Dumb generator question

SolMan
SolMan Registered Users Posts: 15 ✭
in Off Grid Solar & Battery Systems #1
Is there a reason that a generator with a twist-lock plug output connection could not be used to connect to a Trace 4024 for battery charging?
This is a Generac 7500 watt portable unit which only has plugs for output connections.

I could plug one end into the gen and cut off the other end and wire into the inverter...
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  • Cariboocoot
    Cariboocoot Banned Posts: 17,615 ✭✭✭
    #2
    Re: Dumb generator question

    As long as the Voltage is right, the connectors don't matter.

    I don't remember the input on a Trace 4024, but I think it's wire terminals for 240 VAC?
    Making sure the charge programming is right shouldn't be too much trouble with a 7kW generator either.

    My Outback is "hardwired" at one end with a 120 VAC plug at the other for the Honda 2000. Works fine.
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  • KeithWHare
    KeithWHare Solar Expert Posts: 140 ✭✭✭
    #3
    Re: Dumb generator question
    SolMan wrote: »
    Is there a reason that a generator with a twist-lock plug output connection could not be used to connect to a Trace 4024 for battery charging?
    This is a Generac 7500 watt portable unit which only has plugs for output connections.

    I could plug one end into the gen and cut off the other end and wire into the inverter...

    There are NEMA specifications for most twist lock plugs. Looking at the prong configuration, you can tell whether the plug is 120 volt or 240 volt.

    Wikipedia has a description of NEMA specifications at http://en.wikipedia.org/wiki/NEMA_connector.

    I've also used the Hubbell catalog to figure out which twist-lock device is which:
    www.hubbellcatalog.com/wiring/catalogpages/section-b.pdf

    One way to handle a generator is to install an outlet (essentially a male plug) in a weatherproof box convenient to where the generator will be, then create an extension cord to go from the outlet to the generator. This will be a lot neater than having a cord hanging out of the inverter.

    Keith
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  • SolMan
    SolMan Registered Users Posts: 15 ✭
    #4
    Re: Dumb generator question

    Great idea Keith!
    Hadn't thought of that. That's what I will do.
    This genset has both 120V and 240V twist-lock outputs, but I think this 4024 has only 120V (3 wire) gen input, so it should be fine.
    However, the 120v gen output is rated for 30A. Is that enough? Will the Trace 4024 just take whatever it's given or will it somehow try to pull more?
    The genset has circuit breakers...
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,613 admin
    #5
    Re: Dumb generator question

    I don't know about the Trace specifically, but that general class of Trace/Xantrex inverters usually has a programmable setting for the maximum current draw at 120 VAC (or generator circuit-breaker rating).

    Set it for about 1/2 the output rating of the genset and see how everything works. You may then be able to increase to 75% or have to drop back a bit if the genset does not perform well.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • SolMan
    SolMan Registered Users Posts: 15 ✭
    #6
    Re: Dumb generator question

    Thanks all.
    Gonna set it up this weekend.
    Will let you know how it works.
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,485 ✭✭✭✭
    #7
    Re: Dumb generator question

    Some generators have a 240v/120v switch to allow full power capability of generator at 120vac only.

    It switches two 120 vac windings between series connection for 240vac to parallel connection for 120vac.

    As outlined earlier, a NEMA 120vac twist lock plug (three prongs) is different then a 240 vac twist lock plug (four prongs). You can get 120vac from a 240 twist lock wiring one of hot sides and neutral. For this arrangement you are loading only half side of generator.

    I assume you are referring to SW4024. There is MAX AC2 AMPS input setting and MAX AC charging AMPS settings.

    Lets say you have 3500 watt,120vac generator. You would set AC2 IN AMPS MAX to 29 amps or less. AC MAX charger can be set anything less then AC2 IN AMPS MAX.

    When ACout amps exceeds ACin MAX the inverter will suppliment the output, drawing power from batteries.

    When ACout load plus AC chgr max exceeds ACin MAX, the charger will automatically back off to allow ACout to take more of the available ACin current.

    Sometimes when you set AC chgr MAX too high, there can be a problem when generator is initially loaded by SW4024. There will be a sudden full charge max AC current load right after inverter connects to generator, causing generator to bog down which can cause inverter to release from generator due to out of frequency range. If this happens, lower max charging amperage setting.

    Its safer if you mount a box with a chassis mount male connector on outside wall then doing a direct single cord hardwired from AC2in to generator plug.

    Use SOOW #8/4 conductor cord.

    http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&productId=202213702&langId=-1&catalogId=10053&ci_sku=202213702&ci_src=14110944&cm_mmc=shopping-_-googlebase-_-D27X-_-202213702&locStoreNum=6320&marketID=2
    http://www.homedepot.com/h_d1/N-5yc1vZ1xg2/R-100204222/h_d2/ProductDisplay?langId=-1&storeId=10051&catalogId=10053
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