Hi SG
even when this is out of question: the MP2/3 would perfectly fit into 12" Rim with full rubber tires. I tried mine and apart from the high weight/power it was nice to think about.
1) ??
2) the recuperation just takes moving energy into magnetic converted electricity which the controller tries to store back into the battery. Not every battery system likes such currents and such often charge/discharge cycles. I use WINA LiFePO4 with schottky diodes to block incoming charges and a Ultracapactitor section just before to take away high currents while starting and the recuperation surges very well. BUT such funny constellations are very expensive, just to smoothe the wear on the battery.
I did go that way as I can put energy from a second source (mine) into the system when going from such a parallel hybrid to a seriell hybrid.
Your linked accu seems quite small for such a task. Most LiPo have a very limited lifespan as performance was the guiding line. Most RC helicopter pilots are happy to reach 50 charges/discharges as a lifespan.
3) I don't know the SP so well, but with the MP Series I'd now always choose an external one due to cost minimizing which sacrificed a lot of quality.
Cheers
Sam
