BC-900 problems

[viorel00]

My original BC-900 melted in December, and laCrosse replaced it with a new one, V33. The old one seemed quite accurate in respect to battery capacity, I remember that I tested my first set on eneloops with it and I got numbers very closed to each other; as a matter of fact, I still have that set in my dLSR and I keep taking pictures with it. 500 pics later and they're still going strong. But I digress.

Now let's talk about the new charger. I loaded a new set of AA eneloops in it, and on discharge mode I got almost the same numbers on all 4 cells: ~1485 mAh, on cells that were 6 month old. But on charging cycle, one cell registered 2.05 Ah (which I believe) and another one 2.40 Ah (which seems too much to me). The other two cells were in between.

Then I did another discharge cycle and I got almost idnetical capacities, 2000 mAh, but then again on the charging cycle one battery went up to 2.40 Ah. I suspect it is always the same bay, bay no 4. But I need to make some noted form now on to be sure.

I suspect that bay 4 is overcharging by about 20%, could this be possible? I just don't trust the calibration of this charger, and I am still afraid that V33 is gonna melt one day (I have seen two reports so far).

too bad, looks nice and decent size. But I am not impressed with its performance.

 

[SilverFox]

Hello Viore,

:devil: Have you considered the Maha C9000? :devil:

Tom

 

[viorel00]

SilverFox,

First, thanks for the results on eneloops. interesting, and your work is highly appreciated.

I haven't looked seriously in the c9000 yet, since I had the BC-900 and I couldn't justify another expense, and now I also have seen all those reports about c9000 missing termination in some cases, just like my old bc-900 did, except c9000 does not seem to cook the batteries as bad as bc-900.

I am considering buying another eneloop charger (I have the slow 4 bay version, I might bet the 2 bay fast version as well, since it works at 240V) and either dump my bc-900 on eBay, or just keep it for measuring capacities, but I have to watch it and and pull the batteries out once the discharge is done.

 

[wptski]

There's no such thing as a "Eneloop charger"! They are just Ni-MH cells when it comes to charging.

 

[viorel00]

There's no such thing as a "Eneloop charger"! They are just Ni-MH cells when it comes to charging.

yes, they are NIMH cells, no doubt about that. I was talking about the eneloop charges referring to the BRAND of charger, not to the TYPE of charger. Yes, it says ENELOOP on the charger. Saying there is no such thing as a eneloop charger would be like saying there is no such thing as SANYO battery, they're all NIMH.

I guess it is a question of semantics after all.

 

[tacoal]

It is easy to identify who causes the problem. Mark the battery you think overcooked and place it in another bay to charge again. If it is still overcooked, then the battery is the devil. If not, the charger is the devil, specifically, one bay has problem.

The overcooked battery will get hotter than normal one toward the end of charging process.

On the other hand, it is suggested to charge the battery to 110% to 120% of the battery capacity on a timed (dumb) charger. In the break-in mode of famous C9000, the battery will be overcharged to 160% of battery capacity though the charging rate is 0.1C. So I think you worried too much.

 

[viorel00]

tacoal, the test you suggest was already under progress, thanks. I don't think I have a bad battery since these are brand new eneloops

 

[tacoal]

tacoal, the test you suggest was already under progress, thanks. I don't think I have a bad battery since these are brand new eneloops

From the overcooking in C9000 to melting down in BC-900, all are battery related. Specifically, some new high capacity battery for BC-900 and some battery for C9000. I know eneloop has a good quality, maybe 99% (or 99.9%)
is good enough to generate good signal for termination, but the 1% (or 0.1%) is still there to generate marginal signal.

Morever, the new battery is more problematic than those 'experienced'. That's why C9000 has special break-in mode.

 

[Mike abcd]

My original BC-900 melted in December, and laCrosse replaced it with a new one, V33. The old one seemed quite accurate in respect to battery capacity, I remember that I tested my first set on eneloops with it and I got numbers very closed to each other; as a matter of fact, I still have that set in my dLSR and I keep taking pictures with it. 500 pics later and they're still going strong. But I digress.

