Generator or invertor?

[supton]

Might not be in the right folder, but I do see other generator posts here...

I would like to get something for backup power. House has a transfer switch, and wiring to the outside of the house already. I just lack a generator.

I'd like to run one of those 2kW invertors; smaller so they store easier; less gas burn too. Nothing in my house runs on 240, so if I wire up the cord myself I should be able to run both legs to the generator, if it's 120 only. [Don't like the idea, but it seems possible to me.]

Only thing is, I want to run fridge, furnace and well pump. I have not measured startup on the fridge; but it's 25 years old now, and makes noise... Furnace motor says 115V, 2A, 1/7hp -- but it's motor code T, which means it draws upwards of 40A on startup! That's 4.7kW right there (very reactive too). [Haven't found the paperwork on the well pump yet.]

I'm guessing that means I need one of those loud 5.5kW jobs. Yes/no? or might the Honeywell controller on the motor have some capacitor-start on it that reduces the startup surge?

[It's a shame that one can't have a generator outfitted to their car somehow--that always has fresh gas, and a motor big enough to start anything in the house. Or at least something that could go onto the lawn tractor. I only need a generator every couple of years--but when you need one, you need one...]

 

[oilboy123]

Yes my sister has a ford 300 six cylinder for a generator. My other sister has a generator she bought for her house in Seattle. She realized she never needs it. It's sitting in my garage right now with about 20 minutes run time. She bought it 3 years ago for $800 I just filled it with gas for the first time 2 months ago and it started right up. To bad you live so far away. Because she would easily sell it for probably $500

Sounds like you have some heavy start up loads.

 

[shooter250]

It would take a very large inverter to start and run the loads you have listed, and if you could find an inverter large enough I wonder if your car's alternator could power it or if it would cause the car to die.

I would look at getting a generator. If you have sensitive electronic loads, Honda makes some great inverter generators, but they are much more expensive than a typical generator.

Also, well pumps typically have high starting currents. Don't forget that when sizing your generator.

 

[supton]

That's what I figured--need a big one, 5.5kW--but it's going to sit for the vast, vast majority of the time. Shame.

Re: car setup. Too much for the standard car altenator, so it'd have to be another head unit. Guess it'd be too much for a serpentine drive, let alone V. Too bad no one has figured out how to sell a combo lawn tractor / snowblower / generator setup (then again, that'd be pricey!).

 

[eljefino]

Many inverters output square wave or modified sine wave; motors in particular don't like it and at the least sound funny.

A cheap generator makes AC with a sine wave as a result of the physics involved.

My $89 HF two stroke generator will carry a modern fridge. It barely carried my old one if I "hacked" it by revving it up on a hair dryer then doing a quick switcheroo. New fridges have capacitor soft starts.

Go check the breaker on your well pump; if it has a bar across the switches your pump runs on 220 and needs tons of power. No inverter you can find in stores will handle that. If the well pump has a single pole breaker, like mine, it runs on 110. This is mostly for shallow wells ("jet pumps").

My ariens snowblower has a removable front end that turns into a rototiller, garden pickup truck, and some other gadgets. The engine is less than $100 of the cost of modern OPE, thanks to "chonda".

If you can hold out to Black friday you can probably get a 3300 watt generator for $200 from pep boys or harbor freight. This is a sweet point on the price/value scale IMO. (I believe it's because of the preponderance of 6.5 hp engines and the weight of 100 lbs is just enough for a "one man lift" for cheaper shipping etc.) Yeah you should time the fridge to not run with the water pump.

 

[supton]

Hmm, there is one pair of breakers with a bar; but the labels don't match between the door on the breaker (where you jot down what controls what) and the transfer switch (where it was jotted down on some masking tape). Will have to trace that down at some point.

I do know the lights in the house flicker a pinch on the furnace kicking (maybe something else too) but they never do for the well pump.

Just want to make sure the invertor is properly ruled out before I spend lots of money. As it is, I need to build a shed or something to house this thing in.

 

[Cup of Joe]

I purchased a new 5500w generator at pepboys for $512 out the door after Irene. After storms craigslist is a good spot to find generators.

