Running portable generator off vehicle fuel tank.

[jjrbus]

On another forum someone posted about running a Honda EU2200i off the original fuel line from the removed Onan. I have been using the mighty little Honda forever and never heard of tapping into the vehicle fuel supply. Does not seem right? Any input on this.

[shastagary]

he did pull fuel from the rv fuel tank as the compartment he used was the original generator compartment and the fuel line was already there.
when he filled the generator tank to full it would over flow into the catch bottle so he could see when the generator tank was full he later installed a night vision camera and a switch inside by his camera monitor to see the overflow bottle so he could release the momentary fill switch and stop the pump.
he had a hour meter and a compartment fan plugged into the generator also.

[jjrbus]

Interesting setup with the predator. Youngster seems to have put a lot of thought into it, yet he did not pull fuel directly from the vehicle tank. Wonder what his thinking was?? Is he old enough to drive?? LOL

[shastagary]

this guy set up his predator generator to be refilled with a manual activated electric fuel pump and a catch bottle to see when its full
he later installed a night vision camera and a inside remote switch to fill the generator.

youtube Generator Project - RV Living

[Bobbo]

Keep in mind that propane only has about 80% of the BTUs per volume that gasoline has. You have to derate the generator by about 20%. So a Honda EU2000i that is 2000 watts surge and 1600 watts continuous is only 1600 watts surge and 1280 watts continuous on propane.

[Skibane]

Another option would be to install a propane conversion kit on your portable generator, and plumb it into one of the RV's existing low-pressure propane lines.

[jjrbus]

I am not a mechanic, the only experience I had was when I had my gas tank cleaned and lined. I had the tank bolted in and most of the hoses hooked up. Took a break and when I came back out gas was coming out of one of the small lines that was not hooked up. I removed the gas cap releasing the pressure and the gas stopped flowing. I had put about 5 gallons of gas in the tank to check for leaks.

[Grit_dog]

jjrbus wrote:
On another forum someone posted about running a Honda EU2200i off the original fuel line from the removed Onan. I have been using the mighty little Honda forever and never heard of tapping into the vehicle fuel supply. Does not seem right? Any input on this.

If you don't have a RV where there is already an aux fuel line and pump to a built in generator, it would be very prohibitive IMO.
If you do, then it would still be quite involved to make it a Hands Off system, although it could easily be a handy storage tank and gas pump to fill a remote located generator.

[valhalla360]

Modern vehicle fuel systems are sealed for emissions reasons and get fussy if that seal is lost. How exactly would you be tapping into the tank?

The outboard tank with honda transfer cap really makes far more sense.

[wa8yxm]

jjrbus wrote:
I have used the external tank for years. My concern is the vehicle fuel system is pressurized, would it push fuel through the Honda? Just does not sound right.

The vehicle fuel system is not pressurized... There is a pump (External to the ONAN generators but very close to it)( specific to that line. the line pre-that pump is not pressurized might be slight vacuum in fact.
A Separate line to the main engine IS pressurized. But that is for the Motor home's motor.

[Skibane]

wa8yxm wrote:
With most makes of generator you are correct.

With a HONDA. they put on on the generator at the factory.

As someone posted up thread the HONDA is designed to suck fuel from an external "Extended run" tank.

Drawing fuel from a tank sitting right next to the generator isn't the same as drawing it through several dozen feet of fuel line to a tank mounted somewhere else on the RV.

Depending on the particular RV, there may also be some additional restriction from a fuel filter.

[wa8yxm]

Skibane wrote:
You'll need a low-pressure electric fuel pump (to replace the one on the Onan you yanked out of the RV), along with an adjustable fuel pressure regulator to reduce the fuel pump's 4-5 PSI output to just a small fraction of a PSI (which is what the pressure coming out of a gravity-fed fuel tank would normally be).

With most makes of generator you are correct.

With a HONDA. they put on on the generator at the factory.

As someone posted up thread the HONDA is designed to suck fuel from an external "Extended run" tank. they even showed a photo of the set up.
Honda sells the tank and the "Modified" gas cap needed to use it.

The procedure is fill the "on board" tank. and the external. replace the original gas cap with the "extended run" cap and it sucks the extended tank dry. You then swap caps back (Running off the on board) While you run to ye old fuel pump to refill the extended tank.. Can run a long. long, long time that way.



TO THE ORIGINAL POSTER

Be sure to put a shut off valve line (two in fact) in the line from the RV's primary tank. One manual and one "Quick Disconnect" type to insure the line does not express fuel when the tank is filled.

[jjrbus]

I have used the external tank for years. My concern is the vehicle fuel system is pressurized, would it push fuel through the Honda? Just does not sound right.

[Skibane]

You'll need a low-pressure electric fuel pump (to replace the one on the Onan you yanked out of the RV), along with an adjustable fuel pressure regulator to reduce the fuel pump's 4-5 PSI output to just a small fraction of a PSI (which is what the pressure coming out of a gravity-fed fuel tank would normally be).

This prevents the generator engine from running rich or flooding out, due to excessive fuel pressure.

For safety's sake, the electric fuel pump will need to be connected so that it shuts off if the generator engine dies for any reason.

Many portable generators have a 12 volt DC "battery charger" output that can be used for this purpose - basically, the battery charger output powers the fuel pump whenever the engine is running.

You'll also need to add a "prime" bypass switch that allows the fuel pump to be manually turned on for a few seconds while starting the generator.

[Bobbo]

I just use an extended run fuel system. The 6 gallon tank lasts a couple of days at moderate amp draw.

Extended Run System