Confessions of a Boondocking Generator User

For years we've boondocked with solar and wind power. "Have inverter, will travel," has been our motto. A few months back we picked up a truck camper for use in "field research" where our fifth wheel is too unwieldy to go.

When we started looking for a truck camper, it wasn't our intention to buy anything fancy or "tricked out." But as it happened, a much abused "high end" camper came on the market cheap, and--since money talks and we could use a "fixer upper" for technical articles--we wound up getting it. Again, it certainly wasn't our intention to have an RV with a generator, but there it was.

With the press of time we wound up making our first big field trip with the "new" camper before we had the chance to get solar panels mounted or a wind turbine put in place. That left us on the road depending on the truck alternator to charge the camper battery system. But you know how one thing leads to another. Miserably hot weather and high humidity suddenly necessitated the use of air conditioning--and well, with a generator handy, it became possible. Firing up the "genny" to zap a quick dinner at the end of a long road day too, was helped by having that propane generator available.

I know, I've disparaged thoughtless generator owners before. Listening to the "Onan Chorus" on an otherwise quiet night gives me the willies. I hope our experiences as "boondocking purists," won't turn us "Jekel and Hyde" fashion into those who run the noisy thing day and night. Actually, it's one of the quietest generators we've heard, but nevertheless, it seems like there's a big principle involved. For now, we're definitely looking forward to getting the wind turbine set up, and running the computer with the help of the inverter. The quiet definitely has its virtues.

How Much Battery Does Your Inverter Eat?

We posted an earlier blog entry on the wonders of using shower power provided through the media of an inverter. An inverter is a device that changes battery power into something more edible to devices like power tools, computers, televisions, and such.

Like everything else in life, there's no such thing as a free lunch, and if you use your microwave to heat yours, there is a certain and fearful toll to be taken. The more "shore power" your device uses, a LOT more battery power will be consumed. Let's take our "Nuke me some lunch!" scenario.

Let's say your RV microwave oven uses 1,000 watts (check out the data plate on the back of whatever device you're using) to operate. To heat up a couple of plates of last night's leftovers, let's say you'll be operating the microwave for 5 minutes. How much battery power will you "eat" for lunch?

The formula is quick and easy: Battery amp-hours consumed is this: (AC Watts/12) x 1.2 x time of use (in hours). Our microwave operates at 1000 watts, divided by 12 equals 83.3 times 1.2 (the inverter isn't completely efficient, so this factor allows for inefficiency). That equals 100. We multiply this against the usage time, 5 minutes divide by 60 gives us the "hours of use" of .083. The total amp-hours consumed in reheating lunch equals 8.3.

That may not sound like a whole lot, but if you were charging your battery with a 100 watt solar panel, it would take over an hour of strong, full sunlight to "pay" for heating up your lunch. That doesn't even take into account battery charging inefficiencies. This is one of the reasons you'll see serious boondockers running a rooftop full of solar panels.

So before you start firing up the inverter, run some quick calculations and see if you can 'pay the inverter piper.'

New to Solar? You Need a Regulator

If you want to safely use solar panels on your rig, they need to have a system to stop them from charging when your house batteries are full. At night, without a regulator system, the solar panels will turn into a "load" and actually cause your batteries to discharge.

There are "self regulated" panels available, the trouble is, their output is so small it's hardly practical for an RVer. Commercially built solar panel regulators are like a visit to Starbucks. You can get plain (OK, with creme and sugar) or you can add everything in the way of bells and whistles. What do you get with your cappuccino? Some fancy regulators have built in meters that show battery voltage and charge current--that's a great bonus--and even those that track your battery "bank account" by showing how much power you've used, verses how much you've stored. Of course, the more you get, the more you pay.

A plain-brown-wrapper regulator that simply that stops charging when the battery is full, and restarts charging when the battery needs it is great if you're on a budget. Just make sure you always buy a regulator that has more capacity than you need now. Later if you expand your solar power "farm" on the roof, you won't need to invest in another regulator.