Truck as a generator?

Yes, if your truck is like this

Over at diesel-generators.org, opinion is divided over whether to use a giant old diesel truck as a generator. Assuming you get the truck for next to nothing, the question is whether the inefficiences of a non-purpose-built generator outweigh the benefits of a (huge) 7.3 litre Ford diesel engine acting as a generator.

Its a nice idea, since generators can easily cost up to $1500, and still be relatively noisy and energy-intensive. But on the whole the experts are against using a vehicle as a generator.

“The engine in the truck is designed and built to move the truck,” says one reply. “There are far cheaper to run and more effective options for direct charging any battery bank.” ie a purpose built generator.

While not denying that there are disadvantages, the reaction of other experts is: “For emergency and the occasional deep cell charge up, yeah why not?  One negative: its overkill – 7.3 litres is enough to power “A LARGE HOTEL” rather than just act as a generator, says another poster, wrongly.

‘Course, if you have a Chevrolet Silverado or a GMC Sierra with optional gas/electric hybrid engines, they are designed to  double as a generator.

General Motors says the hybrid engine improves fuel economy by 10 percent. Plus, four 120-volt power outlets will allow drivers to plug in compressors, power tools, refrigerators, home heating systems and televisions – no matter where they are.

As long as it came for free, I like the idea of using an American truck as an occasional generator, to supplement solar power. It saves money on buying another Chinese-made gadget, extends the life-cycle of the truck,and, hell, you could even store stuff in back.

However, if you are buying at market price,then an auto is probably not the answer — a fixed speed stationary engine has much different cam and fuelling profiles, and a very accurate engine speed governor fitted to ensure the correct frequency and phasing at all times when the batteries are being charged

11 Responses

  1. The problem with using big truck engines as generators is the potential for cold packing. I don’t know if it’s a problem on the fords but the Cummins 5.9 apparently doesn’t like to sit and idle. You could run it a little faster but this would increase the noise output and fuel consumption.

  2. The problem isn’t fuel usage. I’d pour 10 gallons an hour into a generator and be happy about doing it if it was quiet. Going dry camping is pointless if the generator I’m runing is louder than traffic around my house. To get one that any sane person would call quiet that has more than 4,500 watts rated, you’ll need to spend close to $3,000. We can put people on the freakin moon, but this is somehow hard for us to accomplish? If no one makes such a generator head to mount in a POS Civic, maybe I should. I can think of more than a handful of desert campsites that would buy it faster than I could produce it.

  3. Came across this thread and found the discussion both interesting and informative.
    But my question is a bit unique..
    I’m a commercial floor layer and at time find myself on sites away from the grid, and using generators. Problem is my vinyl welding tool is a glorified heat gun with many delicate coils inside and chews extreme power. Any fluctuations in power WILL damage the coils and ruin the welder, and leave an incorrect weld. So… What I’m thinking is a personel dedicated weld power source, and rather then the purchase of another bulky item to lug about, use the engine and fuel I already carry…
    Any thoughts or feedback is appreciated :)

    1. The best place for this question is the Technical forum – please try and post there. My guess is that it will be fine as long as you do not power your welder direct from the motor – but only via a Sine Wave Inverter – they are quite small and light and you can buy them on Amazon for a few hundred at most – but make sure you get a sine wave inverter and not just any inverter

  4. A 5.9 Cummings 12valve produces 40hp at 800rpms and consumes less then 1 gal an hour. I’ve been running a setup like this for years, the engine produces both heat (I use the radiator as radiant floor heating) and power for my shop AC to batteries. I thought of buying a lister but the more I looked into the Cummings was a better bet. Plus free heat. You could use any engine, I recommend a diesel though. I choose the Cummings because it did not have a electronic control, you only need power to start it. I took of the turbo because at low RPM it does nothing for you.

