Good to know all that. I'm capacity testing the cells individually--I actually disassemble the laptop battery packs to salvage individual cells--so everything should be pretty close to balanced.
The cells (18650 lithium cells, same as the Tesla Model S) are 3.7V nominal, and I have them configured in sets of 4 in series, each set has 3 in parallel to triple the AH and continuous A output. (Don't ask why I chose 4 cells in series instead of three, three would have been much easier and I'm considering changing how the packs are built once I get my 16 testing modules done).
Each pack has a nominal voltage of 14.8V and a max A output of 15A based on the batteries being able to handle about 2C, and with the capacities I've been using they range from 6AH to 8AH.
Based on the specs on the motor, and the starting resistor, I've optimistically guesstimated that I'll need ~90A to get started in the lowest speed. My 16 packs will put out 120A in the 2 lower speeds, and 60A in 48V speed. I have fuses inline with the packs, so I won't destroy any BMSs or batteries, I hope.
I understand that 120-60A is not going to be enough to get going anywhere fast, but I hope it's enough to go around the block so I can get some current draw readings.
I'll attach a few pictures of the packs I'm making. In the first, I'm testing a power distribution thing I made for the Aux battery, the second shows it installed in the CCar under the driver's seat. I'll need to make some holder so they don't slide around while driving.
In terms of work though, I'm beginning to wonder if it would have been better to just get some pre-made module...
