Thanks again ohaya for the hard work you are doing testing and reporting. I’m pretty weak in this area of knowledge. It seems like the 633 - 849 mA is not right due the the amount of time you stated these cells took to charge. Hopefully, one of the folks with deep knowledge in this area can help out.
I think I should get mine tomorrow. I don’t have any test equipment beyond DMM’s and an used oscilloscope I just got. I can do a crude run time test using the same flashlight against a fairly new NCR18650A (3100mah) so see what that indicates.
No problem, as I’m kind of curious about this kind of stuff :), but it is puzzling, and a bit frustrating so far.
One other/new thing that I’ve found, that I didn’t mention earlier, is that I’ve been testing trying to charge a couple of these on a “normal”, non-hobby charger, a TrustFire TR-003p4, that I have. The strange thing (to me) is that it seems like that appears to work “better” than the Accucel, in the sense that, for the first set I tried in that, it actually brought those batteries up to 4.20V, without all of the discharge-charge rigamarole that I’ve been doing with the Accucel. One thing with that is that the TR-003p4 won’t charge the batteries in their initial state, at 1.9V. The lights stay green, i.e., the charger either doesn’t “see” the batteries, or thinks that they’re already charged.
So, what I did was put each of them into ANOTHER 1-battery charger I have, for a few minutes, which brought the voltage up a bit, to 2.5V+, and then put it into the TR-003p4, which then “saw” the batteries (red light). I did that with 4 of the batteries already once, and they all got charged to 4.20-4.22V.
I haven’t had a chance to try a discharge test with any of those on the Accucel yet, because it’s tied up with the other stuff :(…
I started another thread, because I’ve been seeing a “VOL SELECT ERR” on the Accucel, which stops the charging. I don’t understand what’s causing that :(…
BTW, I do have a “theory” about why the TR-003p4 appears to be working better than the Accucel: I think that whatever is causing the Accucel to get that “VOL SELECT ERROR”, it’s causing the Accucel to stop charging the battery, basically stopping the Accucel from fully charging the battery.
On the other hand, the TR-003p4 doesn’t seem to have any problems that cause it to stop charging the batteries prematurely, so it keeps charging them until its termination voltage, ~4.20V.
I really need to try a discharge test on the Accucel with one of the batteries that I charged on the TR-003p4, I guess :)…
I think that I’ve figured out why I was getting those low results from the discharge tests. Basically, it looks like the Accucel will, for some unexplained reason, stop the discharge test, even though the battery is showing something like 3.7+ volts.
So, I’ve been re-running a discharge test on one of the NCR18650 batteries, and when I stopped at 3.72V, I noted the discharge, and then started the Accucel discharging again.
You may want to double check the connections to the cells. When I try to use magnets (instead of normal holders), my charge times double and triple. I also can hear buzzing sometimes when I use magnets. Obviously, I’m not getting a good connection the way I’m doing it.
I think that I had checked that. It’s the “Ending Voltage” setting, correct? If so, that was already at 3.0V by default.
Through this morning, the discharge test went as follows:
1st: 646 mA - 3.72V, then started discharge again
2nd: 623 mA - 3.55V, then started dischrage again
3rd: 455 mA - 3.42V. I had to stop the discharge test, because had been up all night
I just woke up and started the discharge test for the 4th time, and it started at 3.42V.
I thought about that, last night. I have another, spare single battery charger that doesn’t appear to work, and I’ve been thinking of hacking that so that I could use it as a battery holder for the Accucel. For now, I’m stuck with magnets…
which seems to indicate that discharging to 3.0V is not good for the battery.
Does anyone know if this is true/correct?
Also, that thread says to use Nimh discharge, and then you can select the ending voltage for the discharge. Has anyone tried that?
It just finished the 4th discharge test, and got 597 mA ending at 3.32V.
So:
1st: 646 mA – 3.72V, then started discharge again
2nd: 623 mA – 3.55V, then started dischrage again
3rd: 455 mA – 3.42V. I had to stop the discharge test, because had been up all night
4th: 597 mA - 3.32V
So now total is 2321 mA.
I just started the 5th discharge test. Should I let it go down to 3.0V???
For the capacity tests you can go down to 3.0V - see the battery tests from HJK.
Since it is under load to 3.0V based off what amperage you are testing - it will bounce back to around 3.4-3.5 when the load is taken off depending on the age of the battery.