 

[roadrunner1]

If you check around you can find a generator head that can be run using a lawn tractor. Northern Tool would be a good place to start. I have seen them before, its a very economical setup for back-up power.

 

[Cujet]

Are you talking about something like a Honda 2000W inverter generator? or a 2000W inverter, powered by a car battery, maybe even hooked to your car?

The Honda really only makes about 1600W continuous. Same goes for the Chinese copies.

Most cars won't run a 2000W inverter at full load for very long. Unless you have a huge alternator.

Yes, I suggest an 11HP (that's 5500W ! ) generator for most people. However, your loads may be considerably lower. So, you could very well do with a 3000W conventional genset. There are Chinese ones that will run my 1.5HP well pump without any trouble. Remember, a conventional generator has good surge capability to start small motors.

 

[supton]

I've thought of getting the Honda EU2000i (think that's the model): quiet, easy on gas, etc. Smaller means easier to store too.

My ramblings on a car invertor would still involve some sort of generator head, as I don't know of any standard auto altenator being able to provide the kind of wattage required. And enough underhood space for it. But it'd make for about the most convient setup.

If I were to find a good deal on a used 3kW one, I'd probably try that. But if I buy new, it seems like a better idea to go full bore and do 5kW, as I would a) know it would work, and b) it'd run the whole house w/o thinking about it. At 3kW I'd have to keep an eye on things--not a bad idea, but the 5kW one has much more of a margin.

 

[MolaKule]

I can give my experience and opinions with a Honda EU3000i I had previously:

Cost: $845.00 (excluding tax).

Mechanical Noise including exhaust: Low

Electrical Noise: Very high. I.E., don't expect to run any TV's or radio's without intereference, unless you buy an extra elecrical filter for the output ports.

Power Surge capability for appliances: Poor

Output: Modified sine wave; in actuality, a "stepped" voltage waveform.

Since it didn't meet my needs, I sold it to my sister-in-law for use in her camper.

I have since purchased a 220V generator from Menards (a JD-TECH) with a 13Hp engine with about 6,000 Watt running capacity for $678.00 (including tax). Now it is louder but barely blinks when any appliance is swithced on.

Each HP has an equivalent of about 745 Watts, but the actual power you get out of an alternator, after subtracting system inefficiences, is equal to 0.65 X 745 or 485 Watts.

So, for an engine of 11 HP, electrical output is about 5,327 Watts maximum.

 

[supton]

Still doing my research: any reason for picking Generac over a B&S? In the 5,500W, that is. The B&S Storm Defender is something like 5.5kW with a big surge rating (forget what it is now). I usually think of B&S as being indestructable; but I suspect I'm thinking of their ancient sidevalve motors. Surely Generac has spare parts in the US?

 

[Cujet]

I don't think you need 5500W. I think you would do well with a Chinese 3500W unit. 6.5HP.

Remember, the big ones really gobble the fuel. 15 gallons/24 hours on an 11HP generator.

 

[supton]

Friend of mine corrected me on the breaker box: I didn't realize that the legs alternate across the panel. Thus 240 isn't across, it's two adjacent breakers. So, the pump is 240AC; the transfer switch looks to use two of its breakers for the pump (one on each leg). 20A breakers.

[Annoyingly it appears that the washer/dryer is on of those legs--not sure what is on the other--seems not quite right, the whole setup, to me.]

I dunno, I guess if a 3.5kW unit has a 5kW surge rating then it should handle the furnace. I want to go smaller; but the furnace ratings worry me. Just the burner is 4.7kW surge (115Vac, 2A, but motor class T); plus the circulating pump and the draft motor (circulating hot water, oil fired, horizontal flue). But I guess one can exceed the surge rating... ?

 

[itguy08]

If you need 220 I think you definitely need at least a 5500w unit. Most of the ones I've found under that rating don't have the 220 plug or can provide 110 or 220 but not both.

Not sure I believe that the motor will use 40A on startup and if it does it will be very briefly so a regular generator should have enough inertia to power through it. I would think you would be fine. Make sure you get a good return policy and do a dry run prior to needing it.

