# La Crosse BC-900 Charger Warning



## SilverFox (Jan 9, 2006)

1/9/2006 

Many of you are familiar with the La Crosse BC-900 charger. It has a lot of excellent features and has been highly recommended by myself, and others.

In the last month, there have been several reports of meltdowns with this charger. At first I thought it had to do with charging high capacity cells at a low charge rate. Several have reported their chargers and cells melting together when charging Energizer 2500 mAh cells at 200 mA. However, I just recently became aware of another melt down involving Sanyo 2500 mAh cells in the test mode charging at 1000 mA and discharging at 500 mA.

I have been in touch with La Crosse and have discovered that the high temperature shut down on the BC-900 is set for 160 F. It seems that once the outside case of the cell gets to 160 F, there is some momentum left and the cells continue to heat up resulting in a melted case.

The other problem is that the BC-900 does not completely stop the charge in the event of high temperatures. It shuts the charge down until the cell cools off, then resumes charging again.

I have instructed people to keep a watchful eye on their battery charging, and to keep combustibles away. As a result, there have been no reports of loss of property (other than chargers and cells). 

I have had no problems with my charger, but in light of the recent reports, I feel a word of caution is advised.

If you have any problems, you can contact La Crosse at 888-211-1923.

Tom


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## BatteryCharger (Jan 9, 2006)

Wow, that sounds like something worthy of a recall.


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## Grubbster (Jan 9, 2006)

Yikes! My brother-in-law bought my 71 year old mother-in-law one of these chargers for Christmas. She is the type to put a battery in there and forget about it. Guess I need to make a phone call.


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## dfred (Jan 9, 2006)

BatteryCharger said:


> Wow, that sounds like something worthy of a recall.




To cynically paraphrase Fight Club: "A new battery charger built by the company starts charging at 200ma. The overtemperature behavior of the design is flawed. The charger melts and burns with everyone trapped inside the house. Now, should we initiate a recall? Take the number of chargers in the field, A, multiply by the probable rate of failure, B, multiply by the average out-of-court settlement, C. A times B times C equals X. If X is less than the cost of a recall, we don't do one." 

Not all companies think like this, but there's an element of truth there. A counter example would be Nikon's recent recall of a whole bunch of li-ion batteries even though there'd been only 4 confirmed incidents with no injuries. Or, then again, maybe X was greater...

I have seen a few comments about melted LaCrosse chargers and batteries, but have there been cases of the burning/melting of surrounding materials or the production of smoke/fumes?


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## cacer (Jan 9, 2006)

hi,

i got the same charger and the first thing i have done was opening !
i read about that the ptc`s sometimes have no contact to the cells.
in my case the ptc under the first and second cell had only contact to the plastic-case (and not to the metal) . i fixed that.
could that be a part of the "melting problem" ? in that case the charger recognize only a lower temp and can`t stop heating up.

oh,and i got firmware 31 .

greetz
cacer


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## senna94 (Jan 9, 2006)

SilverFox said:


> 1/9/2006
> 
> Many of you are familiar with the La Crosse BC-900 charger. It has a lot of excellent features and has been highly recommended by myself, and others.
> 
> ...






I just ordered the BC-900 today and had been debating whether to get it or the 8 cell Maha. I guess I made the wrong choice. Just out of curiousity, where have you read these reports? Have any CPF users actually had one melt down? I guess I am trying to asess just how big of a problem it is. Was Lacrosse any help in reasuring you or offering to give you a refund?

Thanks,
Paul 


:huh:


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## Beacon of Light (Jan 9, 2006)

And I thought my only problems with this charger was relegated to 2 faulty power supplys. I will be aware. Since I've had 3 units now, I was accustomed to leaving the charger fill with batteries while I was off at work. Now I will have to rethink that strategy.

Just when I thought I finally had what appears to be the perfect charger, this news....


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## mccavazos (Jan 9, 2006)

dfred said:


> I have seen a few comments about melted LaCrosse chargers and batteries, but have there been cases of the burning/melting of surrounding materials or the production of smoke/fumes?



When my BC-900 went down, It was the smell that first alerted me. It was really dark in the house, so I have no idea if there was smoke or not...


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## mccavazos (Jan 9, 2006)

senna94 said:


> I just ordered the BC-900 today and had been debating whether to get it or the 8 cell Maha. I guess I made the wrong choice. Just out of curiousity, where have you read these reports? Have any CPF users actually had one melt down? I guess I am trying to asess just how big of a problem it is. Was Lacrosse any help in reasuring you or offering to give you a refund?
> 
> Thanks,
> Paul
> ...



Mine completely melted down, and I made a post about it here on CPF. LaCrosse is replacing my charger and batteries, and gave me a UPS return slip so that I could mail the melted one back at no expense to me. I talked to a guy named Brian, He was very nice and very helpful.


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## senna94 (Jan 9, 2006)

Beacon of Light said:


> And I thought my only problems with this charger was relegated to 2 faulty power supplys. I will be aware. Since I've had 3 units now, I was accustomed to leaving the charger fill with batteries while I was off at work. Now I will have to rethink that strategy.
> 
> Just when I thought I finally had what appears to be the perfect charger, this news....



How long have you had yours and what version do you currently have? Did Lacrosse replace it or did you go through your distributor? I am dissapointed because I asked Thomas Distributing if they had had any problems with the BC-900 and they told me no!!!!!!


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## underdust (Jan 9, 2006)

I bought one of these about two weeks ago, but I have yet to even open the box. These "meltdown" stories have me a little worried, so now I'm kind of waiting to see how everything plays out before I begin putting it into regular use.


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## nuggett (Jan 9, 2006)

I have had mine for 3 weeks now, no problems so far...version 33


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## tacoal (Jan 10, 2006)

SilverFox:
1. Is this the first charge of those sanyo 2500ma battery? Sanyo is an OEM of Energizer.
2. Is the third party power supply used (the 3.3 Volt)?

I think something is wrong with the CPU when melting down happens or the MOSFET is malfunction. The MOSFET is NTGS3443T1 with max current 3 A, almost no margin at all

My BC-900 works fine for over 6 mos. I'm plan to change the MOSFETs with one having some margin.


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## SilverFox (Jan 10, 2006)

Hello Tacoal,

Welcome to CPF.

The Sanyo batteries, as I understand it, had several cycles on them and were being tested to match capacity in a multi cell application. It was not the first charge on them.

The BC-900 was used with the stock power supply.

As I mentioned before, I have had no problems at all with mine, which is a version 32 unit. I use mine all the time with all kinds of differing capacity cells. I am very pleased with the performance of my unit.

However, there have been enough reports of things getting hot, that it prompted me to get in touch with La Crosse and ask them some questions. When I found out the cut off temperature was set to 160 F, I decided that I needed to pass on a warning. Basically that high a cut off means that if the charger misses the end of charge signal, and you don't notice that the cells are getting hot, you will most likely end up with a meltdown, and ruin the cells you are charging at the time.

I still like the BC-900, but I keep a pretty close watch on it while I am charging. I have always charged on a fireproof surface, so I am not worried about the actual heat, but I would hate to ruin a set of cells that I have spent an extended amount of time conditioning and cycling.

I am not sure if we can "adjust" the high temperature value, but it sure would be nice to have it kick in at around 120 - 130 F range.

Tom


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## snoofer (Jan 10, 2006)

Heres my meltdown story:

My La Crosse BC-900 just took a nose dive and "fried" four batts and the center part of the console, and display.

Funny thing about this situation is, I had set the charger to charge at 200 mA in order to wake up to fresh charged batts for Christmas morning.

My wife came into the room and stated that something smells burning...I didnt think anything of it, then about five mins later-I hear what sounds like sizzling hot popping sounds.

I jumped up and ran to the bathroom disconnected the plug, ran and got some pliers and pulled out the batts and placed them on an old rag and started squirting water on them--(still sizzling).

Bottom Line:

I'm out a charger, 4 batts, and a wife that keeps telling me how I could have burned down the house! (she's right).

The batts were the "Digital" brand from Walmart 2000 mAh

And heres a pic:





EDIT: This was the 2nd time charging these batteries.


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## lamperich (Jan 10, 2006)

@ snoofer

do you know how fast a 56 k Dial up inet connection is???????


to complet the thread https://www.candlepowerforums.com/threads/100382&page=2
There you find another Foto.


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## senna94 (Jan 10, 2006)

Does anyone know if the BC-900 has a UL listing or a European Conformity certification CE???

Paul


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## Mr_Light (Jan 10, 2006)

I have a had a BC-900 for about a month without problems so far... I am wondering if their are any other chargers which display similar quantitative voltage/capacity info? If so what would the least expensive alternative be?


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## SilverFox (Jan 10, 2006)

Hello Snoofer,

If you haven't already, would you please call La Crosse at 888-211-1923 and report what happend.

They are telling me that they are not aware of this happening, and I just want them to know that it is a real issue.

Thanks.

Tom


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## SilverFox (Jan 10, 2006)

Hello Paul,

My unit has a CE label on it.

Tom


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## tacoal (Jan 10, 2006)

Hi SilverFox,

Thank you for the reply.

It is strange that the melting down happens even when charging current is 200ma. 
In worst case, about 2V X 0.2A =0.4W heat will be generated in the battery, 
supposing no energy is transferred into chemical one. I don't think such heat 
will cause the melting down. It might be the malfunctioning of the CPU there or 
the chemical reaction inside the battery.

