Comparison What's best for standby power?

[The Fred]

Hard to beat a dedicated LP unit ready to roll at the flip of a switch or automatically. Ours is 12 years old and replaced the battery one time do all maintenance ourself. Opted for manual switches because of the cost of electronic switching. Flip on a light switch genset comes alive, flip the transfer switch and power is restored, end of story. Even the wife does it without complaining.

12K Onan/Cummins unit has been very reliable. Wasn't cheap but well worth the insurance policy. One unit runs complete household and large shop including metal lathe, milling machine (at the same time) vehicle hoist. The only thing it won't do is start the 7.5 hp 220 volt single phase air compressor.

Fred

 

[Gary Fowler]

It is hard to beat the ease of use with the propane stationary whole house generators with auto-transfer switch especially if you have a 500-1000 gallon propane tank. Look to spend $5000+ for a good one. I have heard some bad things about Generac units engine reliability so I think I would stay away from those. If you have frequent outages, I think they are worth the money especially if you have wife alone or even yourself alone to have to hook everything up on a PTO genset in the dark and freezing weather. The other thing is the noise of a tractor setting just outside your window where as the self contained whole house type are really quiet during operation. The other way to go would be a diesel powered unit if you could hook up a fuel supply straight to your fuel oil tank but that would be even more expensive for a comparable KW rated genset. There are pros and cons to each system, you just have to decide which of the pros outweigh the cons for each one.

 

[TSO]

I have a 6250w gas generator with a Briggs. Sits in the garage by my circuit panel. The house is wired up and my Gen connector cord is long enough to keep it outside the closed garage doors when in use. It'll only handle 30amp unfortunately, so my electric cooktop, and combo oven/microwave don't operate. (I need to get gas alternatives or a bigger genny) But, it will handle my well, and my sump pump ... along with everything else in the house under 30amp.

Another Downside is that the previous owners wired my barn off a 60amp fuse off the main panel, so when running the genny, my barn is out.

I would love a standby gas/propane setup. I will eventually have one, but cost has been my main factor. Especially considering I've only put about 30 hrs on the genny since I bought it (maintenance is just the $5 worth of oil I change)... And I bought it used for $299 (old widow previous owner with about 5 hrs on it ... retails for $599 @ the big box store) and gasoline is cheap enough and easy to come by.

If you are using it regularly, I would say the standby genny would be better. If you have the money to spend, I would say the standby genny would be better. For every factor except cost ... I would say the standby genny would be better

 

[aczlan]

That's why a small pto unit appeals. The 17 hp Bolens is a garage queen, spending most of the winter snug beside the box stove in the shop. The question is what it could run with its 3 speed pto, and how to get a proper revolution setting without a tach.

Easy, just get a Kill-o-watt meter and adjust the engine RPMs to get 60hz

Trouble is that the TAFE, the most likely generator tractor, is almost always hitched to a heavy pto appliance, either the snowblower or the bush hog. It's not easy to unhitch, and I'd be unlikely to take the snowblower out of service unless I knew it would be a long outage. The Massey Ferguson's winch is similarly hard to remove. It also produces evil-smelling exhaust. The Kubota or the Bolens are easy to unhitch. Maybe I should size a pto gennie to the 21 hp Kubota. It could run the generator without removing the belly mower. Then the Bolens could run it in a pinch.
Are 7.5 KW 3 pt hitch gennies any good?

No problem in running an oversized generator on a tractor, zzvyb6 runs a 50kw PTO generator with a 22HP Deere mower:

Well, based on discussions by users here, the PTO power level is usually 1.6 to 2 times the kw rating of the alternator. However, you need to figure out how much power you really need to survive, exist, or live off-grid. 15Kw is a LOT of juice. Also, having a much bigger alternator won't hurt anything if your tractor is rated at a lower power level. I have a 50kw WinPower that I run off my 35 hp CUT and also from my 22 hp diesel lawnmower. Running a well, furnace, garage door openers, TV, modems, chargers and decent lights doesn't come anywhere near my F-935 lawnmowers output capacity limit. You hear it hit the throttle but that's all I notice.
You might want to consider reworking your breakers to drop out low priority circuits and front load the high priority ones and balance the 220 loads in the box. Put your router in a high priority circuit (in my case for example).

Yes, you will lose a little bit of efficiency, but not a whole lot and you gain a some "flywheel" to smooth out the peaks when a large load turns on if you use a larger generator.

Might be a used large genset for cheap on your local Craigslist.

Aaron Z

 

[Lou66]

Depending on how much money you have to spend.. But I have 22kw Generac,, hook to natural gas and fully auto. comes on within 30 second when power is lost. rated at 200amp.. total cost was a little less than six thousand.. that included the slab, electrical and running about 40' of 1 1/4 piping.. I did all the work myself.. Lou

 

[newbury]

<snip>
Situation:

Large, double house in Leeds County, Ontario. Small generator panel. 120 v stair climber, two furnaces, two fridges, propane furnace and oil furnace, electric water heater. 5 KW is a bit light for the job.

