Continuing my current obsession with lithium-ion batteries, I wanted to know more specifically what kind of capacity I would get out of my "bricks" in my electric scooter "bike"...
Finding a test load was a bit of an annoyance. At least one with any significant current draw. I started with an inverter to run something on AC, but the low voltage shut-off on it kicked in half way through. So I boosted the output, but that was a PITA and flaky. I needed something simple and reliable. And I had a box full of incandescent 12v bulbs from switching over a few cars to LEDs, so this was my setup:
I remembered making something similar as a kid for much smaller bulbs. Nothing to it but a 1x4 with 5/8" holes and two pieces of aluminum foil:
Good for burning off 10 amps! (and doesn't care if the voltage drops, either)
So far, I've been getting a good 21AH out of each of the smaller bricks that makes the bigger brick:
That's actual, usable amp-hours, under load and going through the BMS for both charging cut-off and low-voltage discharge cut-off. Cells settled around 4.15v after charging (a touch low), and low voltage cutoff was a hair below 3v.
Temperature makes a fair bit of difference too, according to the data sheet for the cells. And its fairly chill in my work shop.
I'm fairly pleased with the results. 21ah under a decent load totally blows away lead-acid, and the battery weighs 1/3rd as much.