I think the shutdown temperature could be changed by changing the resistors near 
one of the holes where the thermal sensor is mounted. They are two 7.500K 
precision resistors in parallel, 3.750K equivalent. Since the thermal sensor is 
measured about 9K @70F, a 6K resistor will change the shutdown temperature to 
about 120F, I think. Need to be confirmed by experiment.

So keep an eye on those 2500mah batteries and above when they are being charged.

I'll order another one as backup in case melting down happens on me.


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## senna94 (Jan 10, 2006)

I called LaCrosse today and was put on hold while the tech. helping me asked around. He was told that there had only been one unit overheat that they knew of. :thinking: 

I guess until you know for sure if your unit is defective it would be prudent to take some precautionary measures.

1) Place unit away from walls and anything flammable.

2) Place unit on a metal tray or other non flammable surface.

3) If possible place near a smoke detector.

It is really a shame to have to take such measures but I guess it is better to be safe than sorry.

:sweat:


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## Sigman (Jan 10, 2006)

I've not even used mine for the first time yet - and have to say that this info is certainly bothering me!

*Maybe they are waiting for their first law suit?! * 

*Is the loss of my house or worse yet - my family or a member of my family worth it?

Unacceptable!*


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## LeDfLaShEr (Jan 11, 2006)

Just to put in a word for the BC-900 charger- I use mine all the time and have yet to have a problem.

I've charged my cells at 1 amp and they barely even got warm. I've put them on refresh cycles at 500 mah that lasted several days and nothing got warm.

I've used good cells in them, I've used crappy cells in them.....never had a problem.

After using RC car chargers that make packs so hot that you can't even pick them up, I wasn't sure the BC-900 was working on the 1 amp setting until I used a multimeter to check things out. Sorry some people have had bad luck, but the charger has worked as advertised for me.


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## wptski (Jan 11, 2006)

I posted in the Charger Comparison thread where I took a dual input temperature meter using two K-Type bead probe. I wrapped it around two of the cells enough times to insure contact.

The La Crosse BC900 at 1000ma charge rate on four 2000mAh cells reached 110F and at 1800ma charge rate on two 2000mAh cells reached 130F.

These were Titanium 2000mAh cells. On the other hand I've charged four MAHA 1800mAh 700ma and the unit shut down for high temperature! This makes me wonder if it's the cells. Has there been meltdowns with any cells other than 2500mAh Energizers?

I got some new "Made in China" 2300mAh Duracells that I'm trying to break in. I did one cycle on a Sirius Pro Former and tried a auto discharge on a Schultze 330d. It has four hour max limit for Ni-MH and at 3 1/2 hr is wasn't half way discharged. This could be due to these young cells being unstable or it didn't like my eight cell spring type holder. I just used the auto D/C cycle on a couple of DeWalt 14.4V Ni-CD packs with no problems


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## regnim (Jan 11, 2006)

:thumbsdow The 2000mah La Crosse Tech cells that came with my charger melted down, so it is not just the 2500mah cells. I caught it in time and just the cells were damaged. Thomas replaced the cells, this was about 6 months ago, before I found out about the problems this charger has. Don't remember the charge rate, charger just went into a reset loop, displaying 32 then a blank display then 32.....


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## SilverFox (Jan 11, 2006)

Hello Regnim,

Welcome to CPF.

La Crosse does not seem to be getting the information that these overheating problems are happening. I am not sure if Thomas Distributing is relaying the information to them.

If you don't mind, would you call La Crosse at 888-211-1923 and report to them what happened?

Thanks.

I would also ask that if anyone else has had overheating issues, they should contact La Crosse directly even if Thomas Distributing has already taken care of the problem. La Crosse can not remedy a problem they do not know exists, and I want to make sure they know about this.

Tom


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## Pellidon (Jan 11, 2006)

Because of my days with RC car packs and melting one with a timer rapid cooker. I almost always use a secondary fan to blow on the cells. I just charged up some new 2000's on a Lacrosse with a fan and without. The cells without the secondary fan were warm but not overly hot. Less than a RipVan 4000 or my Maha 204 heats them up. They were stone cold room temp with the fan. 

I'm using a Radio Shack 12 volt wall wart and a 12 volt DC 3" box fan. Soon I will make a bracket to hold it over the unit rather than have both sitting on their sides. I charged all cells at the 700ma rate. 

I had an old Maxell charger that got cells very warm compared to my others. It also killed several cells due to it's overheating them. It now resides in a waste dump.


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## photo2000a (Jan 11, 2006)

just wondering, don't the charger's turn off based on temp? if you cooled it (via fan) wouldn't the batt's maybee over charge???


[


QUOTE=Pellidon]Because of my days with RC car packs and melting one with a timer rapid cooker. I almost always use a secondary fan to blow on the cells. I just charged up some new 2000's on a Lacrosse with a fan and without. The cells without the secondary fan were warm but not overly hot. Less than a RipVan 4000 or my Maha 204 heats them up. They were stone cold room temp with the fan.


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## regnim (Jan 11, 2006)

Silverfox, I have called La Crosse and they have advised me to send them my charger. It went out via Fedex today. We will see what they have to say.


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## jtr1962 (Jan 11, 2006)

I believe the power supply/reset problems are directly related to the overheating problem. Granted, poor thermal coupling and a high setting for shutdown temperature are poor engineering choices, but the problem boils down to the fact that the charger sometimes misses the end of charge signal. I attribute the BC-900 continuing to charge "full" cells directly to the power supply problem. In simple terms, the power supply is "noisy" due to poor decoupling. The small negative delta V exhibited by fully charged cells is easily lost amid all the noise. Once modified as described in this thread the charger should be less prone to meltdown. That being said, I've noticed other chargers with 700 mA or 1000 mA charge rates allowing cells to get uncomfortably hot. For that reason I'm now in the habit of having a fan blowing on any charger when I'm charging at 500 mA or greater. It can't hurt, and it might just prevent the kinds of meltdown problems we've been seeing. I'll also second Tom's recommendation to always charge away from combusibles.

As for changing the reset temperature on the BC-900, I'm going to look into it. The temperature sensor is a simple PTC thermistor, meaning that the resistance goes down as the temperature increases. My idea is to measure the resistance at 160°F and 130°F, and then put a shunt resistor in parallel with the thermistor so that the charger "sees" 160°F when the actual temperature is only 130°F.

Overall as I've said already the BC-900 is a great idea in concept, but has so many rough edges that it's more like a pre-production prototype. Hopefully if LaCrosse ever releases a BC-900 version 2 it will address all the issues we've seen.


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## senna94 (Jan 11, 2006)

I just recieved my BC-900 and am running the test cycle on 4 2500mah Energizer cells at 1000ma. I decided to put my charger on top of a glass to provide extra ventilation underneath. I will be monitoring the temp closely and keep my fingers crossed.

Paul


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## tacoal (Jan 11, 2006)

Hi regnim:
Is the charger works fine after the melting down?


I just read some documents from Panasonic dated August 2005.

In the document, the thermal cut off temperature is recommended to 55C(131F) for A, AA and D; 50C(122F) for AAA http://www.panasonic.com/industrial/battery/oem/images/pdf/Panasonic_NiMH_ChargeMethods.pdf So the BC-900 is set to high for it. Other related documents can be found at http://www.panasonic.com/industrial/battery/oem/chem/nicmet/index.html

Another finding is when temperature is high and charge current is small, the -delta V is hard to detect, even no -delta V at all, esp. for those high capacity batteries So keeping batteries cool by a fan is a good idea to allow BC-900 to get that -delta V more easily.

Battery with high internal resistance is another factor for the melting down case.


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## wptski (Jan 11, 2006)

I don't know! Is there a right or perfect point in temperature to shut down the cycle? Could the -deltaV point be lost if the cycle is stopped just prior to that point and restarted several minutes later??


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## mccavazos (Jan 11, 2006)

senna94 said:


> I called LaCrosse today and was put on hold while the tech. helping me asked around. He was told that there had only been one unit overheat that they knew of. :thinking:



I think that this might be my charger. LaCrosse was a pleasure to deal with. They had an excellent customer service program. I was just told that my new charger arrived in the mail. As soon as I get my hands on it, I will send back the melted one so that they can figure out what went wrong.


Chris


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## tankahn (Jan 12, 2006)

What a regret. With so many kind people here having favorable experience, decided also to get one last Monday. Its too slow, takes me almost 24 hrs to test my batteries. With 2 charging cycle I can't be attending to it all the time.

Since I can't sell a potential fire-hazard away in full conscience. I don't know what I can do with it. 

Flame me if you want. The BC-900 unit is made in China. I am Chinese but would avoid buying any China made electrical stuff if I can. QC must be an alien concept there. Was in Shanghai when I forgot to brought my charger with me. Went to a store and every piece they show me is broken. I got a camera with german words stamped on it and the film cover just popped off. In Singapore where I lived, many Chinese made aquarium pumps went up in smoke.

I bought Triton charger at the same time. Its a pleasure to use. Its flying off the shelves here.


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## SilverFox (Jan 12, 2006)

Hello Tankahn,

Are you aware that in the test mode you also have control over the current setting?

