Discharging accuracy testing....

Turak

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Jul 24, 2007
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I recently started wondering about the accuracy of my new BT-C2000.

So, I decided to test the following;

CBA II - Running on Windows XP PC using v2.4.5 Battery Analyzer PRO software version

MH-C9000 #1 - Version OH0AA

MH-C9000 #2 - Version OH0DA

BT-C9000 - v2.0 Firmware

BT-C3100 - Don't have yet

BC-900 - v33 Firmware


I used the MH-C9000 to actually charge the battery. Waiting for it to complete, then waiting 2 hours (using a timer for consistency) for the top off charge to complete.
The battery was then immediately pulled, no resting and put into the various chargers and discharged at exactly 400 mA using the 'discharge' function of each unit.

So far, I am amazed at the consistency/accuracy of the units tested/results so far.


So far I have only tested the CBA II, the MH-C9000's, and the BT-C2000 with a single Eneloop Battery (Generation 1, Lightly/Moderately used, about 200-300 cycles on it so far) in slot 1 only. Performed each test 3 times on each unit.

Here are the results so far;

CBA II

Test 1 - 1905
Test 2 - 1912
Test 3 - 1907


MH-C9000 #1

Test 1 - 1865 (BAD TEST. Forgot to let it go through the full 2 hours top off charge.)
Test 2 - 1901
Test 3 - 1912
Test 4 - 1905


MH-C9000 #2

Test 1 - 1909
Test 2 - 1903
Test 3 - 1908


BT-C2000

Test 1 - 1901
Test 2 - 1902
Test 3 - 1905


I was amazingly impressed at the results so far.
 

johnmeyer

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Aug 3, 2011
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Thanks for the time and effort needed to complete these tests.

The only reason I find the consistency surprising is that to get the same results, you had to do an excellent job at getting the cell into exactly the same state of charge each time. Beyond that, about the only thing that I can think of which would change the results from one charger to the next is what cutoff voltage they use. I just got the BT-C2000 and it is hard-wired to cut off at 0.9V. I don't know if the others use the same cutoff. It doesn't take much engineering to create an accurate current source, so I'd expect that to be very similar between units, and obviously the clock should be exactly the same for every charger.

The one other thing, as I think about it, that might have caused a variation is whether the charger/tester keeps the discharge current absolutely constant during the discharge. I have been doing a few tests on my new BT-C2000, and it appears to reduce the discharge current towards the end of the discharge cycle. This taper might affect the results compared to a charger that didn't do this, but your results sure don't show any statistically significant differences.
 

Viking

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Very interesting test.
I hope you will test the other chargers as well when you get them.
 

mcnair55

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Does that mean your torch is going to run better than mine? I charge batteries in what ever comes to hand currently a Nitecore but it could be a Tesco own label charger.
 

Viking

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Does that mean your torch is going to run better than mine? I charge batteries in what ever comes to hand currently a Nitecore but it could be a Tesco own label charger.

Yes that may well be the consequence.
It all depends on how lucky you were with the purchase of charger , and how closely you keep track of your cells.

This however has more to do with your own carelessness in the choice of charger , not so much the accuracy and consistency shown at the display of the charger. The later is of importance when testing batteries.
 

mcnair55

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Yes that may well be the consequence.
It all depends on how lucky you were with the purchase of charger , and how closely you keep track of your cells.

This however has more to do with your own carelessness in the choice of charger , not so much the accuracy and consistency shown at the display of the charger. The later is of importance when testing batteries.

Must admit cannot recall ever reading on the instruction label anything more than how to use.I must be a very lucky person as i pop in batteries that come to hand out of my battery box,never had issues in 9 years of collecting torch,s and using Eneloop or type.
 

WalkIntoTheLight

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I know you're being satirical, but the one case where I wouldn't use one of those cheap packaged chargers is if it's a dumb timed charger. I don't think Eneloops or other LSD cells like to be overcharged on a regular basis. Other than that, I think the difference between an expensive smart charger and a cheap smart charger is mostly cosmetic. I'd be okay with using a smart charger that charged in pairs, as long as that's the way I always used the cells.
 

Viking

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Hi WalkIntoTheLight

Actually that was the reason why I emphasized it also depends of how closely he keep track of his cells. A dumb charger can be an ok choice if that's the case , even the solely time based ones.
He just have to make sure all the cells are empty or at least nearly empty before charging , otherwise he could cause damage due to overcharge. But unlike the pair charger he will be sure the cells are always full and ready to use ( if the cells has the right capacity for the charger ).


For a pair charger ( which isn't a smart charger ) he would have to make sure the cells are at least in approximately same state of charge before charging. Otherwise both under and overcharge can be the result. The under charge can be quite significantly. He could easily end up with one of the cells is only half full , when the charger says done. But he will probably like most people not be aware of it as a charger problem. The majority will most likely either blame the batteries or the device for poor performance , or even more likely just don't know what they are missing.

I would also add ultra fast chargers to the list of chargers with issues people should be aware of.

The reason smart chargers are prefered by many is that they uses a microprocessor to monitor every single cell independently to determine when it is fully charged and then terminates accordingly. Although they uses different algorithms to do so , this main principle stays the same for all of them.

There are many affordable smart chargers around.
 
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