How to select generator size?

T

tom91ita

New member
okay, i can do the conversion for KW to HP in case i want to drive a small compressor or other equipment, but how do equate a 3 hp compressor start-up in rush current requirements with the peak vs. steady load rating of a generator?

i am also considering just going the bottled nitrogen route for tires and miscellaneous impact requirements and going with a small generator for recharging items and lighting, etc.

any recommendations for how big for use at the track or brands?

tia, tom
 
I would also look at Yamaha. Last year I stood next to a 3k kw unit and it was so quite that you could carry a normal conversation right next to it.
 
Originally posted by vwmann1@Aug 12 2005, 08:49 AM
I would also look at Yamaha. Last year I stood next to a 3k kw unit and it was so quite that you could carry a normal conversation right next to it.
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That would be a Yamaha Inverter Generator - VERY cool (from a sound standpoint); rather UNCOOL from a pricing standpoint.

EF3000iSE or EF3000iSEB

http://www.steadypower.com/catalog/yamaha_...e903e2565fabfce

$1700 for the non-boost version; $1900 for the boost version (that can handle more of a surge than the non-boost version).

You can find a lot more power for that kind of money, or a much cheaper generator for that kind of power. Nope, it's not as quiet. Your call. :D

Jarrod
 
Originally posted by JIgou@Aug 12 2005, 03:13 PM
That would be a Yamaha Inverter Generator - VERY cool (from a sound standpoint); rather UNCOOL from a pricing standpoint.

EF3000iSE or EF3000iSEB

http://www.steadypower.com/catalog/yamaha_...e903e2565fabfce

$1700 for the non-boost version; $1900 for the boost version (that can handle more of a surge than the non-boost version).

You can find a lot more power for that kind of money, or a much cheaper generator for that kind of power. Nope, it's not as quiet. Your call.  :D

Jarrod
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As was stated, get the biggest one you can afford. I can tell you from having worked in the construction business, where we needed portable power all the time, you're not going to run any kind of compressor on less than a 5kw unit. I have the little 4-gal pancake, and when my generator crapped out, and I borrowed someone's 3kw, it just didn't cut it.

You can get a 5000 - 5500 watt unit for around $500, but it's going to have a Briggs & Scrapiron or Tec*mshot motor. Will work fine, but not the quietest thing out there. But then again, a 5kw Honda will run you 3x - 4x as much.

One of the things I like about mine, is it's 110/220 VAC and 12 VDC.
 
I did all kinds of research before I went out and got mine. I wanted one I could keep at home in case the power went out as well as one I could haul to the track. You can get something for $500-700 that will work fine, but will be a little loud. The more money you spend, the quieter the generator gets. You'll also get things like electric start on the more expensive ones. Honda seems to be the brand everyone points to for quietness, but you pay for it.

I kind of split the difference. I went for one of the generac brand generators from home depot. I got the 4.5kW one and they also have 7kW. It's not super quiet, but it's not extremely loud either. It comes with some cool features like electric start and idle down that are usually only on the higher priced ones. Think I paid a little over $700 for it.

Go to any RV website and do a search on generator and you'll have more info than you want.

David
 
I am a little suprized at all the sugestions for the run of the mill generators. I work in construction as well and the regular generators are very LOUD. I purchased a Honda EU2000i because I wanted quite. It was around $870 delivered and I use it to run lights, fan, heater (small), recharge radios and camcorder, and laptop. It will not run the air compresser but I have yet to fully understand why you need an air compresser at the track.

I would just like everyone to be considerate of there neighors at the track. I have been to the track more than a few times when some big rig pulls next to me and unloads a big @$$ loud generator and but it behind thier trailer so they don't have to hear it. It is then right where I have to listen to it all day as I sit under my canopy. I don't like it when others do this to me so I got a quite Honda. There is nothing more anoying then comming off the track to relax and have to listen to someone else's generator in your ear. If you do bring the loud one's put them right by where you sit as to not bother those who don't want to listen to it.

