Not sure if anybody is interested in this info but I think sharing info is good and I learned a lot from other users on this forum so I'll just rapid fire things I have found along the way to getting this scoot running.
Keep in mind the bms behavior is how it works alone, without the normal oem dashboard or oem controller hooked up to it. I've read they work differently when using stock oem components with them.
-The Lyft bms didn't allow enough current when hooked up to a 1,000 watt controller with a 38 amp current limit. At full throttle, it would shutoff and recover maybe five seconds later. If I kept the throttle pinned, it would shutoff completely and I would have to disconnect the battery for it to work again. I bypassed the bms doing this and it doesn't cut out anymore. To bypass the bms during discharge, I cut off the bms negative wire at the bms, then soldered that wire directly to the battery negative wire to give me a direct connection from the XT60 to battery negative. Since the charge wires are separate, charging with the bms should be unaffected and it should still balance the cells like normal. But there is no longer any over-current or over-discharge protection from the bms.
-I also tried a Spin battery. It would not run for more than 5 seconds before shutting down with any throttle setting. Bypassing the bms solved that problem as well. The Spin bms only charges up to 40.3 volts, which I gather is about 90% capacity. The Lyft battery charges up to 41.4 volts which seems like 100%. The lower voltage of the Spin battery also reduced top speed to 20 mph and it seemed a little less peppy during acceleration.
-If anyone reading this uses a Brainpower controller, use the learning wires. I hooked up mine without the learning wires and it spun forward so I thought it was good but the phase wires or Hall sensor wires were wrong. It made a horrible vibration but still spun pretty fast. After troubleshooting and hooking up the learning wires, the controller electronically fixed the miswired phase or Hall wires and it was as smooth as a trapezoidal controller gets. Still not sinewave smooth or quiet but there is tons of torque.
-My Brainpower controller had 3 speed settings and they all worked and made a noticeable difference. It is on the fastest setting now and I doubt I will ever change it. I tested the stock Lyft Max throttle and it was able to get full output from the controller easily.
I used 12 gauge solid copper romex wire for the power and phase wires and they seem to be large enough for the current demands.