# Trouble with La Crosse BC-900



## PKT (Dec 5, 2005)

I was charging 4 2500mah Energizers on the low setting
at night the following morning the charger and batteries
were cooking. The batts were leaking, labels peeling,
the charger was warping from heat the middel of the
lcd screen had turned black.
I had used this charger for....maybe a year with no
problem and considered it my high end charger.
Now I'm unsure of what to replace it with.
Anyone else have any troubles with this unit?


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## Flash_Gordon (Dec 5, 2005)

The first thing I would do is put the whole mess in a ziplock bag and send it to LaCrosse. They should replace your charger and cells.

I was one of the early people on this forum to to own and praise this charger. The capabilities are excellent-if it worked reliably. I too am about to scrap it.

Yesterday, I put 4 new Sanyo 2500's on and ran them through the test cycle. It took about 7½ hours at 700 mA charge current and the resultant readings were as expected. Today I put four more new cells on and just checked it. Over 12 hours have passed and the readings look like end results but it has not finished. When I looked at the elapsed time it reads 3½ hours. Now I am going to pull these apparently fully charged cells off.

I have had it with this thing. Too flaky and quite possibly dangerous. Resets for no reason and constant charging cannot be good for your cells or maybe your house.

Like you, I don't know what to get as a replacement. I have already bought and returned the new Maha 801D. Primary charge current at 2000 mA is too high, IMO and the condition cycle at the lower current takes forever, 24-36 hours.

Looking for a solid recommendation. I just charge AA's and I do not want or need some expensive charger that needs an external power source.

Mark


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## lamperich (Dec 5, 2005)

PKT said:


> The batts were leaking, labels peeling,
> the charger was warping from heat the middel of the
> lcd screen had turned black



Can you post a photo, i can not believe that....






The BC900 has a temperature sensor, am i right?


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## Flash_Gordon (Dec 5, 2005)

Yes, it has a circuit board mounted temp sensor. However, there have been numerous reports in this forum of melted and sunken buttons. If the unit itself is melting I have to question the safety factor provided the sensor.

Even if you have a bad cell short out, run away, whatever, it is supposed to have protection for this too.


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## juancho (Dec 5, 2005)

I have two of the La Crosse 900's and they haven't failed me yet, but after that experience I will keep a tight look out for trouble.


My others chargers are two Maha 777 plus II, which I use with 9 batteries holders.
I also have two vanson 6988 for slow charging (250 mah) and two quick one hour chargers from RayOVac which overheat the cells too much.

I will recommend NO MATTER WHICH CHARGER YOU USE to have a small fan blowing gentle air.

It will be smart (I will have to look for a couple) to do the charging on top of ceramic tyles. (just as a precaution)






regards
Juan C.


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## SilverFox (Dec 5, 2005)

Hello PKT and Mark,

It is interesting that a lot of problems with a variety of chargers have occurred while charging new cells.

The reason for this is that it is difficult to detect the end of charge signal. New cells often are the most difficult to charge properly.

My La Crosse charger has performed quite well, however I do take some precautions...

The first charge on a new cell should be done at a 0.1C rate for 14 hours. This means that if you have a 2000 mAh cell, you should set the charger for 200 mA, and pull the cells at the end of 14 hours. Don't wait for the charger to shut off, just pull the cells at the end of the charge time.

Depending on the cells, you may have to do this more than once...

Once your cells are "broken in," keep in mind that the end of charge signal is quite small (usually in the 3-5 mV range). It is recommended that to get a strong end of charge signal you should charge at a minimum of 0.5C. This means charging at 1000 mA for your 2000 mAh cells.

I am of the opinion that if you want to utilize the La Crosse's (or any other chargers) refresh function, you should first do a timed 0.1C charge. Then you can do some cycling to work the cells and get the capacity up.

I must also add that there are always units that malfunction. As Juan has pointed out, it is best to charge on a fire proof surface and to keep an eye on the charging process.

This is just some food for thought...

Tom


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## minimig (Dec 5, 2005)

SilverFox said:


> Hello PKT and Mark,
> 
> ...
> The first charge on a new cell should be done at a 0.1C rate for 14 hours. This means that if you have a 2000 mAh cell, you should set the charger for 200 mA, and pull the cells at the end of 14 hours. Don't wait for the charger to shut off, just pull the cells at the end of the charge time.
> ...



I have a dumb/timer Uniross Sprint Photo that I was about to give away, now I will keep it to "first charge" new batteries.

This forum is a mother-lode of information, thanks for that food for thought.


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## Flash_Gordon (Dec 5, 2005)

Hi Tom-

I appreciate the information. I have been charging my Sanyo 2500's at 700 mA. I have now completed the second test cycle on both sets and the results have improved. I see capacities where I expect them to be.

Next time I will step up the charge current to 1000 mA. I was just trying to walk that line between too slow and too hot. At 700 mA I would call them just warm to the touch so 1000 should be fine. That will also speed up the cycle time to a more reasonable length.

I had no idea that the end of charge signal was related to charge current. That would possibly explain the behavior I was seeing. I just got concerned when these cells were charging at 700 mA much much longer than should have been required.

The LaCrosse is a pretty sophisticated and capable charger. It would be nice if they would provide better information in the manual. Most people that buy this charger with these advanced functions could understand your recommended procedures and follow them.

I do think it is a very good idea to put your charging setup on a fireproof surface and babysit it at least a little. I'll be doing this from now on.

Mark


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## Lightmeup (Dec 6, 2005)

When I read these threads about many "high-end", or at least fairly expensive chargers malfunctioning, it really makes me wonder. How do all the typical electronically unsophisticated consumers that buy NiMH battery/charger packages at Walmart or RatShack for under $20 avoid burning their houses down or ruining all of their equipment?