  5. Longchamp
    In answer to your question about horsepower. Yes 5-10 HP is more than plenty. I just returned from Florida where we assembled a DC genset capable of 8 kW output plus a water maker. that is some serious battery charging. Incidentally the battery bank was Sonnenschein 2v cells having 950 amp hours capacity. In case someone is wondering why so much it was designed to include running electric on demand water heater and air conditioning on a 20 meter power cat that is going to cruise the world mostly in the tropics but also a side trip to Alaska for most modest off-grid applications a 2- 4 HP motor is plenty. You can add a smart external regulator to an automotive alternator instead of running a fixed RPM genset with poor power factor and lousy regulation

  6. mark, your pickup will really be using up much more fuel than
    a generator would, my 5 hp one uses about 0.6 litres (sorry cant
    think in gallons) an hour, my car (a 2 litre common rail diesel
    which is a good bet in europe) uses 3.6 litres to 6 depending the way i drive (3.6 at 2000 rpm or 50 miles an hr).

    i guess when you have a 3 litre engine in that pickup that will run at
    900 tpm or so when you use it for a generator…
    you will spend about a third of what you normally spend

    if thats okay with you, its okay but using it that way for a year
    will not prolong the life of the car as such…

  7. I am moving back to Panama where I was born and grew up. We want to live in a nice home in the mountains and then travel during the week exploring the country. We want to buy a four wheel drive diesel pickup and put a camper on the back in the bed. We don’t want to have to carry a separate generator unless absolutely necessary because it could get stolen while we are sleeping or hiking. We are hoping that the truck can double as the generator and run the AC and other lightweight functions we will need while “camping” in the countryside. Does anyone out there have any ideas about this????

    Mark now in NC: 919-624-7905

  8. years ago before i ever bought any serious offgrid equipment,
    i had the idea of using a cheap used citroen ax with a 1,4 litre
    diesel engine and charge a load of car batteries, just to keep the house lighted overnight and run some low-wattage entertainment gadgets – it somehow never worked and finally we wrecked the car, then someone stole those starter batteries… well nowadays i wouldnt even try, and certainly not with an engine above 1,5 litres.

    however i dont trust those cheap chinese diesel generators either –
    i mean, nothing against the chinese – china is obviously the most
    intelligently managed country on the planet since quite some time,
    and if there is any hope then it is with and not without china…
    they have a better culture than we do, and probably also the better
    government – not having to try and get elected by a countries averagers every four years gives you time to get real stuff done.

    but the machinery they produce right now just doent live up
    to our expectations 2/3rds of times, or not for long.
    never will i buy the cheap rolexes they keep offering…
    and a well made non-chinese diesel generator costs real money,
    while a well-made gasoline generator is available
    at below 500 dollars or euros –
    with sufficient and intelligent charging power
    (that isnt usually in-built) such a generator
    shouldnt be needed more than maybe 12 hrs per week,
    and only if its overcast, so its bearable.

    how highly powered the generator is depends on your
    necessities, for the average off-gridder
    usually 5-10 hp will be more than enough, but thats only a guess –
    what do you say, elnav ?

  9. Nick
    You said “As long as it came for free, I like the idea of using an American truck as an occasional generator, to supplement solar power. It saves money on buying another Chinese-made gadget, extends the life-cycle of the truck,and, hell, you could even store stuff in back”.
    I suppose it depends on how occasional you mean but I think you chose the wrong reasons to favour the idea.
    It will not save money and it will definitely not be free.Those old engines will use a lot of fuel even idling because they are operating in the least fuel efficient portion of the power curve.
    I had to depend on my truck for emergency power once and it nearly emptied the tank idling to power an inverter to keep the freezer cold during a heat wave of +32 C.
    An idling engine is inefficient because the compression ignition is slow and the injection pump enrichens the fuel mix to compensate for the slow speed. Perhaps during the August heat wave the engine did get up to operating temp but more often sludge builds up in an engine that is idled extensively. The alternator is also running slowly so it does not put out anywhere close to its rated output. Which means you need to run the engine much longer than if the alternator was putting out its full potential.

  10. I have used a 6.9 L ford diesel engine fitted with a big 130 amp altnator in an emergency.
    Concerning the comments “if its free why not”. My short answer is; but the fuel burn and the maintenance on the truck engine is NOT FREE. As a once or twice event you really don’t care what it cost you to get out of trouble but if the emergency last more than one day and is likely to recur this is not a good idea. For a better idea look to the post by Marshall C concerning his genverter or look for an article by me in the next week or so.

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