Sorry if this comes across wrong but it has ruined more than a few weekends.

Michael
 
i have seen several higher end generators rated at 76 dB.

i haven't really studied why the noise is there. is it that just a better muffler is needed on the engine or is there significant sound deadening around the generator portion itself?

i too have been bothered by loud generators that seem to be required all night and have the exhaust fumes pointed in my direction.

like i said, i think i may go the nitrogen bottle route too. better for the tires and can be used for the impact if the cordless won't get it. that could also make the smaller hondas work and keep them more in my $700 price range. also with regards to room.

any one using the larger 12V to 120 V inverters?
 
Originally posted by ilateapex@Aug 12 2005, 11:43 AM

I would just like everyone to be considerate of there neighors at the track.  <Snipped>
Sorry if this comes across wrong but it has ruined more than a few weekends.

Michael
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Amen to that. I hate listening to a noisy damn engine all day, and sometimes all night, long.

Don't know why a 3KW unit wouldn't run your pancake generator, Bill. My 2.5KW Suzuki runs my pancake ($89 HF special) just fine.

BTW, for a reference point, the Suz isn't as noisy as most. Not Honda quiet, but not nearly B&S or Tucumsa (sp?) loud. I don't know what they cost, I got mine used when someone added A/C to their trailer and needed a bigger unit. I don't have A/C in my trailer; 2.5KW has been enough for anything I've wanted to run.
 
Any thoughts/experience on the noise level of the Robin engines? Harbor Freight has pretty good deals on generators using that engine.
 
I dont know about HF, but if you got to any good dealers in generators they usually have the DB rating...I would go for the highest power lowest DB unit I could find.

But then if I can get a space with power I dont have an issue paying for access to the box.
 
I have the Yamaha 3K unit mentoned above.

It is pricey, but it is SO well built.....and the power is CLEAN. And it is the quietest going. It's the real deal.

How long will you own it? If you get a good one, you will own it a loooong time, and Yamaha is years ahead in quality than most, excluding Honda.

The Hondas are nice, but you have to get wheels and stuff as options, and it ends up costing even more!

As for generators at the track...there ought to be a law about them, and the moderately or noisy ones should be shut down.
 
If you have the space (and $$) to give up, I'd strongly recommend an Onan RV unit. You can get a reman'ed 7KW unit for about $2500. I got one for my LQ trailer, built an exhaust system using a car muffler, and installed a 34 gallon fuel cell. Total cost, including shipping - about $3K.

I also have a Coleman 6.5KW, with a Honda engine and a wheel kit, from Sam's Club (under $1K about 4 years ago). It IS noisy - both mechanically and exhaust-wise . . . sounds like a BIG lawnmower, with a rattle. I consider it untenably-so for extended use at the track - especially at night. It does have the advantage of providing both a 110 and 220 supply, though.

For quiet - look for one that meets National Park Service sound level requirements.
 
Originally posted by tom91ita@Aug 12 2005, 11:54 AM
but how do equate a 3 hp compressor start-up in rush current requirements with the peak vs. steady load rating of a generator?

i am also considering just going the bottled nitrogen route for tires and miscellaneous impact requirements and going with a small generator for recharging items and lighting, etc.

any recommendations for how big for use at the track or brands?

tia, tom
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Well, depending upon the type of motor, it can take an initial spike of up to 2x the current to get it going.

I also have to second the ONAN, stunned that ONAN wasn't mentioned earlier in the post. I have an older 4kW emerald plus, a friend has one of the newer micro quiet models. They are pricey, and if I didn't have one already built into the tow vehicle (RV) I would probably do without...

I bought a small compressor to bring to the track, too damn noisey and worthless for powering air tools. I don't like to have to wait for the thing to fill back up 3 times to change 4 tires. We have enough time between sessions that I can use a standard ratchet and torque wrench to change tires...no need to be that lazy. For a compressed air source I bought a Nitrogen bottle and regulator for less than the price of the compressor I returned to Lowes. It takes zero electricity, stores in the same amount of space, no noise pollution, a $7/refill has last 6 race weekends so far.

