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Small Gas Generator with Xantrex Inverter/Charger?

Discussion in 'Boat Electronics' started by Walt Bilofsky, Mar 6, 2005.

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  1. Has anyone had experience trying to drive a Xantrex inverter/charger
    with a small gas generator?

    The specs for the Xantrex Prosine 2.0 inverter/charger say that when
    it's plugged into shorepower (or an external generator), it will
    automatically reduce the charger load to keep the AC source voltage
    above a minimum level.

    If that's to be believed, I should be able to run a portable 1 KW
    generator into the Xantrex, and have it draw as much current as the
    generator can serve up, but not overload it. I should also be able to
    have AC appliances running off the Xantrex, and still charge the
    battery with any AC power left over.

    Has anyone actually done that? Or had any experience with that kind
    of setup?

    - Walt Bilofsky
     
  2. Read the manual for your inverter/charger CAREFULLY _before_ buying
    the generator.

    I have a TrueCharge 40 which a simple calculation says can be easily
    driven by a 600 watt generator - so I bought a Honda 600W generator.
    The charger trips the breaker on the generator every time I try it,
    because that (and probably most similar chargers) have an awful power
    factor - the charger actually draws about 8.5 amps at 120V, while the
    40 amp at 12 (more like 14) volt output suggests that it should take
    560 watts or 4.7 amps.

    The TruCharge 40+ has no provision to limit the input current - don't
    know about the ProSine.

    --
    Peter Bennett, VE7CEI
    peterbb4 (at) interchange.ubc.ca
    new newsgroup users info : http://vancouver-webpages.com/nnq
    GPS and NMEA info: http://vancouver-webpages.com/peter
    Vancouver Power Squadron: http://vancouver.powersquadron.ca
     
  3. Larry W4CSC

    Larry W4CSC Guest

    Why go to all that complexity, when you can buy an inverter-powered gas
    genset like the Honda EU3000is, getting rid of the heavy 60 Hz alternator
    iron in the first place?

    http://www.hayesequipment.com/eu3000is.htm

    I've got one bolted to two brackets on the back door of my service stepvan.
    You can hardly hear it running as it runs so slow (around 1200 RPM until
    you get 1800 watts on it when the computer opens the throttle for more
    power). I also own the 1000 watt model, but the 3KW runs slower than the
    tiny engine in the 1KW EU1000i and makes less noise because of it.

    It's the finest small genset I ever owned....electric start, has an AGM
    starting battery inside it...Hayes has an aftermarket remote starting panel
    if you want to mount it. Cranks right up even in the coldest weather.
    Hey, it's a HONDA 6.5 hp 4-stroker. Has 12A at 12V for charging batteries
    separate from everything else. There's two 20A wall outlets and a 30A
    twist lock 115VAC outlet to plug the boat into. It will produce
    continuously 23A, 25A intermittently. I'm powering two 6000 BTU wall A/C
    units in the truck plus my service desk in air conditioned comfort. It
    WILL run as advertised...3.4 gallons at full load for over 7 hours! 20
    hours at 1/4 load (average?) on the tank with the Econo Mode ON, reducing
    the engine speed to minimal.

    As the 60 Hz is generated by a 3KW inverter I have yet to be able to
    destroy. The alternator is a very high frequency set of coils that looks
    like the stator in an outboard motor around the flywheel of the engine.
    There is no "alternator" sticking out. The three-phase, high frequency AC
    is simply rectified into a few hundred volts and fed to the huge 3KW
    inverter as DC for its use. Output is even certified to run computers and
    is ROCK STABLE at 60 HZ and 120VAC right up until the computer finds out
    you overloaded it and it simply trips out electronically to protect the
    inverter. A yellow LED warns you of impending shutdown, which then simply
    turns red when the power is cut off. Indestructable!

    Of course, it's a gasoline engine with all the CO coming out of it with the
    cooling air exhaust, whos heat should help RISE away from the boat being
    blown by the fan....not just left to cool and fill the hull with CO gas to
    kill everyone. But, you be the judge of that....

