[serialk11r]

Alright, it's not budging at 11.3, so these only have 20Ah capacity, unless my current measurement is completely wrong (I doubt it, 54A sounds completely reasonable for ignition + headlights + fans). I'm gonna ask for a partial refund, see if I can swap in some better cells or figure out which ones are bad.

I guess they're technically still more useful than a small lead acid since the internal resistance is lower, but this isn't very encouraging. I did hook it up to a dead Group 24 lead acid battery with jumper cables, and it managed to crank a 3.5L V6 engine without much trouble, so in a way the performance is quite impressive. I recall doing a similar exercise once with a dead 10Ah AGM battery hooked up to my fully charged 30Ah lead acid, and it really struggled to crank a 1.8L 4 cylinder.

EDIT:
Okay I just read this paper and decided I need to reserve judgment until I do another test. Apparently, some cells have a steeper voltage curve, and it's possible that if I run this battery down to 10.0V I can get nearly double the energy out. Still not the advertised 40Ah, but over 30Ah would not be bad for what is effectively a 300 dollar discount.