Generator Recommendation

Discussion in 'The Garage' started by LuNoTiCK, Nov 1, 2012.

  1. LuNoTiCK

    LuNoTiCK Diamond Member

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    I need a recommendation for a generator (not for me) for a minimum of 7500W. It's meant to power the boiler, and needs to be 220V. Would prefer it to be reasonable reliable, but also reasonably priced.

    I also am aware if you have common sense you would buy a generator in the summer when they are cheap.
     
    #1 LuNoTiCK, Nov 1, 2012
    Last edited: Nov 1, 2012
  2. LTC8K6

    LTC8K6 Lifer

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    You mean 7.5 megawatts?

    No, 7.5 kilowatts?

    :p
     
  3. LuNoTiCK

    LuNoTiCK Diamond Member

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    lol right!
     
  4. NutBucket

    NutBucket Lifer

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    Honda or Yamaha.
     
  5. thecoolnessrune

    thecoolnessrune Diamond Member

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    If you have a smart-boiler you may need a generator that delivers clean power (generator power is pretty much the worst power source possible). If that's the case, you'll want to look into an inverter generator instead of a typical generator. That or run the feed through a UPS. Both are expensive options though.

    You also didn't state what sort of fuel you were using. Gas, Diesel, Propane, NG, etc. Or some combination of them.
     
  6. Ferzerp

    Ferzerp Diamond Member

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    Here is one, but it only works when it's sunny.

    [​IMG]
     
  7. BUTCH1

    BUTCH1 Lifer

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    More than double the price of a comparable unit from Briggs or Craftsman or Troy-bilt. If your gonna run it every day for several hours the build quality of a Honda would be worth it, for occasional use no need to spend $1K on a 2Kw genny..
     
  8. WackyDan

    WackyDan Diamond Member

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    Unless you need that generator to power electronics, charge batteries, etc. Inverter generators are always more expensive than the run of the mill generators you find at your local Home Depot/Lowes.
     
  9. JCH13

    JCH13 Diamond Member

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    Check your surge power requirements. A co-worker of mine got a professionally installed generator system, and the surge requirements for his water pump and furnace (to let them start up without browning out the circuit) put him at a 20kW generator.
     
  10. LuNoTiCK

    LuNoTiCK Diamond Member

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    Thanks for all the advice guys, there's a lot I need to look at then.
     
  11. jagec

    jagec Lifer

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    WTF? That sounds ridiculously over-spec'd just for the sake of making it a "start it up and don't think about it" system.
     
  12. thecoolnessrune

    thecoolnessrune Diamond Member

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    Keep in mind that very few inverter generators exist. Honda only has a few and they have "i" in the name. Yamaha uses the same naming scheme but nearly half their generators drive an inverter. In either case, expect to pay nearly double the cost of a traditional 3600RPM AC generator. But if you are running things with electric motors or smart electronics, your devices will thank you for using an inverter. Electric motors run hotter on traditional generators and some electronics simply won't run on them.

    That being said, if you have a dumb boiler (by dumb I mean, heating element and thermostat), then just get a traditional generator and safe some money.

    If you have a smart boiler (such as an in-line water heater), or are also planning on running electronics, then invest in an inverter generator to save your electronics, especially if you're running motor loads.

    There are lots of places that explain the differences but ultimately it comes down to a traditional generator spins at 3600RPM engine driving an Alternator. 3600RPM / 60 seconds gives you a 60Hz cycle suitable for 120/240 Volts in North America. As you might imagine though, this power is not steady. The engine itself is not perfectly smooth and the noise and uneveness in the power changes as the load changes (or the engine changes speeds).

    An inverter generator creates AC power at a much higher frequency (a variable frequency), that goes into an Inverter, which converts this high frequency AC power, to DC power, then recreates a pure sine wave AC feed at 60Hz (or 50Hz, and some let you select which). This disconnects the motor from directly driving the load, and therefore the engine is free to slow down or speed up as needed, saving fuel. It also guarantees a clean feed of power constantly.

