Converting a Generator to Propane

[Goodspike]

Goodspike

I looked at the kits that allow it to run on dual fuel but the kit maker says right on the web site that this comes at a cost to efficiency. If you need to leave the gasoline carb intact then the propane needs to be introduced into the intake manifold at a non-premium location. (The premium location being used by the gasoline jet). I didn't like the idea of losing some of my efficiency just for the ability to one day use gasoline, the benefit didn't equal the cost for me. This inefficiency may not exist on gennys that were designed and built to run on two fuels, it may only be a factor when you're doing a conversion.

Interesting.  Not sure why that would be the case.  As a practical matter I never run mine on gasoline so you're really not losing much.  NG is my first choice, propane second, and I keep a fair amount of the latter around, so it would have to be a very long power outage to need to turn to gasoline.  Although a major earthquake could cut off my NG supply, meaning I'd need to turn to gasoline faster.

 

[skydivemark]

Not sure if resurrecting an old thread is proper or if I should direct message the OP, but I'm just curious how the conversion went.

 

[Viajeros]

Can’t comment on the conversion. But a thumbs up to propane operation on a portable. We bought a dual fuel 3400 champion as a back up for critical loads. Nice not storing gas. Propane stores forever. We occasionally exercise it as recommended and use the Tesla as a variable load. We vary it between 12 and 24 amps. Works well. The champion is also super quiet. We have never put gas in the tank.

 

[skydivemark]

Very Nice!

 

[JayArr]

Hi Mark

Still in progress. I ran into a hitch with the wiring of the stator on the genny, it was wired for 240V 15A but I wanted 120V 30A so I could put a TT-30R on it. I had to pull the whole stator off and undo the loom to re-wire it. I also had to move my propane tanks forward on the tongue and weld up a frame to make a platform over the batteries for the genny to sit on. While I was at it I re-plumbed the propane regulator to inside the tank cover and ran hard line all the way with an extra valve for the genny. That's all done and now I just need to finish assembling things.

 

[JayArr]

more

 

[Ex-Calif]

Nice fab work. Have you calculated new tongue weight?

 

[JayArr]

Not yet but I'm not too worried. I was low last time I weighed, tongue weight was 395 lbs on a total weight of 4724 lbs = 8.3%.

I weighed the car by itself on the scale 5934 lbs. Then hooked up the trailer and drove back onto the scale leaving the wheels of the trailer off the scale and weighed the car a second time, 6329 lbs. By my logic the tongue weight is the difference, 395 lbs.

Then I pulled forward so that the trailer axles were on the scale but the car wasn't and noted that weight, 4329 lbs. I add the tongue weight of 395 to 4329 to get a total trailer weight of 4724 lbs.

I've read that tongue weight should be 10%-15% of total but I've also got load stabilizing bars, do these alter that 10%-15% target?

I think that adding the generator up front may increase my tongue weight into the target zone on 10%-15%.

 

[Larry N.]

do these alter that 10%-15% target?

Not appreciably. And 10% is far from ideal, so the stabilizers will help from that point, but probably (IMO) aren't really needed once you hit about 12-13%. It's about fore/aft balance, much like a tailwheel aircraft vs a nosewheel aircraft, where the taildragger's center of gravity being behind the main wheels means you have to be very careful to not let things get even a little sideways since that weight tends to want to make the aircraft want to swap ends. Conversely, in a nosewheel type aircraft, the CG is ahead of the main gear and that same slightly sideways attitude leaves the aircraft tending to straighten out by itself. It's essentially similar to driving a forklift forwards vs. backwards, etc.

 

[Gary RV_Wizard]

I've read that tongue weight should be 10%-15% of total but I've also got load stabilizing bars, do these alter that 10%-15% target?

Those bars are for weight distribution (WD) on the tow vehicle and in most cases have no effect on stability. The exception to that would be WD systems that also have anti-sway built in, e.g. the Reese Strait Line, Equalizer, etc. WD doesn't change the trailer balance formula - just how the tow vehicle carries the weight. As Larry explained, trailers are balanced with 10+ percent of the weight forward so that the backend follows the nose (the coupler on the tongue). The greater the weight on the tongue, the lesser the tendency for the rear to sway.

