Geo Metro plug-in parallel hybrid EV - in progress

[Coyote X]

I was going to pull my name off the list because I have not had time to actually finish it yet

I had nothing to work on yesterday so I thought I had a perfect chance to maybe swap out the sprocket and do some more wiring. Went to the store in the van to pick up some rear brakes for it figuring I could get them swapped out quick before working on the Metro and saw a trail of antifreeze coming out from under it when I got to the store. So later that day the van had new brake shoes, water pump, belts, and hoses. My metro didn't get touched for another weekend

The car is driving me nuts sitting there with probably just 3 or 4 hours to finish it but every time I go to work on it something else needs fixing and is a higher priority than the car since I have other things to drive for now.

[lectruck]

Well that's just how it happens, you are so close to the finish and everything keeps getting in your way. Good luck on the next window of opportunity.

[ev59rag]

Maybe I missed it so kindly direct me to the correct post #.... but how are you going to synch the speed of the motor and the ICE itself... or you are just going to use one and then the other depending on the situation?

So if you are using EV then ICE is in neutral... then if youre going to shift to ICE then you just idle the EV... is this assumption correct?

[Coyote X]

Yep the two motors have independently controlled throttles. The electric motor is connected full time to the CV axle so it is always spinning. It is a small load when idling so it should not matter much. The gas motor is a normal 5 speed and be in neutral/engine off while electric only. For added performance I could use both at the same time to get more speed but I am not sure what kind of extra performance that will give me yet.

The trigger throttle on the shifter works great the way it is now. With a voltmeter connected to the hall sensor it is a very smooth linear movement. I ordered a few more hall sensors and instead of the potentiometer on the brake pedal for regen I will probably use a hall sensor and magnet.

I seriously considered ordering 150 solar cells and building a charge controller of some sort. But I am not sure how or what batteries to charge with them. Charging the 12V battery would let me run alternator free most of the time. Charging the 72V set would give me more range on electric. I guess the best thing would be to convert the entire electrical system to 72V and use one pack for it all. But that would be a lot of work. I am not sure what to do with solar power, if anything, but it is something I would like to do once I figure out what to do with it.

[Coyote X]

Had all day to work on the car. Cleaned up the garage a bit then I took the cv axle out and welded the new 44 tooth sprocket to the hub. I started messing with some other stuff and ended up burning my fingers. So after getting aloe on them and making them feel better it was dark out and my fingers are stiff, I figured it was time to call it a day.

Maybe next weekend I can actually get something done

[Christ]

RE: the electrical system - how hard would it be to DIY a simple DC/DC convertor to bring the pack voltage down to 12v to run the car's electrical system?

Is that outside the range of ability?

[bennelson]

There are lots of little DC/DC converters out there you can just BUY.

My motorcycle has a $10 converter I bought from Ebay that converts the motorcycle's 48V drive system down to 12v for the headlight, turn signals, etc.

It would save you the space of the 12V battery in the engine compartment, but since this is a hybrid, it might be better to leave the original battery for the gas engine and alternator to recharge.

On the other hand, completely remove the alternator and 12v battery, and just run all electric off the drive batteries for maximum efficiency!

Even using a DC/DC converter, you would still want at least a small battery in there to smooth out loads being turned on and act as a backup in case of a problem with the converter.

[Christ]

Using a DC/DC, would that effectively make the car's battery another addition to the system pack, or no? (To increase the AH rating for the pack, not to up the voltage.)

[Coyote X]

I thought about getting rid of the 12v battery. But for now until I really know what goes on with my daily driving conditions I am better off leaving it. It could be useful to get a 72V to 14V converter and do away with the alternator and normal battery. The car will still see normal voltage and not have the alt load.

But I don't know what kind of converter I would need that could handle the headlights, wipers, and defroster all at the same time as well as powering the computer and fuel pump.

I am probably going to go with a garden tractor battery to save space for my main battery. If it goes dead I could always jump start myself without a lot of trouble

[Christ]

I ran a L&G battery for 2 years in my yard truck... never had an issue. It was a carb'd Ford p'up though.