Inverters; go big enough to be of any use for compressors and you'll be needing a jump start in no time at all.
 
I agree w/ the comments about the Onans, probably the best out there. Robin engines are good (made by Suburu), and will rival Honda for sound level.

Ty,

I guess I should have elaborted a bit. A 2.5kW unit may run a small compressor, but it won't run anything else at the same time. Also, the one I used only had a 15A breaker, and would only put out 12A. You may have a 20A circuit (but probably a 15A). A 2.5kW unit should put out ~20A, but you're running at absolute max output. Probably isn't supplying enough for the startup surge, which will shorten the life of whatever you're trying to run.

Being in construction, I run not only a compressor, but a chop saw, table saw, battery charger, lights, etc. Can't be always running out to reset the breaker, or telling someone they can't use the saw because the compressor is running. The 5kW Coleman I have has 2 20A circuits, and will surge to 6250W. Yes, it's loud, but it was 4x-5x less than a similarly equipped Honda. Not to mention, I already had it for work.

If I was going to go out and buy one, and didn't want to spend over $2k, I'd probably go get the Honda 3000i. 3kW and 58db. Going to cost somewhere between $1500 and $2000. It's a compact design, and will handle a decent amount of stuff. Those little 1kW and 2kW units, while being handy for a couple of lights, and maybe a radior or battery charger, won't really handle much else. To me, $1000 for the Honda 2kW unit is a waste of money.

As far as compressors at the track, anything that's going to have enough snot to run air tools is going to be too damn big to haul around. The N2 bottle thing is probably the way to go, but will put limitations on where you can travel. I finally broke down and bought a 1/2" electric impact gun (got a DeWalt display model for $30 from Lowe's). Wouldn't want to use it all the time, and it's not as fast as an IR-231 hooked to a N2 bottle, but it's a good comprimise.
 
May I suggest the Onan diesel powered 7.5 QUIET generator, attached to a 40 foot Newmar Dutchstar motorhome. Your power source would also come with your tow vehicle, your lodging, changing area, rest area, restroom, eating arrangements, parts carrier and air supply for what ever. Did I mention that I sell RV's???? We are talking a mere $280,000 list, with a full 150 gallons of diesel and 100 gallons of water........all kidding aside, recreational vehicle generators are designed to run at 1800 rpm's, the average Wallmart models run at 3600 rpm's, thus quieter, but much more expensive. As in anything, I would guess, the largest you can afford would be the way to go. If your enclosed trailor has a/c, you would need at least a 4.0. "You can do a small job with a large tractor, but you can't do a large job with a small tractor"....see ya at the races......
 
The new hybrid full size trucks are coming with outlets so you can use them as a generator. How cool is that!!
 
Jeff,

I saw one of the hybrid GMC's about 2 months ago. Very slick! Had outlets both in the cab and in the bed. Couldn't get a straight answer from the sales guys though, one thought it was 2500W, the other thought it was 4kW - 5kW. Never bothered to research it, because I wasn't buying a new truck. Cool technology though.
 
Generators?

Minimum 50KW Kohler with control circuits for automated weekly self testing and grid disconnect/connect in the event of a power loss and at least one 50A 220V, 3-phase circuit. Put it on an isolated concrete pad and fuel it from an underground tank holding a week's worth of your favorite fuel. Don't use an above-ground tank, the hurricanes will knock it over.

Hey, so what if you can't move it? :D

Gregg "Bring 'em on!" Baker
Orlando, FL
 
Heehee . . . I've got an Onan 7500 Quiet Diesel in my MH. It's great, but I didn't think anyone was into $10K worth of generator just for the track. Diesel pushers are the way to go - just make sure it has a diesel generator (NOT propane)!

And Gregg - the stationary backup generator is a good idea for the house. We're doing that with our new one - only we're using a 15KW natural gas unit. You don't have to buy fuel unless it turns on, and it doesn't go bad sitting in the tank.
 
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