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## blr2005 (Dec 6, 2005)

Despite its complexity, the BC900 is not quite so smart when it comes to a propper charge termination. Apparently it uses a simple -dV algorhytm with quite large voltage drop and an absolute temperature as a backup. The result is overcharging, even at low currents. At 700 mA charging current it heats my cells up more than my Lenmar pro66 does at 2A charge current! The reason is that the Lenmar has dT/dt termination (temperature gradient rather than absolute temperature). Once the cell temperature rise reaches 1 degree per minute the charger switches to trickle mode. This and 0dV (peak voltage detection) are the propper methods for charging NiMH cells. Unfortunately, there are very few chargers on the market that charge properly. If you read the cell manufacturers technical papers you'll see that -dV is not recommended as a primary charge termination method. According to Sanyo it can be used (with 10 mV drop per cell max.) at the expense of 20% reduction of cycle life. I've seen chargers (and suspect the BC900 is also like this) that terminate when a voltage drop of 20-30 mA has been detected. By this time even at lower currents your cells are frying. Using one of this I wouldn't expect more than 100-150 cycles and the capacity will start decreasing even sooner.
What I do is using the BC900 only for cell testing/matching and use a better charger (Lightning pack 4000N, Lenmar Pro66, Lenmar Mach1 gamma) for day to day charging.


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## SilverFox (Dec 6, 2005)

Hello Blr,

Welcome to CPF.

I believe you may be misunderstanding the Sanyo information.

The - delta V termination is utilized by most of the high end chargers because it gets more capacity into the cells under a wider variety of ambient temperature conditions. Temperature is used as a back up in the event the - delta V signal is missed, as you have indicated.

The ICE and Triton chargers can terminate on maximum temperature, but I am not aware of any charger that is utilizing dT/dt for termination.

Sanyo indicates that they are rating their cells by first charging them utilizing a -deltaV=10mV for their charge termination. Here is the discharge information on their HR-3U 2500 mAh cells. Since I expect a battery manufacturer to list their cells performance under the best possible conditions, I would conclude that using a - delta V = 10 mV termination is not detrimental to the normal cycle life of the cell.

I believe the confusion comes from this document. In chapter 3 I believe they are saying that while you can use a NiCd charger to charge the Sanyo cells, it will reduce the cycle life by 20%. (NiCd chargers typically utilize a 20-30 mV delta V value.) To keep from damaging the battery, you should utilize a - delta V of 10 mV or less.

It is also interesting to note that Sanyo suggests that in order to get a proper end of charge termination you need to charge at a rate between 0.5C and 1C.

This means that when you compare charging at 700 mA vs charging at 2000 mA, charging at a lower rate should end up with hotter cells and may possibly do damage to them in terms of cycle life.

I would also like to know where you got the idea that the Lenmar Pro66 uses temperature as a end of charge signal... I was unable to find a spec sheet on that charger, so I called them. They told me they use -delta V termination on that charger...

Tom


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## lrp (Dec 6, 2005)

Thanks guys....I'm learning so much here!!!


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## lamperich (Dec 6, 2005)

SilverFox said:


> I believe you may be misunderstanding the Sanyo information.
> 
> The - delta V termination is utilized by most of the high end chargers because it gets more capacity into the cells under a wider variety of ambient temperature conditions. Temperature is used as a back up in the event the - delta V signal is missed, as you have indicated.



100% agree

also worth to read.
http://panasonic.com/industrial/battery/oem/images/pdf/Panasonic_NiMH_ChargeMethods.pdf


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## lamperich (Dec 6, 2005)

lrp said:


> Thanks guys....I'm learning so much here!!!



YEAR - Internet can be a powerfull knowledge-source...


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## Flash_Gordon (Dec 6, 2005)

This thread started with PKT's very negative experience and some of my issues with a particular charger.

On the positive side, much good information has been posted as well as links to some excellent reference material.

I expect my battery/charger results to improve. I only wish the manufacturers would provide at least some of this information with their products. If you tell me how to use your gear in the best, most efficient way it's better for both of us. If I can't or won't follow guidelines and instructions, then it is my fault.

Mark


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## N162E (Dec 6, 2005)

Flash_Gordon said:


> there have been numerous reports in this forum of melted and sunken buttons. If the unit itself is melting I have to question the safety factor provided the sensor.


HUH!!...........What?..........Please point me to ONE reliable mention of buttons melting into the charger. You say there are "Nunerous Reports" one should not be hard to find.


Flash_Gordon said:


> On the positive side, much good information has been posted as well as links to some excellent reference material.


Please define what you call "Good" information. The manual that comes with this charger tells you all you need to know, if you read it.

I have 2 of the real early 900s and both of them sense end of charge without any problems at all charge rates. I might also point out I have not tampered with them and use the stock "Wall Wart"


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## blr2005 (Dec 6, 2005)

Thanks SilverFox for posting a link to the Sanyo technical paper, this was the one I was refereing to. Exactly in Chapter 3, as you pointed out, the Sanyo engineers list several methods for charging their NiMH cells and state that the following ones are suitable: 1) 0dV (also known as peak voltage detection or PVD); 2) dT/dt (temperature gradient) and 3) delta T (temperature difference i.e. cell-ambient). It is stated that although -dV can be used it shortens cycle life by 20%. If used, however the dV value should be kept BELOW 10 mV/cell. Clearly -dV is not the first choice. If you look at the graphs you'll se that 100% SOC is reached at the plateau of the overvoltage curve and NOT after the inflection, i.e. when the voltage drop occurrs the cell is already overcharged.

The "idea" about Lenmar Pro66 comes from the manual, which can be found at http://www.lenmar.com/manuals.asp

Besides it is not difficult to see that the Lenmar charger uses some better termination control. At the end of the fast charge(2A current) the cells measure 42-43 degrees C. Run the BC900 at 1.8A and you'll end up with cells 10-15 degrees C hotter than that. Same with, say Vanson V6000, which charges NiMH cells at 2A. Both use -dV at high currents and overcharge badly. You'll be lucky to get 100 cycles out of your cells treating them like this. Sanyo NC-MQR02 charges 2 cells at about 1.2 A with PVD and end of charge temperature again in the range 40-42C. Now compare this to Maha 401FS in fast mode (and they call this cool charger LOL!!!). 

