torstai 29. elokuuta 2013

Get your motor running, again

Yesterday I spent the whole day working on the car. It was worth it though. I got the high voltage parts all wired up and the wheels spinning using the controller. Here's the proof.

I had the idea of putting the high voltage cabling inside some clear plastic tubing, but the cables didn't want to go in so I just gave up on that idea. The cables routed below the car doesn't look half to me though.

Plenty of room below the car now. Kind of makes me sad to have all that space that cannot be easily put to use. Oh well. At least I got a lot of crap out that could fail the yearly check.

perjantai 23. elokuuta 2013

New cable

I finally found a good place to get some proper, orange 50 mm2 cable and other useful stuff for my electric car conversion. To my surprise the place to go to is IKH. They sell all kinds of tools and tractor parts, but also heavy cable and such. They had up to 70 mm2 right there in the shelf. I figured I could get away with 50 mm2. Especially since I'm not exactly creating a supercar.

I got 10 meters of the cable. I had some red cable from Biltema before that was 6 m in length, but it turns out it wasn't quite long enough. I hope 10 will do. Maybe I should have measured how much I need. I also got some clear 40 mm diameter tube to use as a conduit from the back of the car to the front. I got the idea from this Damien Maguire's youtube video:

Very nice, clean and hopefully durable solution. My cabling from first go from the trunk to below the read seats, where there are a couple of holes already available for bringing the cable down to the underside of the car and then using the exhaust pipe tunnel into the front.

The heater in the picture is a cheap 1000 W cabin heater. I'll see if the heating element would happen to work on 80 volts DC as well. The fan most likely will not work in any case.

tiistai 20. elokuuta 2013

Tank out, batteries in

Yesterday I finally took out the gas tank from the kWsara. Main motivation was to make room for battery cabling. I've decided to have a single simple battery box in the trunk for now. It's actually an aluminum box from Biltema. Right now it houses the 25 CALB SE40AHA 40 Ah cells from the kWsaki motorcycle. They should be good for about 30 kW and 3 kWh.

The battery box also houses the main contactor and a cut-off switch. Essentially all electric power can be contained within the box simply by turning the switch off. I also got some gland nuts for the cables to exit the box in a clean and secure way. Cables within the box are just 35mm2 for now, but the longer cables are 50mm2. I'll need to get some more though. The 6m roll of cable I got earlier doesn't reach to the front of the car and back.

Taking the tank out took some doing. First few bolts came off nicely, but just as I though I had them all out I found the last one. For some reason the last one always turns out to be the one rusted out and nigh impossible to remove. Eventually it did give up and I was able to wiggle the tank out from between the handbrake cables. Spilling of some gasoline left in the tank could not be completely avoided.

I also used a 5 V 2.5 A D-Link power brick to top up the the cells which we're a little lower than the rest. Now they seem to be quite happily resting at about 2.95 to 3.02 volts like the rest.

lauantai 17. elokuuta 2013

Taking apart

Yesterday I proceeded to take apart the battery pack of the kWsaki motorcycle. I'll need the cells for my initial build of the kWsara electric car. I'll see if I can get more batteries later for the car and/or the motorcycle. Of course if I can't get the car to pass MOT then I won't have to.

In any case I thought it would be a good idea to empty the pack before dismantling it. This way it would have the least power stored in case I mess something up in the process. It turned out to be a little challenging and I couldn't avoid letting some sparks fly, so I guess I was on the right track. The minus cable of the pack had slipped into contact with the positive end of the 12 V lead acid battery. A little slip of a wrench into the chassis of the matorcycle resulted in some fireworks along with the bolt in the end of the minus cable welding into the battery terminal.

So yeah, let's be careful out there. Other than that there were no mishaps. I had pushed the pack down to 50 volts, about 2 volts per cell, but it had bounced back to 74 volts by the time of disassembly. All but two cells were at 2.95-3.00 volts. The remaining two were at 2.71 and 2.80 volts. Not sure why, but I may have sucked them a little bit more empty while bottom balancing, they may have been worse cells, I may have hurt them by sucking them too low or maybe some of the sparks I've made have caused them to get a little bit more empty. The difference isn't very big though, since the voltage drops very quickly below three volts. All in all I'm not worried and will just add some more juice into those two cells or suck the others a bit lower.

The cells aren't very clean due to my open design of the battery box and the fact that the braces had rusted rubbing some of that rust into the cells. The cells whoever seemed quite uninterested in their external appearance. Perhaps a more close box would be in order though. The next incarnation of the battery pack will be different anyway, so I'll see what I can do. That's for next summer in any case. I took the bike off insurance for this season.