    Lastly, if this is a stationary area for just powering this boiler, and you have an NG feed, you should really consider a hybrid fuel generator. In the cases of power outages, hurricanes, etc., gas is usually still flowing to customers. In these cases you will have a constant feed of fuel to your generator if it is hooked up to an NG feed. In the cases where the NG feed is turned off, You still have the option of running off gas or a Propane tank.
     
  13. BUTCH1

    BUTCH1 Lifer

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    Hmmm, I've seen plenty of regular genny's powering TV's...
     
  14. thecoolnessrune

    thecoolnessrune Diamond Member

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    Not surprising at all. :) This area is very similar (if not identical) to UPS's (modified sine wave vs pure sine wave).

    This link shows oscilloscope views of sine waves of various UPS's and Generators that shows the differences between modified sine wave, and pure sine wave UPS's, and inverter vs alternator generators: http://www.jkovach.net/projects/powerquality/

    The differences are obvious. Power Supplies (used in electronics, including computers and microwaves), expect a sine wave at 60Hz (or 50Hz, depending where you live). Now nothing is perfect, and electronics are built to handle variations, but not by much. Essentially whatever is not a pure sine wave, the power supply has to account for. This is by drawing more power if its a sag, or "eating" power if its a spike (using layman's terms).

    Power supplies all have different limits. That's why some computer power supplies will not run on basic UPS's while other's will. But what is universally true is that is much harder for a power supply to filter and work with that sort of power. Some power supplies will not have a problem with it (well designed computer supplies and most TV's will compensate, but run hotter), while cheaper power supplies either won't run or fail completely (wall warts tend not to work)

    For electric motors it depends on what kind of motor it is and how well specc'd it is. Doing rough math on a pure sine wave vs a modified sine wave, most electric motors will have either a 20-30% power reduction, or have to work 20-30% harder to produce the same amount of power. An over-sized electric motor won't have a problem with it but motors that are not designed to operate with such a reduction can burn out since they will run hotter in the first place. This reduction will not be as bad off of a generator vs a modified sine wave UPS, but there will be a reduction. A generator must be sized to account for these losses as well (A 5000 watt motor load for instance would require 5500 watts to do the same amount of work on a standard, alternator ran generator).

    To the OP, there are also forums for campers and other activities where people will talk about the load trying to run on a generator and mention whether it was successful or not (or caused damage). Can always try there :)
     
    #14 thecoolnessrune, Nov 3, 2012
    Last edited: Nov 3, 2012
  15. andylawcc

    andylawcc Lifer

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    whao, thanks Coolness.
     
  16. andylawcc

    andylawcc Lifer

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    hey, can you recommend a generator for this sort of application?
    http://www.chickenhawkracing.com/faq.php
    under 1200W and inverter-less should be okay?

    i checked on ebay and found many brands and models.
    my friend tried the Harbor Freight ones and he said it sucked and didn't perform as desired. meanwhile, my other biker friend got one off ebay (he said its green) and it works okay but just loud and hell. Honda and Yamaha's ones are the way to go.
     
  17. sdifox

    sdifox No Lifer

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    why would you use an electric boiler that needs a generator? Why not just a gas boiler?
     
  18. thecoolnessrune

    thecoolnessrune Diamond Member

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    It depends. You'll want more than 1200 watts (you always want a buffer of power, the amount depends on who you ask but 50 watts isn't enough), and if anything, power is cleaner the less load the inverter is put in, especially in the case of standard generators.

    You basic thermostat controlled tire warmer will work on the most basic of generators. Heck, you could feed it an almost square wave of power and it would be fine. Heating elements are dumb loads as are mechanical thermostats so you don't have to worry about inductive loads increasing startup power needs nor do you really have to worry about the cleanliness of the power.