Now let's talk about the new charger. I loaded a new set of AA eneloops in it, and on discharge mode I got almost the same numbers on all 4 cells: ~1485 mAh, on cells that were 6 month old. But on charging cycle, one cell registered 2.05 Ah (which I believe) and another one 2.40 Ah (which seems too much to me). The other two cells were in between.

Then I did another discharge cycle and I got almost idnetical capacities, 2000 mAh, but then again on the charging cycle one battery went up to 2.40 Ah. I suspect it is always the same bay, bay no 4. But I need to make some noted form now on to be sure.

I suspect that bay 4 is overcharging by about 20%, could this be possible? I just don't trust the calibration of this charger, and I am still afraid that V33 is gonna melt one day (I have seen two reports so far).

too bad, looks nice and decent size. But I am not impressed with its performance.

Slot 4 might not actually be over charging. It might just be an error in the mAH reported. I suspect it measures the voltage drop across a shunt resistor to determine current. If the shunt resistor value is off, it could report the wrong mAH and not be over charging.

I'd expect an overcharge to show up as higher capacity if the cell is tested immediately after the charge cycle.

If I were in your position, I'd contact LaCrosse, explain the problem and request another replacement.

I've done a lot of testing on the C-9000 and would not suggest it as a BC-900 replacement.

Mike

 

[3rdDerivative]

Yuck, My one week old BC-900 display switch is already working differently then the mode or charge buttons. When I got it, all had a firm, tactile click. Now the center only does if I hold the switch button at a odd angle.

Does anyone know is this a precursor symptom to the switch issues on the BC-900? Usually this type of switch operations either just quits or develops a very erratic operation just by a slight touch.

 

[wptski]

Yuck, My one week old BC-900 display switch is already working differently then the mode or charge buttons. When I got it, all had a firm, tactile click. Now the center only does if I hold the switch button at a odd angle.

Does anyone know is this a precursor symptom to the switch issues on the BC-900? Usually this type of switch operations either just quits or develops a very erratic operation just by a slight touch.

Isn't or does it really become a Press/Hold to operate? Mine's been like that for a long time!

 

[3rdDerivative]

Just noticed, it has a hang, holds for a second then releases. So if you are trying to flip display, now takes about a second or two for it to release then I can press again. Oh well, it may have to go back to Amazon. Not sure if it is worth the getting a replacement. May just hold off and see what Maha does with C9000. At worst case, just get the C9000, again, for it analyser function.

 

[viorel00]

Hi, I decided to run a test where I charge each battery in a different bay, 100 mA discharge, 200 mA charge. So after 4 cycles I have a 4 x 4 matrix with capacity for each battery-bay combination. I just finished the third cycle and I am about to start the last one, and so far look like bay 4 overcharges by 25-30% (2.57, 2.59 and 2.65 Ah) while bay 2 is spot on (2.01, 2.01 and 2.05 mAh). These are all a new set of 4 AA Eneloop by the way.

Shall I repeat the test with 500 mA charge current, or contact LaCrosse and demand another replacement?

 

[SilverFox]

Hello Viore,

Charge at 1000 mA and tell us what you get.

Tom

 

[Mike abcd]

Hi, I decided to run a test where I charge each battery in a different bay, 100 mA discharge, 200 mA charge. So after 4 cycles I have a 4 x 4 matrix with capacity for each battery-bay combination. I just finished the third cycle and I am about to start the last one, and so far look like bay 4 overcharges by 25-30% (2.57, 2.59 and 2.65 Ah) while bay 2 is spot on (2.01, 2.01 and 2.05 mAh). These are all a new set of 4 AA Eneloop by the way.

Shall I repeat the test with 500 mA charge current, or contact LaCrosse and demand another replacement?

