Splitting the Generator Voltage - Looking for opinions

fooddivafooddiva Registered Users Posts: 15
We just purchased a new generator for our 24V system. It's a Honda EM6500SXIA. (Not our first choice but the only one we could afford at the time) Our 16 batteries are in bad shape, so we will be replacing them very soon. However our plans are to take the 240 volt, 50 amp outlet and use the 120 volt leg to power the house service panel and the other 120 volt leg to the inverter's battery charger. We have a Trace 4024 inverter and a new Xantrex Charge controller. This would be accomplished through using a contactor relay and using 10 guage THHN wire.

Any opinions on doing this?

Comments

  • System2System2 Posts: 6,290 admin
    Re: Splitting the Generator Voltage - Looking for opinions

    Not sure what you are trying to do but the SW4024 has a gen set input. Not sure you need an external switch. I assume you supply power to the house through the SW4024 when the genny is off. If you have 120V system (1 4024) Connect the genset to the SW4024 and let it send the power to the house. I think some of the Hondas can be wired to provide 50 amps at 120. Splitting the power may be a problem as if you place a high load on the generator, the inverter may kick off on the batt charge due to frequency errors. The SW4024 needs 60, +- 3 Hz Running all the power through the Trace will allow you to fix the load on the genset. Trace can cut charging under high loads from the house. If you are doing manual start/stop the Trace will sense the power and charge the batteries. Trace can handle full auto if you have start wiring on the generator.


    Bruce
  • BB.BB. Super Moderators, Administrators Posts: 29,981 admin
    Re: Splitting the Generator Voltage - Looking for opinions

    I could only find the manual for the EM6500SXKA (not "IA")--so I hope I got the right one...

    The manual implies that you should be able to flip a switch to 120 VAC only operation and that you can add the two 120 outputs into one full current 120 VAC output.

    If you cannot, you should look into the Xantrex or Outback Auto Transfomers which would support a single full amperage 120 VAC circuit based on the 240 VAC output of your generator...

    The reason I am suggesting this is that you don't (apparently) need any 240 VAC power. And, the SW4024 includes an automatic switch between Generator power and inverter/battery power (sort of like a giant UPS--uninterruptible power supply; using generator power to supply AC power to the output plus charging the batteries when the generator is running, switching over to battery/inverter power when the generator is off).

    This would then support the maximum ratings of the SW4024 inverter and charger, plus you can add your second charger and other generator only loads without worrying about trying to balance the current across two separate circuits (each with less rating than your 4kW SW inverter).

    However, please read the manuals (or get knowledgeable help) with the inverter, charger, and generator. I have not worked with any of the devices listed and could be wrong in my above suggestions--Although I am pretty sure that the above (combining into one 120 VAC circuit) is the "optimal" configuration.

    Your method would work if you don't need a full 45 amps but need a maximum of 22 amps of 120 VAC. But since you have a 4kW inverter/charger, it would seem that a combined 45 amp maximum 120 VAC generator output better matches your inverter capability.

    I am not sure where you would install the contactor (or what you are using it for)--and, assuming you are in the US, you should refer to the NEC (National Electric Code) for the proper wire rating (ratings also depends on conduit size and fill). Also, the gauge of the wire should be increased if you have long runs to lessen voltage drops.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • mike95490mike95490 Solar Expert Posts: 8,569 ✭✭✭✭✭
    Re: Splitting the Generator Voltage - Looking for opinions
    The manual implies that you should be able to flip a switch to 120 VAC only operation and that you can add the two 120 outputs into one full current 120 VAC output.

    If you cannot, you should look into the Xantrex or Outback Auto Transfomers which would support a single full amperage 120 VAC circuit based on the 240 VAC output of your generator...


    My opinion too. You don't want to overload 1 leg of the generator, and have the other leg with 80% reserve. You will smoke one set of windings.

    Go with a honking big 240 - 120 transformer, and reduce the load on the windings, or see if there is a switch to parallel the genset windings.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

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