CPF, most users have encountered no problems with stock v32 or v33 units. It would be interesting to know the room temperature of the failed chargers. Did any fail in temps of 70F and lower?


----------



## Turbo DV8 (Jun 7, 2007)

DrLex said:


> Murphy still hates me, however, because I just had a totally unrelated power outage in the entire house..


 

"Unrelated?" OK, uh-huh. Riiiiiiiiight!


----------



## NA8 (Jun 10, 2007)

jayflash said:


> Still...if I'm correctly judging from correspondence on the CPF, most users have encountered no problems with stock v32 or v33 units. It would be interesting to know the room temperature of the failed chargers. Did any fail in temps of 70F and lower?



Oh, we're just lazy. I've got a BC-900 ver 32 and it resets quite a bit. In fact I don't bother running test mode anymore because I'll never see the data. I haven't tried it in less than 70F temps, and I don't think I will be either. I wasn't going to bother with the mods, but the research I've been doing suggests the Maha charger might not be ready for prime time either. I may just do the capacitor mod and replace the push buttons. Oh, and never leave it ON alone either  Then again, I might look into some of the $100+ chargers. It could be these cheap chargers just can't hack it.


----------



## 45/70 (Jun 10, 2007)

Well, I check in on this thread once in a while. I have a version 32. I put one 100uF tantalum on the board, as it was mentioned that three, really didn't make any difference and, all I had at hand was the 100uF. It doesn't reset anymore but still has all the other problems. Won't terminate below 500mA (or sometimes @ 500mA), batteries get too hot (I guess V 33 did fix that), crappy buttons etc.

I have a C. Crane but it doesn't seem to like anything but D cells (never tried C's, don't have any). It never seems to fully charge AA or AAA's. I'm waiting to see just how many problems the Maha has, I guess. :sigh:

Dave


----------



## hundsmiachn (Jul 28, 2007)

Hi

I recently found this thread about the BC-900 charger. Can somebody please repost the pictures of the mod again, the picture links don't work anymore...

thanks in advance
regards
miachn


----------



## Lightingguy321 (Jul 29, 2007)

nikiwind said:


> 32 like the everybody.


I have a version 33 board and I think I am going to open it up and take a look on the insides. I have loads of I think Mylar(?) capacitors and they have the numbers 102, 103, and 104 stamped on them, what are the farad ratings for those three numbers?


----------



## nikiwind (Aug 8, 2007)

I don't know why there are no pictures.
I still have them on pBase.
You can see them:

http://www.pbase.com/nikiwind/lacrosse_bc900&page=all


----------



## NA8 (Nov 30, 2007)

Finally got around to doing the mod. Got a ver32 that was resetting a lot. Put in two 220ufd 10volt electrolytic caps. They were pretty big, so I put them across to the center grounds. Kind of the long way around circuit wise, but it still worked. These were two of the worst caps you can buy I'd imagine. I got them in a $5 assortment of caps from Radio Shack. Ugly stuff with real dirty leads. Surprised they didn't blow up. Had to cut a hole in the bottom plate to make room, but it makes for better airflow. (Don't try this at home kids, someone might grab something they shouldn't.) Still had clearance on the stock legs, but I added some rubber feet to raise the charger up a bit more. Ran the Test Mode the last two nights and no resets, even banging all the buttons after the test to read the data. Accidentally kicked the power cord and knocked it off my desk about 31" to a face down soft landing on a bunch of cables. Picked it up and all the batteries were still in place and the test was still running fine. The mod works (for the resetting problem) and it doesn't take a lot to do it. Find some smaller caps though and pass on the hack job on the bottom plate.


----------



## NA8 (Dec 1, 2007)

Couple of pix of the hack job.


----------



## NA8 (Dec 3, 2007)

nikiwind said:


> I don't know why there are no pictures.
> I still have them on pBase.
> You can see them:
> 
> http://www.pbase.com/nikiwind/lacrosse_bc900&page=all



I played around with one of your picture's, reposting the same address (lifted from the CPF page source code) in the Practice Posting forum. The picture came right up. The only difference I noticed was an extra space: 

> <br that apparently should look like ><br in the page source code. 

Pretty weird. You might be able to get the pictures back in the messages if you go into edit and experiment a bit.

PS Thanks for the great mod. :thanks:


----------



## nikiwind (Nov 20, 2008)

Just fixed pictures links.

Enjoy


----------



## TakeTheActive (Jan 2, 2009)

*Is Anyone Else *NOT* Seeing These Great Photos?!?*



nikiwind said:


> *Just fixed pictures links.*
> 
> Enjoy


Can everyone *EXCEPT* ME see these pictures?  [I tried both Firefox 1.5.xxx and IE 5.50.xxx on two different PCs.] 

