Generator Backup

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dsp3930
dsp3930 Solar Expert Posts: 66 ✭✭✭✭
in Grid Tie and Grid Interactive Systems #1
My existing Generac 5500XL generator is not playing nice with my Xantrex XW6048 inverter/charger. It just appears that the older generator is not producing stable enough power for the Xantrex to qualify it and get a stable green AC2 light on the cabinet. (The SCP shows it putting out 132v @ 70+ hz when running wide open without idle control, and then a more sane 125v @ 58hz with idle control on. ) My guess is that since it is an older unit, it is using a mechanical governing system and not a better/newer electronic one. (that is safer for modern electronics)

Long story short ... does anyone have any specific recomendations for a new generator in the $800-1500 range? Supplemental power during extended outages and portable power are my main uses.

My preferences:
I'd like it to be suported by the Xantrex AGS (auto generator start) module
120/240 30A twist lock plug
Modest sound level (Though neghbors are not really a concern .... as I have three grain dryers next door. Any generator would sound like a music box in comparison.)
Gas or Propane

Thanks!

David
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  • BB.
    BB. Super Moderators, Administrators Posts: 33,447 admin
    #2
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    Re: Generator Backup

    Tony/Icarus has recommended looking in RV Scrap yards for old (Onan?) gensets... Cheap, quiet, and fairly reliable. Probably in the 6-10kW Range. Good for backup power--not necessarily for prime mover type operations.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
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  • mike95490
    mike95490 Solar Expert Posts: 9,583 ✭✭✭✭✭
    #3
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    Re: Generator Backup
    dsp3930 wrote: »
    125v @ 58hz

    Will it sync at the 125/58 ? - Wait, I think the 6048 needs 240V generator input before the charger will run?
    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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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #4
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    Re: Generator Backup

    I do indeed suggest looking into Onans from RVs. What I can't comment on is how well they play with XW inverter/charger. I know that you can get pretty stable freq. with the mechanical governor of the older models. Someone else with some experience with the XW should comment. (I know the Ebay link will go away, but a 6.5 kw commercial goes for under $1000 on a buy it now) http://cgi.ebay.com/ebaymotors/ONAN-6500-KW-GENERATOR_W0QQcmdZViewItemQQhashZitem3efbafddeeQQitemZ270510579182QQptZMotorsQ5fRVQ5fTrailerQ5fCamperQ5fPartsQ5fAccessories#ht_500wt_992

    Often times you can find them for ~$3-600

    Can be made to run on LP or Natural, and wired to auto start.

    Tony
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  • Solar Guppy
    Solar Guppy Solar Expert Posts: 1,989 ✭✭✭
    #5
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    Re: Generator Backup

    You need a 240V not 120V generator, that the issue, not the frequency being off a few Hz.
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  • dsp3930
    dsp3930 Solar Expert Posts: 66 ✭✭✭✭
    #6
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    Re: Generator Backup

    I was referring to a single leg of the 240 coming out of the twist lock 120/240 30A plug on the generator.

    Onan ... I'll go take a look around for them.
    Consumer reports noted that the Briggs Elite Seires were of pretty good quality.
    I was also looking at one of the Honeywelll units.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #7
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    Re: Generator Backup

    Beware, there are Onan, and then there are Onans.

    They name plate a number of POS single cyl. gennies that are just like any other genny of the type.

    The Onan Rv series (emeralds and the like) are still pretty good gennies, we have one that is 10 years old with ~10k hours on it and it runs perfectly.

    The older generation air cooled twins are tanks. CCK versions were 1800 rpm units that ran ~5kw and could be had in all kinds of wattages, many wireable for 120/240 or just 240 or just 120. There are some 50 hrz units out there.

    Many of these units can also be found with welders attached with is has an appeal to some. For the definitive info on Onan gennies, try here:http://www.smokstak.com/forum/forumdisplay.php?f=1

    Good luck,

    Tony



    PS I have a 1947 CCK 3.5 kw auto start, sold under the Montgomery Wards name plate. I don't use it much any more, but it starts first crank, keep perfect voltage. I'll never let it go1
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    #8
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    Re: Generator Backup

    The idle setting is meaningless. You should not use this mode when connecting to XW inverter.

    Sounds like you are too high on rpm setting. There is likely a knob on the generator below the carborator to adjust this. It adjusts the tension on the wind vane spring linkage to center rpm setting. Usually mounted on engine block below carborator. If you are at 70 Hz it means your engine rpm's is 4200. It needs to be 3600 rpm to produce 60 Hz.

    On an XW or most grid sync'd inverters, if a surge load appears, and is allowed to pass through to generator, the generator may bog down for a second as 'peddle is put to the metal' to bring back up to 3600 rpm speed. The XW inverter has a freq range allowed and a max rate of change that it can maintain phase lock to generator. You have to check the amount of 'bog down' on surge load on your particular generator. Electronic regulator equipped generators are generally better.

    On XW you can set the generator input max draw current level lower to help relieve the generator from slowing up too much on surge load. The batteries will supply the surge power preventing too much surge load on generator.
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  • icarus
    icarus Solar Expert Posts: 5,436 ✭✭✭✭
    #9
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    Re: Generator Backup

    Not to pick nits, but frequency of gennies is related to RPM (in conventional generators) but 60 hz can be accomplished other ways than 3600 rpm. 1800 and 900 rpm units are out there, and I suppose you could find a unit that runs at 7200 rpm or even 450 rpm, but in essence it needs to be a multiple of 60.

    A small gennie owners best friend is a Kill-a-watt meter. It is the only cheap method available for us to sync the freq accurately. I set my gennies up for ~62hz with no load, witch usually translates to ~130vac. Put the genny under 50% load and it falls to ~60 hz @120vac. If you run closer to 80% load, sync it with the 80% load.

    Tony
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  • RCinFLA
    RCinFLA Solar Expert Posts: 1,484 ✭✭✭✭
    #10
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    Re: Generator Backup

    Generac 5500XL generator requires 3600 rpm. It's a single pole field generator. It has an electronic field current regulator but relies on old fly-wheel wind or oil vane system for engine speed control.

    Most cheap DVM's now have freq function that is accurate enough to set gen speed. Just adjust speed for 60 Hz at plug.
    I recommend putting 1 to 2 kW load on gen when setting freq. (hair dryer, toaster, etc.)
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