Forum Discussion

shepstone's avatar
shepstone
Explorer
May 01, 2021

Onan 5500 and batteries

Hey guys, I have a 2021 GD 380fl with Onan 5500 built in generator. Works great but I want to add a battery bank and use an inverter for smaller loads so that the genny isn’t running so much. Not knowing how the Onan is wired in I’m assuming that it has a switch of some sort that will switch it from shore power to generator, How can I add a battery bank with inverter into the mix? And is it possible or necessary to use the switch that the Onan has? I know that I can run a extension cable from the batteries inverter to the external shore power plug with suitable adaptors but I’d prefer to use an internal automatic configuration. Thanks.
  • Not sure on solar but it’s a prossiblity same for temporary power pole, but it’s mostly going to come from onboard generator and smaller inverter generator. Don’t know why the battery is lighter, maybe it’s the general nature of Lithiums or perhaps this particular model.
  • So you will recharge with solar? Or will there be a 120 volt shore power "drop"?

    I don't understand why the battery weighs so much less than other similar capacity units.
  • wa8yxm's avatar
    wa8yxm
    Explorer III
    pianotuna wrote:
    Complicated way much more expensive,

    wire a sub panel for items you wish to run from the inverter. Power that panel from the inverter output.


    Not all that much more expensive but

    That's the way to do it.
  • First off Thanks to everyone for their replies. I appreciate it. I have since purchased a 300 amp hr lithium battery from Canbat and a 3,000watt pure sine wave inverter from Renogy and also Renogy battery monitor. After researching much more than I expected I have come up with either replacing the existing automatic transfer switch with a 3 way unit or adding another 2 way ats at the front compartment for the generator and the inverter. Since a 3 source switch is rare and expensive I think that a second 2 way ats for the gen and inverter is the way to go. Any flaws that you can see in my plan?

    https://www.amazon.ca/gp/product/B07RP5B5P7/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1

    https://www.amazon.ca/Renogy-1000W-Solar-Inverter-Cabin/dp/B07MKN7MM3/ref=cm_cr_arp_d_product_top?ie=UTF8&th=1

    https://www.canbat.com/product/12v-300ah-cold-weather-lithium-battery/

    I should add that this will be our full time home for the next 2 years as we build our house.
  • There are definitely cheaper etc alternatives. However the price he was quoted for a PSW upgrade is likely reasonable but depends upon what he currently has.

    OP None of this is rocket science and with research etc it can be a DIY project.
  • Complicated way much more expensive,

    wire a sub panel for items you wish to run from the inverter. Power that panel from the inverter output.
  • A friend of mine, that used to run with us a lot, would often plug into one of my Honda EU2000i generators instead of running his 7000 watt Onan diesel (on his diesel pusher motorhome) for light loads. We both used automatic battery chargers on our rigs.

    After he used my Honda a few times, he bought one of his own. Even with having to carry a gas can, he said it was much more efficient than to run than his Onan for light loads.
  • Simple way:

    Set fridge to propane, switch converter off, plug shore power cord into inverter output.

    Or you can automate all of the above, for a LOT more expense.
  • Connect the inverter to the existing battery bank and use it's AC output. From there it gets more involved with new or expanded battery bank and AC circuit wiring. Battery chargers may also be involved.

    Even more involved would be to add a whole house inverter that powers can power the entire RV AC.

    Virtually every RV with a built in gen has an ATS that switches between shore and gen power. Batteries, chargers and inverters are independent.

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