If you have 2500 mAh capacity cells, select the test mode, then select a current of 1000 mA. It will take roughly 5 hours to do the discharge, then roughly 2.5 hours to charge them back up. This works out to only around 7.5 hours for a full cycle.

I will also point out that there have been no reports of fires, only plastic melting. If you place your charger inside a baking dish, or on a platter, or on a plate, or on a ceramic tile, or on a silicon hot pad, you should be well protected against hot plastic.

On the other hand, I agree that the Triton is an excellent charger. I would also advise you to charge on a non combustible surface while using the Triton as well.

Tom


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## tacoal (Jan 12, 2006)

By google's translation, I found a German page to change the thermal shutdown temperature. The link is http://www.digicamfotos.de/index3.htm?http://forum.penum.de/showthread.php?id=24339

By replace a 7.5K resistor with a 10K one, the thermal shurdown temperature will drop 5C(9F) to 53C(127F). 

From the page, it seems the shutdown temperature for BC-900 is bellow 60C(140F)(FW 33?), rather than 71C(160F) here. 

They also point out that the melting down happens on 200ma changing current might be the bad thermal contact, bad battery .....


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## senna94 (Jan 12, 2006)

How prudent would it be to modify a unit that is already known to have a problem that the manufacturer is as of yet unwiling to acknowledge. If the manufacturer ever does decide to recall these units, it is unlikely they will accept one that has been modified. Not to mention that this would probably void your warranty. :thinking: Lets say that after you modify the unit it still fails and heaven forbid it melts and causes damage to your property. Then you have really exonerated LaCrosse from any liability by virtue of having modified the unit.


Just a thought.

Paul


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## jtr1962 (Jan 12, 2006)

Thanks for the info, tacoal. You saved me a lot of work! I'll be doing that mod on my chargers right away. I'll just point out that by replacing one of the 7.5K resistors with the 10K one, the net result is a resistance of 4.286K instead of 3.75K (two 7.5K resistors in parallel). Apparently the BC-900 compares the resistance of the two thermistors to this reference value, and shuts down the channels where the thermistor resistance is lower. BTW, I measured room temperature (70°F) resistance of the thermistors at around 12.2K.

Since I have 4.7K resistors handy, I'm going to be removing both 7.5K resistors and replacing them with the 4.7K one. My cutoff temperature should be another 5°C or so lower than their modified temperature, or around 48°C. I feel a lot more comfortable with it there.


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## tacoal (Jan 13, 2006)

Hi jtr1962,

You are welcome!

The resistance of the thermistors in my BC-900 is measured only about 9.2K at 70F. 12.2K is about 30% above the 9.2K. This might be another factor causing the melting down.

I also checked the waveform around the thermistors. It seems it measures the time charging a capacitor (near the hole) from 0V to about 1.2V through each of the thermistors or the reference resistor to check if the temperature is higher than the reference.

I also noticed that there will be a gap between the metal plate and the battery if it is not well installed. This would make the charger think the temperature there lower than real one.


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## SilverFox (Jan 13, 2006)

Hello Jtr,

I have also noticed that the thermocouple contact with the metal strips may be in question. I believe someone (on the German camera site) mentioned modifying the thermocouple placement to insure better contact. 

Mine has a bit of thermal paste as well. When I put my unit back together, I added additional thermal paste to insure good heat transfer.

Tom


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## wptski (Jan 15, 2006)

Well, add me to the growing list of La Crosse BC900 meltdowns!  

I had just purchased sixteen Duracell 2300mAh AA made in China. These had been formed on a Sirius Pro Former and cycled four times on various RC chargers. This is the third batch that I was running a Test Mode(1000ma/350ma) on. I had been watching the unit and this was the first cell to complete the discharge showing 2.37Ah which is about the same as the others from this batch that I've tested.

A few minutes later I looked closer and noticed the it's button had dropped!  I started to smell something burning and the LCD on that slot started to turn black. So I quickly pulled the plug. Funny as the cells aren't warm or anything!

Just took it apart and the button is melted and stuck to the circuit board!

The worst part of this is that I'm one of the first CPF'r to get this charger from J.S. Burly's and I'm sure that's over a year ago! 

EDIT: As it turns out, my PayPal shows payment on 1/16/2005!  Can't cut it any closer than that! :wow:


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## SilverFox (Jan 15, 2006)

Hello Bill,

Wow, this is not good news at all...

When you contact La Crosse, ask them what they think is going on. I would be interested to hear what they have to say.

Tom


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## wptski (Jan 15, 2006)

Tom:

I'll be calling them tomorrow!

I did think of something else too. As I mentioned this was the third set of DuraCell 2300mAh cells that I ran in 1000ma/350ma Test Mode. I was having trouble with the Mode button while trying to get to the Test Mode and I believe it started with the second batch too.

I finished charging those four cells in a MAHA MH-C401FS in fast(1000ma) mode because of all this talk about charging at 1C with these larger cells. I also have two MAHA MH-C204W which do two cells at 2000ma or four at 700ma with -DeltaV, zero DeltaV, Temperature and Time cutoff. I think that I'll start using these at 2000ma for those DuraCells.


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## jtr1962 (Jan 15, 2006)

wptski said:


> A few minutes later I looked closer and noticed the it's button had dropped!  I started to smell something burning and the LCD on that slot started to turn black. So I quickly pulled the plug. Funny as the cells aren't warm or anything!


It seems that the MOSFETs on the board generate enough heat sometimes to cause the buttons to drop. For that reason I recommend using a fan if you're operating the charger over 500 mA.

On a more positive note, I did the temperature modification as I described (and checked the thermal coupling of the thermistors as Tom recommended), and refreshed 48 cells at 1000 mA _without_ a fan. The charger stopped charging when the cells were about 120°F (warm to the touch but I can keep my hand on them continuously). Before the cells would get hot enough that I couldn't keep my hand on them for more than a few seconds. I still recommend using a fan at higher charge currents to prevent charging from being stopped due to overheating. Also, the charger seems to pick up the end of charge signal better with cool cells. No need for a huge fan. An 80 or 120 mm PC case type fan either set on top of the charger or on the side is enough cooling.


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## wptski (Jan 15, 2006)

jtr1962 said:


> It seems that the MOSFETs on the board generate enough heat sometimes to cause the buttons to drop. For that reason I recommend using a fan if you're operating the charger over 500 mA.
> 
> On a more positive note, I did the temperature modification as I described (and checked the thermal coupling of the thermistors as Tom recommended), and refreshed 48 cells at 1000 mA _without_ a fan. The charger stopped charging when the cells were about 120°F (warm to the touch but I can keep my hand on them continuously). Before the cells would get hot enough that I couldn't keep my hand on them for more than a few seconds. I still recommend using a fan at higher charge currents to prevent charging from being stopped due to overheating. Also, the charger seems to pick up the end of charge signal better with cool cells. No need for a huge fan. An 80 or 120 mm PC case type fan either set on top of the charger or on the side is enough cooling.


jtr1962:

A bit late for mods!  This was the largest capacity cells that I've ever used in the BC-900. What capacity are the 48 cells that you refreshed? What about your recommended power supply?

I just charged two of the 2300mAh Duracells in a MAHA MH-C204W at 2A with a dual input temperature probe monitoring both cells. They both got just over 140F before it finished charging. The highest temperature was 143.3F I'm running a second set right now. The highest I read on the BC-900 at 1.8A was 130F.

Your BC-900 stops at 120F with your mod, so what happens after it restarts, does it still complete the cycle?


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## jtr1962 (Jan 15, 2006)

wptski said:


> A bit late for mods!


Agreed in your case since the damage is done. 



> What capacity are the 48 cells that you refreshed? What about your recommended power supply?


Nexcell 1800 mAH. I purchased them about 2 years ago. I did the test with the stock supply but the alternate supply can be purchased here. I noticed the charger does get a little warmer internally with the alternate supply since it's 3.3V instead of 3V. If I can get the alternate supplies open I might be able to find an adjustment pot to bring them down to 3V.



> Your BC-900 stops at 120F with your mod, so what happens after it restarts, does it still complete the cycle?


Yes, it will reset, start charging again, and eventually complete the cycle. The problem is that with lots of starts and stops it takes way longer. For that reason I recommended using a fan.


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## wptski (Jan 15, 2006)

jtr1962 said:


> Agreed in your case since the damage is done.
> 
> 
> Nexcell 1800 mAH. I purchased them about 2 years ago. I did the test with the stock supply but the alternate supply can be purchased here. I noticed the charger does get a little warmer internally with the alternate supply since it's 3.3V instead of 3V. If I can get the alternate supplies open I might be able to find an adjustment pot to bring them down to 3V.
> ...


jtr1962:

I was hoping that you tested with some 2300mAh or larger cells.

High temperature cutoff is a safety feature and not something that should happen frequently! I wondering if the cycle is interrupted too close to the termination point, it may cause problems? These larger cells need higher charge rates to insure proper detection of termination voltage drop but now were generating more heat! I think that we need some new designs for these new generation cells.

I once had a problem with a third party cellphone battery charger and called Tech Support. They had instructed me to just stop the cycle and restart it again! Darn thing never worked the same after that!!


----------



## jtr1962 (Jan 15, 2006)

I also have 14 2300 mAh Nexcells. I'll try recharging them at 1000 mA without a fan and see if there are any problems.

