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What to blame.. well pump or generator?

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  • What to blame.. well pump or generator?

    Hi folks,

    I installed an off-grid PV system on my mothers 160 acre farm. It has been working great, with one irritating exception. We frequently get a 'high volts AC' fault on the power center when the generator is running. It wasn't a big deal in the summer, but now that winter is here they really need a reliable backup.

    The system consists of the following:
    (12) Helios Solar 250w panels
    (8) Rolls-Surette 6v, 400ah batteries
    Generac Eco-gen 6kw generator
    Power center with (2) Magnum 30amp inverters, Outback Flexmax 80 charge controller, auto-start module

    As far as I can tell, the trouble is (at least partially) caused by the well. The well has a 2hp 230v single phase pump about 270 feet down. The control box inside lists it at 10amp running, 13amp startup. (Both of which seem surprisingly low) The well is near the house, about 200ft from the inverters and generator. When the well turns on, the load is heavy enough to cause a drop in voltage in the house and mess with some electronic devices regardless of wether on generator or inverter power.

    It seems to me that when the well turns on the generator revs up to compensate, and overshoots the voltage. Or when the well shuts off the generator fails to throttle down fast enough and the voltage spikes. I haven't caught it in the act, so I can't be sure.

    When the power center detects the high volts coming in from the generator it throws the fault and switches to battery power. The generator doesn't get shut off however, and just continues running without the power doing anything useful.

    This was my first installation so we had a local solar installer check it over and do some of the AC wiring. He initially agreed that the well is wreaking havoc on the generator, and wanted to install a pump that would be more gentle. The tech crew at Magnum agreed that could be causing the fault. The tech crew at Generac said the generator is meant for charging batteries, not running wells.

    Now, after talking with Magnum again, our solar expert wants to swap our generator with a bigger Kohler one. There is a couple in the area that has 'too big' of a generator and we might be able to trade, but we wouldn't have a warranty on it.

    I just wanted to see if anyone has ideas/experience with wells and generators that might help, especially if there is any way to avoid replacing the pump or generator. The worst scenario would be replacing them both. I tried reducing the charging rate of the batteries to reduce the load on the generator, with no effect. There doesn't seem to be any way to reduce the power centers' sensitivity to voltage fluctuations.

    My concern is that regardless of the generator running or not, when the well turns on it causes a significant voltage drop. Replacing the generator will not effect that and I worry that we'd eventually replace the well pump anyway.

    I assume well pumps use more power as they age.. I'll try to run some tests and find out how much amperage the pump actually uses.

    There is a 240v conversion kit for the ecogen, does anyone know if that could that alleviate some of the strain on the generator?

    Thanks for any thoughts/ideas/opinions!