The dimensions are taking into account both bags combined. I am using the large which fits a 12x5x6 inch LiFePO4 pack in each bag with barely enough space for foam padding. My entire pack weighs almost 40 pounds, and unfortanately the seams at the straps began to tear. Ultimately, I've cut them...
I was scratching my head over the battery placement problem on my own Paratrooper. Wish I had a garage/workshop and some fabrication skills. I wound up stuffing my LiFePO4 batteries into a Mountainsmith backpack for dogs (size large), and used straps to hold it over the top tube and pressed...
Sorry I'm late to the show. I got in touch with Justin at Grin Technologies about this same exact issue on my 40a Infineon controller. He says that a pad labelled P22 on the circuit board needs to be shorted to ground for the ebrake to cause regen. Not confident enough with my soldering skills...