Somehow, I didn't think so, thus, I *GOOGLE'd: *'Firefox PBase' and found:
*PBase changes upload name and no photo shows. Please help!!*
.
*PBase Help System - FAQ - Linking*
.
*PBase Help System - FAQ - How Do I get the direct linking URL?*
Initially, I also noticed that when I QUOTE'd one of *nikiwind's* original posts, all of the IMG URLs began with "*i*.pbase...", while the ones in the thread that *I* could see began with "*www*.pbase..."

For me, the LINK: http://i.pbase.com/v3/54/594354/1/48935242.TEK00008.PNG results in:


> *Forbidden*
> 
> You don't have permission to access /v3/54/594354/1/48935242.TEK00008.PNG on this server.
> Apache/2.0.58 (Unix) Server at i.pbase.com Port 80


while the LINK: http://www.pbase.com/nikiwind/image/48944382.jpg works fine.

Thus, giving me the idea "maybe" the LINKs look OK to *nikiwind* since he's LOGGED into PBase / has an account / has a local cookie on his PC / etc...

So, below please find *MY* test:
First, you should see a QUOTE of *nikiwind's* Post #20.
.
Then, you'll see it repeated with:
- an A: IMG (the original LINK)
- a string of 60 hyphens
- a B: IMG (my 'modified' LINK)
Please let me know WHICH BROWSER you are using *AND* whether or not you can see BOTH or just ONE of the images.

Thanks! 



nikiwind said:


> Board (bottom view) before modifications
> 
> 
> 
> ...



Board (bottom view) before modifications

A:




*------------------------------------------------------------*
B:





Board (top view) before modifications

A:




*------------------------------------------------------------*
B:





Board (bottom view) after modifications

A:




*------------------------------------------------------------*
B:





A:




*------------------------------------------------------------*
B:





A:




*------------------------------------------------------------*
B:





A:




*------------------------------------------------------------*
B:





I think unit has this problem because of bad design.
No high volume low ESR (impedance) capacitors on the board, relatively long wires with some inductance from power supply and PW supply limited reaction time for the step load (overshot and undershot). All of it especially glitches (overshot and undershot) make the measurement system not reliable and this is the reason to selfreseting behaviour and other "glitches".

P.S. to *nikiwind: *THANKS for the great thread!


----------



## nikiwind (Jan 12, 2009)

When I'm not logged in I can see only "B" - Safari browser - Mac OS Leopard.
When I'm in - same things - only "B"


----------



## Black Rose (Jan 12, 2009)

Does the latest version of this charger (35?) still have the problems that this mod tries to resolve?

I need a charger that will allow me to charge my NiCd cells that have high internal resistance.
The two chargers I currently have will not do this since they consider the cells to be problem cells.


----------



## nikiwind (Jan 12, 2009)

I don't know


----------



## TakeTheActive (Jan 12, 2009)

nikiwind said:


> When I'm not logged in I can see only "B" - Safari browser - Mac OS Leopard.
> When I'm in - same things - only "B"



When you're not logged into PBASE , can you see the pictures in your original post: *20* ?

After each *A: * is your original LINK.

After each *B: * is my new LINK.

My theory is that when you're logged in to PBASE, PBASE displays 'Private' IMG URLs to you that begin with "*i*.pbase..." which ONLY YOU can see. When I go to: http://www.pbase.com/nikiwind/lacrosse_bc900&page=all, PBASE displays 'Public IMG URLs to me that begin with "*www*.pbase..." that I believe EVERYONE can see. (To date, you're the only person to reply to my question.  )

If my theory is correct, if you update your original posts with the "*www*.pbase..." IMG URLs, then EVERYONE will be able to see them.


----------



## TakeTheActive (Jan 12, 2009)

Black Rose said:


> ...*I need a charger that will allow me to charge my NiCd cells that have high internal resistance.*
> The two chargers I currently have will not do this since they consider the cells to be problem cells.


It's my understanding that *nikiwind's* mod (Bypass Capacitors) dealt with noise spikes affecting the microprocessor and *jtr1962's* mods (Alternate Transformer and Ground Loops) dealt with voltage drops. The only solution to charging cells that the BC-900 or MH-C9000 reject is to use a 'less intelligent' charger, such as a PS1.



Black Rose said:


> Does the latest version of this charger (35?) still have the problems that this mod tries to resolve?


It's been a few weeks since I was reading the BC-900 archives but wasn't the microprocessor problem 'Resetting When Adding a Third or Fourth Cell'? I have a BC-900 v33 and I haven't experienced that problem. And, I don't recall reading about it except in v32 threads.

Maybe *jtr1962* will read this and chime in...