Yes, I did hear that if the charging cycle is interrupted there may be problems detecting end of charge when it resumes. That might be one reason LaCrosse set the cutoff temperature so high-so that it would be a backup in case the -dV/dt detection failed, but normally wouldn't come on. I only had a problem with two of my cells. They kept starting and stopping from overheating. I finally took them out when the charger said that 2.7 AH had been pumped into them even though they were _still_ charging. I figured they were plenty charged by then.


----------



## tacoal (Jan 15, 2006)

The current sampling resistors will generate more heat than those MOSFETs. The On-state resistance for NTGS3443, the MOSFET in BC-900, is about 0.1 ohm; the sampling resistor is 0.2 ohm.

One thing happened this afternoon when I charged the Rayovac 2000mah battery in 700ma refreshing mode. Since this is the second time to change these batteries, I checked them about 20 minute. At time, when it is in charge mode, the battery and charge is very hot when I put the charger in flat wood surface. The surface is hot too. Then, I elevate the battery end of the charger about 2 in by something, i.e. the charger is in a sloping position. After this, the batteries and the charger stay cool even in charge mode.

So it is a good practice to put a fan against the charger or put the charge in a sloping position so that the air circulation could bring away more heat from the charger to keep it stay cool.

jtr1962:

Did you measure the shutdown temperature before you did the mod?


----------



## jtr1962 (Jan 16, 2006)

tacoal said:


> jtr1962:
> 
> Did you measure the shutdown temperature before you did the mod?


Just by feel. I've done a lot of experiments with thermoelectric modules where I measured temperatures of hot and cold plates, so I have a pretty good idea of what various temperatures feel like. Before the mod, the cells were getting to about 140°F. Afterwards, roughly 120°F. Granted, this is all just by feel, but it agrees pretty well with the actual measurements in the article you linked to earlier.


----------



## SilverFox (Jan 16, 2006)

Hello Tacoal,

I have been using a small rock to elevate the back sides of my BC-900 and Energizer 15 minute chargers. It seems to help a lot.

Tom


----------



## BVH (Jan 16, 2006)

Does anyone have a source for a very quiet, 120 volt, miniature fan that moves just enough air to cool the charger/batts?


----------



## SilverFox (Jan 16, 2006)

Hello Jtr,

There seems to be two firmware versions of the BC-900. I believe most of the problems we have been hearing about are with version 32. The Germans have been discussing version 33, which seems to shut things down at about 127 F (about 53 C). 

Does your charger have version 32?

Tom


----------



## wptski (Jan 16, 2006)

I wonder if the user in this thread:BC-900 Meltdown ever got his replacement and what version it is, 32/33?

I tried calling La Crosse about my BC-900 twice and got dumped after a few minutes to voicemail! I left a message the second time. They might be closed today because of the holiday!

EDIT: I emailed them also!


----------



## tacoal (Jan 16, 2006)

jtr1962 said:


> Just by feel. I've done a lot of experiments with thermoelectric modules where I measured temperatures of hot and cold plates, so I have a pretty good idea of what various temperatures feel like. Before the mod, the cells were getting to about 140°F. Afterwards, roughly 120°F. Granted, this is all just by feel, but it agrees pretty well with the actual measurements in the article you linked to earlier.


 
I see. Thank you for the info.


----------



## jtr1962 (Jan 16, 2006)

SilverFox said:


> Does your charger have version 32?


Yes, version 32 like pretty much everyone's here. I wonder if they did a board redesign with version 33 or just a software change.


----------



## nuggett (Jan 16, 2006)

In my version 33 manual, it states the charger will shut down if temps exceed 127 deg, then restart after cooling


----------



## wptski (Jan 16, 2006)

nuggett said:


> In my version 33 manual, it states the charger will shut down if temps exceed 127 deg, then restart after cooling


nuggett:

How long have you had your BC-900?


----------



## BVH (Jan 16, 2006)

I took delivery on my second BC-900 from Amazon about 5-6 weeks ago and its version 32 firmware.


----------



## tacoal (Jan 16, 2006)

jtr1962 said:


> Yes, version 32 like pretty much everyone's here. I wonder if they did a board redesign with version 33 or just a software change.


 
The one I use now is 32. The second one is on its way, I think it should be 33. I'll check them when I get the new one.


----------



## nuggett (Jan 17, 2006)

Had my version 33 about 1 month


----------



## wptski (Jan 17, 2006)

Looks like making contact with La Crosse about my meltdown BC-900 is going to a bit of a problem!  

I emailed them yesterday and left voicemail too. Nothing on my answering machine and no email either from them. I called again and got dumped to voicemail after maybe seven minutes just like yesterday, so I left another voicemail marked as "urgent"!


----------



## Sigman (Jan 17, 2006)

*They haven't returned my call either!* Fine - I get the message!

*They get no more of my money and I'd not recommend them after this!

**There are just* *too many other options on the market!*


----------



## wptski (Jan 17, 2006)

Ah! I used that old trick of calling just before they close! Gacha! 

I talked to some girl that didn't know too much about the charger and heard nothing about these problems lately. She couldn't ask around because everybody else had gone home for the day. I have a RMA# but no freebie yet like somebody else got but who knows, maybe I'll get a call like they did.


----------



## Grumpy (Jan 17, 2006)

Would it do any good if someone contacted a Consumer Safety Comission or whatever it is called?


----------



## regnim (Jan 17, 2006)

Sent my charger to La Crosse on 1/11 and they received it on 1/13. Today, 1/17, I got a replacement. Firmware version 33. Put a fully charged set of Energizers 2500mah in it and set it for 200ma charge. Unit charged for about 10 min and then went to "full". So far so good, now trying the test mode, on my glass desktop just in case. No note or any reply, wonder if they even looked at my old charger, just sent a replacement.


----------



## wptski (Jan 17, 2006)

regnim said:


> Sent my charger to La Crosse on 1/11 and they received it on 1/13. Today, 1/17, I got a replacement. Firmware version 33. Put a fully charged set of Energizers 2500mah in it and set it for 200ma charge. Unit charged for about 10 min and then went to "full". So far so good, now trying the test mode, on my glass desktop just in case. No note or any reply, wonder if they even looked at my old charger, just sent a replacement.


regnim:

Did you send/receive a new power supply too?


----------



## Mike abcd (Jan 17, 2006)

regnim said:


> Sent my charger to La Crosse on 1/11 and they received it on 1/13. Today, 1/17, I got a replacement. Firmware version 33. Put a fully charged set of Energizers 2500mah in it and set it for 200ma charge. Unit charged for about 10 min and then went to "full". So far so good, now trying the test mode, on my glass desktop just in case. No note or any reply, wonder if they even looked at my old charger, just sent a replacement.



Charging 2500 mAH cells at 200 mA is just asking for trouble IMHO. All the cell manufacturers warn about using -dV/dt at low charge rates because the peak is very small or non existant. The reported lower temp cutoff of the V 33 firmware should help but the 200 mA rate won't do your cells any favors.

The 200 mA default rate of the BC-900 is definitely a major issue. I pity the average consumer who thinks slow charging on it is "better". I continue to use mine without issues but I also always use higher rates except on carefully timed 200 mA "top off" charges. I also use it on a non flammable surface to be safe...

I just started playing with a Lenmar Mach 1 Gamma charger that can terminate charging on the rate of cell temp change as advised by the cell manufacturers. It charges MUCH quicker then the LaCrosse and it's hard to feel ANY temp rise with my finger thermometer. Only downside is it doesn't fully fast charge cells or have any measurement capabilities. They have to be left on trickle charge for a full charge. An initial test seems to show it fast charges to about 90% (using the BC-900 to check capacity). BTW, it has a small fan but it's only used to cool the electronic section and not the batteries. I suspect they need it to keep temps stable for the dT/dt termination. About $30 delivered from Amazon or Newegg with four crappy Lenmar 2300 mA AA.

Mike


----------



## regnim (Jan 17, 2006)

wptski said:


> regnim:
> 
> Did you send/receive a new power supply too?


 
I sent them the charger and supply, they sent me a complete new charger/supply/case/batteries.


----------



## regnim (Jan 17, 2006)

Mike abcd said:


> Charging 2500 mAH cells at 200 mA is just asking for trouble IMHO. All the cell manufacturers warn about using -dV/dt at low charge rates because the peak is very small or non existant. The reported lower temp cutoff of the V 33 firmware should help but the 200 mA rate won't do your cells any favors.
> 
> 
> Mike


 
Yeah I know, but I wanted to be sure it would shut off and it seemed to work fine. If the power was interrupted while I was away it would start charging again at 200ma and I wanted to be sure it would shut off. 10 min probably did not hurt the cells any.


----------



## mccavazos (Jan 17, 2006)

wptski said:


> I wonder if the user in this thread:BC-900 Meltdown ever got his replacement and what version it is, 32/33?
> 
> I tried calling La Crosse about my BC-900 twice and got dumped after a few minutes to voicemail! I left a message the second time. They might be closed today because of the holiday!
> 
> EDIT: I emailed them also!



Where does it list the version on teh charger? I still have the melted one, until I have time to send it back, so I can check the version on both of these.


----------



## wptski (Jan 17, 2006)

regnim said:


> I sent them the charger and supply, they sent me a complete new charger/supply/case/batteries.


regnim:

:wow:


----------



## Shark (Jan 18, 2006)

mccavazos said:


> Where does it list the version on teh charger? I still have the melted one, until I have time to send it back, so I can check the version on both of these.



