What to do when that sun stays hidden behind the clouds for weeks on end? Well, the answer is a backup generator powered by non-ethanol, high octane fuel. To take the batteries from 35% of discharge to 100% full is about four hours of generator time on our 6,800 watt Rigid generator from Home Depot. To equalize the batteries or overcharge the batteries enough to clean off the lead plates, it takes about 6 hours, which we do once a month. This picture was taken on our fifth time we had to use the generator this year. We used the generator twice in January 2014 and again from November through January 2015. So from February through October, it is all solar. During November through January, it is a mix of fuel and solar. We use about 3 gallons of gas for each charge up from 35% to 100% full on the battery bank. We used the generator 7 days this past year, so our electric bill is about an average of $4 per gallon times 21 gallons used, which equals an $84 electric bill for 2014 and early 2015.
I admit I have not maintained my generator as I should have. It was a financial compromise when I bought it. It is a loud, loud, machine, making a lawnmower seem like a peaceful babbling brook. However, the generator has been a faithful companion, has run everything I have asked it to and without complaint. I just add oil when necessary and purchase the highest octane gas for it. If I was to use the cheaper gas, it could cause serious problems for the carburetor if I let it sit as long as I do between uses. During the last charge of the season, I run it one extra time with fuel stabilizer for 5 minutes to prepare it for the next winter. The generator has run out in the rain, snow, sleet, and hail. The generator has shaken loose its air filter, its electronic shutoff buttons, and casing for the 240v plug, but it still works fine as we rigged the air filter with bailing wire, shut off the generator using the gas shutoff valve, and carefully plug in the house to the 240v plugin. It has been a great generator for the past 5 years. Before we installed the solar panels and batteries, it ran every day for a few hours. When I installed the batteries, it ran every 4th day. Once the solar panels were installed, it runs only 7 times a year at the most, thus far.
Now most of the time, we leave the generator running in the pump house to quiet the noise and protect it from the elements. The generator charges the house, but also runs the house at the same time it is charging. During this time, we turn the well pump on to fill our cistern, run load after load of laundry, sweep and vacuum the house, and we top off our batteries on our laptops and cell phones. By doing this, we are preparing our battery bank to last till the next sunny or partially sunny day. Our batteries are rated for around 700 discharge/charge cycles at 20%. This means the batteries will be taxed to a point of no return around the 700th charge cycle if we drop to 20% charge each time. During the winter we never allow our battery bank to drop below 30%. When our battery bank approaches 40%, we begin planning to use the generator to charge the system. Since we use the generator only seven times a year, that doesn’t mean our batteries will be good for 70 years; however, if we properly maintain them, we should easily get 10 years out of them.
For this generator, we hope to retire it before it shakes itself apart for a hydrogen generator in the future, an exercise bike generator, and a generator which uses the difference in hot and cold to create electricity on the wood cook stove, a TEG / thermo electric generator. However, I believe we still have plenty of time left until this die hard generator’s retirement.