dead battery

Well, haven't had much to post about in quite a while. Generally I come home, plug the car in and in the morning I unplug it and drive it to work. Simple as that.

Tonight it wasn't so simple...
It was a misty morning so I drove to work with my driving lights on - not the headlights, just the driving lights - it wasn't dark, or rainy just a little misty. So I park in the lot in plenty of time for my 9:00 meeting and at when I return to my car at 6:00 - nothin'. No dash lights, no familiar thump of the contactor, just nothin'. At first I wasn't sure what had happened, then I noticed that the light control was still on - the battery was dead. Without the 12v battery, the contactor won't close, the controller won't get operating voltage, nothing will work.

Now I sat for a minute and remembered something... When I first built the car I had the DC/DC converter connected directly to the pack, but it was constantly charging the battery and draining the pack, so I put in a relay so that the DC/DC converter was only active when the key was on. Now there was a small mechanical switch on the side of the relay that allowed you to activate it manually, I knew if I could get the relay to close, the DC/DC converter would provide the 12v needed to get the car to work.

I popped the hood and unscrewed the cover of the High Voltage Enclosure to access the relay, With a flash light I checked either side for the switch - there it was on the driver side - just below 2 high voltage leads. I   turned the ignition key on then dug a pen out of my laptop bag thinking it would safely flip the switch, but it wouldn't reach it. I thought about it for a minute, but I knew I had to use my finger to do this. I put my left hand behind my back (an old trick I learned from a TV repairman - you don't want to touch ground with your left hand when you get a jolt on your right and have the shock pass through your heart...) and with my right index finger reached between the wires and pushed the little plastic tab in.  It made a satisfying clack as the relay closed and the 12v from the DC/DC converter kept it that way.

I closed the hood and got behind the wheel. Everything looked normal now., As I turned the key into the start position I heard that familiar thump of the contactor and we were mobile.

It was dark and with the headlights on I knew eventually the 12v would drop pretty low and the controller wouldn't like it - maybe enough to stall out - so I took the streets home. Sure enough, about a mile from my door the "Check Engine" light came on solid but she continued to drive fine. I got her home and safely into the garage.

I can't think of another car that will start with a completely dead battery. I've compression started a lot of cars, but never with the battery completely dead. Even the old crank-start cars needed a battery for ignition, right? These electric cars are somethin' aint they?