When you first plug in the power supply the version number should show up momentarily. I think in slot 4 on the LCD.


----------



## Mike abcd (Jan 18, 2006)

regnim said:


> Yeah I know, but I wanted to be sure it would shut off and it seemed to work fine. If the power was interrupted while I was away it would start charging again at 200ma and I wanted to be sure it would shut off. 10 min probably did not hurt the cells any.



Good point on it's behavior after a power failure. I used to see a lot of glitches and short outages but the local power company really cleaned up their act several years ago and it happens so rarely now, I tend to forget about the possibility.

I agree, 200 mA for 10 min into even a fully charged 2500 mAh Energizer (Sanyo) is a non issue.

Mike


----------



## tacoal (Jan 19, 2006)

I got the second BC-900 today. It comes from Amazon.

The package changed from a paper box to a sealed plastic one. Contents are the 
same.

The firmware revision is 32, not the expected 33.






The assembly is worse than before: a thin layer of dust inside the charger, 
large block of solder for those parts that are not SMT. this may be due to the 
manual soldering.

The PCB board has some changes, primary around the thermistor. The hole changed 
from a round one to a square one. This hole now is used to install a stand for 
the thermistor. This will provide a better contact between thermistor and the 
metal. I do not find any circuitry change.

The waveform is the same. Glitch is still there.

Just add a 500uf capacitor around the power socket, the nikiwind’s mod. The 
glitch on power is gone but the charging current has glitch now.


----------



## wptski (Jan 19, 2006)

tacoal:

What do you mean that the charging current has a glitch now?


----------



## Pellidon (Jan 19, 2006)

BVH said:


> Does anyone have a source for a very quiet, 120 volt, miniature fan that moves just enough air to cool the charger/batts?



I bought a 12 volt 2" square fan and wired it to a Radio Shack 12 volt wall wart. I used the modular plug type PS so I could dissasemble the fan from the wart for storage. It puts out more than enough airflow for the job and is quiet. A 5V CPU fan with a smaller charger would work also I'd think.


----------



## tacoal (Jan 19, 2006)

wptski said:


> tacoal:
> 
> What do you mean that the charging current has a glitch now?


 
The charging current waveform took from the sampling resistor has overshoting after adding the capacitor. That means the big di/dt. It is harmful to the device sometimes.


----------



## twolf (Jan 21, 2006)

tacoal said:


> The firmware revision is 32, not the expected 33....The hole changed from a round one to a square one.



Does the firmware 32 indicate also the temperature (like the firmware 33)?
See https://www.candlepowerforums.com/threads/104220

What is your board revision?


----------



## Xe54 (Jan 21, 2006)

Sigman said:


> *They haven't returned my call either!* Fine - I get the message!
> 
> *They get no more of my money and I'd not recommend them after this!
> 
> **There are just* *too many other options on the market!*



Unfortunately, there are not many options. The LaCrosse is the only charger with multiple independent channels that give many options for testing, refreshing, etc. cells.

I really wish there were more options, but all the other chargers just charge, or maybe dis/charge, but give no quantitative data. The much more expensive ones like Triton are great, but can't tell you about the differences between individual cells, unless you charge one cell at a time.


----------



## regnim (Jan 21, 2006)

Well, I am happy to report that my replacement rev 33 is working fine. I have been charging various cells with various states of charge and have not been able to produce a runaway overcharge. Mostly Energizer 2500mah cells but some others as well, and all seem to end up with as much charge as my Maha charger. Also the buttons work much better now, more responsive.


----------



## wptski (Jan 25, 2006)

La Crosse received my BC-900 on Monday and shipped something to me the same day! I assume another BC-900 but I wonder what version and will I be able to trust it again?


----------



## wptski (Jan 25, 2006)

Got it today! Brand new in a box, batteries and all. It's the newer V33 too.


----------



## SilverFox (Jan 25, 2006)

Hello Bill,

Great news... Time to do some tests to see if version 33 runs cooler.

Tom


----------



## Freedom1955 (Jan 25, 2006)

I've had my V33 for awhile now and have never had a problem with it over heating.


----------



## wptski (Jan 26, 2006)

SilverFox said:


> Hello Bill,
> 
> Great news... Time to do some tests to see if version 33 runs cooler.
> 
> Tom


Tom:

Somewhere it was said that this newer version will cutoff at 120F and when I tested my older one at 1800mAh it got up to 130F. At 1000mAh it got up to 110F. We'll shall see!


----------



## wptski (Jan 26, 2006)

Freedom1955 said:


> I've had my V33 for awhile now and have never had a problem with it over heating.



When my melted the cells weren't warm!


----------



## twolf (Jan 26, 2006)

wptski said:


> this newer version will cutoff at 120F


Can you tell me the max charge temperature in RAW?
see
https://www.candlepowerforums.com/threads/104220

Tomas


----------



## wptski (Jan 26, 2006)

Tomas:

Doesn't it say in the link you provided that it's 35 in RAW format?


----------



## twolf (Jan 26, 2006)

Temperature measurements are difficult. Many users told, they have very hot accus with the firmware 33.

I'm looking for a second measurement


----------



## wptski (Jan 26, 2006)

Tomas:

I checked two 2300mAh Duracells at 1800mAh but it appears that they weren't run down enough as it terminated at around 40 min with 124F. I'll have to try that again with a discharged set.

I discharged another 2300mAh Duracell on a Duratrax ICE first at 2A down to .9V, then again at 1A, again at .7A and finally at .5A. Charging at 1000ma, it terminated in 76 min going by the highest temperature of 107.2F on my Fluke 54-II. Now that should have took longer to charge. I never really checked the charging times on my old BC-900 though! Hmmm, it finished a bit soon at 1800mAh too. Wonder if the charging current is really what it's set at?

The only way one could check the RAW-Wert value at max temperature is too catch it when it did shut down, pull the plug and replug it in to look at the values, correct?


----------



## wptski (Jan 27, 2006)

Well, here's something that I don't remember raeding about in V33!

You can charge both a single AA or AAA in Slot 1/4 at 1800mAh and the other slot will show "null".

I also looked at it's signal. As was mentioned in another thread, it's PMW but it's very fast. I'll post a screen of the signal some time later. I tried reading current with a good low current clamp probe and probably because of the PWM, I assume, the reading was way below the set current!


----------



## minimig (Jan 28, 2006)

Xe54 said:


> Unfortunately, there are not many options. The LaCrosse is the only charger with multiple independent channels that give many options for testing, refreshing, etc. cells.
> 
> I really wish there were more options, but all the other chargers just charge, or maybe dis/charge, but give no quantitative data. The much more expensive ones like Triton are great, but can't tell you about the differences between individual cells, unless you charge one cell at a time.



Hello,

There are some options, but in Germany  

There's a brand, Voltcraft AccuTrainer AT3+ that does what the BC900 can do, but I don't know how extensive is it's capabilities. Then there's the Voltcraft ChargeManager 2010 and 2020 that can handle C, D and 9V. Look here (UK Conrad site) for more info.


----------



## lamperich (Jan 28, 2006)

minimig said:


> Hello,
> 
> 
> 
> There's a brand, Voltcraft AccuTrainer AT3+ that does what the BC900 can do, but I don't know how extensive is it's capabilities. Then there's the Voltcraft ChargeManager 2010 and 2020 that can handle C, D and 9V. Look here (UK Conrad site) for more info.



they are pretty popular here in the EU.

the cm2020 is also not perfect :-/
http://cm2020.sourceforge.net/ 
No timer to limit charging time.


----------



## wptski (Jan 28, 2006)

I discharged two 2300mAh Duracells, connected my Fluke 54-II dual input temperature probe with K-type wire beads to the cells. One in Slot#1 and the other in Slot#4. Set the charger for 1800ma charge and kept and eye on it too.

I was there at about an hour into it and Slot#1 had passed 127F the listed cutoff point but Slot#4 was lagging by 10F. The temperature in Slot#1 was climbing fast and what I've seen before it had passed Dt/dt cutoff which was normal for -deltaV termination which normally terminates a few minutes after the Dt/dt point. It hit 133F in Slot#1 and it cutoff, so I plulled the plug and reinserted it. I got a RAW, 46/48 but the cells showed FULL so I didn't bother restarting the cycle. Where did that RAW value of 35 for cutoff come from??

Funny, I've rechecked the RAW values from time to time and they are all over the place! Last check was 04/09. Part of the cooling process? Ah, back to normal 20/21 when I started!

I did notice one thing now though. The button for Slot#3 doesn't work but I'm not sure if it worked right out of the box. I hardly ever used those buttons on my old BC-900 either.


----------



## wptski (Jan 29, 2006)

I ran another temperature test on two 2300mAh Duracells at 1800ma charging rate.

This time I let it run the whole course while watching closely at the higher temperature. Slot#1 shut off at 134F but Slot#4 was again lagging, I'll have to check the K-type bead for placement, etc. Slot#4 followed at 124F. About 15 minutes later at 113F Slot#1 restarted again and at 108F, Slot#4 restarted. After five minutes or so more charging both cells show FULL.


----------



## wptski (Feb 2, 2006)

I installed four made in Japan 2300mAh Duracells from the same batch that melted my old BC-900 in my new BC-900.