107 acres, tractors: 37 hp diesel, 35 hp diesel, 21 hp diesel, 17 hp diesel, 30 hp gas

Fuel sources: 250 gallon furnace oil kept full, three 250 lb. propane tanks and one 100 lb. tank. Some gasoline in cans.

We're on site every night except in very rare situations.

Since the infrastructure improvements following the Ice Storm of 1999, power outages have been very rare. I recall two significant outages since 1999, so if past practice is any indicator, the generator will receive very little use.

Question:

PTO vs propane vs portable gas: what's your advice?

Another advantage of the PTO is it's "portability".

The whole house $5,000 flip a switch setup is nice but if it's only used twice in 14 years that's about $350/year for very occasional dedicated usage.

<snip>
No problem in running an oversized generator on a tractor, zzvyb6 runs a 50kw PTO generator with a 22HP Deere mower:

Yes, you will lose a little bit of efficiency, but not a whole lot and you gain a some "flywheel" to smooth out the peaks when a large load turns on if you use a larger generator.

Might be a used large genset for cheap on your local Craigslist.

Aaron Z

Thanks for that link I knew I had read it here.

And a 20KW in NC for $1500
http://www.tractorbynet.com/forums/private-party-ads/295361-pto-generator-20kw-sale.html

 

[Mickey_Fx]

As Gary said, there are pros and cons to each setup. Here are a few things to keep in mind.

* For a PTO setup, for proper speed, you can use something like a Killawatt meter, abt $30, one of the functions is line freq. Do not use voltage output as an indicator for engine speed. As load changes, how well does you tractor gov hold its speed. Induction motors are not too happy when trying to run with line freq above/below the designed freq input.

* Propane fuel, the ability of liquid propane to vaporize is dependent up temperature. During winter with temps down around freezing, it takes a large tank (surface area needed for the liquid to vaporize). On the Yamaha web site they have charts showing how large a tank you need to run a genny at various temps. For a ~7kW genny @ 20F it takes about a 400 gal tank to supply adequate fuel. You can overcome this IF you have a propane tank with a liquid tap, i.e. wet leg, running liquid to the genny and use heat from the engine to raise fuel temp before vaporizing.

One also need to asses the necessary power loads Vs the nice to have loads and duration of the outage and freq of outages. I have a genny that can put out 6.5kW steadily for long periods. What I have my power panel set to operate using the genny is: Well pump, refrigeration appliances (4) and most of the low current items. I have alt ways to cook, heat water and have a 40k btu pellet stove for heat. To keep fuel usage down I also have a small 1kW inverter genny I use to power the pellet stove, TV, computer, etc which combined uses less than 500 W. This little genny will run ~6 hrs at half load on 3 qts of gas. The larger genny will operate intermittently as I need to replenish the water supply and keep the food at a safe temperature. To keep generator usage down, if we have advance notice of a storm that might cause a power outage, we fill the bathtub with water. That can handle washing and flushing the stool for a couple days.

For the info you have supplied I'd say, give a serious look at a pto genny. You may have to try out several tractors to find a suitable one that can hold line freq close to the nom 60 hz. I like to see line freq kept in the range of 62 - 58 Hz.

 

[3v0]

Starting a diesels is not a problem if you equip it with a tank or block heater and plug it in before the power goes out. They start like a champ.

 

[BHD]

if you have a tractor that is some what matched to the generator size I would consider the pto unit,

where I think some go wrong is they have a big tractor and only need about 15 hp to run there alternator, but since the tractor has to run a given rpm for the proper cycles, the tractor is running at normally 1800 and many times drinking fuel that is not necessary for the generator out put, and the cost per hour is way up there, my tractor when running at 2100 takes over 4 gallons an hour, and more depending on load, and If I connected that to a 10,000 watt unit it would not even know it was there, a small tractor would most likely run it for half or less per hour, maybe a gallon an hr, on light loads,

other wise I would go with the LP stationary generator, one thing is the propane unit most likely will start under cold temps, (mine is easy starting)

 

[Redneck in training]

The size of the generator and the tractor doesn't have to be exactly matched. The generator has to be matched to the load. In other words it has to be able to handle starting current of a well pump, compressor, heat pump in addition to cooktop, lights, refrigerator etc. Fuel consumption of the tractor is more or less proportional to power used by the load so the size of the tractor engine makes only marginal difference. You can run oversized generator (within reasonable limits) on a lower power tractor as long as the tractor is able to provide the power required by the load.
Selection of the generator is a statistical problem. How often and for how long the unit would be used. The convenience versus cost is also thing to consider.
I personally like the PTO generator.
Almost no maintenance between uses.
Small size easy to store.
Easy portability even for large units. You can take it to remote places on the farm and power up hand tools, welding equipment, lights etc.
The bad part is that utility tractors have small fuel tanks and therefore the tractor has to be attended (refueled) during operation. 5 gal of diesel contain 203kWh. Considering 30% efficiency you could generate about 64 kWh on 5 gal of diesel fuel. You want to put the generator on the tractor with the largest fuel tank.