So, I was able to get the Little Frog made with 52v 14s3p by BMSbattery for $250 USD and NCR18650PF Panasonic
batteries. I will be replacing the BMS with a 60A bluetooth BMS (will set to 30A max) to charge to 56v 80% SOC for battery longevity. Will get the weight up when I get a scale. Photos below via google photos. Hope this people make decisions around the product/solution.
I have it on my mountain bike temporarily, but purchased it for my commuter. It's a little bouncy in the back for my mountain bike (I took it on the trails once) - good for commuting though and convenient to carry around to take into work.
It can fit a PSWpower 20A sinewave controller, and a S06 controller (BMSbattery), but by calculations, not the s09 controller - which I wanted the most. It doesn't fir the external Magic Pie controller (see the photos to understand). It needs to fit the metal part which the plastic shell covers. Happy to take and share measurements if anyone needs them.
https://photos.google.com/share/AF1QipM ... JGT2Y5YWtB