On another note: I have been waiting for a reply from an undisclosable source (sorry, NDA involved) on permission to post some data about the EIG cells.
I've been using some pre-used (unknown conditions) cells in a long-term test on CrazyBike2 including for my lighting pack, for some time now. One thing I want to report is the safeness of these cells under a condition that would probably be "fatal" to many other cells, and the hardiness of them after the incident. It's partly documented in my CB2 thread but some details had to be left out at the time.
http://www.endless-sphere.com/forums/viewtopic.php?p=566839#p566839
I used to park my bike out front of my workplace, and normally no one ever messed with it, but once I forgot to unplug my 12V pack's connector, and someone turned on my headlight and a turn signal (when I didn't have a working blinker, and had to manually blink them), and it sat there on at least a ~6A load during the shift till it ran down to 0V on all cells.
I recharged it at a 100mA current limit, back to 4.0V/cell, using a lab PSU. At the time, expecting it to blow up and flame out, I did it outside on concrete with a metal trashcan over it...but nothing happened, except that it charged normally up to 9.6V when I had to leave for work, so I unplugged it from the charger. When I got home 5 hours later, it had actuallly gained another 0.75V, not sure why. Possibly because the outside temperatures had increased during the day (though cooled later before I got home; still might have left the pack a bit warmer than when I left).
Continuing charging at 250mA at some piont (I forget exactly what voltage I changed it), and then with no problems for a while upped it to 500mA, it reached 11.1V at about 12Ah back in it. I kept disconnecting it when leaving the house, and it always held it's voltage after disconnection from charger and meter.
The cells stayed in balance even when they were at extremely low voltages (0V up to 3V), from my periodic checks during the recharge cycle. They were within 0.02V of each other each time I checked, using the Fluke 77-III.
Eventually it got up to 12.2V, with 12.3V as the final goal (4.1V/cell). Still in balance, still no problems charging, no sign of heat or swelling or anything unusual. Charge current had dropped to 0.49A with the voltage rise. Had about 18Ah in it then. Later it finally reached full, at something close to 20Ah.
Discharge testing then began:
http://www.endless-sphere.com/forums/viewtopic.php?p=570899#p570899
I used the Venom RC charger from SoSauty. Some notes:
The Venom says it will do 5A discharge testing, but that isn't really true. It might do 5A at a certain total wattage, which is a lot lower than the wattage put out by the pack at 12.3V. At that voltage, it only does 2.0A. Eventually, when the pack reached about 11.8V, it increased to 2.1A, and later to 2.2A at around 11.6V. (this was the opposite of the way I wanted to do the test, but at least it was a test. Also, due to the inaccuracies of the Venom I discovered in the testing, I suspect at least a half an amp less current draw than it reported throughout the testing).
Given the Venom's inaccuracies in readouts that I've determined, there's essentially no balance issues with teh cells (it read at most 0.03V difference, and I don't think that was a real difference, just problems in the Venom itself).
There was no heating of the cells during charging or discharging AFAICT.
There is some data on the cells via Logview, but bugs in Logview I wasn't aware of led to loss of much data. Screenshots of some of the data is in posts after the link above.
I also did recharging via the Venom, which was around 4A in reality, and I was convinced the pack wasnt' going to burst into flame yet, so I started using it on the bike again for the lighting pack. At some point I got an Accucel6 from Ebikefanatic, and have been using it to recharge it as 3s (4.2V/cell...yeah, I know it's only supposed to go up to 4.15V on these cells...but it already survived a 0V event, so, what's the harm?
) at 5A. I haven't tried logging the charging yet, but I expect that's not 5A constant, probably a lot lower as voltage goes up to maintain wattage, just like the Venom did.
I also did a couple of 0.5C recharge tests with the big Sorenson, at 10A, from fully discharged (3.0V/cell) to max (4.15V/cell), and no cell heating. I did a similar test when I first started using the cells, though at that time I had incandescent turn signals (before Texaspyro sent me those MR16 LEDs I put in there), and was using a 4s / 16.4V pack, before I took one cell off to keep from blowing up the LEDs.
I typically use at least 8Ah before I recharge, and have a couple times let it go to 14-16Ah used just to see if it's still got the capacity it had, and so far it still does, matchign the voltages it should have according to the EIG datasheet for that SOC. I use the headlight on bright most of the time (day or night), so 6A constant load, and additional intermittent few hundred mA load with turn signals and brake light, for my typically-10-minute trip to work and back home, with occasional trips elsewhere for up to an hour and a half or so of riding time, and very occasionally 2 hours.
So far it's had maybe an 8Ah cycle every few days since late spring, maybe midsummer? I forget exactly. And usually doing similarly before the incident.
Anyhow, just to say that at least at about 0.3C discharge levels, and 0.5C or 0.25C(peak) charge levels, these cells can be killed to 0V, and still be brought back and used without issue for up to full capacity. I don't yet know how cycle life will be affected, and I have not done a high-rate discharge test because of the way I use this little pack, but in my usage scenario, there's been no discernable damage. I'd like to be able to test the internal resistance of an undamaged cell (should be <3milliohms @ 1khz) and one of the ones taken down to 0V, but I don't think I have the test equipment for that.
There is also a traction pack but it has not experienced any unusual conditions. (14s at first, then 16s; would use more but the charger I have doesnt' go any higher and I haven't gotten round making a super-long extension cord for the 220V for the big Sorenson so I could stick it in series with it, or use the Sorenson and an Artesyn "server" PSU in series for high-rate charging. So it gets charged at max of around 4A, but the charger ramps it's rate up and down so average is probably 2A or less.)