Using two inverters connected to same battery bank?

nginxnginx Registered Users Posts: 5
Hello,

I already have a 850W inverter. I recently acquired another 1KW inverter. I want to connect both the inverters to the same battery bank. The 1KW inverter will be mainly used to power all low power devices in the house like lights, fan, laptops, TV etc. The 850W inverter will be only used to occasionally power the washing machine and a small microwave, not at the same time of course.

I will NOT be connecting both the inverters to the same line. The hot wires for the washing machine & microwave are separate from the rest of the house. But they do share the neutral wire with the rest of the house. The neutral wire is much much thicker than any of the hot wires. However, will the shared neutral cause any problems with the two inverters? I won't see the magic smoke right?

Comments

  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Using two inverters connected to same battery bank?

    Hi "nginx", welcome to the form!
    If the inverters are MSW and not Pure Sine, there could very well be smoke from sharing the same neutral wire. The "neutral" from virtually all MSW inverters is floating, meaning it is NOT at ground potential reference either to actual ground, or to battery negative. These floating "neutral" voltages vary between inverters and will result in current flow on the neutral, between the two inverters. This in turn is very likely to result in smoke.
    That said, it would not be a problem with most, if not all available good quality pure sine inverters.
    On another note, what you're powering with you're 1kw inverter, I and many others use the Pure Sine, Morningstar TS-300, A truly awesome little inverter.
  • nginxnginx Registered Users Posts: 5
    Re: Using two inverters connected to same battery bank?

    Thanks waynefromnscanada.

    Both my inverters are Pure Sine wave inverters. So I guess I am in the clear? Good to know.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Using two inverters connected to same battery bank?

    As long as the neutral wire can handle the combined load, and if the inverters are designed to have their neutral grounded (which I believe all, or almost all pure sine inverters are), you SHOULD be in the clear.
    By the way, reason many of us use a small inverter for small loads, is because of the idle power draw being a lot lower than with most larger inverters. Over a 24 hour period, it can make a substantial difference.
  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Using two inverters connected to same battery bank?

    Always check the manuals about grounding just to be safe.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • westbranchwestbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Using two inverters connected to same battery bank?

    And if in doubt after reading the manual, contact the manufacturer too
     
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  • BB.BB. Super Moderators, Administrators Posts: 32,007 admin
    Re: Using two inverters connected to same battery bank?

    Yea--Some manuals really dance around the whole AC Neutral/grounding issue.

    For the most part, if they do not specifically say it is OK to connect one AC lead to ground--Then assume it is not safe to connect AC Line to ground for neutral bonding.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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