Off grid power systems commonly include a generator for backup when the sun and wind are not enough to keep your batteries charged. We have built our own inexpensive gensets using small engines (lawn mower) and car alternators. Gasoline is expensive, and refilling a generator every few hours can be dangerous and messy, along with high carbon monoxide output, so we show how to convert small engines to run on propane, methane (natural gas which includes biogas), and gasoline. Home made charge controllers and battery maintenance is also covered.
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