Choosing a Generator

There are many choices available for fossil-fuel-powered backup generators. We've made our first choices clear on the previous page...a home built, antique or dedicated charger is really a more efficient, quieter, simpler energy saving choice than the regular generators we discuss below. However, we realize some folks have more money available than time. So here's some information to help you make an informed choice. Please post to our discussion board if you have any information to share regarding your experiences with battery charging using fossil fuels!


  • Gasoline--The most common choice,but not necessarily the best in all climates.  Advantages: Easily available at the gas station, can be carried home in cans, has the most power compared to it's weight, works in most common generators, inexpensive (well, relatively so!).  Disadvantages:  condensation problems in cold weather, more frequent maintenance required than with propane, smelly to transport unless you have a pickup truck.
  • Propane--An -excellent- choice for remote power backup, if the propane trucks have decent access to your location.  Advantages--No cold weather starting or condensation problems, maintenance infrequent because of little carbon buildup on cylinder heads, gasoline generators can usually be converted to propane easily at home. (more on this here later)  Disadvantages-- 10% less power than gasoline, must be transported in pressurized bottles, more expensive than gasoline.
  • Diesel--Another good choice for remote power. Advantages--efficient engine uses less fuel per watt, very low maintenance, can be purchased at most gas stations, can be carried in cans.  Disadvantages--Noisy generators, fuel more expensive, more smoke and smell, harder to start in cold weather. Biodiesel can also be brewed from vegetable oil and used, and engines can be converted to burn straight vegetable oil (SVO).
        All generators give less performance at higher altitudes.  Reduce the power rating on the label of the generator by 1% for every 1000 feet you are above sea level, and subtract another 10% if you converted it to propane.

Generator Types

  • Standard hardware store generators--  Examples: Coleman, McCullough, Homelite.  These are available almost everywhere.  Since the Y2K scare, they often  can be found at very low cost in the classifieds. Better grades  ("contractor grade") available, but are more expensive and have only slightly better maintenance records (Generac, Dayton, Honda).  These generators run at 3600 rpm, resulting in very high maintenance costs.  Maintenance must be performed every 20 hours of run time or so, or the generator will die quickly and prematurely.  Advantages--lowest cost, available almost everywhere.  Disadvantages--Not very reliable in a remote backup situation, extremely high maintenance, noisy, most power is wasted when just charging batteries, short service life.
  • Slow run "industrial" generators-- Examples: Onan, Kohler.  These run at only 1800 rpm, making for a much more reliable generator.  Highly recommended, but very expensive.  Advantages--very reliable due to slow rpm run speed, most can run on propane with simple conversion kit, very quiet, low maintenance, very long service life.  Disadvantages--very expensive, hard to find.
  • Diesel generators--new Chinese models are available at very low cost compared to traditional choices.  Slow running and reliable, but have other problems for a remote power application.  Advantages--low rpm run speed, very low maintenance, long service life, very reliable.  Disadvantages--Hard to start in cold weather, fuel different than most cars and trucks (needs different containers, etc.), noisy.