----------



## nikiwind (Jan 12, 2009)

TakeTheActive said:


> When you're not logged into PBASE , can you see the pictures in your original post: *20* ?
> 
> After each *A: * is your original LINK.
> 
> ...



When I'm not logged I can see only options *"B"* - your links.


----------



## ledlight (Jan 12, 2009)

I bought the BC-900 last March - I realized recently it does not properly charge the battery in the first slot - they always come out low voltage. If I put them in one of the other slots they charge okay. I have emailed LaCrosse a couple times but never heard back from them, so will just send it in one of these days. If I remember I will open it up and take some pictures to compare to the older model - hopefully I received the newest model at the time when I bought it !


----------



## Black Rose (Jan 12, 2009)

When you plug it in it shows the version number in the far right(?) LCD screen.

I think the latest version is 34 or 35.


----------



## Bobo The Bear (Jan 12, 2009)

Black Rose said:


> When you plug it in it shows the version number in the far right(?) LCD screen.
> 
> I think the latest version is 34 or 35.



That is the correct, it's the last 2 digits on the far right. Latest version should be 35.


----------



## Turbo DV8 (Jan 12, 2009)

TakeTheActive said:


> It's been a few weeks since I was reading the BC-900 archives but wasn't the microprocessor problem 'Resetting When Adding a Third or Fourth Cell'? I have a BC-900 v33 and I haven't experienced that problem. And, I don't recall reading about it except in v32 threads.


 
Both of my v33 units had a tendency to reset spontaneously, or after you put in all four cells, wouldn't let you program the first two slots unless you unplugged the wall wart to reset. I had to do the capacitor mod to both v33 units (and of course my v32 also). Although the problem can be corrected within the unit itself by installing caps, if LaCrosse had used quieter power supplies (better filtering within the PS), it would not have been an issue in the first place, regarldess of what version the unit is. Consequently, as long as LaCrosse hasn't added any additional filtering within the BC unit, and they still use the same unaltered PS, I would expect the resetting problem to remain to varying degrees from unit to unit, regardless of version.


----------



## Black Rose (Jan 12, 2009)

Such a simple fix, yet they won't correct the flaws in the unit and/or power adapter.


----------



## ledlight (Jan 13, 2009)

Bummer - I thought when I ordered the BC-900 last March I was getting the latest version - and it says it is Version 33 . I got this from Thomas Distributing. Well it is going to get mailed back to LaCrosse for warranty - hopefully they will send me back the newest version! 
Anyone have any experience dealing with LaCrosse on warranty issues ? 

Now I wish I had spent the exta $20 and gotten the MAHA. 



Black Rose said:


> When you plug it in it shows the version number in the far right(?) LCD screen.
> 
> I think the latest version is 34 or 35.


----------



## TakeTheActive (Jan 14, 2009)

*HELLO!?! Is Anybody Home???*



TakeTheActive said:


> Can everyone *EXCEPT* ME see these pictures?  [I tried both Firefox 1.5.xxx and IE 5.50.xxx on two different PCs.]
> 
> ---snip---
> 
> ...


I would be *VERY* APPRECIATIVE if at least 'a few' of the responders to this thread since 01-02-2009 @ 11:01 PM (besides *nikiwind* - THANKS!) would PLEASE answer my "*Can You See 'A' and/or 'B'" Question*: 
*Black Rose*
*ledlight*
*Bobo The Bear*
*Turbo DV8*
*Thank You!*


----------



## NA8 (Jan 14, 2009)

Using Opera 9.27 I can only see the pbase pix, B stuff. 
I cannot see any pix in the original post #20. 
I'm not logged into anything except CPF.

I've had good luck with these guys: 

http://www.imageshack.us/


----------



## Black Rose (Jan 14, 2009)

*Re: HELLO!?! Is Anybody Home???*



TakeTheActive said:


> I would be *VERY* APPRECIATIVE if at least 'a few' of the responders to this thread since 01-02-2009 @ 11:01 PM (besides *nikiwind* - THANKS!) would PLEASE answer my "*Can You See 'A' and/or 'B'" Question*:
> 
> *Black Rose*
> *ledlight*
> ...


I only see the B pictures using FireFox 2.0.0.20 and IE7.


----------



## N162E (Jan 14, 2009)

ledlight said:


> Anyone have any experience dealing with LaCrosse on warranty issues ?


----------



## Mr Happy (Jan 14, 2009)

*Re: HELLO!?! Is Anybody Home???*



TakeTheActive said:


> I would be *VERY* APPRECIATIVE if at least 'a few' of the responders to this thread since 01-02-2009 @ 11:01 PM (besides *nikiwind* - THANKS!) would PLEASE answer my "*Can You See 'A' and/or 'B'" Question*:



The "i.pbase.com" links do not work (direct linking to the server from outside is forbidden). The "www.pbase.com" links seem to work OK. This will be true for everyone as it is a configuration on the server. Use the www.pbase.com form to make images show up.


