In this part, we’re going to discuss one of the most important, if not THE most important, parts of the system. The power inverter.
There are two (well, three really) kinds of power inverters.
The one we ignore is the Square Wave power inverter, which produces an AC current with a square wave. Square Wave inverters aren’t very efficient, and the output power only vaguely resembles what you get from a tandard grid powered outlet. Don’t get these.
Modified Sine Wave inverters are an option for most standard applications and are a good choice for an overall inverter. They produce an AC waveform that’s between the square wave and a pure sine wave. Better on the stuff you power, and reasonably good effiency wise.
Problem is that anything requriing timing or precise motor speeds don’t operate reliably on a modified sine wave inverter. Unfortunately for us, that covers most medical equipment.
Which brings us to True Sine Wave Inverters, the only choice for powering medical equipment off of a battery bank. For most of these inverters you actually get a better quality current than you do off the grid.
Sounds great, I know, but these things are much more expensive than modified sine wave inverters. Quite a bit so, depending on the load rating. They use computers to control the current wavelength and sometimes even automatically turn the inverter on or off when there’s a load on it.
These are perfect for medical equipment. You can actually damage sensitive equipment if you run it with a modified wave or square wave converter. I know someone who blew out a CPAP by running it in the car off of a cheapo car inverter. Not a good plan when things are normal … could be deadly in an emergency situation.
Since they’re expensive, I’d recommend that you size it big enough to run your medical gear and maybe a bit more. Then buy a modified sine wave inverter for the bigger but less sensitive things like appliances and whatnot.
You can hook both of them up to the same battery bank and power them both at the same time which reduces your effective cost per watt.
I don’t have any specific recommendations for brands or models, just make sure that you get a true sine wave inverter for that sensitive gear.