I have tested about 30 chargers, and believe me, the ones using -dV run much hotter, many unhealthy hot and some dangerously hot. It is possible to design a kinder -dV charger with 2-5 mV/cell but this means better sensing electronics=higher cost. On the other hand most users don't mind getting reduced cycle life.


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## glire (Dec 6, 2005)

The only times I had problems with the BC900 is when I used the "recommended" Cisco 3.3V power supply: BC900 runs too hot. And, yes, I got the two middle buttons melted. N162E, I can report that 

Now, I'm using back the stock power supply. So far not any more problems.
Learned lesson: don't mod something working great only because others have troubles...


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## Mike abcd (Dec 6, 2005)

blr2005, have you used the Lenmar Pro66 with 2500 mAH cells. The 71 minute max time cutoff in the manual looks low based on the 2A charge rate assuming you have to put in about 10% more than the cells capacity for a full charge. Do you need to leave the cells trickle charging to reach full capacity? The Pro66 trickle charge current is a little high for my tastes to leave cells in overnight.

Thanks for posting this info. I've actually found the BC-900 to be pretty good at charge cutoff assuming a reasonably high charge rate but I've been aware the NiMH manufacturers didn't advise- dV cutoff. I just wasn't aware of any chargers that used dT/dt until now. I'm curious how they manage to get the temp probe in good conatct with the cell for both AA and AAA sizes but your statements that it works is enough for me. I'm going to try to track one down even though I've hated Lenmar based on my experience with their NiMH cells.

Mike


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## PKT (Dec 6, 2005)

*Re: Trouble with BC-900*

Thanks Flash
Lots of good info, alot of it's over my head though.
Thomas Distributing has a new charger-MAHA MH-C808M.
Expensive but sounds like it may fit a few of the parameters
mentioned here.
More info at Maha's site. Take a look tell me what you think.
Thanks for all the feedback.


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## SilverFox (Dec 6, 2005)

Hello Blr,

Thank you for the link to the Lenmar Pro66.

The manual states under specifications that the charge termination is -dV = 10 mV, followed by DT, Max V, Max T, and Max time. I believe it is significant (after discussing their chargers with them) that they list -dV first... but it is nice that they have several back up methods of charge termination, including DT. I will have to do some more research on this charger.

In defense of the BC-900, I usually charge at 1000 mA and the cells come off at around 42-44C.

Sanyo recommends terminating the charge if the battery temperature during charging exceeds 60C. I have noticed that some chargers run a bit hotter than others, but most of them stay below 60C.

Did you find any chargers that were running at or above 60C?

The issue of cycle life is complex. I have 2400 mAh cells that I have roughly been keeping track of cycles on. I now have about 150 cycles on them, all being charged on -dV chargers. 50 of the cycles have been on the Energizer 15 minute charger. They are not showing any signs of problems, and have shown a slight increase in capacity. I figure they should be broken in by the time I get another 100 cycles on them...

The idea of using DT for charge termination is interesting. Can you point me to any chargers that list that as the primary method of termination? I am wondering, if it really is an issue, why it is so difficult to find a charger that lists it as the primary charge termination. Perhaps Sanyo will get into the charger market and show us how well it works.

Tom


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## blr2005 (Dec 6, 2005)

Mike abcd said:


> blr2005, have you used the Lenmar Pro66 with 2500 mAH cells. The 71 minute max time cutoff in the manual looks low based on the 2A charge rate assuming you have to put in about 10% more than the cells capacity for a full charge. Do you need to leave the cells trickle charging to reach full capacity? The Pro66 trickle charge current is a little high for my tastes to leave cells in overnight.
> 
> Thanks for posting this info. I've actually found the BC-900 to be pretty good at charge cutoff assuming a reasonably high charge rate but I've been aware the NiMH manufacturers didn't advise- dV cutoff. I just wasn't aware of any chargers that used dT/dt until now. I'm curious how they manage to get the temp probe in good conatct with the cell for both AA and AAA sizes but your statements that it works is enough for me. I'm going to try to track one down even though I've hated Lenmar based on my experience with their NiMH cells.
> 
> Mike


 
The Pro66 timer is apparently set to ensure full charging of 2300 mAh cells which is currently the highest under the Lenmar brand. I very seldom run my 2500 mAh cells down flat so 71 minutes is enough but I agree that in general it may not be and leaving it on trickle will do the trick. 
Close inspection showed that the termocouples are attached directly to the springs contacting the cells anode. 
I agree on the Lenmar cells. Their chargers may be good but the cells are nothing more than cheap chinease-made ones. If you can get the charger only IMO it will be a better deal. Another good one from them is Mach1 gamma chrger. It borrows some tricks from LiIon charging i.e. it reduces current at the end of the charge. 

SilverFox,
Chargers with multiple charge terminations utilize whatever comes first to terminate quick charge. My measurements show that almost always dT/dt will kick in first. Concerning cell skin temperature it is difficult to measure accurately. The best I found is a carefully callibrated IR termometer. Thermocouples usually give me 3-4 degrees lower reading due to less than ideal contact. I'm still to see a charger using delta T, but Sanyo makes several chargers using PVD. Also, the cell temperature depends on its ability to absorb overcharge. Not all cells are created equal in this respect. It depends on the ratio between the Ni and MH active material packed into the cell. Very generally older lower capacity cells are better. Manufacturers recognize this and try to solve it by incorporate some recombination catalists into the cell walls. These aid the recombination of hydrogen and oxygen and lower internal pressure


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## eluminator (Dec 6, 2005)

Temperature is apparently not the only way to do it. My CCrane/Saitek chargers don't use temperature and they work fine for me. They use a combination of dv/dt, dv squared/dt squared, and a reduced current near the end of the fast charge. They seem to be smarter than the average charger cuz they're fully automatic. I can put anything in there from one AAA cell to four D cells. They analyze the situation, figure out what they're up against, and then go to work.

For whatever reason though, they can't get the full charge in the modern 2500 mah AA cells. Could it be the manufacturers are cheating a bit? Some of my old "no name" and "Kinetic" brands still deliver 100% of the rating on the label, but the AA Duracells and Energizers I bought in a brick-and-mortar last week are around 90-93%.