----------



## TakeTheActive (Jan 14, 2009)

*One More Time...*



nikiwind said:


> Just fixed pictures links...



*nikiwind*,

Since everyone (THANKS to those who replied) can see the *'B'* IMG URLs, would you please update your original posts, one more time, using that format?

Thanks!


----------



## ledlight (Jan 23, 2009)

Thomas Distributing told me to send it back to them and they would replace it. Good customer service. I wonder if LaCrosse had sent them some old versions? I will find out when the replacement arrives ! 



ledlight said:


> Bummer - I thought when I ordered the BC-900 last March I was getting the latest version - and it says it is Version 33 . I got this from Thomas Distributing. Well it is going to get mailed back to LaCrosse for warranty - hopefully they will send me back the newest version!
> Anyone have any experience dealing with LaCrosse on warranty issues ?
> 
> Now I wish I had spent the exta $20 and gotten the MAHA.


----------



## Turbo DV8 (Jan 24, 2009)

ledlight said:


> Thomas Distributing told me to send it back to them and they would replace it. Good customer service.


 
Man, do you ever owe Eugene at Thomas Distributing a cold one... or two! To take a return on an item they sent you ten months ago, and one that is not malfunctioning at that, is exemplary and above and beyond the call, if ya know what I mean. You owe them another order in the future, and having demonstrated customer service like that to you, I'll bet they won't have to twist your arm for the order!


----------



## ledlight (Jan 24, 2009)

Well - it did have a problem - it doesn't charge the battery in the first slot correctly if four batteries are in the charger. Until I figured it out I thought I had a lot of bad batteries ! When I purchased it, their website said they only sent the newest version of the BC-900 which at the time was at least version 34. I recently read this thread and learned that what I got was version 33. I emailed Thomas Distributing and asked them if I should return it to LaCrosse and they said to send it back to them. So I don't think I am taking advantage of Thomas Distributing. And coincidently, I had emailed LaCrosse Technology before Christmas and again on 1/7/09. I just today got a response from them saying to send it back in. Too late - I would have sent it in to them if they had responded promptly. 

Anyway, I will purchase from Thomas Distributing again, but it was their decision to have me return it to them - I am assuming that they will get credit from LaCrosse for it so won't be out any $$. I wouldn't expect them to loose on the deal or I would have sent it directly to LaCrosse Technology. 

I am not trying to take advantage of anyone - just get the warranty fullfilled for a defective product !





Turbo DV8 said:


> Man, do you ever owe Eugene at Thomas Distributing a cold one... or two! To take a return on an item they sent you ten months ago, and one that is not malfunctioning at that, is exemplary and above and beyond the call, if ya know what I mean. You owe them another order in the future, and having demonstrated customer service like that to you, I'll bet they won't have to twist your arm for the order!


----------



## ledlight (Jan 27, 2009)

The replacement BC-900 arrived today and it is version 35 and so far seems to be working excellent - all four batteries charge to the correct voltage now. I haven't put too many batteries through it but so far so good ! 




ledlight said:


> Thomas Distributing told me to send it back to them and they would replace it. Good customer service. I wonder if LaCrosse had sent them some old versions? I will find out when the replacement arrives !


----------



## Rado (Oct 8, 2009)

Hello everyone, and thanks for the information-packed thread!

I've been using this charger (the European variant named Voltcraft IPC-1, firmware version 35) for a few months now, with no real issues so far, other than plug-related reset when fiddling with the unit. But no resetting, as described here, after adding/removing cells, or preliminary switch from discharge to charge.

But recently, I've tried to charge new GP batteries, which (sadly) turned out to be fakes and not genuine. Their real capacity is only 150mAh or so, and they behave ... oddly. While charging/discharging these, I've noticed strange voltage glitches indicated by the LCD. What's worse is that these glitches remain - they now happen with all cells that I use (Varta, GP, Duracell) and I don't think that I've seen them before I ran into the fake GPs... (though I may be wrong and maybe I just never noticed)

I went through this thread completely, and only ran into a single reference of this problem by jayflash, back in 2006 (the time flies!)



jayflash said:


> When charging, all four displays will briefly change to the same reading, every 15 seconds, and then return to whatever they were originally indicating.



For a better idea of the problem, I took a cellphone video and uploaded to youtube - you can check here - the glitch occurs at about 0:06:
http://www.youtube.com/watch?v=UrvwubBDnHA

*More details:* this happens exactly every 15-16 seconds, and only during the DISCHARGE cycle. It starts when the voltage of the cell drops below approx. 1.20V, and the gap between the "normal" indicated voltage, and the "drop" voltage shown for a short moment grows as the voltage gets lower. For example, once the voltage of a cell gets below 1.0V, the gap is about 0.07V (i.e. it jumps from 0.97V to 0.9V and I'm afraid it may start the CHARGE cycle preliminary in these cases). 

