Project update: After going back and forth on frame material I got some 1" aluminum EMT conduit. It’s 6005, roughly 27mm OD with 2mm walls. It seems plenty strong, it’s light, and it’s cheap! It can also be easily bent with a conduit bender. I’m going to bend up a frame in a day or two to check fitment on my harness.
I’m still waffling on battery choice… 3 6s 22000 mAh bonka packs in series (two on the right frame arm, one on the left) is the best setup from a cost and power density point, but it means that I’ll have 250 amps running through 4m of 8 AWG wiring and I’ll have 2.5 kg more on the right side than the left. Splitting the batteries evenly between the two arms (3 6s 13000 mAh packs in series on each arm, with both arms running parallel into the ESC) gives me more like 125 amps running through 2m of wiring and the whole setup will cost more and weigh more per wH. If anyone has an alternate suggestion, I would love to hear it. Ultimately I need to get 66 volts to the ESC, I need around 1.5 kWh of power, and I would like to keep the weight of the batteries balanced between the two arms.
Can someone post the part number for the switch used on the openPPG power system?