I am not sure why you keep stopping the test and then restarting it. To get a true value you need to start from a full charge and then do a full constant discharge. if you keep stopping and restarting you may be over-discharging the cell.
I’m stopping the 5th discharge test at 200 mA @ 3.28V, because worried about discharging it to 3.0V, so total was 2521 mA down to 3.28V.
So this battery, part of the 12 that I removed from the Fujitsu battery packs, appears to have pretty good capacity (vs. apparently 2900 mAh rated capacity).
Sounds good ohaya. Common sense says they seem to be good cells based on the following:
They are taking 4.2ish volts
Took a good amount of time to take initial charge.
Your capacity test results.
Condition of battery case (appeared new and untampered)
Date isn’t too bad for never used battery
Thank you again for relaying this find to BLF and for all your work testing and reporting. Much appreciated
You’re welcome. I guess that I have to repeat the disclaimer that I’m not telling anyone what they should do with these, if they come in with the 1.9V initially, but just conveying what I did and what happened.
I got lots of warnings that the things I did shouldn’t be done, and, honestly, I’m very confused about the conventional wisdom (which I was also aware of before this) vs. what happened when I did what I did (and reported here), but as I said, I’m just reporting.
I will say that I also got in a USED pack yesterday, where 6 out of 9 of the batteries were < 1.0V. In that case, since I knew up-front that this was definitely a used pack, I tossed those 6 batteries immediately, and didn’t do anything with them. I kept, and am charging, the other 3, which all had ~3.8V to start with.
Sounds like the batteries are doing ok. Is the hobby charger still tripping with the error or has it stopped?
You could let the batteries or battery rest after being fully charged, for a day or two and then check the resting voltage. With a healthy cell the battery should not loose much voltage. Post your voltages if you decide to do the test.
Since an earlier message on a thread I started on the “VOL SELECT ERR”, I’ve been only using the Accucel to charge after initially bumping the battery voltage up using another non-hobby charger, and then using the Accucel on the battery, and haven’t been getting that “VOL SELECT ERR” anymore. However, when charging and discharging, I do still see the Accucel stopping (without an error).
For example when I did a discharge test starting last night, it stopped, and I had to start the discharge test 5-6 times. Each time, it’d run for awhile (sometimes, a long while) and then just stop.
I’ve also seen a similar thing happen when charging.
The batteries do appear to be good though, e.g., on the one I did the discharge test on, it looks like it was showing about 2500 mAh capacity.
I’ve been checking the batteries after charging. I marked the voltages off of the charger, and then have been checking voltages intermittently. Voltages seem to be about the same, maybe with .01V changes.
Got my battery today. Man, that was fast delivery. Battery was not in a sealed antistatic package as I would expect for a new battery, but it was very well packaged for shipping. The battery clearly has never been used. I inspected it under magnification and could not find a single scratch, mark, etc. The contacts look like they have never made “contact” with anything before. It appears to be in perfect condition. No codes on outside to indicate age.
I’ll report back after I get a chance to crack it open. May not be tonight though.
Sounds like the batteries are doing great. A normal new li-ion would drop to around 4.17v within a day or so, so yours seems fine. I still can’t figure out why your accucel-6 charger is giving you problems. It should discharge and charge with out any problems to the end of the cycle.
Does it do the same thing with other li-ions not from this pack? Just wondering if maybe the charger is faulty or bad connections.
This is the first time I’ve actually used it for discharging, so I don’t know if it’d behave the same with batteries that weren’t from these packs. I don’t recall it doing it with other batteries when charging, but I haven’t really been using it for much charging either.
It’s definitely a puzzle, and I kind of am thinking the same as you, i.e., either the charger is bad or maybe connection. However. re. the latter, the charger is in a corner with nothing else and no one around it when it stops.
Opening those packs is pretty easy. Start just at the connector, wedge it there and then open the side and then one half should pop off.
Getting the batteries out of the charger, however, isn’t that easy, but be careful. They have some really sticky tape or glue that attaches them to the pack housing.
Ohaya, I thought of something that could be possibly the problem judging by the mah your are seeing while charging then it cuts off, they seem to be close to the same until the charger gets close to the constant voltage stage. Check in the charger menu to see if you have the safety timer set to low or the capacity cut-off set to low. If safety timer is set to 30min it will cut off after 30mins. If the capacity cut-off is set to 600mah it will cut-off at 600mah.