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## blr2005 (Dec 6, 2005)

eluminator said:


> Temperature is apparently not the only way to do it. My CCrane doesn't use temperature and it works fine for me. It uses a combination of dv/dt, dv squared/dt squared, and a reduced current near the end of the fast charge. It seems to be smarter than the average charger cuz it's fully automatic. I can put anything in there from one AAA cell to four D cells. It analyzes the situation, figures out what it is up against, and then goes to work.
> 
> For whatever reason though, it can't get the full charge in the modern 2500 mah AA cells. Could it be the manufacturers are cheating a bit? Some of my old "no name" and "Kinetic" brands still deliver 100% of the rating on the label, but the AA Duracells and Energizers I bought in a brick-and-mortar last week are around 90-92%.


 
d2V/dt2 is the second derivative of voltage in respect to time. When this changes sign it means that the voltage start to increase in a slower rate. Not exactly PVD but close, it is quite safe and even can undercharge slightly, but the cCrane charger uses a top-off charge to get the cells to good capaciy. It is a good charger, it uses 4 stage charging and a negative pulse during the fast charge stage.


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## SilverFox (Dec 7, 2005)

Hello Blr,

I spent some time researching what the battery manufacturers recommend for charge termination. Sanyo is not alone in recommending temperature as the most favorable method. I might even go so far as to say that there is a general consensus in that regard.

However, I was still puzzled why Sanyo would put -dV way down on the list, yet utilize that method for their discharge capacity curves...

It seems that during the charging process, temperature starts to rise before the voltage flattens out and starts to drop. As you have observed, the charge will terminate sooner if the charger utilizes temperature as an indicator, or if the -dV value is set a bit high. (I noticed that the Pro66 utilizes 10 mV as its termination value. I am used to seeing 3-5 mV for the -dV value, so that might explain why you are noticing the charge being terminated on temperature instead of voltage.)

I found a Cadex article that finally put everything into perspective. It said that while charging to full charge results in more cycles, a slight overcharge may result in around a 6% increase in capacity from the cell. That means that if your light runs for 60 minutes, you could get an additional 4 minutes, or so, from slightly overcharging your cells.

So, if you impatiently hover over the charger waiting for the light to turn green and immediately grab the cells and expect them to perform at full capacity or better, it may be better to utilize a charger that uses -dV termination (in the 3-5 mV range).

On the other hand, if you are a little more laid back and are interested in treating your cells a bit better, the change in temperature termination would be better. I believe you can get to full charge by simply letting the cells trickle charge for a while after the main charge has completed.

Tom


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## blr2005 (Dec 7, 2005)

I found a Cadex article that finally put everything into perspective. It said that while charging to full charge results in more cycles, a slight overcharge may result in around a 6% increase in capacity from the cell. That means that if your light runs for 60 minutes, you could get an additional 4 minutes, or so, from slightly overcharging your cells.

Tom[/QUOTE]
Hi Tom.

That was my guess as well, i.e. why Sanyo charged their cells with -dV for the capacity tests. That way they could get some more discharge capacity.

From what I have tested it looks like dT/dt of 1 degree Celsius per minute coresponds roughly to the voltage peak, i.e. PVD or dT/dt would give roughly the same charge completeness and end of charge temerature. Talking about the end of charge temperature one should also take into account the construction of the charger. Some chagers heat up significantly, and if the cells seat up close to each other the heat cannot be dissipated efficiently. This contributes quite significantly to the heating of the cells. Unfortunately the LC-BC900 is one of them. Were the cells seating a few millimeters apart their end of charge temperature would have been lower.

PS: Just charged 4 cells in the BC900 at 1A. The end temperature was 52C


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## SilverFox (Dec 7, 2005)

Hello Blr,

Yes, it sure helps if there is some distance between the cells. When you cram them right together, there is little chance for any air flow.

I also just finished the charge side on some cells in the BC-900. At a 1 A charge rate with 4 cells, I am only seeing 45C. I wonder why the big difference...

At 52C you should be very close to tripping the overheat cut out.

Tom


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## aosty (Dec 7, 2005)

SilverFox said:


> Yes, it sure helps if there is some distance between the cells. When you cram them right together, there is little chance for any air flow.



I'm not crazy about running a fan (noise) - how about laying a CPU heatsink on top of the cells to dissipate some of the heat?


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## blr2005 (Dec 7, 2005)

SilverFox said:


> Hello Blr,
> 
> Yes, it sure helps if there is some distance between the cells. When you cram them right together, there is little chance for any air flow.
> 
> ...


 
It might be the cells we are using. This was done with Lenmar 2300 mAh cells I got with the pro66 or the way we measure cell skin temperature. I use an IR termometer. i figured it gives higher readings than using termocouples probably due to the fact that termocouples os difficult to attach so they make firm contact with the cell. What are you using? Next I'll try it with Sanyo indutrial 2500 mAh cells. I guess these will run a bit cooler


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## SilverFox (Dec 7, 2005)

Hello Blr,

I will be interesting to see how the Sanyo cells do...

I use a thermocouple that has been calibrated to read properly off the skin of the battery. I use a rubber band to hold it in place and I centered the calibration at 60C because that is my upper limit for battery testing.

Tom


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## lamperich (Dec 7, 2005)

@ blr and silverFox

45 vs 52 C


can you also post the ambiente temperature?


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## SilverFox (Dec 7, 2005)

Hello Lampe,

It's 20C at my place.

Tom


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## VidPro (Dec 7, 2005)

to add
dont forget that a power outage, could change normal operation completly.
dump the power, then turn it back on, and it goes back to 200ma.
add in if it didnt think they were full and starts charging again when the batts are already at 1.45, and at the low charge rate, it will not see the cutoff Again.

looking at the voltages everyonce in a while can give you clues as to how it is working.


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## blr2005 (Dec 7, 2005)

lamperich said:


> @ blr and silverFox
> 
> 45 vs 52 C
> 
> ...


 
Same here 20C. To be exact 19.8 if it makes any difference.


