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DIY Plug-In Hybrid Car

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Step 2: Generator

Picture of Generator
demand-regulator.jpg
The heart of this project is a generator, which creates electricity for the propulsion system.

A friend of mine is an RV mechanic. A while back, I got an RV generator from him. It was non-functioning and pulled out and replaced with a new one. He told me that if I could fix it, I could have it.

He was also kind enough to loan me the repair manual!

Since it's an RV generator, it's already approved for use in vehicles, has a remote start feature, and uses a 12V starter with negative ground (just like on any old car!) The generator is a brushless, computer-controlled, variable speed generator, sometimes called an "outrunner". (Because the permanent magnet rotor is on the outside of, and revolves around the stationary internal stator.)

It's a 3400 watt generator - pretty powerful for how big it is.

Going through the manual, I followed all the troubleshooting suggestions, checked the spark, air filter, and oil - all the typical things you would do for a small engine.

Not included with the generator when I got it was the muffler and the propane regulator. It took me a while to find the exact right regulator. It's a fancy Garretson brand, "demand-type" regulator. The regulator prevents any propane from flowing through to the generator UNLESS there is vacuum on the output end. When the generator runs, it creates vacuum, which opens the valve and allows the right amount of propane from the tank to the generator.

I also needed a primary regulator - the one that goes right on the LP tank. It required an 11 inches of water column regulator, which could provide at least 100,000 BTUs. Those are pretty common. I picked one up at the local hardware store for $23. The Garrettson demand regulator was mail-ordered and cost $50, plus shipping.

Much of the time spent on the project was just to get the generator working right. It requires pretty specific regulators, and the fact that it was partially non-functional when I got it meant I had to really learn some troubleshooting. However, a FREE generator was part of the inspiration for this project as the cost was right.

The other thing I like about this generator is that it runs on LP gas! While I would prefer to run the car on electricity (from renewable sources, whenever possible) some hydrocarbon fuels are better than others. The propane burns really clean. This is a four-cycle, single cylinder engine. (Much better than 2-cycles! Ick!) Gasoline is smelly, nasty, and volatile. Also, it goes bad.

In the Chevy Volt, if you never use the gasoline generator, the generator will eventually run automatically, all by itself, just to run some of the gasoline through to help keep it from going bad in the tank. You don't need to do that with propane.

 
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