Solution for grid power only available at night

    I have a rather odd situation: I have grid power available at night when nearby outdoor lights come on, and solar power during the day. I have 5 Schuco S-158-SP panels in parallel connected to a Xantrex C40 charge controller, which is then connected to 3 UPG 12V 100Ah AGM UB121000 batteries in parallel and an AIMS Power 2000W inverter. With these components, the system will be only off-grid and not utilizing the night time power, however, my power consumption will be more than the solar output on a cloudy day, so without a secondary source of energy, my system will die in poor weather (which here in WNY is like half the year). Ideally, I would like to switch to charging my batteries using the grid power at night, but a secondary option would also be to just switch the loads to run off grid power, rather than the batteries, at night. Are there any charge controllers on the market that could switch between the mutually exclusive solar and grid power? Or even an inverter that could switch to grid power just to keep my loads running during the night should the batteries get low or die? Is there any sort of component on the market that I could simply add to my system to work with my current charge controller and/or inverter so I don’t have to replace one or both?


    Michael Goldberg commented 1 year 10 months ago

    Thanks for your question. If my assumptions are correct, your total system size is only 790 watts (compared to the current national average of 5,000 watts). That said, all you would need is a small Inverter/Charger option with Grid-tie capability (Xantrex, Outback, possibly Midnite Solar). That unit would replace his existing charge controller and would be at the center of a 3-way connection between panels, batteries, and the grid. Most units capable of inversion, charge control, and grid management will offer at the very least a basic programmable schedule to accomplish what he is looking to do. My concern is that going with one of our mainstay inverters (like an SMA, or SolarEdge) would result in a system that never turns on, as most inverters require a minimum of power before they even start the DC-AC conversion. Hope this is helpful.

    1 year 10 months ago
    Asked by
    Mychaela Navel