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## blr2005 (Dec 7, 2005)

Sanyo 2500 mAh industrial just finished charging at 1 A on the BC900. The two inner cells measure 50C. The outer ones measure 47 and 48C. Previous test was done only on the inner cells (stupid me) but it could be said perhaps that the Sanyo runs a bit cooler. Still it is hotter than what Lenmar pro66 does at 2A charging current and way more than Lenmar Mach1 gamma (variable current max 2A) and Lightning Pack 4000N (1.6 A). What remains to be established is completness of charge. I know that Lenmar Mach1 puts about 10% less charge than a typical -dV charger. If left to trickle for 4-5 hours the results get close (I could dig the discharge graphs PM if interested). From your tests SilverFox it looks like the BC900 also charges completely. Now I have to test the pro66.


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## SilverFox (Dec 7, 2005)

I will add that my temperature measurements are on inner cells as well. I was going for maximum temperature and figured the outer cells would be cooler.

Tom


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## glire (Dec 8, 2005)

This thread has become very interesting.

Tom and SilverFox, I wonder what conclusions we may get from your discussion.
-Most charger manufacturers use -dV for detecting end of charge while most NiMh manufacturers recommend dT/dt;
-thus -dV is easier to implement, and, if cells don't get too high in temp, that should be safe enough;
-excess temperature would hurt cells, excess charge shouldn't (so leaving cells permanently under trickle charge or using a cheap slow charger with no end detection shouldn't hurt them, right?)

I use my BC900 mostly at 350/700mA discharge/charge with AA and 100/200mA with AAA. Given my experience, new cells are running quite hot during their first charges, then they keep warm after few cycles.

I'm very happy with the BC900 because it has a very informative and quite accurate LCD screen. It's affordable. And ice on cake, it charges my NiMh's and let me use them 
Just waiting now for another manufacturer which would propose a safer charger without removing any of the LaCrosse features... for a similar price.

I opened once the BC900 when the buttons melted. I was thinking to move the electronics on an old NiCd charger which has more space between cells (and can hold C and D cells also). The problem was moving the LCD: there are no cables or ribbons to connect it to the PCB!


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## blr2005 (Dec 8, 2005)

glire said:


> This thread has become very interesting.
> 
> -excess temperature would hurt cells, excess charge shouldn't (so leaving cells permanently under trickle charge or using a cheap slow charger with no end detection shouldn't hurt them, right?)


 
Actually, not. Increase in temperature during end of charge and overcharge is due to gas evolution at the cell electrodes (oxygen and hydrogen) Recombining these gasses produces heat (the reaction is exotermic). Parallel to this the internal pressure increases. If the rate of gas evolution exceeds the recombination rate the pressure increases sharply and the cell vents. 
Overcharging at low currents does not produce such dramatic events but still the cell internals are exposed to higher pressures. If left for a long time the electrode structure deteriorates . Shorter term overcharging (several hours at c/10) induces crystalline formation, often called memory.


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## snoofer (Dec 25, 2005)

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).

Any info on where I need to send this "melted unit"?
I had purchased this through Thomas Distb.

Thanks for the Help.


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## VidPro (Dec 25, 2005)

snoffer, i would think that it PROBABLY missed seeing the Voltage drop, and slowly baked the batteries.
sizzling and poping indicate a battery overcharged, over its overcharge specs, which can occur when the voltage drop is not spotted. 
the voltage drop can be harder to find if the batteries are charged when you put them in, or the charger got a AC power disconnect when they were charged, or if they just arent cycled, and it misses the drop.
i would send the whole thing back to where you bought it, and if they wont do anything, back to lacross.

and it could have burned down the whole house, under specific conditions, when the overcharged battery becomes unsealed and a SHORT, starts somthing on fire, that unit without flamables around it is not likly to start a whole fire, but to melt things.

if you want to prevent that possibility from ever occuring, however rare it might be,
put the things in a metal can, that is insulated to keep the floor or shelf from melting, and not shorting anything because of the metal. keep flamables away from the thing.
basically if your paranoid, make a containment system, that you could start a small fire in, and it would neither build up gas internally in it, nor ketch anything around it on fire.
an open top can, with a insulated base, sitting where nothing above it can ketch.
i use an old cookie can, with the top of it put on the bottom.




i think i finnaly figured out what is with the 3rd battery, those that have one may know about it.
I think it has something to do with where the heat of the unit (charge discharge) is getting out.
because when i put the thing next to a light breeze, which would cool the most external components, AND it was running at its higher capacity, that is when i saw the 3rd battery differential. i switched the 1st for the 3rd, and it was not the battery.
So without dissasembling it, i am assuming that the 3rd discharge resister (or something) is the one that is least or most effected by forced cooling.



i scratched that (removed something incorrect)


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## PKT (Dec 26, 2005)

lamperich said:


> Can you post a photo, i can not believe that....
> 
> 
> 
> ...



Here is a picture...my first


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## nikon (Dec 26, 2005)

PKT said:


> I was charging 4 2500mah Energizers on the low setting
> at night the following morning the charger and batteries
> were cooking.....


 

I had the same thing happen yesterday and it looks as though I caught it just short of disaster. I had it on a discharge/charge cycle with three of the same batteries on the lowest setting. The batteries had been charged a few times before. I'd checked it when it was about halfway through charging and it was OK. Then I checked it about two hours later. The charger was very hot and pressing the buttons didn't change the display. The batteries were too hot to touch. I'm using it again today and it's operating normally, but I'm keeping an eye on it.


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## PKT (Dec 27, 2005)

snoofer said:


> 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.
> 
> ...



We may be able to send these back to a USA service
center that I think was on the micro instruction book
that I can't seem to find...


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## wptski (Dec 27, 2005)

I still have all my paperwork that came with mine.

La Crosse Technology
116 South Oak Street
La Crescent, MN 55947-9912

[email protected]

507-895-7095 M-F, 8:30am-5:00pm (CST)

Slightly different address in the manual!

