3100 watt inverter battery bank

[donzinger]

I have a 3100 watt Magnum Research inverter. I have 4 - 6 volt golf cart batteries. It seems to eat those up pretty quickly in my opinion. Anyone else with an inverter this size? Are you running more batteries or do you think my battery bank should be bigger? I have room for 2 more and I also have a 370-watt solar panel setup running.

[sundancer 87]

An inverter isn't all that energy efficient so it will eat batteries. The rule of thumb for inverting is 10 to 1. 10 amps DC to make 1 amp AC.


The inverter does use battery power to work but the biggest culprit is the load the inverter supplies.
Never a bad idea to add more batteries to the bank as long as the original bank batteries haven't been in service for more than a year.
Keep in mind about adding batteries, you may need more solar and larger charge controller.

[ewarnerusa]

I agree with what sundancer 87 said. 4 x 6V batteries is a lot of capacity, but 3100 watts of inverter load is a lot to supply. So what are you using that inverter for and for how long is it supplying the loads? Then we can make a guess on if your current battery capacity is adequate. Is the inverter possibly supplying power to your converter while you are off of shore power?

[donzinger]

Hardwired. Mainly run refrigerators, ice machine and radio or tv. Father in law runs same battery configuration on 2000 watt inverter for better part of the day. The Magnum Research inverter I have is supposed to be "smarter" than the older Xantrex unit and is only supposed to invert enough to supply the demand being "requested". I also have the solar and by the end of the year I will have the AGS-N wired in so I will be able set it up and forget but just seems to drop the voltage rather quickly.

[ewarnerusa]

Any comment on how you are making sure the converter is not being powered by the inverter?

[sundancer 87]

Ice machine and refrigerators, as you know, have compressors in them. The compressor motor is an inductive load rather than a resistive load. The induction motor needs plenty of power to start, just the same way as an A/C does.
You have a big load to start those machines and a smaller load to run them. Get yourself one of those watt meters and monitor the loads. The inverter will provide what you need but the battery bank can't keep up for an extended period of time.
More batteries and another solar panel will help of course.
I had a digital amp meter that showed the amps pulled from the battery bank during use and showed how much was returned to the bank during charging.

[donzinger]

Originally Posted by ewarnerusa

Any comment on how you are making sure the converter is not being powered by the inverter?

Converter was removed as part of the inverter install as this unit is also a three stage battery charger/converter/transfer switch as well.

[donzinger]

Makes sense. That is also why I try to run the coach refrigerator on LP when dry camping

[ewarnerusa]

I've heard of RV refrigerators that have some type of door seal heater to reduce condensation build up when used in high humidity areas and this heater sucks a lot of power. Does your unit have one of these heaters that can be switched off?

Humidity Switch on Dometic Refrigerators

[donzinger]

Not sure on the heater. I'd have to look. But the second refrigerator in the garage area is a residential one albeit small.