Two Inverters Off Of The Same Battery Bank?

[Lenny's OffGrid RV Living]

I have a 3,000-watt 12v to 120v inverter wired into my 12v battery bank now and only using the 120v outlets for now. Since the 3KW has a 30-watt standby power draw, I also have a 1,000-watt inverter that I wanted to wire in as my primary inverter and only turn on the 3KW when I need to run something that needs that higher power ability. The 1KW inverter only has a 10-watt standby power draw.

Can I just connect both of them to my battery bank? I'm thinking I can but I wanted to run my idea by the group, just in case. Do I need to do anything else other than connect the cables to the 1KW inverter? Do I need to run the cables all the way to my battery bank (about 3') or just connect them to the + and - terminals on the 3KW inverter which already has 2/0 cables connected to it from the battery bank.

I have 1,000 watts of solar panels running on two Epever MPPT charge controllers and four 100ah LiFePO4 12v batteries in parallel.

 

[mopat]

sure it will be fine

 

[GLC]

First, are you already consuming the 3000 watts on the first inverter? If not why a second one? Second, If you are already using 3000 watts, what size is your battery bank? 4000 watt draw will drain things quite quickly. But the true answer is, that you can connect them but should you? And yes, run cables back to your battery bank.

 

[schmism]

at the min you could run the 1kw one from the lugs of the 3kw one. <-this has issues

1) you cant disconnect and remove the 3kw without also shutting down the 1kw
2) if you had a disconnect between the battery and the 3kw, and shut it off, it will also shut off the 1kw.
3) you would need to ensure that the cables supplying the 3kw can handle all 4kw of load (~350 amps which 2/0 isnt going to cover)

As your unlikely to find cable to handle 350a it looks like the best option is to run both back to the battery with their own disconnects and their own fuses.

 

[SolarQueen]

Each inverter should go back to the battery bank, or a bus bar, through it's own breaker or fuse on its positive. Read the manual for recommended size.

 

[pollenface]

I have used a 500w & 2000w inverter from the same bank, no problems. The 500w ran 24/7 and the 2000w was switched on/off when needed

 

[RCinFLA]

The larger the inverter power capability the more the overhead power consumption. Larger and/or more paralleled MOSFET's with greater gate capacitance to switch at high frequency. Good reason to not use an inverter with power capabillity greater than you really need.

A 12v 3KW inverter pulling close to 300 amps is already pushing the realistic bounds of a 12v system so don't run them simultaneously.

 

[Lenny's OffGrid RV Living]

I installed the 1,000 watt inverter on 11/14 with the supply (+) line going to a 150 amp breaker so it's protected and would probably trip the breaker if I pushed it with the microwave and something else running at the same time.

I also ordered 300 more watts of solar panels since this is my first fall/winter trying to run exclusively off the solar system. With the sun being further in the southern sky and shorter days, even with full sun all day, I haven't been getting my battery bank back up to 14.4+ range.

 

[2009Bounder2020]

I run 2 inverters for same reason. My 500 watt runs the tv and audio. I have a 3000 hooked up to run occasional power tool / air compressor. I run the little one off the lugs. The 3000 has proper wires and fuses. I have a fuse going to the 5oo as well. It’s much more efficient and I leave the little inverter on 24/7