La Crosse Technology, Ltd.
190 Main Street
La Crescent, MN 55947

www.lacrossetechnology.com


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## snoofer (Dec 27, 2005)

WPTSKI,

I'll contact them this morning...........Thanks!


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## SilverFox (Dec 27, 2005)

Hello Snoofer,

They also have a toll free number... 888-211-1923.

Tom


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## lamperich (Dec 29, 2005)

https://www.candlepowerforums.com/threads/102533

a curios thing about 3 malfunctions is it always happens in combination with 
energizer 2,5Ah rechargables.

@ snoofer
also energizer 2,5Ah????


thx @ PKT

Some already speculate that the charging current maybe was to low to determ a dU
you need somthing like ~0,2C
But that´s NOT MY knowledge. i only post that suggestion here.


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## wptski (Dec 29, 2005)

I wonder if that was always on the first charge with the 2500mAh Energizer's too?


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## snoofer (Dec 29, 2005)

wptski said:


> I wonder if that was always on the first charge with the 2500mAh Energizer's too?




It was my 2nd charge on the "Digital" brand from Wallmart.

It was set to charge at 200mA


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## wptski (Dec 29, 2005)

snoofer said:


> It was my 2nd charge on the "Digital" brand from Wallmart.
> 
> It was set to charge at 200mA


snoofer:

Some have claimed that the BC-900 doesn't terminate or stop when low current is selected, worse yet on a new cells.


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## Mike abcd (Dec 29, 2005)

Seems like all the failures have been with ~2500 mAH cells charged at 200 mA. Has anybody had a similar failure when charging at a higher rate?

A number of the NiMH tech documents I 've read point out the the magnitude of the -delta V si smaller at lower charge rates and it appears to be the reason a 1C rate is advised. It looks like these failures are the result of the smaller end of charge delta V coupled with the sensitivity of the BC-900 in detecting it.

I've settled on charging 2500 mAH Energizers at 700 mA. They don't get as hot as at 1000 mA and the charging terminates reliably with about 2700 mAH total charge when charging fully discharged cells.

Mike


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## wptski (Dec 29, 2005)

Mike abcd:

I just posted that very question in a RC Forum today! Got any links to the tech ducuments that you read this in?


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## lrp (Dec 29, 2005)

I charged some Sanyo 2500 cells at 200 and had no problems, it took approx. 6 hrs. to charge full.


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## wptski (Dec 29, 2005)

Hmmm, so what's the problem? The Energizer cells or the BC-900?


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## Mike abcd (Dec 29, 2005)

wptski said:


> Mike abcd:
> 
> I just posted that very question in a RC Forum today! Got any links to the tech ducuments that you read this in?



It's a small world. I've been spending time at the forums at rcgroups.com since picking up an E-Flite Blade CX co-axial heli a few weeks back.

Duracell keeps the good stuff hidden a little. Go here and download the full technical bulletin.
http://www.duracell.com/oem/rechargeable/Nickel/nickel_metal_tech.asp

It make take a few tries. I've had trouble downloading it.

In section 6.2.1
"the voltage drop of the nickelmetal
hydride battery is not as prominent as that of
the nickel-cadmium battery and may be absent in
charge currents below the C/3 rate, particularly at
elevated temperatures."

I realize the 700 mA rate I use on the 2500 mAH Energizers is actually under C/3 but at room temps, it seems to work well on the BC-900. I'm not shocked that it's having problems at 200 mA though as it's less than 1/10 C.

BTW, someone here at CPF posted that the Lenmar Mach 1 Gamma and Pro 66 chargers actually use the delta tempature / delta t method that is decribed as optimal in the Duracell docs. That combined with a 1 hour or so in the BC-900 at 200 mA would seem ideal.

Mike


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## planex (Dec 30, 2005)

Well darn it, my BC-900 is starting to act up now. I haven't had any meltdowns thankfully, but when I plug in the adapter the charger powers up, displays 32 in the 4 th slot and then null for all the slots. But a second or two later the charger shuts off. When I unplug the adapter, the display comes back to life for 4-5 seconds and then turns off. I usually need to repeat the process 3 or more times to get the charger to stay turned on. I have also experienced a few random shutdowns while charging 4AA's at 500ma. I e-mailed tech support so hopefully they will replace the unit. 

I really think the bc-900 is a great charger with all its features, but unfortunately it seems to have many quality control issues. I am kind of afraid now after reading other people's posts to leave it unattended.


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## wptski (Dec 30, 2005)

Mike abcd:

Thanks, good link and no problem d/l the file.

EDIT: That's a great file! I find it interesting about voltage depression or the dreaded memory effect in Ni-MH cells. It says that it's better to discharge to below 1.2V to 1.0V to avoid the effect! How much electronics equipment is designed with that in mind?


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## Mike abcd (Dec 30, 2005)

Most stuff seems to take cells well below 1.2 V. If you find something that doesn't just run the discharge cycle on the BC-900 periodically.

It was nice to see some data on the capacity loss caused by frequently topping off cells and see that it's mostly reversible.

Mike


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## Krakpot (Feb 27, 2006)

Add me to the list of burned down BC-900





I was charging four Lenmar NoMEM 2000mAh batteries at 500mAh over the week-end and after a few hours of charging, while having dinner close to the charger, began hearing a sizzle sound. My wife also noticed it so I walked around and found the batteries piping hot with peeling labels. Managed to pop them out with a knife and sure enough, found a melted charger underneat cells 2 & 3.

The charger is version 32, had it for about a year of light use (no more than 2-3 cycles per week), cells had many cycles on them (10+).

I will be contacting La Crosse later this week for a replacement but after this episode, may not have the confidence to use it again...

If anyone has a replacement to suggest, I am looking for a simple but good charger for 4 (or up to 10-12) AA batteries, don't care much about cycle time and can work with overnight charge but also don't need a super fast charger that will cook the cells...


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## Sigman (Feb 27, 2006)

Krakpot said:


> If anyone has a replacement to suggest, I am looking for a simple but good charger for 4 (or up to 10-12) AA batteries, don't care much about cycle time and can work with overnight charge but also don't need a super fast charger that will cook the cells...


Ditto!

