Author Topic: Inverter Outlets work on Genset but low voltage on shore power  (Read 583 times)

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Offline DiscoveryOwner

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Hi, We are having trouble figuring out this issue. Running on the Genset, the inverter outlets all  show 118 volts and operate fine, and the inverter/charger charges the house batteries normally.  Today we plugged in at a park and the post shows 122 volts, the A/C in the coach operates normally, but the inverter outlets are only showing 88 volts and don't operate, and the Xantrex remote panel has the charge light lit up, but it doesn't act like it's charging..the light is staying on "red" instead of shifting over to yellow and then green.  We called a mobile rv repair person and he is mystified..he's double checked the post power, and we have tried both the 30 amp and the 50 amp with a converter plug. This is a 2000 Fleetwood Discover 37G, 30 amp coach.  Any ideas?

Offline ziggyh

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Re: Inverter Outlets work on Genset but low voltage on shore power
« Reply #1 on: June 11, 2018, 09:18:54 PM »
My first thoughts would be to check the transfer switch.

2007 Revolution LE

Offline Brett Wolfe

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Re: Inverter Outlets work on Genset but low voltage on shore power
« Reply #2 on: June 12, 2018, 05:33:16 AM »
The low voltage on the inverter-powered circuits is likely the result of TWO things:

The inverter is a modified sine wave, so most voltmeters WILL read low as they don't accurately reflect voltage of MSW. Yes, I am assuming that your Xantrex unit is MSW-- though they do make true sine wave inverters-- need to know what model you have.

The inverter is not seeing 120 VAC from the main breaker box from shore power, so it is inverting.

Question:  Is the inverter/charger still charging the batteries when on shore power?

When the inverter/charger sees 120 VAC from an external source (generator or shore power) it does TWO things:
"Passes through" the 120 VAC using its built-in ATS.
Charges the batteries.

Try turning OFF the inverter-- this has zero affect on either passing through or battery charging, but will not allow the inverter to invert.  If what I think is happening (outlets are seeing only inverted power) then you will read no voltage at the outlets.

Let us know what you find.

Yes, the ATS is a likely starting place.  BUT, if one of the hots is not making contact, other things in your coach such as one of the roof A/C's would also not work.  From the ATS onward, there is no difference between generator and shore power in terms of wiring.
« Last Edit: June 12, 2018, 06:58:00 AM by Brett Wolfe »