Also, this happens regardless of the current (I only use 200-500-700-1000mA charge currents) and the number of cells (happens with a single cell or all 4 loaded). In the video, the glitch is visible with cells number 2 and 4, but just a few moments later the 2, 3 and 4 were affected.

*Question: *can this issue be related to the power glitches described by nikiwind, and eventually addressed by the mod (soldering the caps) or not? Does anyone else here get the same behavior?

I should be able to get my hands on a friends brand new Voltcraft IPC-1L soon, so I'll be checking if it does the same thing. the 1L version is black and is limited to a maximum of 1000mA charging current (should be the only difference).

Thanks for any input and ideas!
Rado


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## TakeTheActive (Oct 8, 2009)

Rado said:


> ...*More details:* this happens exactly every 15-16 seconds, and only during the DISCHARGE cycle. It starts when the voltage of the cell drops below approx. 1.20V, and the gap between the "normal" indicated voltage, and the "drop" voltage shown for a short moment grows as the voltage gets lower. For example, once the voltage of a cell gets below 1.0V, the gap is about 0.07V (i.e. it jumps from 0.97V to 0.9V and I'm afraid it may start the CHARGE cycle preliminary in these cases).
> 
> Also, this happens regardless of the current (I only use 200-500-700-1000mA charge currents) and the number of cells (happens with a single cell or all 4 loaded)...


I see the "Bouncing DISCHARGE Voltage" on my BC-900 with *CRAP* (or approaching *CRAP*) high Internal Resistance cells (>1.80VDC MH-C9000 Impedance Check Voltage | *Interpreting Maha MH-C9000 Impedance Check Voltage*). I thought it happened at ~10 second intervals and only affected the *CRAP* cell.

What happens when you DISCHARGE a new / vibrant AA Eneloop @ 100 / 250 / 350 / 500mA (20 / 50 / 70 / 100% Duty Cycle)?


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## Turbo DV8 (Oct 8, 2009)

Doesn't this have something to do with the pulse nature of the charger? Seems normal to me. I own three.


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## Rado (Oct 9, 2009)

TakeTheActive said:


> What happens when you DISCHARGE a new / vibrant AA Eneloop @ 100 / 250 / 350 / 500mA (20 / 50 / 70 / 100% Duty Cycle)?



Well, I don't have any Eneloops, but as I have already mentioned, my charger now does this with ALL of my cells at various discharge currents (including older but still very good Vartas as well as brand new GPs)... 



Turbo DV8 said:


> Doesn't this have something to do with the pulse nature of the charger? Seems normal to me. I own three.



I don't think so - such inconsistent voltage indication looks like a flaw to me. Do you know if any of your BC-900 chargers does the same thing, or can you please check when using the DISCHARGE cycle next time?

Thanks guys!


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## TakeTheActive (Oct 9, 2009)

Turbo DV8 said:


> Doesn't this have something to do with the pulse nature of the charger? Seems normal to me. I own three.


Yes, it is the nature of that charger and it's Duty Cycle. IME, it's also related to a cells Internal Resistance - i.e. the higher the IR, the bigger the voltage spread ('Open Circuit' vs 'Under Load'). On healthy, vibrant cells I may only see a .01VDC swing; on *CRAP* cells, maybe .06VDC.

For me, it's just another 'tool' to identify healthy vs *CRAP* cells. 

Try some of each in your collection and tell us what you see...


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## TakeTheActive (Oct 9, 2009)

Rado said:


> Well, I don't have any Eneloops, but as I have already mentioned, *my charger now does this with ALL of my cells at various discharge currents (including older but still very good Vartas as well as brand new GPs)*...


Is the voltage spread consistently .07VDC?

I await the results of either a test with new cells on your old charger, or your "_friend's brand new Voltcraft IPC-1L _" with your old cells.


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## zipplet (Oct 9, 2009)

My Lacrosse BC-900 also has the voltage bounce during discharge. I have also observed that the bounce is worse with crap cells.

The charger is about 12-18 months old.


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## KiwiMark (Oct 9, 2009)

Hey guys - I have 2 of these chargers, the older one is a Ver 32 and the newer one is a Ver 35. I haven't read the entire thread, but I have seen mention of the charger being happy to run from 3.3V and the supplied power supply being not so good. 