Tom - suggestions from our CPF subject matter expert?

LaCrosse needs to acknowledge this - when I spoke to them, they pleaded ingnorance...I sent mine back with a return authorization - haven't received the replacement yet.

I'm not a happy camper!


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## ginaz (Feb 27, 2006)

seems to me that the problems lie with the charge rate of 200ma. i just recently purchased the lacrosse from amazon (ver. 33) and have been pretty much refreshing batteries nonstop since i got it with no problems. i am using the 500/1A rates and i put a heat sink on top but it doesn't really get that hot. evidently some have had problems a year or more down the road so caution rules the day. does sanyo make a charger? i am looking at the tg2800 but i like having a capacity number i can compare.


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## TooManyGizmos (Mar 6, 2006)

:bump:

Any more news on this important subject ? .:huh2:


has the issue been resolved ? . 


.


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## archae86 (Mar 6, 2006)

*v10 expectations?*

I just bought a LaCrosse BC-900 from Amondotech.

On the back side just under Made in China it is marked:

"8N5 V10 U"

Should I assume this is Version 10 to be compared with versions of 33 or higher mentioned by folks posting here? 

Edited after helpful comment below to say mine is actually v*33*, based on the bay 4 number displayed briefly before the lamp test on power up.

The reports of self-destruction in this thread are alarming. For the several cases where the selected charging current was 200 mA, it seems highly unlikely to me the destruction was caused simply by failure to terminate and consequent overheating of the battery spreading its destruction to the charger. For a 1/10C charging rate to contribute massive destruction in less than a day should not happen. Those of us with experience watching the Ray-O-Vac 1 hour charger blister and split our batteries' protective coverings have seen how hot charge rates of well over an Ampere per battery get--hot, but not the sort of destruction reported here, so to get this at 200 mA seems unlikely. It seems more likely that an electronics failure either caused charging rates to go to many times more than selected, or a more local fault not necessarily involving the batteries.

Any comments from those experiencing the problem?

My problem is that I really like the diagnostic capabilities of the charger so far, though for everyday an travel use I'd more likely stick to my TG-2800, which is lighter and generally seems to terminate with the batteries only comfortably warm, not seriously hot. But I'm afraid of destroying batteries or worse. Think I'll find a ceramic tile at the least.


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## Krakpot (Mar 6, 2006)

FYI - on the back of my melted charger it says "BN4 V00U". The version number (32 or 33) shows up for a second on the display when you first plug the unit.

La Crosse gave me an RMA number and will ship a replacement unit once they receive my defective one. Turn around will be 3-4 weeks. Their answer to my inquiry as to WHY the charger melted down ?



> The overheating is caused by a defective temperature sensor


 I have often charged at 200mA and 500mA without problem and the batteries were hardly getting warm at all during a cycle. The charger melted down at 500mA with four 2000mAh batteries on charging cycle and the batteries were so hot I couldn't touch them with my bare fingers.


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## wptski (Mar 6, 2006)

A charge rate of 200ma isn't that high but if it never terminates, it's a problem. Nobody knows what's really happening but most cases were new cells at 200ma. Mine melted using 700/350ma Test mode on the third batch of new 2300mAh Duracells with about six cycles on them and almost a year old to the day. The new version just shuts off earlier for high temperature, depending on the cell size that could be 2-3 times a charge cycle. Seems like a bandaid fix to me! Your adding about twenty minutes to every charge cycle. 

Go by the number shown in Slot#4 LCD when you plug in the cord, V33 is the latest.


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## tacoal (Mar 6, 2006)

For new battery and some high capacity batteries, the internal resistance is high so that the MPU cannot sense the correct charging current when the summation of the voltage on battery and voltage on sampling resistor is high than 2.2 volt, the ADC reference voltage. This is the design defect.

It seems the BC-900 use about -5mV as terminating criteria or 2 digital numbers from max voltage, supposing it uses 10 bit ADC. The problem of not terminating the charging is that the battery does not generate this - delta V, either for new battery or the high temperature of the battery. Another reason might be the change of charging behavior of new high capacity battery. These batteries may use new formula in order to get more capacity. These batteries might not generate - delta V at all. And it seems the BC-900 uses - delta V as the only terminating criteria, not smart enough.

For rechargeable battery, the higher the temperature of battery, the more difficult to generate - delta V. So a fan is very good practice to keep the battery cool and to generate - delta V more easily.


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## Sigman (Mar 6, 2006)

Received my replacement, it's version 33 firmware/software - haven't tried it, may end up selling it. I don't know...right now my primary charger is my CCrane unit. Love it!


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## flashlightguy (Mar 8, 2006)

I just bought a BC-900 (V33) and it seems to work ok, but I found one problem.
If I put a full set of batteries in it, and put it on test, it starts to cook them.
I was reading over 1.5v on these and they were getting pretty toasty.

Is there a cutoff voltage on the cells? 1.5v is pretty high I think for a nimh cell.

Thanks


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## Sigman (Mar 8, 2006)

...just merged flashlightguy's post/thread with this thread.


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## Handlobraesing (Mar 10, 2006)

My BC-900 just did a totally weird thing.

I have four 600mAh AAA's that came with a walkie talkie and these tests out around 500mAh in test mode using 100mA discharge/200mA charge.

Today, I charged them from partially drained to full in 1000mA mode (1.667C). After about an hour, the left two sides reported "full" and were trickle charging at around 50ish mA with cumulative charge of around 550mAh. The right two reported ~650mAh cumulative, 000mA charge current and stayed at that without "full" display.

Something is acting up.


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## bcwang (Mar 10, 2006)

Handlobraesing said:


> My BC-900 just did a totally weird thing.
> 
> I have four 600mAh AAA's that came with a walkie talkie and these tests out around 500mAh in test mode using 100mA discharge/200mA charge.
> 
> ...



That's what happens when the cells overheat and the charger shuts the charging off until things cool down. 1 amp on AAA cells with no forced cooling is probably too high.