I went through a similar calculation before we got our generator (5500w from Harbor Freight) and I knew we could run most of our important things off a Honda eu2000i as we borrowed one. But that was in the summer and I did a worse case and thought if it were in the winter we'd want to run the furnace or a space heater or 2 to keep warm. At 1500w per space heater that's 1500-3000 watts right there. Our furnace doesn't have a plug do I'd have to do some rewiring to wire it directly to the generator so that's not ideal for short power outages. So a 5500 watt makes sense.

Yes, a 5500 will use more gas than a 3000 watt one but IIRC ours will run 8 hours at 1/2 load which is good enough for us and where it will be 99% of the time.

 

[tig1]

My advise. Don't fudge on size because of money or gas usage. With generators more the KWs the better. Why? Your needs may change down the road.

 

[supton]

Good points.

re: gas consumption. House stays reasonably warm for a while, so the plan has always been, run for 30 minutes or so, maybe an hour; then cycle off for several. That way gas can stretch out. Which is a good thing: I go through maybe ten gallons of gas per year, between the mower and the snowblower. Keeping 10-20 gallons on hand for the generator seems to me to be lots of work.

 

[eljefino]

What kind of storm will leave you without water?

After Irene we could flush the toilets easily by filling 5 gallon buckets under the gutter, or from the "spring only" stream that came back to life. For potable water, plan ahead and fill some old milk jugs?

An ice storm will have ice all around you that could be melted. Of course you want heat to do that, so we're back to this generator if you don't have a wood stove. I've not heard of this "type T" motor but if your furnace runs on your typical 15-20A breaker, a mechanical (non invertor) 2500+ watt generator will chug through any startup load it demands. After all, it doesn't trip your breaker during the milliseconds of overcurrent.

I killed my fridge after Irene trying to run my shallow well jet pump and the fridge at the same time, with too much inrush current, and had a brownout. If your well runs on 220 it's very expensive to fix, and you don't want to kill it with a brownout.

If you *do* get a huge gas guzzling 5500 watt deal, watch for HF coupons and get their little 2 stroke 900 watt generator for <$100. You can be a hero and lend it out or use it for your fridge when you don't want to make a ton of noise and burn a ton of gas.

 

[itguy08]

My plan for the "gas management" is that I've got 2x 5 gallon jugs (with date stickers) + 2.5 gallon jug in the shed. I keep the generator about 3/4 full of fuel and use that for the monthly tests. I plan to run that out and then refill with fresh Sta-Bil fuel and repeat. I've blown through 5 gallons this summer with the pressure washer and lawn equipment so I think we'll be OK.

The 5 gallon jugs will get used in the lawn mower, snowblower, weedwacker, etc throughout the year. Once the date on the jugs is 6 months or so I'll dump them into the cars and refill with fresh gas + a shot of StaBil. That way I've always got fresh gas and the cars will get a little "free" fillip.

If there was a situation where I couldn't get to the station or every station within, say 20 miles was out I've got a 19 gallon and a 14 gallon tank that would be full and always fresh. That would be the 2 cars.

Also, don't forget you can always cook on a grill. We grill even in the winter (just takes longer) and with a side burner + the grill surface we should be able to cook just about anything anytime. Just make sure you have a spare propane tank that's full. When Irene knocked power out for a day and a half I cooked breakfast on the grill, had coffee courtesy of the borrowed generator and kept the fridges cool.

 

[supton]

House has a 50 gallon propane tank--so the stove top works, just not the oven, if the power goes out. Would love to tap into that--but those generators tend to be pricey.

Good points about the water. Technically, the lake in the backyard is all of 100 yards away. Frozen over during a good storm, of course; but not miles and miles away. Last ice storm it was a nuisance on the bucket brigade; but that paled next to no lighting and no heat.

Interesting, there is a HF I guess somewhere near here (MA?), two generators wouldn't be a bad thing (small one left on for lights, change over to bring up the heat...) As long as it's four stroke, I'd be happy: not going back to two stroke!