Kingfish
100 MW
Greetings from the rainy northwest.
I recently did an assay on my entire LiPo booty, separating the wheat from the chaff, the germ from the seed, ferreting out the good, the bad, and the ugly packs. Some have been way-dead for a long time but I kept them around in their own little cinderblock ward; none of them ever had a high charge: When a pack goes I’d discharge it to about 3.5-3.8V/cell. Some that went over-volt got the freezer-treatment during discharge… and they is way dead.
Anyways the assay turned up some interesting facts:
To be fair, the only thing I have ever done to any of these packs is repair the Balance wires when then separate at the solder joint or are pinched. But I have yet to take a pack completely apart.
Aside from puffy issues which I hope to leave behind (dead cells seem to have the lion’s share anyways), has someone documented the complete separation before? I’m looking for a thread on this; can only find puffy repairs - which are illuminating, though incomplete for my needs.
Anyone try this?
~KF
Papa, will I be able to see the fireworks tomorrow?
When yer Mom gets home... possibly, though likely too rainy to appreciate the 4th of July celebration.
I recently did an assay on my entire LiPo booty, separating the wheat from the chaff, the germ from the seed, ferreting out the good, the bad, and the ugly packs. Some have been way-dead for a long time but I kept them around in their own little cinderblock ward; none of them ever had a high charge: When a pack goes I’d discharge it to about 3.5-3.8V/cell. Some that went over-volt got the freezer-treatment during discharge… and they is way dead.
Anyways the assay turned up some interesting facts:
- First, every pack is the same, except purchased in leaps; they’re all Zippy FlightMax 5S1P 15/2C 5000 mAh. The first purchase was in February 2010 (I think). In later purchases the battery size was very slightly reduced by 1-2mm a side, though the weight remained the same.
- Of the entire lot, I’ve lost 19% to physical damage or single dead cell. After my first road trip I discovered a handful had become over-volted due to flunky Meanwell advice. Those units are puffed and isolated, and they ain’t coming back; I’ve drained them to death, but still save them for parts.
- The most popular cell to go bad is #2 by a 2:1 margin.
- The least popular cell to die is #5.
- And almost as rare, having 2 dead cells in one pack.
To be fair, the only thing I have ever done to any of these packs is repair the Balance wires when then separate at the solder joint or are pinched. But I have yet to take a pack completely apart.
Aside from puffy issues which I hope to leave behind (dead cells seem to have the lion’s share anyways), has someone documented the complete separation before? I’m looking for a thread on this; can only find puffy repairs - which are illuminating, though incomplete for my needs.
Anyone try this?
~KF
Papa, will I be able to see the fireworks tomorrow?
When yer Mom gets home... possibly, though likely too rainy to appreciate the 4th of July celebration.