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## wptski (Mar 10, 2006)

Is that a v33 model? I always wonder what would happen if the charger happened to stop the cycle too close to the termination? You may have shown what happens. It's almost like inserting fully charge cells. My manual for my Schultze 330d cautions against inserting fully charged cells.


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## flashlightguy (Mar 10, 2006)

wptski said:


> Is that a v33 model? I always wonder what would happen if the charger happened to stop the cycle too close to the termination? You may have shown what happens. It's almost like inserting fully charge cells. My manual for my Schultze 330d cautions against inserting fully charged cells.


 
Yeah it's a V33 that I have. It's starts cooking them if you put in a set of full batteries for testing. It looks likew you have to just discharge them first.


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## wptski (Mar 10, 2006)

I've done that with my old v32 unit but not with the v33. You gotta watch it and see how it reacts, if it does what your expecting or not Sometimes, you can't fool into doing what you want!

I was trying to cycle the set of LaCrosse AAA that came with my v33 unit on my Schultze. They had a few cycles on them but missed the termination point but I caught it at almost 1000mAh and a bit war too.  Got to watch those new cells.


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## Handlobraesing (Mar 10, 2006)

wptski said:


> Is that a v33 model? I always wonder what would happen if the charger happened to stop the cycle too close to the termination? You may have shown what happens. It's almost like inserting fully charge cells. My manual for my Schultze 330d cautions against inserting fully charged cells.



Yeah, mine's a v33.

Another issue with this charger is that the readout voltage during discharge is off by a varying degree depending on current.

At 0.5A discharge, the read out is lower by 0.1v compared to actual cell voltage, which would cause the discharge to cut off at 1.0v even though the display reads 0.9v


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## lasercrazy (Mar 11, 2006)

Wow. After reading this thread I will never buy this charger, what a POS.


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## wptski (Mar 11, 2006)

Handlobraesing said:


> Yeah, mine's a v33.
> 
> Another issue with this charger is that the readout voltage during discharge is off by a varying degree depending on current.
> 
> At 0.5A discharge, the read out is lower by 0.1v compared to actual cell voltage, which would cause the discharge to cut off at 1.0v even though the display reads 0.9v


A Schultze 330d built in discharge program discharges to 1.0V instead of .9V. I haven't check my v33 but the v32 was accurate as far as the .9V cutoff goes.


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## EV_007 (Mar 11, 2006)

When I charge/test 2300 - 2500 mAh batteries, the display shows dashes. Is it due to the fact that the unit cannot display digits over 1999 Even though it can charge up to 3000 mAh batterries? How does one accurately measure mAh capicity over 1999 in this charger?


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## wptski (Mar 11, 2006)

EV_007 said:


> When I charge/test 2300 - 2500 mAh batteries, the display shows dashes. Is it due to the fact that the unit cannot display digits over 1999 Even though it can charge up to 3000 mAh batterries? How does one accurately measure mAh capicity over 1999 in this charger?


Funny, it should show 1999mAh as 1.99Ah, mine does! It shows the capacity in Ah instead of mAh.


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## SilverFox (Mar 11, 2006)

Hello EV,

I believe the dashes mean that the charging cycle has stopped due to excessive heat build up. If you let things cool down for awhile, it should continue and show the capacity at the end of the test cycle.

If you are looking at the capacity during a charge cycle, you need to keep in mind that you always put more in than what you can get out.

Tom


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## wptski (Mar 11, 2006)

SilverFox said:


> Hello EV,
> 
> I believe the dashes mean that the charging cycle has stopped due to excessive heat build up. If you let things cool down for awhile, it should continue and show the capacity at the end of the test cycle.
> 
> ...


Tom:

The BC 900 shows 000ma when it pauses for excessive heat.


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## EV_007 (Mar 11, 2006)

Ahhh, okay. Thanks for your replies guys.


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## SilverFox (Mar 11, 2006)

Hello Bill,

Thanks. I have only run across that situation a couple of times and could not remember what it shows.

Tom


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## wptski (Mar 11, 2006)

SilverFox said:


> Hello Bill,
> 
> Thanks. I have only run across that situation a couple of times and could not remember what it shows.
> 
> Tom


Tom:

If you had a v33 unit which cuts off at a lower temperature, you'd see it frequently!


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## Krakpot (Apr 8, 2006)

> FYI - on the back of my melted charger it says "BN4 V00U". The version number (32 or 33) shows up for a second on the display when you first plug the unit.
> 
> La Crosse gave me an RMA number and will ship a replacement unit once they receive my defective one. Turn around will be 3-4 weeks


Received my replacement charger this week and it is now a V33 with "8N5 V10 U" on the back, it also says 300-3000 mAh AA/AAA accus. They didn't ship replacement batteries so I am out a set of four 2000mAh AA.


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## bcwang (Apr 8, 2006)

Krakpot said:


> Received my replacement charger this week and it is now a V33 with "8N5 V10 U" on the back, it also says 300-3000 mAh AA/AAA accus. They didn't ship replacement batteries so I am out a set of four 2000mAh AA.



Guess you should have just sent the charger


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## koala (Apr 9, 2006)

So this charger is not very friendly with fully charged cells? My Maha-C401FS does it well. My BC-900 is on the way from Amondotech, can't wait to try out all the reported bugs .


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## wptski (Apr 9, 2006)

Krakpot said:


> Received my replacement charger this week and it is now a V33 with "8N5 V10 U" on the back, it also says 300-3000 mAh AA/AAA accus. They didn't ship replacement batteries so I am out a set of four 2000mAh AA.


I just returned the charger and wallwart. They sent a whole new kit, bag, cells, etc.


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## Krakpot (Apr 9, 2006)

> I just returned the charger and wallwart. They sent a whole new kit, bag, cells, etc


 I also returned just the charger & adapter but included pictures of all four damaged AA batteries. I was expecting a new box complete with batteries & accessories but received a new charger & adapter only...


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## wptski (Apr 9, 2006)

Krakpot said:


> I also returned just the charger & adapter but included pictures of all four damaged AA batteries. I was expecting a new box complete with batteries & accessories but received a new charger & adapter only...


Maybe they are getting low on full replacements?


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