Set to charage at 700ma. I wasn't watching it but took a look and was surprised to see it had cycled off for high temperature at 1:57 into the charge for 1100mAh. About ten minutes later it resumed and about twenty minutes later it cycled off again. About seventeen minutes later, it resumed at around 1400mAh.

It looked safe enough to hit the sack but woke up to find three cells FULL at 1600mAh for three hours. The last cell cycles off again. Later on, the last finished at 1800mAh for 3:47!

This might be the first time that I've charged four cells in this BC-900 and for sure it's the first time with 2300mAh cells. I didn't think that it would hit the high temperature limit while charging at 700mah!


----------



## SilverFox (Feb 2, 2006)

Hello Bill,

This almost sounds like bad, old, or marginal cells...

Tom


----------



## wptski (Feb 2, 2006)

Tom:

They are brand new cells with no more than 15 cycles on them! I'm not saying that there isn't a problem with them though. I bought two eight packs and have charged some of them on my C808M with no problem. This is the v33 BC-900, not a v32 and there may be more differences than we know about. I remember mentioning in a post that I had seen pulses about every second with my data logger. I now have a scope which shows 2ms ON pulses every 17ms. If you compare this to the PWM used on the C808M in which the effective current depends on the duty cycle or pulse width. If it indeed had a 1s OFF pulse width before and has a 17ms now, its effective current is much higher! Just a pure uneducated guess on my part.  I may buy some Sanyo 2300mAh just to see if it's the cells or not.

I was surprised that there wasn't any comment on my post above somewhere that with this new v33, you can charge a single AA or AAA at 1800ma in Slot #1 or #4.


----------



## Sigman (Feb 2, 2006)

I finally got to speak with someone in their customer service department. She gave me a return authorization number for me to send mine back to be "checked out". She didn't offer to send box or pay for shipping, but that's small price to pay to insure my house doesn't burn down!

Mine's brand new, only been plugged in to verify V32, but I just don't want to gamble! Nothing like driving up the street and seeing the fire department in front of your own house!


----------



## greenlight (Feb 2, 2006)

How do you verify the version number?


----------



## wptski (Feb 2, 2006)

greenlight said:


> How do you verify the version number?


When you plug in the power cord look at the LCD in Slot#4. If you have v33, the RAW-WERT temperature value for the left/right side will appear in Slot#1/#2


----------



## greenlight (Feb 2, 2006)

greenlight said:


> How do you verify the version number?



Darn, mine is v32. I'll be careful!


----------



## Sigman (Feb 3, 2006)

BTW, when I called them I spoke with "Amphon". She said (and she put me on hold while she "checked with others") that they hadn't heard anything about this problem!

We all know this couldn't be "totally true", eh? I really didn't appreciate that and felt like she was trying to pass it off.

At the end of the phone call, she asked if I intended on sending it back. I said, "Definitely" and then she took my name, address, phone number, & email address...then she gave me a return authorization number. 

She stated that they would "check mine out", never said anything about replacement. Perhaps I should call them back again today? I'm thinking I will...from what has been posted in this thread - I think her answer was unacceptable.

Maybe I'll email them with a link to this thread....


----------



## wptski (Feb 3, 2006)

Sigman:

They told me also that they haven't heard of any meltdown reports. I doubt if they checked mine as they shipped a new one the day they received my old one!

I had mine almost a year before the meltdown. It was on the third batch of four using the 700ma/350ma Test Mode when it happened.


----------



## Sigman (Feb 3, 2006)

Could it be that they feel that their liability is at stake with an admission of a problem?


----------



## bcwang (Feb 3, 2006)

wptski said:


> Tom:
> 
> They are brand new cells with no more than 15 cycles on them! I'm not saying that there isn't a problem with them though. I bought two eight packs and have charged some of them on my C808M with no problem. This is the v33 BC-900, not a v32 and there may be more differences than we know about. I remember mentioning in a post that I had seen pulses about every second with my data logger. I now have a scope which shows 2ms ON pulses every 17ms. If you compare this to the PWM used on the C808M in which the effective current depends on the duty cycle or pulse width. If it indeed had a 1s OFF pulse width before and has a 17ms now, its effective current is much higher! Just a pure uneducated guess on my part.  I may buy some Sanyo 2300mAh just to see if it's the cells or not.
> 
> I was surprised that there wasn't any comment on my post above somewhere that with this new v33, you can charge a single AA or AAA at 1800ma in Slot #1 or #4.



Hi Bill,

I've got a v32, and with good sanyo 2500mah cells, it shuts off multiple times before finishing charging at 1amp unless I keep a fan blowing on it. So I'm not surprised yours is doing it with 2300mah duracells.

I don't understand what is different about v33 and slot 1 and 4 charging. I can charge using my v32 in slots 1 or/and 4 at 1800ma. Could you elaborate a bit more?


----------



## wptski (Feb 3, 2006)

bcwang said:


> Hi Bill,
> 
> I've got a v32, and with good sanyo 2500mah cells, it shuts off multiple times before finishing charging at 1amp unless I keep a fan blowing on it. So I'm not surprised yours is doing it with 2300mah duracells.
> 
> I don't understand what is different about v33 and slot 1 and 4 charging. I can charge using my v32 in slots 1 or/and 4 at 1800ma. Could you elaborate a bit more?


bcwang:

This might be something that I just missed! The manual shows using Slots#1 and #4 to get 1800ma, so that's what I tried with v32. I noticed that with v33, I could get 1800ma with Slot#1 or #4 only! Can you can set it at 1800ma for a AAA cell too?

I never charged anything higher than 2Ah cells with v32 till I melted it in Test Mode with the 2300mAh cells. At 700ma with 2Ah cells, I never noticed it cycle OFF for high temperature.

I picked up four 2500mAh Energizers which are rebranded Sanyo cells at Target. They were the same price as the 2300mAh Duracells, $9.99,  full price!


----------



## bcwang (Feb 3, 2006)

wptski said:


> This might be something that I just missed! The manual shows using Slots#1 and #4 to get 1800ma, so that's what I tried with v32. I noticed that with v33, I could get 1800ma with Slot#1 or #4 only! Can you can set it at 1800ma for a AAA cell too?
> 
> I never charged anything higher than 2Ah cells with v32 till I melted it in Test Mode with the 2300mAh cells. At 700ma with 2Ah cells, I never noticed it cycle OFF for high temperature.



Bill,
I tried again just now with my V32. With either AA or AAA cells, I can get 1800ma in slot 1, or slot 4, or slot 1 and 4 at the same time. If you put one battery in slot 1 or 4, and set the charge rate to 1500 or 1800ma, then the other slot will show null. But once you put a battery into the other slot, it will allow you to select 1500 or 1800ma and both will charge. I might be confused as to what you're really trying to say is different.


----------



## wptski (Feb 4, 2006)

bcwang said:


> Bill,
> I tried again just now with my V32. With either AA or AAA cells, I can get 1800ma in slot 1, or slot 4, or slot 1 and 4 at the same time. If you put one battery in slot 1 or 4, and set the charge rate to 1500 or 1800ma, then the other slot will show null. But once you put a battery into the other slot, it will allow you to select 1500 or 1800ma and both will charge. I might be confused as to what you're really trying to say is different.


bcwang:

You have it correct and the same as I have found too! The manual isn't correct or changes were made after it was written.

Here's something else but I really didn't look into it very much as to what is really happening. Press/hold the Mode button and then press the Display button while a cell is charging. I had one cell in Slot#1 at the time.


----------



## wptski (Feb 7, 2006)

Here's a composite of screen captures of the BC-900 using a low current probe. Starting at the left, the somewhat high trace is 200ma and then it's 500ma, 700ma, 1000ma, 1500ma and 1800ma. The higher the current setting the longer the pulse.

I've yet to figure out why all of these read about 1A. I've put the question to the manufacturer of the probe and scope. No answer so far.

Similar traces on a MAHA MH-C808M, MH-C401FS and a old MH-C210 which are all pulse width modulated chargers all read correctly. I'm guessing that it doesn't like the cell extended outside the charger with clips, wires, etc. or something in the probe's specs. I just tried much heavier wire with the same results! It's a bit confusing.


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## tacoal (Feb 8, 2006)

Hi wptski,

What is the resistance of the probe?
I have measured the charging current directly by measuring voltage on the 
current sampling resistors (5X1 Ohm in parallel) using a Fluke 97. The charging 
current varies depending on the battery and the number of battery to be charged. 
When one battery is charged, the current could reach 2.5A. When four batteries 
are charged, the current could go down to 1.2A. Since each battery starts the 
pulsing charging at different time, the first one will have biggest charging 
current first, then the current gradually goes down when other batteries switch 
in. https://www.candlepowerforums.com/threads/91384 shows this case 
by the voltage stepping down when each battery switches in.


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## wptski (Feb 8, 2006)

tacoal:

I forgot to state that it was a clamp probe, so it's unintrusive. I have two of the same kind of probes. I was only charging one cell in Slot#1. The other chargers, only the C-808M has a 2A output which shows correctly on my Fluke 123. The C210 is 300/800ma and read correctly also. The C204FS is 300/1000ma and also read correctly too!

I have seen specs for some clamp probes where rise time is mentioned but not for the ESI-695 that I'm using. Even Fluke probes don't mention that spec either.

