Setback, repair, and lessons learned

I set out this morning to log my commute. I started logging one event per second - took about a minute to get on the bike and going - headed out of the driveway and as I turned left, wham! full "throttle!" The bike took off FAST - but the brakes won. There was smoke and the main fuse blew (goodbye 40 bucks :-( ) I immediately began cursing the controller and throttle. However, since I was logging, I saw something else was to blame when I reviewed the output at lunchtime (had to drive my car to work.) Something south of the controller must have shorted to ground. That thought was correct - When I got home tonight, I found that the inexpensive #4 cable had welded itself to the frame of the bike through the insulation. OUCH! I have encased all wires in conduit and have put a fuse on just about every wire going anywhere on the bike :-) In the graph of the data you can see me starting out - moving in the driveway - coasting into the street and then all Hell breaks loose as I ease onto the throttle. I let off the throttle when I felt it take off, and you see the throttle position is correct at zero as is what the controller thinks is the current. The telltale sign is the battery voltage which went all the way down to 8.7 before the fuse blew. This says that the current was not going through the controller - but somewhere else. The culprit is the crappy insulation on the #4 cables coupled with the fact that I'm using a 3 wire 48 - to 12 v DC - to DC converter that forces me to ground the 48v system to the frame of the bike due to the 12 volt system being negative ground. Unfortunately, the negative side of the 48 volt system is the one that goes through the controller - the positive is directly connected to the motor - therefore anything "going to ground" from the negative side of the house past the controller is going to send upwards of 500AMPs to the motor. 3 lessons learned - 1.) I didn't go for the kill switch, I reached for the clutch which no longer exists - therefore I may install a spring loaded clutch that kills a seperate contactor that kills all onboard power - 2.) I had a big, thick, unfused ground strap from the battery negative to the frame of the bike. I have installed a 10AMP fuse so that if anything more than the onboard lights, horn, blinkers draw through that wire, it will open the fuse. 3.) The cheap wire was pierced by rubbing on some sharp welds and a bolt - I have encased it all in conduit.