Recent content by BatteryMooch

Thanks but thatsthe test report that I wrote. :) They have changed what cell they wrap. Its no longer the NCR18650GA with a three leg top contact.Its a lower capacity four leg top contactcell with a lower current rating now.

Capacity = 2542mAh and 2561mAh(BK Precision 8601 load) DC IR = 52-53mOhms (15mS pulse at 7A) Rated at 35A and 3600mAh by Enook but those areabsurdly exaggerated ratings. The four leg top contact means LG Chem or a China manufactured cell IMObut I dont know which. The printed codes on the can...

Ive seen that NASA doc, thanks though! So easy to overlook something like that when designing a pack. :)

This is all it says on the first line? Are you sure you havent missed any letters/numbers?

Did you decide on any particular methods yet?

Any data on changes in the leakage current rate, pre- and post-soldering? I can see that as being the primary indicator of damage. Except for thermal runaway, of course. ?

Vapcell is a decently popular brand of cells targeting flashlight users and vapers. They rewrap cells from the big OEMs and also use cells from the smaller China factories. The continuous current ratings on the wraps are, for the most part, accurate. The max or pulse ratings are, of course...

Probably already punching them out. :@

Ive done it by using a motorcycle battery directly connected across the cell under testwith reversed polarity. This forces reverse charging at incredibly high current levels.The key to making it work was the use of very low resistance wiring/connections to ensure that enough current flowed to...

I agree with daromer, avoid spraying anything. Especially if it contains a volatile carrier as it could affect the seal at the top of the cell. Perhaps you can try a thin film of conductive lubricant to block oxygen but not interfere with using the cell? You wouldnt have to go through a lot of...

Sorry to hear about all theproblems youre having but I wanted to let you know that i have really enjoyed reading this thread and learning about your setup! I hope you find solutions soon.

Ive seen some chargers react badly to cells with crappy (low quality cells from the smaller China factories)or damaged spot welds. The voltage on the cell tests as good but soon after charging or discharging starts the bad/damaged weld point(s) go very high resistance and the charger drops to a...

Where did my other reply go? Hmm...I messed up somewhere. Thanks! I really enjoy the work Ive been able to do testing cells and exposingbattery wrapping companies with their crazy exaggerated ratings for their cells. Im looking forward to soaking up some of the great knowledge here for putting...

Was the charger still balancing when it stopped charging? Could you have hit a cell-to-cell voltage imbalance limit? You might have to charge each separately first and then charge/balance the pack.

Welcome! New York City native here. Im also new to SLS and trying to absorb as much as I can before diving into building a powerwall. Batteries I know a few things about but very little about solar and sizing powerwall installations. There is some great info here!