If you have been keeping up on the a123 module thread (click here)
, you already know I bought (1) 28s3p and (3) 7s3p modules, to make a 49s3p pack for the VoltsBus. That is 178.85v hot off the balancer, 60ah, 9,firstname.lastname@example.org nominal, 7,761wh usable at an 80% DOD.
I installed that pack in the bus today, and took it out for a spin, stopping at the beach for the first time since it was gas-powered, stopped at the video store on the way back. I covered 4.4 miles, and consumed 1,977wh (12.1ah), so incredibly the bus only used 450wh/mile! I was mostly doing 30-35mph along surface streets, but there are steep hills along the route, so I was expecting 1,000wh/m, 450whm is was quite pleasing.
I did have some trouble on the way back. I was cruising up the steep hill, put it in third gear, and heard a wierd grinding sound - picturing the clutch hub coming free of the shaft. I had plenty of momentum to carry me up the hill to the light, and when it went green, everything was fine, no noise, plenty of power. Shortly thereafter, I'm going up a gradual hill but accellerating hard, I put it in third again, weird sound again, and I lost driving force. Voltage fine, but no amps, which makes me think of an EV problem that belies the grinding sound I thought was clutch.
I run out of momentum 30' from the crest of a hill I could have coasted on home from. Hop out, check the controller, I can feel a spot of heat on the huge aluminum cooling plate so it might have just gotten hot and tripped the thermal... So I power off the controller - takes a long time to drop to 0v from 162v - but when I turned it back on, I had power!
Because of the power-off, I lost stats on vmin, but when I got to the beach, my aMax was 185a, and my vMin was 154.0, or 3.14v/cell. Resting voltage was a rock-steady 162.7v both at the beach and when I got home, or 3.32v/cell. This power is conducted through @25' of 4/0 cable to the controller. I think the 48s PSI pack dropped to 120v on a 250a load. CLICK HERE to see a 360 panorama of Voltsbus at the beach. If you are on a smart phone or tablet, hit gyroscope to see the 360 even better!