Recently bought two of these 10S-3P sticks from Battery Clearing House. NCR18650BD cells, 10A, 3200 mah when new. Advertised as "fairly discharged"
https://www.batteryclearinghouse.com/products/30-cells-high-grade-panasonic-ncr18650bd-10a-3ah-cells-in-10s3p-pack $47 for two. and reasonable shipping charge of $16 for two. I also added a 60Ah 4.2V lipo prismatic cell that weighs six pounds.
One came in functional at 39V. The other had shut down with most of the groups at 2.7V, and two at 2.2V, I touched a 2A 42V charger to both ends of the stack, bypassing the BMS, and the the two low groups took about 10 seconds to jump to 2.7V. Encouraged, I watched as all ten cell groups quickly passed LVC, I reverted to the charge port. The BMS does work, and they're functional scooter packs. They can pass 26A (my biggest controller), I believe, though I could be wrong, that these cells in he second pack weren't damaged by going down to 2.2V.as they just got there by the whole stick being run down.
At 20A, I'm seeing about a 5-6 V sag. This is not consistent with the 63 milliohms series resiatnace I measured on one cell group, but that's better than 12V predicted by that IR. The sag is enough to shut down the battery if I pull throttle at 35V. So operational life is about 5AH. If I go easy on power, I can get 7+AH out of them. If I ran two in parallel, the sag would be avoided, and probably see 12-14 useful AH, Not bad for 50 bucks,
Drawback is these packs are almost 2 feet long, Hard to fit on a bike. They were hanging a foot off the luggage racks on my other bikes. Here they are on my beater cruiser. wrapped up under the frame, Ugly, but it was a test run.
I'd like to cut this stick in half and fold it, but there is a circuit board that runs the length of the pack which holds the cells and contains a functional BMS, I'll just put these packs away in my outdoor storage til next year. Figure it out then.