I'm looking to install a UPS style backup on 2 circuits in my home.
1. The sump pump, max draw 5 amps runnning.
2. The gas fired boiler heating system. It requires electricity to set off the ignition spark as well as run the 2 circulator pumps. Average draw just over 1 amp, if both pumps are running. There's also an electronically operated flue damper.
The setup requires and inverter/charger and several deep cycle batteries. The inverter/charger is quite smart. Everything runs off of AC when available. Batteries are charged and cycled for long life. The type of charge depends on what type of battery is being used. When AC goes out the inverter does the transfer and runs off the batteries. There's an adjustable low voltage cutoff so the batteries aren't drawn down to near zero, which shortens their life even if they are deep cycle. A thermal monitors battery temperature at all times and controls the rate of use and charge accordingly. Options include testing the system via the display, a remote display, 2 phase 240 volt output on higher powered units, and starting a generator at low battery voltages.
Here's the question - There are 2 types of DC to AC inverters, there's modified sinewave and pure sinewave. Modified sinewave is misnomer, it's a sqaure wave masquerading as a sine wave, and it's a lot cheaper. Even "pure sine wave" output doesn't even look like a pure sine wave, but it's a lot closer. Now the sump pump will run fine on either one, but what about the heating system?
For those interested in this project I can tell you that the cheap inverters, like the 2000W units that sell for $199, are no different than the 1000watt PC power supply that sells for $19. They're cheap and dangerous. I'm looking to deploy a unit typically meant for marine use, meaning it has more seals of approval than even the most decorated power supply from Seasonic could muster. And it all has to comply with code, otherwise an insurance investigator can note discrepencies and decided whether or not to pay for an insurance claim if there's ever a fire, God forbid.
People who put money and political ideology ahead of truth and ethics are neither patriots nor human beings.