I'll take a look at the link that you provided now.


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## tacoal (Feb 9, 2006)

I see.

The pulsing charging in BC-900 has a cycle time of 19.6ms (51Hz). I know some chargers use longer cycle time like 1 sec. This might be a factor.


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## wptski (Feb 9, 2006)

tacoal said:


> I see.
> 
> The pulsing charging in BC-900 has a cycle time of 19.6ms (51Hz). I know some chargers use longer cycle time like 1 sec. This might be a factor.


tacoal:

A few things are strange about this. One of the other PWM chargers that I check had a frequency at times way above 20kHz bandwidth of the ESI-695 probe and it still read correctly although the current rate of the charger was lower. I don't remember if was the 800ma or 1000ma charger.

I got another response of ESI yesterday. In the first response they couldn't duplicate the problem with a test at 57Hz at around 20V but now they are going to retest at 1.5V again.

My initial connection is/was a bit of a jury-rig due to the contacts on that type of charger. I use a clip easily on the negative side but the positive side I'm using a 1/4" x 1" super magnet to a clip. Both go out to a AA spring type holder. I have good clamps made up with power pole connectors for my other chargers, etc. I luckily just got a power pole insertion/removal tool, so I removed the connectors. The leads are #13 wire and just a few inches long too. I just held the leads to the contacts on the BC-900. Still got the same 1A at 200ma charge rate! 

I hope that my contact at ESI clears the confusion up. If you wouldn't have stated that you measured the current at the sensing resistors inside, I was starting to think that really the max charging rate might be only 1000ma and that it's PWM. In order to double check that I was going to charge two 1800mAh cells and check the time it took to charge.


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## tacoal (Feb 9, 2006)

BC-900 is very sensitive to the resistance in the charging loop since it does not regulate the charging voltage. A 0.05 ohm will drop the current by 200ma.

I replaced the MOSFET NTGS3443T1 by Si3473DV, which has low on-resistor, and found out the charger was hotter than before. After checking the waveform, the charging current could reach 3A when one battery is charged. I had to insert a 0.05 ohm resistor to the charging loop to reduce the max current (by about 200 to 300ma). When charging current reaches 3A, I noticed the voltage on sampling resistor and battery might exceed 2.2 voltages, which is the ADC reference voltage. In this case, the charger cannot get correct current reading and may cause troubles, I think. I also notice that some one in this forum said the charger is hotter when the 3.3 volt third party power supply is used. I think this may be the same result as I changed the MOSFET.


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## wptski (Feb 9, 2006)

tacoal:

I doubt if I added much resistance during my last, if anything I probably had less! Forgot to ask but what version do you have, v32 or v33? I wish somebody out there had a low current clamp probe and a scope.

One thing that I'll have to look at agin is prior to getting my Fluke 123 I had connected a Dataq data logger to my BC-900(v32) and seen pulses but they were exactly at 1 second intervals! Nothing that slow on this v33 unit. I'm going to look at that log again and make sure about the interval. At 1 second it's closer to other chargers that read correctly that I've checked. I could also log this BC-8900 too to see what I get.


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## tacoal (Feb 9, 2006)

Hi wptski,

My BC-900 has the firmware 32. It is possible they changed the algorithm in 33.

As for the waveform, you could refer to http://www.digicamfotos.de/index3.htm?http://forum.penum.de/showthread.php?id=17111. They inserted a 0.1 ohm resistor to measure the waveform. You could tell the cycle time (10ms/div) and current (in red 1.6=174mv/0.1ohm) in those photos. Theses photos may be based on firmware 32.

According to my measurement, the BC-900 does have 1s cycle to measure the temperature. After the measurement, it has full one charging cycle (19.6ms) sporadically even in 200ma charging mode. I think this is a firmware bug.


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## wptski (Feb 9, 2006)

tacoal said:


> Hi wptski,
> 
> My BC-900 has the firmware 32. It is possible they changed the algorithm in 33.
> 
> ...


tacoal:

That's 19.6ms ON time at 200ma?

EDIT: I get 2-3ms at 200ma, v33 has to be different in more ways than one! I gave my contact at ESI a 101 class in the BC-900. They seem to think that the probe is reading correctly at this point unless they change their mind and can't understand how La Crosse's manual could be so misleading!


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## tacoal (Feb 9, 2006)

19.6ms is the cycle time including a ON and a OFF interval. This means the charger will ON/OFF at the rate of 51 times per second. As I said in previous post, every second, there is a interval to measure the temperature. So it is supposed the charger controls the duty cycle in one 19.6ms cycle 50 times and uses one cycle to measure temperature in one second.

EDIT:


> I get 2-3ms at 200ma


 the average current will be ON_CURRENT *2~3ms/19.6=200ma, so the ON_CURRENT is about 1.3A~2A.


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## wptski (Feb 9, 2006)

tacoal said:


> 19.6ms is the cycle time including a ON and a OFF interval. This means the charger will ON/OFF at the rate of 51 times per second. As I said in previous post, every second, there is a interval to measure the temperature. So it is supposed the charger controls the duty cycle in one 19.6ms cycle 50 times and uses one cycle to measure temperature in one second.


tacoal:

That's right, I forgot we get the exact same frequency, 51Hz!


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## tacoal (Feb 9, 2006)

wptski said:


> tacoal:
> 
> That's right, I forgot we get the exact same frequency, 51Hz!


 
We get the point!:buddies:


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## wptski (Feb 9, 2006)

tacoal said:


> 19.6ms is the cycle time including a ON and a OFF interval. This means the charger will ON/OFF at the rate of 51 times per second. As I said in previous post, every second, there is a interval to measure the temperature. So it is supposed the charger controls the duty cycle in one 19.6ms cycle 50 times and uses one cycle to measure temperature in one second.
> 
> EDIT: the average current will be ON_CURRENT *2~3ms/19.6=200ma, so the ON_CURRENT is about 1.3A~2A.


tacoal:

Back to the original quiz now! Clamp current probe only shows about 1A amplitude.


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## tacoal (Feb 9, 2006)

wptski said:


> tacoal:
> 
> Back to the original quiz now! Clamp current probe only shows about 1A amplitude.


From the waveform you posted before, it is not the issue of clamp response time. You could see the ON and OFF clearly in ms scale. The only thing I could say is the resistance inserted although you think you contact them well. From the example of that German site, only 0.1 ohm will reduce the current from about 2.5 A (my measure) to 1.6A. You could measure the voltage between battery and charger's negative side and do the same on positive side by a digital voltmeter. You may get about 0.2 volt or more there.

As for the correct reading on other chargers you mentioned, I think those charger can regulate the voltage to keep the current unchanged, just a presumption. Another reason is the PSU. I think those charger use 12V DC or 120V AC, 0.1 or 0.2 ohm in the charging loop does not bring big interference on charging current but 3V PSU does.


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## wptski (Feb 10, 2006)

tacoal:

Measure the voltage drop across my connections? Good idea! My standard connection is lame at best but there's hardly any other way to make a connection and leave your hands free. The better connection, battery clamped up good and holding short heavier wire to the contacts made no diffeerence in the waveform at all, so I think that the coonection isn't the problem. I will do the voltage drop anyway.

Not sure about the power supplies used on the other chargers and I'm away from home now and can't check them. I do have one of those 3.3V supplies mentioned in other threads but never tried it. You mentioned that it may generate more heat as others have too.


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## wptski (Feb 10, 2006)

tacoal:

Checked the voltage drop across the negative wire, 0V but I did get maybe .02V across the magnet connection at the positive end. So, I tried the clamped cell with short heavier wire again and sure enough I must have goofed somehow the first time as I got the this screen below at 200ma charge rate. Whew! Glad to get this figured out!  Thanks for the pointers! :rock:


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## tacoal (Feb 11, 2006)

wptski said:


> tacoal:
> 
> Checked the voltage drop across the negative wire, 0V but I did get maybe .02V across the magnet connectionat the positive end. So, I tried the clamped cell with short heavier wire again and sure enough I must have goofed the first time as I got the this screen below at 200ma charge rate. Whew! Glad to get this figured out!  Thanks for the pointers! :rock:


Yeah, you got it!:twothumbs


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## Handlobraesing (Feb 25, 2006)

I just bought one from Thomas Distributing and mine's a "33" version.

Problems so far:
1. Poorly built. The #3 button on mine was busted upon arrival. It looks to be punched in. The toothpick sized rod that pushes the button was broken. 

2. Running a "test" cycle in +1000mAh/-500mAh, it reported many of my 600mAh AAA cells as having ~1100mAh ish. Something is not right.

3. During discharge cycle, the voltage readout is is 100mV lower than actual cell voltage. 100mV is quite significant when NiMH exhibits ~1.25v during regular use and shows you're nearing the end of useful capacity when you see 1.15v. 

4. LCD has a painfully lousy contrast and flickers.


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## wptski (Feb 25, 2006)

Handlobraesing said:


> I just bought one from Thomas Distributing and mine's a "33" version.
> 
> Problems so far:
> 1. Poorly built. The #3 button on mine was busted upon arrival. It looks to be punched in. The toothpick sized rod that pushes the button was broken.
> ...


Hmm, my replacement BC-900 has a broken #3Slot button too but I don't seem to have the other problems that you mention! Send it back.