This brief video illustrates the tongue weight effect on sway.

 

[skydivemark]

Keep the updates coming Jay, definitely an interesting project.

 

[JayArr]

A whole lot of work but not much progress this weekend. I welded up a muffler mount for the new low tone muffler and I welded up the bracketry to mount the TT30R box and a project box that will hold the start switch and the power monitor display. I also did some wiring and some woodworking but nothing finished.

According to a you tube where they guy compared a bunch of different models, an open frame at 20 feet was about 76db unloaded. The Honda was only 58db unloaded. That's a nice big difference so I have a target to shoot for.

The more useful of the readings he took was at 15A load, at 20 feet, the inverter gennys were all around 67-71db and the open frame was still 76db. I'm hoping that I can get my 8HP Briggs and Stratton at least down below that 67db mark with the quiet box.

Here's something interesting from the video: The Honda is rated on the website as 57db at rated load (15A running). We can see for ourselves from the video that it only gets below 60dB under load if you measure at 50 feet. The trouble is that the standard seems to be 21 feet, that's what the parks boards use for campers. At 21 feet the Honda 2200i is about 67db.

What I'd really like to have is the reading from a big Honda inverter generator (3000i) at a 23A load, at 21 feet. The specs say 57db at rated load (23A) but they don't say at what distance, I'm now guessing 50 feet.

 

[JayArr]

OK, work continues, mostly fabrication work, the base board is installed in the frame and the wiring is all done. 12V wiring from the house batteries will go through a switch to the starter and 120VAC will come from the genny to a TT30R receptacle to plug the trailer into.

It may not look like a lot of progress but it all takes time to figure out the wheres and the hows.

With a little luck I'll get it running next weekend on propane and then I can finish the stator rewiring for the output.

 

[JayArr]

Couple of new pics. This is what a genny looks like if you remove the stator to rewire it. LOL

 

[skydivemark]

Haven't replaced brushes myself - yet - but my understanding is, putting the brushes back in (without causing damage) can be tricky.

 

[JayArr]

I've done it on a few generators Mike and it really wasn't any big deal. You do have to manouver them into place and push them onto the rings without much side pressure so they don't crack but as long as you have some finger dexterity and some patience it only takes a few minutes. Brushes are cheap, I intend to check and/or replace them at least yearly and I'll carry a spare set with us.

 

[phil-t]

Can’t comment on the conversion. But a thumbs up to propane operation on a portable. We bought a dual fuel 3400 champion as a back up for critical loads. Nice not storing gas. Propane stores forever. We occasionally exercise it as recommended and use the Tesla as a variable load. We vary it between 12 and 24 amps. Works well. The champion is also super quiet. We have never put gas in the tank.

Third PIC strikes me as "funny" Propane bottle>>>Generator>>>Tesla. Where's the "green" in that? Just struck me, that's all. How many MPG? LOL

 

[Viajeros]

Third PIC strikes me as "funny" Propane bottle>>>Generator>>>Tesla. Where's the "green" in that? Just struck me, that's all. How many MPG? LOL

Heh heh. . No idea. It’s only for 5 or 10 minutes every month or two. Our neighbour uses an electric heater as the load. At least with the Tesla as the load it will dump a kilometre or two into the Tank. But yah. I’m sure the green advocates would freak if they saw it. Lol. . Great variable load though as I can set the Tesla charge rate anywhere from 5 to 24 amps on 120 volts. Handy. .

 

[JayArr]

I took some pics of the carburetor setup today as I get ready to fire it up.

The firs tthing to do is gut the carb, remove the float, vale, choke and everything else but the little screen on the bottom. Seal up all the holes except fot the gas inlet hole that gets used for the propane.

It needs to be drilled out and tapped as shown in the pic.

 

[JayArr]

I started with a 45 degree 1/4" flare to NPT fitting, this should be about a dollar at the hardware store.

We don't modify the flare side but we do drill out the NPT side and re-thread it.