Cummins as Genset?

[Squantobon]

Anyone use their tox vehicle motor as their electrical generator? Is it good/bad idea? Is it efficient at all?

Or is this more of an emergency use only?

[vsheetz]

Do you mean run the cummins Diesel engine in your truck to charge house batteries, provide for 120vac (via a inverter?), etc.?

The Cummins engine should not be idled for extended periods if time.

Compared to a proper generator I would think it would use more fuel. If you want to power an air conditioner on the house, it would take a very big inverter and battery bank. More...

[1bigmess]

In general, a bad idea, for a couple of reasons.

First, insanely inefficient.

Second, not good for the oil, emissions components (if any), and combustion temps will be low.

If you decide to do this, start getting your oil tested and/or change it more often as a precaution.

[38Chevy454]

The alternator in the truck is quite low output compared to a real generator. Let's say you can get 100 amps out of the alternator, without it overheating. 100 amps x 13 volts (approx, could be higher, but account for resistance loss) = 1300 watts. Any basic generator is 3000-6000 watts range. even the small suitcase sized generators are 1000-2000 watts.

The real generators use less fuel, won't overheat and damage your alternator, and won't cause issues with the emissions equipment on your truck.

in an emergency, it can work, but is not a good solution for a real generator.

[Squantobon]

Ok, thanks. I That's what I kind of figured but I'm no diesel expert.

[1bigmess]

Ok, no one is on their first day.

Diesel is a light oil. It needs the conditions in the combustion chamber to be right in order to fully burn. When sitting under virtually no load, the fuel doesn't burn completely. This can create excessive carbon, and even unburned fuel can wash down the cylinder walls, removing the engine oil film that is reducing wear. Unburned fuel can also dilute the engine oil and reduce it's effectiveness. Your emissions equipment might suffer, too, if you have any.

You've no doubt seen big rigs idling their engines, maybe even all day and/or all night. Idling is bad for those engines, too. But they have about ten gallons or so of engine oil in them. Somewhat of a different story.

Alternators don't make their peak output until you get them to a certain RPM. Each one is different. As stated, 100 amps output sounds good, but it's not. Your engine needs some, your other vehicle systems need some, etc. Sure, it can charge a battery, but at what price, sitting there under the hood with the hot engine, not enough airflow to keep it cool while you wring it's little neck for more. Meanwhile, your 300 something engine is running just to spin an alternator that doesn't take near that to spin. Very inefficient.

The money you could spend for a decent inverter gennie would be saved in the long run by not possibly damaging your tow vehicle engine. They are also much more efficient in their use of the fuel needed to run them, and if the gennie fails, that likely won't leave you stranded on your camping trip.

More than you ever wanted to know about any of this stuff? Have fun!

[Squantobon]

Originally Posted by 1bigmess

More than you ever wanted to know about any of this stuff? Have fun!

No, thank you very much for all that. And yes, part of the reason I asked was because of the big rigs idling and also smaller, SUV types idling I think mostly to keep the A/Cs running. I actually already own a diesel pick up but you'd laugh if you saw it as far as a TV goes. It's maybe 30 years old and I bought it 2 years ago? I like that it's not too thirsty and diesel here (Philippines) is about 10 pesos less per liter. That still makes it maybe $2.20/gallon but that's better than gas at $3.

The other reason I was asking was I noticed options on the ram trucks website for heavier duty or dual alternators and I was wondering if that might be the reason and if that would be a good option to take.

[wingnut60]

If you are going to order a new truck, might make sense to get the dual alternators, but they don't work to put out more amps unless there is a load that requires it. Usually, it is for high-wattage lights, snow plow operation, etc. You have to remember that the charging wire to the trailer is usually the limiting factor to transferring power to the trailer batteries...and that wire is no larger in the dual setups than in the single setups. You will find out quickly that the TV alt is usually only good for keeping up batteries that are already charged, or providing some power if you let the batteries get too low to use the jacks.
Joe

[Squantobon]

I like the idea of having 2 alternators as you have a backup if the other fails but how would you know? My luck would be that when I have a problem charging I then find out I need 2 new alternators. Hahahaha Ok, not so funny.