Thank you for the report ohaya. I too don’t recommend what you did, but I have done the same many times with no ill effects. Sometimes the batteries are able to attain and hold full “new” battery voltages. I, of course, monitor these batteries closely and don’t use them in high current apps.
I wonder where the not lower than X voltage advice comes from. Is it based on any specific testing? In addition to safety, that information would be good for filing an Ebay claim since the battery is not in new condition as advertised.
I also wonder, if you had used the battery pack in a laptop. Would have the protection circuitry prevented it from charging and being used?
Can anyone with real knowledge in this area please chime in on this?
Remember that these are suppose to be NEW batteries, as in “never used”. From their condition and packing when I got it, I now believe that these were actually “new”.
Then, if they are actually new, and thinking about what laptop mfrs recommendations are for a new laptop would be, which is, I believe, to charge up the laptop to full, a couple of times, I think that it may make sense what I had to do. I think that these batteries were actually new, and only charged to a “storage” level, which is what ALL of them were at almost exactly the same voltage, i.e., ~1.9V, and that the “correct” thing, in retrospect, would be to treat them like batteries in a new laptop, i.e., fully charge, then discharge, etc.
I know that that’s what I’ve been told for LAPTOPS, so you’re right, that it is strange that the advice for flashlight batteries would be different? If I had followed that advice, I would’ve already tossed all 12 of the batteries already :(!!
Maybe, the situation is different between “new” batteries that are at low (~1.9V) level vs. “OLD” batteries that have been previously used for awhile, and maybe a long while?
I don’t know the answer to that, but, for now, I will probably go through the same procedure that I described earlier, i.e., fully charge on the Accucel, do a discharge, and then charge again, possibly several times (I think that I’ve seen some pages that said, to do the discharge-charge cycle for maybe 10 times for laptops). Also, I will make sure to monitor the process closely, as I did last night, for the battery temperature, etc.
Anyway, as I said, I’m not recommending any of this, but just reporting what I did, the results thus far, and what I’m planning to do, so take all of this “with a grain of salt”.
I suspect that if you had one of the laptops these batteries fit, you could plug it in, let it charge, and it would work fine and you'd never know anything about what the starting voltage was when it came out of the box. I've had new just-bought-from-the-store laptops that took more than 8-10 hours to complete that first charge before first use.
I’m pretty sure it is 2p3s, but I didn’t get a chance to check the circuitry, because I kind of freaked out when I measured the voltages from the 1st one I opened, like “Why is it 1.9V?”, which is also why I spent most of last night doing that charge-discharge-charge thing. I now know how that other user feels (the person who posted about another battery deal that turned out to appear like a scam!), which, thankfully, I don’t feel like this one was :(…
I have at least one pic that I took, before I discovered the voltage, and then went off and started charging/discharging. I’ll upload the one or ones that I have in a bit.
I think the only way to get 10.8v and 5800mah is 2p3s.
ohaya, has your machine reported capacities on the discharge cycles? I imagine they may be lower in the first cycle or two, but it would be nice to know.
EDIT: Cross posted with your pic. Thanks for sharing that.
So the total mAh/Ah rating of the pack is determined by the number of cells in parallel, right? I thought I had it figured out, then got confused somewhere, trying to get back to where I was before... :Sp
Sorry, I was so flustered by the voltage thing, that I didn’t bother to note the discharge results :(… I know you all are probably getting tired of hearing that, but trying to be candid here.
If you google the NCR18650 and MH12210, it looks like it comes up with a Panasonic 2900 mAh battery, with same wrapping style, so I think that that’s what these batteries are.
One last question ohaya. Sorry for all the questions. I’m wondering if the “C 9907” is date code. Usually the date codes are in faint characters that are formed by perforations going lengthwise on the side of the cell. Usually the last part is a date code. Do you see anything like that on the side of the cells?
They will be much newer. The letters stand for the month and year. Y will be pretty recent, but I don’t have the date codes in front of me. I will get back on that.
I just looked through the Panasonic data sheets and such on these cells. They have all kinds of warnings, but not one mention of taking cells to low voltage being dangerous. The closes thing I could find was the following:
“Overdischarge can damage the performance of the battery. Equip the unit with a mechanism to
prevent overdischarge, especially in situations where the user may forget to turn the equipment off.”
I’m assuming that discharge protection would have been in the Fujitsu battery pack circuitry?
I don’t think these have individual protection circuits. The wrappers on the negative end don’t go “around” to the flat part of the negative end, but only down the side, to within a couple of mm’s of the bottom, so I’m pretty sure about that.
Yes the pack's circuitry handles the protection function, and also does the balancing for charging - that's all the crazy little wires going every which way inside.
Looks like I was wrong about the letters being the month and year. That must be for Sanyos or some other maker. The four numbers are the date. Looks like yours were made in September 2009. Check out post #66 here: