Oh, and I still haven't given up on solar charging, but I think small steps:

1: SLA 26AH (get running, test range, LiFePO should be better numbers)
2: Thundersky LiFePO 20AH pack (use to build/test battery config, BMS, charging)
3. Thundersky LiFePO 40AH pack (the final build)

The bike kit is going rear hub drive for braking/regen, I only use the front brakes as backup for the rears to avoid air time, I'm not sure why I looked on the front hub drive as easier or more portable...

I'm definitely going the Infineon 35W controller with the 9 Continent hub, Cycling Analyst kit. Too many benefits and lots of flexibility as I see it, and I wanna really tune the LVC in the controller - if it hasn't been already...

I'd like to get something so I can measure more accurately the return from the motor though.

In terms of BMS, I'm taking the hobbyist route. I did find some really cool bolt-on packages for the Thundersky cells, but I've never been afraid of a little soldering and testing. That Christmas tree Doctorbass built should scale down nicely to 6S packages. I'll always run two, so the BMS design seems perfect.

The hardest part was finding the cables to wire the batteries so everything could be plug and play - an RC site provided all of that.

I'm still working on water-proofing the BMS... Tricky since airflow is needed for the cooling (fans will be needed)...