    Once you go to the digital line though it would depend. Does the timer built in the control panel synchronize by the AC waveform? If so, these things often have issues with generator power.

    My guess is given the ruggedness that these things are designed to be put through, that their power supply will be well protected and probably have no issues filtering dirty power (especially where those are used).

    If these are going to be used several days out of the week at high loads, then I absolutely recommend getting a honda or yamaha generator right off the bat. The Yamaha EF2600 will go for nearly 9 hours on a tank of gas (since you'd be running half load) and is pretty cheap. If lightness is a priority, The Honda EF3000c is a Cycloconverter type which slots somewhere between an Inverter based Generator (AC -> DC -> AC) and a traditional generator (AC + Voltage Regulation). A Cycloconverter uses the same strategy as an inverter generator by replacing the flywheel of the engine with the AC generator (instead of a shaft connecting to a separate generator). The Cycloconverter creates a very high frequency AC current (like an inverter based generator). Instead of being converted to DC, and then AC however, A cycloconverter "chops" the AC power at intervals to produce a needed frequency. The frequency is typically several thousand Hz like inverter based generators, but is a multiple of the desired frequency so that it can be evenly chopped at certain wavelengths.

    This provides the same power quality of an alternator-based traditional generator but in a much smaller, lighter weight package. The Honda EB3000c can do 3000 peak watts in a 71 pound package, while the Yamaha EF2600 does 2600 peak watts in a 96 pound package.

    Also remember to keep in mind other loads while you are using it. Getting a generator can be additive. First you get it for a designated task, then you find it can be used for a whole bunch of little things around you :p Size accordingly.

    Also, as I said already, you may be interested in investing in a Bi-Fuel kit that would let you use Gasoline or Propane, since the gas put in your bikes often isn't the kind of gas you want running in your generator. Still, a Propane tank isn't much savings on a Gas tank as far as inconvenience goes. Just depends on what your needs are.
     
    #18 thecoolnessrune, Nov 3, 2012
    Last edited: Nov 3, 2012
  19. andylawcc

    andylawcc Lifer

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    thanks for the education coolness :)
     
  20. andylawcc

    andylawcc Lifer

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    i already see this will be happening ;p
     
  21. andylawcc

    andylawcc Lifer

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    actually, if I do get tire warmer, the generator will be used perhaps one day in a month (i roughly go to trackdays once a month), and the generator will run 8 hours max. While the generator will be kept on all 8 hours, the tire warmers themselves will only be turned on for 40minutes, then off for 20 minutes when the bike is on the tracks, and then back on.
     
  22. thecoolnessrune

    thecoolnessrune Diamond Member

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    I think think either of my two suggestions would do you fine. The EF2600 is the cheapest while the EB3000c would get you something lighter for a little more. Either one will have great reliability. I have trouble really recommending anything that isn't a Yamaha or Honda. Heck, take a look on the Briggs and Stratton product page and look at the reviews absolutely tanked on several of their products as so many people who bought them for a cheap generator are now finding the generator (Alternator) is failing on their units when they need them most.
     
  23. andylawcc

    andylawcc Lifer

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    understood.
     
  24. skyking

    skyking Lifer

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    Here is another option. I do not have this generator, but several folks on the RV forums have them and swear by the reliability, function, and build quality. They really test generators out in that application. I will purchase one for my new RV.
    http://boliygenerator.com/index.html
     
  25. BUTCH1

    BUTCH1 Lifer

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    The one petrol genny they showed looked like a very ragged sine wave, the way a petrol genny (not inverter models) work would produce a decent sine wave as the method of generation is the same as the power co's, a rotating inductor inside a magnetic field, problem with small genny's is motor speed variations, the governor does apply more throttle as more demand is increased but that takes time, this is dealt with by overproducing the voltage then clipping off the tops so when a heavy load is applied the voltage won't sag badly. I have an old scope (and a Briggs 4K genny), I might just dig it out to see what it's output looks like..

    [​IMG]