So - on the top of a set of draws I have my charging gear and it includes a 12V charger (runs from 12V DC, not mains) and a computer PSU to power it. The computer PSU is capable of outputing up to 460W with 12V up to 30A and 5V up to 30A and *3.3V* up to 28A. This PSU is nowhere near its capacity and even if I buy a more powerful charger that I am considering the PC PSU could easily power 2 LaCrosse chargers from its 3.3V supply while simultaneously powering 2 x 12V chargers (my 50W one and a new 150W one).

Any experience running the BC-900 chargers from 3.3V? Is this safe? Will my chargers be happy with this?


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## Turbo DV8 (Oct 9, 2009)

TakeTheActive said:


> Yes, it is the nature of that charger... the higher the IR, the bigger the voltage spread ('Open Circuit' vs 'Under Load').


 
Somehow I gleaned the answer to this BC-900 question from the Maha C9000 thread. I think the answer is in this quote from Will Chueh in the C9000 FAQ thread:



> 1) Inconsistent discharge voltage between MH-C9000 and the BC-900
> 
> The MH-C9000 and BC-900 use different methods for measuring voltage during discharge. The MH-C9000 measures the voltage under a 1000mA load, *while the BC-900 measures the open circuit voltage between the discharge pulses.* We chose this particular design because the open circuit voltage does not fully reflect the condition of the battery and that the under-load voltage is the figure-of-merit for real devices. For instance, a highly resistive battery might show a high open circuit voltage (measured between discharge pulses). However, as soon as the discharge current is drawn, the voltage will drop significantly.


 
BTW, yes, all my BC-900's do it, but as I don't make a habit of retaining crappy cells, the voltage fluctuations are very small if at all.


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## N162E (Oct 9, 2009)

KiwiMark said:


> Any experience running the BC-900 chargers from 3.3V? Is this safe? Will my chargers be happy with this?


This was tried o couple of years ago. I don't recall anyone burning their house down but, several BC-900s died early. I do not clearly remember the circumstances but I do remember the general consensus was that we should use the provided charger. I had to replace one awhile back, it was about $10. If you do try this proceed with caution.


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## KiwiMark (Oct 10, 2009)

N162E said:


> several BC-900s died early. I do not clearly remember the circumstances but I do remember the general consensus was that we should use the provided charger.



In that case I think I'll just stick with the supplied charger.


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## Rado (Oct 11, 2009)

TakeTheActive said:


> I await the results of either a test with new cells on your old charger, or your "_friend's brand new Voltcraft IPC-1L _" with your old cells.



Guys, thank you again for all your responses! I did some testing with both chargers, and with 2 sets of cells. Seeing the brand new Voltcraft IPC-1L behaving absolutely the same as my older IPC-1 made me happy - as apparently you were right - and this behavior is OK with these chargers.

I've tried the DISCHARGE cycle with 2 pairs of batteries - one pair being Varta Professional 2700mAh (these are the best I own) and the other one Duracell 2650mAh (the worst ones, beside the fake GPs). I've placed one cell from each pair into the new IPC-1L and the other one into my old IPC-1. Both chargers behaved exactly the same way and the voltage spread was also the same. That is, about 0.01V between 1.0 - 1.15V, up to 0.06V once the cells reached 0.91V. 

The only slight difference was that the voltage spread appeared a bit earlier on the *CRAP* Duracells - it was 0.01V from 1.15V, and about 0.03V at 1.0V, with Vartas lasting a little longer - voltage spread of 0.01V from 1.10V down to 1.0V and only growing once the cell gets below 1.0V. The real-life difference between the Varta and Duracell cells is the following: the Vartas are older (3+ years probably) but maintain their voltage for a few months when fully charged, and also their measured capacity is slightly higher than nominal (2750mAh). I use them for an outdoor GPS receiver. The Duracells are just a few months old, were expensive, but will self-discharge to 0.9V in 7-10 days... their real capacity is about 2500mAh when fully charged.



Turbo DV8 said:


> The MH-C9000 and BC-900 use different methods for measuring voltage during discharge. The MH-C9000 measures the voltage under a 1000mA load, *while the BC-900 measures the open circuit voltage between the discharge pulses.* We chose this particular design because the open circuit voltage does not fully reflect the condition of the battery and that the under-load voltage is the figure-of-merit for real devices. For instance, a highly resistive battery might show a high open circuit voltage (measured between discharge pulses). However, as soon as the discharge current is drawn, the voltage will drop significantly.



Looking at this explanation, there's still something that puzzles me. According to this, BC-900 (or IPC-1) is supposed to measure open-circuit voltage between pulses. Looking at nikiwind's oscilloscope recordings, the pulse charging frequency is approx 51Hz. The voltage bounce occurs each 15-16 seconds. And the bounce is always upwards (i.e. continuously displayed value is 0.91V, and the "bounce" value displayed for a second is 0.97V, indicating that the "bounce" value is the open-circuit voltage). 

