RV Power Inverter Comparison Tips
Comparing power inverts for RV use can get complicated because of the many brands and models.
When you see an inverter for $800 and then see a similar unit for $300 be careful. The may look alike and may have the same watage rating. They may even be the same brand name, But they may be different models with different specifications, features and components. Even though they look alike, they may not be alike.
Many power inverter manufacturers make top-of-the-line models for reliability, maximum performance and durability. They'll then make a similar model intended for light or intermittent use (sometimes called a "consumer" version). There's nothing wrong with this. The "lighter" model will work well if used as intended and can often be 50% or so cheaper.
The bottom line is you're a serious RVer, wanting to power most of the 120V appliance in your recreationa vehicle you'll be demanding the maximum from a power inverter. Therfore you'll want to spend the money to get a high quality power inverter with the capacity you need.
If you're a more casual RVer just wanting to watch a bit of TV or run your computer, you might be satisfied with the light-duty version.
Below are the major factors to consider when comparing RV power Inverters.
Inverter Output Power-- In watts. You'll need to get an inverter capable of more than the max watts you'll use at one time. For how long? This figure may be hard to find. Use the manufacturer's website or 800#. Anyone that can't give an answer should be eliminated. Good companies will show, for example, that their 1,500 Watt inverter might operate at maximum power for 15 minutes and at 1,100 Watts continuously. If their inverter actually does run continuously at its rated power, that should be the only number--but you'd better quiz 'em and make sure.
Inverter Surge Power-- Should range from about 2 times output power to 6 times output power. You need this to start heavy loads, capacitor-start motors and the like. For how long? Most manufacturers don't commonly list this figure. It's short, usually 2 minutes or so. Nothing wrong with that because that's usually all that's needed. If it lasted much longer, it would just get hot and ruin itself
Inverter Idle Current or No Load Power Drain-- An important figure if you'll leave it turned on (idling) so that it automatically delivers full power when an appliance is turned on. This can equal nearly 20 watts of 12-volt power in some brands. (20W at 12V = 1.7Amps). You certainly don't want an idling/standby inverter to constantly drain over an amp-and-a half from your battery. Quality inverters draw only a fraction of an amp (as little as a tenth, or much less, of an amp) at idle.
Inverter Power Efficiency-- Is a critical figure. It should exceed 90% overall in [most] inverters. It should not vary much from partial to full loads. Beware of inverters that advertise 90+% overall efficiency but may drop to less than 50% at some load levels. The above are the key comparison figures. Others, such as output voltage and frequency regulation should also be compared but will be similar in high-quality inverters. Note that top quality inverters will regulate voltage, for example, to within 2% of the rated 120VAC. This is better than your power company, which usually regulates voltage to only �5%!
Comparing Cost-- is the final comparison. As when buying anything else, just make sure you don't mix apples and oranges.