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DO--yourself a favor and gather some information. Flea markets are littered with useless, old-fashioned inverters that people thought were bargains. Read surplus catalogs carefully -- bargain inverters from military aircraft are grossly inefficient (because an engine is always running) and many operate at 400Hz, or cycles per second, instead of the standard 60Hz. Plug into one of these and fry lots of things (clocks are amusing to watch).
DO--read the instructions very carefully, more than once, and hilite the critical steps before attempting to connect an inverter. Some have elaborate instructions (good), but critical safety precautions are buried in the text and easily overlooked.
DO--locate an inverter as close to the batteries as possible, with as heavy a cable as possible (read the instructions). But DON'T put the inverter in the same compartment with the batteries unless you enclose it in its own, vented to the outside, "mini" compartment. Even if you're fortunate enough not to have a spark cause a battery explosion in a poorly located inverter, battery gases in the air will literally "eat" the insides of the inverter.
DO--ventilate an inverter well. They get warm. They need fresh air, just like a stereo or computer. Inverters do well in outside RV compartments as long as they are protected from the elements.
DO--consider small, palm-in-your-hand inverters if that's what you need. Unless your wiring is very skimpy or has puny connections, you can plug these into standard 12VDC receptacles, avoid installation problems and save money. Again, for medical machinery like breathing machines, you can easily move the hand helds from living place to car, etc.
DON'T--ever-attempt to connect the 120VAC output of an inverter to your electrical system with a simple jumper cord using a male connector (plug) at each end. The electrical shock hazard might/might not be a big deal, BUT, you WILL, someday, forget to unplug the inverter before connecting to commercial power or starting a generator. You will then lose an inverter. Guaranteed! (And they won't honor the warranty.)
DO--consider load transfer switches even though they may cost more. (Read the above again and see more details later.)
DO--make sure the transfer switch, if you use one (you might need two in tandem), will handle three sources of power if you also have a generator. (Many remote homeowners, without access to commercial power, can use simple, cheaper switching devices just to go from generator to inverter. RVs might come on commercial power anywhere.)
DO--make sure you know what you're doing when wiring or get help from someone who does. But DON'T get help from someone who doesn't know what he's doing. Guaranteed he will short the whole business out. Even if you use a "professional" electrician, DO make sure he understands that neutral and ground wires in an RV are NOT bonded together.
DO--consider an inverter as a priority item if medical appliances keep you tied to commercial power. (You can even plug the small ones into wheel chair batteries in many cases.)
DO--buy an inverter from someone who will let you return it for full (or nearly full) credit if it's in like new condition, original box, etc. Some inverters will cause radio/TV interference. Some will cause interference only on certain brands or models within brands. Ask first. Good dealers will know most of the static or interference-prone items and can advise you in advance. Good dealers will also allow you to bring your RV to their place of business so inverters can be temporarily connected to test interference.
DO--notice that I haven't mentioned solar panels except casually. An inverter runs from a battery. The battery doesn't know or care where its charge came from. Also note that an adequate solar system can eliminate the need for a generator or commercial power except as a backup.
DON'T--let the above scare you away from inverters. They're perfectly safe if used properly. They're not difficult to install if you follow the instructions. They can just about pay for themselves depending on what you use them for. Some of us used to modify all sorts of things to operate on 12 volts. It can be clumsy, things can get damaged and such modifications void warranties. I encourage people to make a hobby out of electronics so they can do this, but it's really not necessary with the efficiency of today's inverters.
phred Tinseth © 1998-2000 Reproduction Permitted