So this looks like the BC-900 fails to "hit" the open-circuit space between pulses when taking measurement most of the time, and only "hits" the correct spot between pulses once every 15-16 seconds (that is, at the time it displayed the higher "bounce" value). Can this explain the voltage bouncing? I'm sorry if my assumption is not correct, the last time I worked with low-level electronics was the university, and it's been a few years already! 

PS: Additional info for anyone interested: the IPC-1L is black (unlike the blue IPC-1/BC-900) and has a different power source - slightly smaller with output current limited to 2.8A. It also supports only the following charging currents: 200-500-700mA. Its firmware version is 36.


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## Twinkle-Plank (Oct 11, 2009)

KiwiMark said:


> Hey guys - I have 2 of these chargers, the older one is a Ver 32 and the newer one is a Ver 35. I haven't read the entire thread, but I have seen mention of the charger being happy to run from 3.3V and the supplied power supply being not so good.
> 
> So - on the top of a set of draws I have my charging gear and it includes a 12V charger (runs from 12V DC, not mains) and a computer PSU to power it. The computer PSU is capable of outputing up to 460W with 12V up to 30A and 5V up to 30A and *3.3V* up to 28A. This PSU is nowhere near its capacity and even if I buy a more powerful charger that I am considering the PC PSU could easily power 2 LaCrosse chargers from its 3.3V supply while simultaneously powering 2 x 12V chargers (my 50W one and a new 150W one).
> 
> Any experience running the BC-900 chargers from 3.3V? Is this safe? Will my chargers be happy with this?


 
What brand PSU and if the 3.3V its ok with the charger dont see why it wont work.


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## N162E (Oct 11, 2009)

Twinkle-Plank said:


> What brand PSU and if the 3.3V its ok with the charger dont see why it wont work.


Twinkle-Plank, How many BC-900s do you have and how did using a different power adapter work out when you tried it?


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## Twinkle-Plank (Oct 12, 2009)

I tried using 2 on a computers power supply yesterday and it worked just fine and I left in on for almost a day.


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## KiwiMark (Oct 12, 2009)

Twinkle-Plank said:


> I tried using 2 on a computers power supply yesterday and it worked just fine and I left in on for almost a day.



It has been said by N162E that people have tried that and several chargers died early. I didn't take that to mean within hours or even days - more likely within weeks or months. I don't think that running a charger for a day proves much - my older charger is a few years old and still works well, better that than kill it with a few weeks use.


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## Turbo DV8 (Oct 13, 2009)

KiwiMark said:


> ... my older charger is a few years old and still works well.


 
After about two years (using the stock P/S), I've had one BC-900 lose an LED segment, and another one developed a defective display button. The spring contact decided it didn't want to spring back anymore. Still worked, but zero tactile feedback when pushing the button.


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## TakeTheActive (Oct 13, 2009)

KiwiMark said:


> ...*Any experience running the BC-900 chargers from 3.3V? Is this safe?* Will my chargers be happy with this?





jtr1962 said:


> I was recently refreshing some solar garden light cells with my pair of BC-900s when a turn of events led to an interesting discovery. I was running one charger on the stock power supply and the other on this supply. I had already done all of the mods described in this thread, as well as the temperature sensor mode described in this thread (see posts 38, 40, and 41). Anyway, when charging some cells at 1000 mA (with a fan blowing on them, of course), the current on one of the charging stations dropped very low, and the bottom of the charger right under it was extremely hot. I removed the cell right away. Apparently the MOSFET had gone into thermal runaway to the point that with its increased internal resistance it just couldn't deliver the set current. Surprisingly, the charger worked fine upon cooling so the damage wasn't permanent but some have had their chargers go into complete meltdown. I did have to fix a melted button shaft however.
> 
> Anyway, *the problem occurred on the charger with the alternate supply. As mentioned, the circuit board does get notably hotter when using this supply as opposed to the stock supply. However, the charger gets too hot on 1000 mA even with the stock supply. This got me thinking that maybe the BC-900 can happily operate at less than the 3 volts of the stock power supply so I started experimenting. To make a long story short the BC-900 will happily operate at 2.5 or so volts while still being capable of delivering 1000 mA. Any less than that and it works, but can't provide 1000 mA to the cells (although lower current settings work fine).*
> 
> ...



*Reference: MOD: *Alternate Transformer - *BC-900 power supply discovery* - *jtr1962*


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## N162E (Oct 14, 2009)

Twinkle-Plank said:


> I tried using 2 on a computers power supply yesterday and it worked just fine and I left in on for almost a day.


Thank you for the reply. 

Whatever you guys do just be careful. Pretty much anytime anyone tried to "Improve" a BC-900 it led to problems down the line. The "Wall wart" seems to be an integral part of the package. I tried adding capaciters to one of mine a few years ago and suffered the infamous meltdown.