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## Tremendo (Feb 25, 2006)

I got a new one last week from Thomas distributing and it has worked absolutely fine, version 33. Buttons are OK, not super high quality, but after reading posts here, just as I expected. You just learn how to push them better, everything works correctly. I have refreshed about 12 batteries or so (still working on 1 now), it found a dead cell I had paired with a good one. I've been doing the refresh at 1000mAh charge, 500 mAh discharge. It has brought back some AA's from about 800-1200 mAh upto 2,400+mAh.

I'm very happy with the purchase.


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## kiwi (Apr 25, 2006)

I bought a BC-900 a month ago on Amazon. Version 32 firmware!

I contacted La Crosse via e-mail asking if v32 was endorsed by them and safe to use. No answer....

I followed up a week later to their tech support line. Female operator claimed to have no knowledge about the the issue and went away to ask their 'expert'. Funny I wasn't connected directly to him, eh? She came back and said that "_they were aware of the mis-information being put out on internet forums_", however, the expert assured me that there were no differences between the v32 and v33. "_They are identical_". Sounds fishy based on observations on this thread. 

Since previous posts indicate that version 33 appears to be a safety-related fix, should I send it back or is it safe to use? Sigman - How did you get on sending your v32 back (posts #102 and #106)? Did they send you a v33?

I guess a seperate issue from safety is longevity. Not much use if it fails just outside of warranty, notwitstanding safety measures such as charging in a non-flammable container.


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## SilverFox (Apr 25, 2006)

Hello Kiwi,

Welcome to CPF.

The "official" word from La Crosse is that the BC-900 was designed and is made in China. The technical people in China have not been able to get the charger to malfunction, so they do not see any problem at all. 

I was also told that there are several thousand units in Europe, and there has not been a single failure reported to them from Europe. 

At any rate, it seems that we are having all of the problems and our numbers are so small that it is statistically insignificant...

Tom


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## Sigman (Apr 25, 2006)

kiwi said:


> Sigman - How did you get on sending your v32 back (posts #102 and #106)? Did they send you a v33?


After calling them and receiving a return authorization number - sent the charger (only) back to them and they sent me a new charger (only) with version 33 indicating in the window when plugged in.

BTW, I've not used it at all...still using my CCrane charger as primary.


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## rycen (Apr 25, 2006)

How do you tell what version you have?


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## Sigman (Apr 26, 2006)

Plug it in and see what's in the window upon startup...


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## coppertrail (May 21, 2006)

I believe I have Ver. 33. When I power on the unit, I see "12 11 33" briefly on the display. 

I've charged my PowerEx 2500s at different rates; haven't had a problem yet.


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## Flash007 (Jun 16, 2006)

I've received my Lacrosse BC-900 (v32) today.

I have putted 4 used Ansmann 2300 mAh to refresh mode (700/350 mA).
Hope the charger will not melt. I work during this night, and I'll not be at home to supervise the charge process.

I have 2 years warranty on the product.


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## Christoph (Jun 16, 2006)

It's not a good idea to charge while you are away. imho
is there a warranty on your house?

Chris


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## viorel00 (Dec 18, 2006)

Hi, my LaCrosse charger just melted;

http://www.flickr.com/photos/[email protected]/

for details and discussion you can also visit these forums:

http://forums.macresource.com/read/1/215639
http://forums.dpreview.com/forums/readflat.asp?forum=1036&thread=21320289


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## BentHeadTX (Dec 18, 2006)

How old is your charger and what version is it? (The "new" one, V33 or V32?) My V32 charger is around 1.5 years old and sits on a metal plate at work. I am getting a Maha C9000 analyzer for home use next month. Although the LaCrosse has not given me any problems, it is always suspect hence the metal plate it sits on.


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## SilverFox (Dec 18, 2006)

*Re: LaCrosse BC 900 just melted*

Hello Viore,

Welcome to CPF.

Sorry to hear about your melt down.

Keep us informed of what you discover and how La Crosse handles this. They have repeatedly insisted that there is no problem with this charger. I believe they refereed to the number of chargers that have had problems as "statically insignificant..." Whatever that means.

Tom

Tom


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## viorel00 (Dec 18, 2006)

V32 it was. Purchased in May or June 2006 from Amazon.


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## BrianI (Dec 18, 2006)

I have the "Technoline IC8800" branded version of the La Crosse BC-900, which shows 33 in the 4th lcd screen. Bought in the UK July this year.

Reading the threads about the overheating / melting problems I am slightly wary of using this charger! :thumbsdow 

So far I havent read any reports of the V33 chargers suffering meltdown, but for peace of mind I'd rather not use mine anymore!

Things should be design to fail safe, not fail and burn!

-- 
Brian


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## richiem (Dec 18, 2006)

I think maybe the CPU can have sensor or state errors that cause the problems described. I had a situation with this charger in which I was going to charge two AAs and during the charge I pulled the batts and then reinserted them immediately. They instantly started to get hot and I pulled them both again and then pulled the plug on the charger's supply, which reset everything. A faulty power supply with elevated DC output could definitely cause the overheating problem by overloading the charger system and the cells, but I think it more likely that the current monitoring function went wrong in my case and that the cells were being given all of the current that the system could supply. Have not had a problem since.


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## coontai (Mar 2, 2007)

I just ordered the BC-900 today from amazon with some eneloops. I hope I don't have any problems... I let you guys know


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## tacoal (Mar 2, 2007)

coontai said:


> I just ordered the BC-900 today from amazon with some eneloops. I hope I don't have any problems... I let you guys know


 
be careful for first a few charging cycle. put the charger in a slanting position


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## viorel00 (Mar 2, 2007)

tacoal said:


> be careful for first a few charging cycle. put the charger in a slanting position



mine melted after I had it for 6 months and probably ~100 charging cycles.


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## coontai (Mar 2, 2007)

tacoal said:


> be careful for first a few charging cycle. put the charger in a slanting position


 
Got it. More airflow. I have to ask has the later version (33) had any/ as many meltdown problems?


thanks in advance


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## webfors (Mar 3, 2007)

yes, there have been reports of meltdowns with v33. My bc900 melted down after several months of flawless usage, charging 4 AA's at 500ma.

My suggestions are, use it on a metal surface, like a freezer top. Not on anything precious. My meltdown damaged the finish on my hifi speakers. The heat generated from the meltdown was so great the charger itself melted/bent in a concave shape.


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## coontai (Mar 3, 2007)

thanks


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## zeeexsixare (Mar 4, 2007)

LeDfLaShEr said:


> Just to put in a word for the BC-900 charger- I use mine all the time and have yet to have a problem.
> 
> I've charged my cells at 1 amp and they barely even got warm. I've put them on refresh cycles at 500 mah that lasted several days and nothing got warm.
> 
> ...



Same here - I don't know what is going on with all these problems people are having... Mine has been running continuously for 6 months, 24/7 with no hiccups, malfunctions, overcharges, or anything. Wall wart stays cold, unit stays cold to the touch, and batteries warm up just a slight amount (85 degrees F) during 1A charging.


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## Hallis (Mar 4, 2007)

When i got mine about a year and a hlaf ago i ran my CBP1650's through some conditioning cycles to top them off. I noticed that they did get quite warm. I no longer use it. And i do not plan to. I might do a little testing but not sure. 

Shane


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## tacoal (Mar 5, 2007)

viorel00 said:


> mine melted after I had it for 6 months and probably ~100 charging cycles.


 
I meant the battery. If the battery is not used for a few months, it is better to consider it as "NEW" battery.


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## coontai (Mar 10, 2007)

i got mine today from amazon it is v33. It has gotten warm, but not hot to the touch. It works well, but the controls are very weird to get used to. The battery adaptors it came with are garbage, but I really don't care at all. The performance is nice and it has been charging nonstop. I also got some eneloops and have nothing but love for them...


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## Muse (Mar 11, 2007)

zeeexsixare said:


> Same here - I don't know what is going on with all these problems people are having... Mine has been running continuously for 6 months, 24/7 with no hiccups, malfunctions, overcharges, or anything. Wall wart stays cold, unit stays cold to the touch, and batteries warm up just a slight amount (85 degrees F) during 1A charging.


Having read a lot of posts, I think it's worth considering the possibility that some of these problems are due to defects in some units. One poster said he took his apart and discovered some very shoddy soldering work - bad solder joints, some joints where there should have been none (inadvertent connections made by sloppy soldering!!)  He said he fixed the problems.

I'm probably going to order one, but I will open it up and inspect it! It's not something I normally do, but it seems like a good idea with this thing.


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## hoarybat (Apr 11, 2009)

I guys! I have version v33 and as noted in my link below I had a near meltdown and the only reason it didn't was because I checked on the charger. I have always placed mine on a ceramic plate and am glad I took the precaution. I took mine apart yesterday and can confirm that two of the four folded flat plate contacts didn't quite line up as the other two. Not sure if this made a difference or not. But even before I did like a glutton I placed another set of batts in the charger at 1A and placed an ICE pack with a paper towel between the pack and the batts to prevent moisture penetration. I checked the batts every 30 minutes and they remained very cold throughout the complete charge and charged flawlessly. ONly did this once but that was encouraging since the last few sets were destroyed. Here is the update on the new Lacrosse BC-9009 charger in thread below which as shown isn't new at all! Does anyone know if there is a firmware later than V35? https://www.candlepowerforums.com/threads/224231


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