I’ve posted another pack teardown. This one is a ACER AS11B5E battery pack I picked up on eBay.
This pack is a bit unusual. Its an internal pack, but unlike most internal packs, its made with 18650s, rather than pouch cells.
One benefit is that its really easy to get in to. I just had to peel some tape off the thin shell.
Inside, I found eight Panasonic NCR18650A 3,100 mAh cells. Not bad for a $22 new-old-stock pack!
Or perhaps it wasn’t such a deal after all. The pack voltage was ~7.7v, which wouldn’t be bad if this were a 3S pack. On an 4S pack though, that works out to less than 2v a cell. In retrospect, I can now see why the seller wasn’t asking more for the pack, and now that I’ve gone back to check, I see that they have other NOS packs of the same type for almost 2x the price. No mention though that it was marginal
I decided to give it a slow charge to 12V at 200 mA, which didn’t take long. Overnight, the voltage settled to ~11.6v. I am taking it up to 14.8v now at 660mA, which is probably where I’ll leave it until I manage to read out the pack info over SMBus. Then I’ll separate the cells and do a couple rounds of tests.
Pack Summary:
Acer, AS11B5E; 14.8v, 6000 mAh, 87Wh, 4s2p; Panasonic, NCR18650A, 3,100 mAh