I strongly suspect that bay 4 is not actually overcharging but only reporting the mAH wrong.

Do cells charged in slot 4 test at higher capacity? If cells are over charged, you should get a higher capacity when they are tested right away.

As I already posted, if I were in your position, I'd ask for another replacement.

I'd also suggest using a higher charge rate. The BC-900 terminates charge on a voltage drop that happens when the battery reaches full charge. At very low charge rates, the voltage drop gets smaller or doesn't exist. I'd suggest a charge rate of at least 30% of the battery capacity. For the Eneloops, I'd use 700 mA. That should ensure reliable charge termination and keep them cooler than they'll get at higher rates.

Mike

 

[SilverFox]

Hello Mike,

Just a minute now...

Sanyo (and Duracell) recommend a minimum fast charge rate of 0.5 C. That would be 1000 mA for the Eneloop cells. What is your basis for recommending a rate lower than that?

The cell temperature is related to its impedance. This also effects their performance under higher loads. Since the Eneloop cells seem to be able to handle higher loads without problems, it can probably be concluded that they have lower impedance. This means that they can handle higher charge rates without heating up.

Tom

 

[Mike abcd]

Hello Mike,

Just a minute now...

Sanyo (and Duracell) recommend a minimum fast charge rate of 0.5 C. That would be 1000 mA for the Eneloop cells. What is your basis for recommending a rate lower than that?

The cell temperature is related to its impedance. This also effects their performance under higher loads. Since the Eneloop cells seem to be able to handle higher loads without problems, it can probably be concluded that they have lower impedance. This means that they can handle higher charge rates without heating up.

Tom

Hello again Tom,

He's charging at 200 mA and getting reliable terminations. I have no absolutely no doubt that 700 mA is not going to cause him charge termination issues on the BC-900 with those cells. Do you?

To be accurate, they both advise charging at 1C and Duracell warns that -dV may not occur below C/3.

The BC-900 charging circuitry gets hot, like most chargers, and that heats up the batteries significantly. At higher rates, the charger circuitry heats up more and the batteries get too hot for what I regard as healthy. The heating I'm referring to is in addition to the internal heating that happens as a function of cell impedance and charging current. It's waste heat from the charger circuitry heating up the batteries.

When charging 4 AA cells on the BC-900 at 1000 mA, they get hotter than I think is healthy so I prefer not to go over 700 mA on 4 cells. With 2 AA cells I use the outer slots and 1000 mA or sometimes 1500 mA.

Bill's test in the C-9000 termination issue when he charged cells externally shows how big the effect of the charger circuitry heating the cells is.

Haven't we covered this all before?

Mike

 

[viorel00]

He's charging at 200 mA and getting reliable terminations.

I guess that means that charging stops eventually, even though it seems to pump 2.60 Ah into a 2.00 Ah cell. Yes, it stops even at 200 mA. But bay 4 always shows lower voltages that the other three.

The BC-900 charging circuitry gets hot, like most chargers, and that heats up the batteries significantly. At higher rates, the charger circuitry heats up more and the batteries get too hot for what I regard as healthy. The heating I'm referring to is in addition to the internal heating that happens as a function of cell impedance and charging current. It's waste heat from the charger circuitry heating up the batteries.

Then one can use the BC-900 upside down, so that heat from the charger flows upwards, not heating the batteries. LOL, I am not gonna try this.

 

[3rdDerivative]

Well, my less then two week old BC-900 just failed. First the display switch and now the display is acting up. It is a "marvel" of the lowest cost of manufacturing that I have seen.

About the same time as the BC-900, I got the Maha C800S and it seems to be working fine. So, call me crazy, or just stupid, but sine the C9000 does seem to work as a good analyser (really did not like the BC-900 in this area) and the C800S is a good charger, I ordered another C9000 again from TD. It seems well-built and is a good analyser. Charger? I will just trust Maha to treat me right, if needed, when 3 year warranty.