    I paid $1500 for mine because I was lucky enough to stumble on a guy
    bringing it back to my Honda dealer to trade up to the 7KW RV genset. This
    3KW wouldn't pull the two huge A/C units on his 5th wheel camper. It had 3
    hours on it....in the box....warranty and all...(c; Street price is about
    1800-1900. Retail is $2495

    Did I mention you can hardly hear it running??.....(c;
     
  4. Thanks for the info, Larry.

    I was hoping to use the Honda EU1000i. It weighs 29 pounds, so even
    with my aging back I could take it on the boat for week-long cruises,
    then bring it home as a backup during power outages. Might have to go
    to the EU2000i - 47 lbs. (The EU3000 is over 130 lbs.)

    How would your EU1000i do when running an air conditioner that draws 7
    amps? Will it die when the compressor comes on? Any chance it would
    run a 9 amp unit?

    Another possibility - there is at least one 12v DC marine air
    conditioner. If it were running off the battery - and the generator
    were running the inverter's 100 amp charger - then all the surge
    problems get handled by the battery and a 1kw generator works just
    fine.

    Yes, CO is one of the serious problems with this idea. I would
    consider ventilation and maybe extending the exhaust when running it -
    and of course have a CO detector on the boat.

    - Walt Bilofsky N6QH
     
  5. Peter, the manual says:

    "The ProSine 2.0 uses a Power Share feature which senses the AC load
    on the system and gives priority to your AC loads, thereby reducing
    the charger current ... Sometimes the usual AC shorepower sources have
    a low voltage. To avoid loading these weak sources any further, the
    charger automatically reduces its AC current draw as the AC voltage
    approaches the minimum acceptable level (as set by the user)."

    Sounds great in theory, and the ability to set the triggering AC
    voltage level will give some ability to tune the system. But as Wayne
    says, there might be a surging effect - especially if the generator is
    running when the air conditioner compressor goes on.

    That's why I'm looking for people who have tried this sort of thing.
    It's a bit hard to breadboard up a system without making a major
    investment in at least some of the components.

    - Walt Bilofsky
     
  6. Good thought. Hertz Equipment here rents the Honda EU1000i
    generators,

    So here's Plan A - install the inverter and air conditioning system.
    That gives me something that can run off shorepower and, for short
    periods, off the battery. Then rent the 1kW generator, try it, and if
    it doesn't work, buy the 2 kW which should have plenty of capacity.

    - Walt Bilofsky
     
  7. Larry W4CSC

    Larry W4CSC Guest

    I think you're going to be disappointed in the EU1000. It will pull ONE
    5000 btu window air conditioner, sorta like a Carry Cool, but NOTHING ELSE
    when it's doing it. It'll run at full speed, around 4000 RPM? doing so and
    be very loaded down.
    I had it pulling a 5000 Btu window A/C. As long as you were there to
    supervise and save it if the A/C compressor didn't start, it was fine.
    But, I'd find it tripped out when the A/C compressor tried to restart too
    soon with head pressure before the Clixon tripped in the compressor.
    That's no longer an issue with a 3KW genset.

    The little engine in the EU1000i is just too small to pull much of a load.
    It's a great little picnic rig to run a few fans and a TV. It's just not a
    serious power plant.
    12V at 100A = 1200 watts. What's that, 3000 Btu? How awful...useless.

    I'm not very "nautical" when it comes to air conditioners. When they ask
    me what A/C to get for their boat, I always tell them to buy an RV rooftop
    airconditioner dropped into the main hatch and bolted in place. "Marine"
    air conditioners SUCK! ALL the heat sources of the A/C, itself, are INSIDE
    the air conditioned space! How stupid! The A/C's "net output" is the Btu
    it's rated for MINUS all the heat loads of the hot compressor, hot seawater
    heat exchanger, hot fan motor and whatever power the controls generate as
    heat. So, the 12,000 Btu "Marine" A/C nets about something like 7000-8000
    Btu? How silly. The damned thing is NOISY because it's all INSIDE THE
    SPACE! And, its ductwork sucks up valuable storage spaces something awful.
    With a rooftop RV A/C unit, ALL THE HEAT SOURCES ARE OUTSIDE! All 12,000
    Btu is poured into the boat! If it'll make you feel better, have your
    canvas shop make a pretty blue seatcover for it with an anchor or spoked
    ship's wheel on it...(c; They also make a great little seat for the
    bikini-clad beauties to sit on for the helmsman's amusement.

