A 2D sketch of the belt drive, the belt tensioner is at the bottom, you can see the eccentric motion that tensions the belt. The smaller circle you see with the 240 diameter is the brake disc, which almost contacts the motor (5mm clearance)

The batteries are supplied by High Tech Systems LLC - Derek Barger, same supplier as Killacycle. This will be their definitive position, up against the seatback. They will work fine at any angle, as long as the cooling fans are pulling cool air from below and evacuating it above. The pulleys of the drive system are shown. The motor pulley is 22 tooth and the axle pulley is 112, for a 5:1 ratio. Top RPM of the motor is 7500 which will give about 140 km/h. The drive belt is a PolyChain Carbon. Given the torque I will be putting through the system (1 ton pull on the belt) this drive would simply not have been possible with the previous generation of belts which were kevlar based. Have you seen the motorbikes with drive belts, such as big harleys? Well, those were all designed for the kevlar belts. If you were to redesign them for the new generation of carbon belt (pulleys are the same) you could divide the belt width by half. This would make a harley look like it has a rubberband for transmission.

There is going to be a lot of machining work ahead to fit the driven pulley onto the differential.

Batteries, Motor, Frame

Here's the chassis with the batteries & motor in it

The chassis is a Sylva Riot