The viability of using automobiles as generators.

Re: The viability of using automobiles as generators.

TechnTrek,
I for one find the use of a Prius (or other hybrid) as a backup generator fascinating. You do however list 2 other generators in your signature so are you ready to sell those off?

Also, the Prius is a pretty fine niche with it's factory included propensity to charge batteries so I don't want to give anyone the idea that this thread is about how to build or buy a Prius. In addition, for someone looking for a generator, the price tag is such that I don't think many people are going to choose one as a dedicated solution vs other options. I mean, you still drive yours right? You don't just park it to charge your house bank correct?

I think for the sake of this discussion, that i would be interesting to see what people would build if they never intended to drive the automobile except in the case of an emergency backup to their vehicle (as sans to their generator).

As an example, I'll tell you what concept I'd be thinking of (and have thought of) when considering buying a nice generator vs building a dedicated vehicle instead.

First, I like the van, or mini van idea.

Before going too far, I would help out the suspension by adding HD springs (or air springs, but they don't like to sit).
I would fill a good portion of the cargo area with about 500ah @ 24v of batt's (even if I had house batteries I could charge). This would allow it to be completely self contained.
I would add a good sized inverter to the interior. In my case, a 6kw split phase inverter, but people could size these as their budget and needs allowed.
I would install (if space allowed) 2 200a commercial truck alternators. You can get these in 24v of course, and that would be a choice to make.
I would replace the belts with serpentine if not already equipped and take a hard look at if there were anyway to drive an alternator with the flylwheel/flexplate, but that's more involved.
Because the engine is already presumable well over powered for the 4.8kw this pair of alternators could produce, I would size the pulleys down to obtain the required alternator RPM at near idle.

I would create or modify a governor to keep the engine at idle RPM (or whatever RPM was required). Possibly this can be done electronically (it is on most modern engines).

I would add an automatic generator start to the engine. Magnum makes one that would work (I've used one).

I would insulate (wrap) all exhaust and likely add a second muffler (cheap).

If space allowed, I would increase the fuel capacity by adding an additional fuel tank.

I'd also throw a small portable generator in there for field work (something that could be carried places the van couldn't reach)

I would add external connections for reverse shore power, and also DC so one could charge a house bank (in a house).

I would keep an eye on things like oil pressure and water temperature to see if things like a HV oil pump, or additional radiator would be required.

I would consider adding an oil "spinner" to keep the oil cleaner than the filter can (big rigs use these).

...and finally, I would mount 4 PV panels to the top of the van...with charge controller...etc.

My vision of this "portable power station" isn't very creative. The idea is essentially to take what you might find in an off grid cabin, and stuff it in a van instead.

Why? Because a good backup generator can run upwards of 10 grand (think Onan/Generac/etc).
I believe I could build something like this for less than that, and my power requirements are such that I don't need 10-15kw in an emergency, nor to charge house batteries in a non-emergency.
I also think that because you are creating an "inverter generator", that fuel consumption could be lower than gensets forced to run at 1800, or 3600rpm continuously no matter what the load.
In addition, I believe that the modern car engine is better designed than almost any factory generator engine, and that as long as you maintained oil pressure, that one would last longer starting with used, than a new generator motor.
For myself, I'd look for a good fuel efficient Honda or Toyota mini van. A VW like the Eurovan can be had in diesel. I'd have to look into the full sized van idle fuel consumption numbers to see where they land because those American vans can also be gotten in diesel.
In the end though, I am less biased towards diesel in this application than I am with small generators. Gasoline engines are reliable, small gasoline generator motors generally are not up for long term tasking.

All of this said, someone else might have a smaller, or larger concept. Theoretically you could empty out a Honda Civic and perhaps end up with a suitable and even more fuel efficient rig.

Thoughts?

Re: The viability of using automobiles as generators.

Blackcherry04 wrote: »

I guess where you lived would depend on some requirements. The Po Po would be on you, a vehicle has to be inspected, licensed, have at least Liability insurance to be on your property where I live. You'd be in the hole $300 a year before you started with a junker. On the other hand, if it was driver and you could get the output you need, why not. I have a Toyota Camry engine pulling a 20 KW head that uses 2 gph @ 1800 rpm and that ain't cheap.

Am I understanding that you have a Camry engine in front of a regular 20kw generator head governed @ 1800rpm?

If so, 2gph might not be bad at all depending on how many kw it was producing.

I believe I saw once, some newer model import car motors being used on stand alone generators (a company was making them). I'll have to track that down.

Sometimes I feel like there's this wall of denial that for the most part, a generator is just an engine strapped to an alternator. Just as in stand alones, the two need to me matched, and are scalable for output, but also as in stand alones, a large engine is perfectly happy powering a small load (my 7kw gen set putts along producing 1k all the time).
I don't think the engine/alternator combination really cares if its on a cart, or a trailer, or built inside a car or van, in fact... a $500 Astro van cargo area is by far more elaborate than most generator "quiet" enclosures.

Most generator companies use what amounts to tractor engines. I think this is due to cost, but simplicity is a plus too. Of course if you put that same output tractor engine in your car, it would probably get lousy fuel economy and the EPA would be screaming...etc.
I just don't think putting late model car style engines (read high dollar tech engines) in generators is viable to the generator manufacturers. I think it is cost prohibitive (adding many thousands of dollars to the cost over a tractor engine).

That doesn't mean we can't.