    What I can't figure out is why "marine" A/C units don't come with "Easy
    Start Kits". Any RV dealer can supply your new rooftop Coleman with an
    Easy Start Kit so it doesn't draw any more current STARTING it than it does
    RUNNING it! That technology isn't new! The compressor doesn't come on in
    a rush, it starts cranking up slowly. This "kit" installs inside the unit.
    It makes it easy on the genset because it doesn't have a huge starting
    current twice the running current. Why Marine units don't have them is
    silly.
    If you're anchored out, you could always set the genset adrift 50' behind
    the boat in the dingy....that gets rid of the CO problem and any noise it
    makes.

    Every boat needs a smoke and CO detectors....along with a flooding alarm
    that makes sleep impossible in a marina!
     
  8. David&Joan

    David&Joan Guest

    Peter Bennett is absolutely correct. Inverter/Chargers run at .5 to .7 power
    factor which means that the AC current supplied to them will be as much as
    double what the calculation of DC volts * DC amps= DCwatts/115 AC volts
    gives you. It is current which trips out a genset. It is power (watts) that
    overloads its engine.

    The Honda EU1000i is only rated for 850 watts continuous, so it could just
    barely (as Larry notes) run a 5000 BTU, 7 amp Carry On. I am rather
    surprised that it even starts it, as the inrush current is at least double
    the 7 amp running current. Chalk that up to the excellent electronics in the
    little Honda. I had a 2800 watt Coleman generator that would barely start a
    Carry On. And as Larry noted with the Honda, it wouldn't restart it unless
    the freon circuit stabilized its pressure over quite a while to eliminate
    the high head pressure start up condition.

    A better solution is a larger generator or a very efficient charger. IOTA
    makes a fairly efficient charger- about .8 power factor as I recall. Even
    so, the Honda EU1000i will be limited to supporting a 40 amp DC charging
    rate at best.

    David
     
  9. Thanks, Larry.

    The ProSine 2.0 has some nifty features that might let this silly
    setup actually work. Depends on the size air conditioner I'll need
    for the boat. I might need to go to the EU2000i.

    I had a good talk with a Xantrex tech about the ProSine 2.0.

    On the A/C side - the issue is the generator dying when the compressor
    comes on. The ProSine has a transfer switch, and if it sees the AC
    voltage from the generator going low, it will very quickly switch to
    inverter power - and the inverter can supply 4.5kw surge. The voltage
    level for the transfer is settable. So hopefully the ProSine can be
    set to put the generator off line before the load stops it.

    But then of course the voltage will come back up, and the ProSine will
    go back to the generator, right? Yes, but according to the tech, it
    will take 10 or 15 seconds to validate the AC voltage and waveform.
    Plenty of time for the compressor to start. And not enough time to
    take too much out of the battery bank.

    But if the battery's down, the charger is going to want to suck more
    AC power than the generator can supply, right? Well, on the ProSine
    2.0 you can also set the shorepower "breaker current". So if I set
    that to 8 amps, say, the charger will never take more than 8 amps
    minus whatever is going through to the AC loads. So I can tune that
    setting so the charging function doesn't kill the generator either.

    So the only issue is whether the generator will be able to service the
    steady state load of the A/C. That'll depend on the size A/C I need,
    but the spec for a 5000 BTU is 4.9 amps. I think I'll need a larger
    one though. Anyway, worst case, I get the A/C installed, rent an
    EU1000i, find it doesn't work, and go for the 2000i.

    - Walt Bilofsky
     
  10. Larry W4CSC

    Larry W4CSC Guest

    Now, that's a good idea.
     
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