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## Turbo DV8 (Oct 15, 2009)

N162E said:


> Thank you for the reply.
> 
> Whatever you guys do just be careful. Pretty much anytime anyone tried to "Improve" a BC-900 it led to problems down the line. The "Wall wart" seems to be an integral part of the package. I tried adding capaciters to one of mine a few years ago and suffered the infamous meltdown.


 
Be careful in linking cause to effect. I doubt the caps you added to the PC board were the causative factor in your meltdown. If you had problems "down the line" after adding the caps, it was likely yours was destined to melt down, with or without the caps! I've added the caps to all three of mine, and have not had a meltdown in years, and I use them a lot. What adding the caps did do, however, was end once and for all the annoying glitches in the microprocessor.


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## 45/70 (Oct 15, 2009)

Turbo DV8 said:


> .....I've added the caps to all three of mine, and have not had a meltdown in years, and I use them a lot. What adding the caps did do, however, was end once and for all the annoying glitches in the microprocessor.




I did the same to my V.32. It did just as you say, but it retained it's potential meltdown capability. The cap mod (I just used one) was never intended to correct the temperature problem. I did however apply different heatsink compound to the thermistors. It didn't seem to make much difference though.

The buttons are my biggest complaint about the BC-900. They are to the point now that I have to press the buttons damn near through the body to get contact. Perhaps some cleaning of the contact strips would fix that, I just haven't gotten around to it. That aside, it still works well, provided I keep the charge rate within certain limits.

Dave


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## Turbo DV8 (Oct 15, 2009)

I found it interesting that one of the revisions after v.32 is that the thermistor are mounted on plastic standoffs to force them up into the notches. v.32 just had long, spindly legs on the thermistor, and I suspect that it was very easy during final assembly of the case to misalign and cause the legs to crush, causing non-contact with the case contacts.


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## 45/70 (Oct 16, 2009)

Turbo DV8 said:


> I found it interesting that one of the revisions after v.32 is that the thermistor are mounted on plastic standoffs to force them up into the notches. v.32 just had long, spindly legs on the thermistor, and I suspect that it was very easy during final assembly of the case to misalign and cause the legs to crush, causing non-contact with the case contacts.




Well, it's been a couple years, but as I remember my v.32 does have the plastic standoffs. Nonetheless, you do have to be careful when reassembling the unit.

I think the v.33 firmware reduced the max temperature cutout and that helped a bit with the meltdown problem.

Dave


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## Turbo DV8 (Oct 16, 2009)

45/70 said:


> Well, it's been a couple years, but as I remember my v.32 does have the plastic standoffs.


 
Then maybe the standoffs were a mid-revision revision! Or my v.32 was assembled on a Monday or a Friday.


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## oshokry (Jul 25, 2013)

nikiwind said:


> Just fixed pictures links.
> 
> Enjoy



Hi all,

I have a strange problem in my BC 1000: It resets forever, and I can not use it to charge anything anymore. This is a 36 sec video that shows my exact problem:

http://www.youtube.com/watch?v=Sd7rUdTkIq0

Will this fix for BC 900 work for me?
(I hope it is not too late to add to this thread)


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## nikiwind (Sep 11, 2013)

I have restored original pictures which where on the place when I created this thread.
Just funny how small and far from perfect they looks after 8 years 

All information I guess is still valid unless LC updated they schematic 

Best regards to all!


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## nikiwind (Sep 11, 2013)

To all having problems with LC BC-900 and they other devices.

Just switch to Powerex Maha MH-C9000 and forget about problems:

http://www.mahaenergy.com/mh-c9000/

I have two for a couple of years of heavy usage and not a single problem. I like functionality too.
When I opened one to check "internal quality" it was much better than BC-900

Amazon and other places usually have good price for MH-C9000


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## Woodsroad (Sep 12, 2013)

nikiwind said:


> To all having problems with LC BC-900 and they other devices.
> 
> Just switch to Powerex Maha MH-C9000 and forget about problems:
> 
> ...



Just to add another useless opinion to the thread:

I have 4 LaCrosse chargers. I've had them for at least 4 years. They run every day, charging AA's that I use in my photography business. No modifications to the chargers, original power supplies.

Once a year I run ALL of my batteries (80 or so) through to check capacity, and I always run new batteries through several refresh cycles. When I'm doing this, the chargers run day and night for a couple weeks.
Through all this, the LaCrosse chargers have operated flawlessly and battery life has been excellent. I've killed a few cells by discharging them (unintentionally) to zero volts, but, in general, cell capacity is dropping by 5-10% per year (I think...I'll have to double-check my notes).

This experience is more than anecdotal, but far from a controlled study.

My advice: Buy the LaCrosse charger.


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