Propane conversion for my Storm Responder 5500-watt generator

A question I have for the folks in colder climates who run a generator using a 20Lb propane tanks is if a tank warmer blanket is important?

The most that I have had to use my generator in the past is during a rare hard freeze here in South Texas. I have been using gasoline most of the time, but I want to have propane as a backup if needed.

I also know propane can be temperamental when ambient temps drop below freezing because of the tank and regulator wanting to ice up.
 
And too rich gasoline will behave similarly to a too rich propane. There is no opposite.....
Hello R,

I missed your reply back in February and got sidetracked due to medical issues.

The difference is that gasoline will burn cooler and eventually carbon foul the sparkplug. Propane on the other hand burns too hot during combustion and will create piston damage. Propane can still foul the spark plug, but it takes much longer.

Propane is a dry fuel while gas is considered a wet fuel.
 
Are you considering using Gasoline AND Propane on the same unit? Different Carburation is involved. Propane does NOT damage Pistons. I use N.G. in my 14KW Generac. A 20 lb tank is quite small to be used on a Generator.
 
Hello G.,

With my 5500 Watt storm responder I am using gasoline for starting and warmup, then I turn the gas fuel valve off and let it run until it sputters out of gas. Has it sputters near shutting down, I open the valve on the 20lb. propane tank and the engine keeps on going. It's a smooth transition. I do not do this when under a load.

Propane itself does not damage the piston; it is the excess heat caused from the propane being too rich while running for a prolonged period. A rich mixture greatly reduces the generator RPM, and it is easy to see and smell the carbon out of the exhaust. A minor correction to the metering block quickly corrects the issue.

A 20lb bottle with run several hours at moderate load and I keep 4 of them on hand. Propane is my backup when my gasoline supplies get low.

So far, I have not had to use my generators this year, but I still run them all once a month to make sure they are ready. I've been "left in the cold" before and I don't like it.

For the most part I run a 15KW Generac portable with a 16-gallon tank especially if the heat or A/C in the house are needed.

This month I even installed a soft start kit on my house A/C unit so the 5500 Watt generator can run it if needed. It works great.

 
Hello G.,

With my 5500 Watt storm responder I am using gasoline for starting and warmup, then I turn the gas fuel valve off and let it run until it sputters out of gas. Has it sputters near shutting down, I open the valve on the 20lb. propane tank and the engine keeps on going. It's a smooth transition. I do not do this when under a load.

Propane itself does not damage the piston; it is the excess heat caused from the propane being too rich while running for a prolonged period. A rich mixture greatly reduces the generator RPM, and it is easy to see and smell the carbon out of the exhaust. A minor correction to the metering block quickly corrects the issue.

A 20lb bottle with run several hours at moderate load and I keep 4 of them on hand. Propane is my backup when my gasoline supplies get low.

So far, I have not had to use my generators this year, but I still run them all once a month to make sure they are ready. I've been "left in the cold" before and I don't like it.

For the most part I run a 15KW Generac portable with a 16-gallon tank especially if the heat or A/C in the house are needed.

This month I even installed a soft start kit on my house A/C unit so the 5500 Watt generator can run it if needed. It works great.

 
You have it well in hand it seems. Backup for Backup. The switchover works well but the Propane adjustment should be constant with no adjustment required. Propane has Less BTU energy than Gasoline. Burn temps are within 35°F of each other in the 3,450 F range. What IS damaging is using E-15 Gasoline in small engines as we are being forced to do in Canada.
 
Last edited:
Hello G.,

Years of military training and "country life" in general has taught me to prepare by using 2 to 3 levels of "backup".

Fortunately, we still have non-ethanol fuel and E-10 in my area, but E-15 is gradually being implemented. E-15 is just more trouble, and I think even the fuel injected small engines will have a hard time dealing with that stuff.
 
Hello R,

I missed your reply back in February and got sidetracked due to medical issues.

The difference is that gasoline will burn cooler and eventually carbon foul the sparkplug. Propane on the other hand burns too hot during combustion and will create piston damage. Propane can still foul the spark plug, but it takes much longer.

Propane is a dry fuel while gas is considered a wet fuel.
Nope. Backwards.
Propane 1 gallon=91,452 Btu
Motor gasoline 1 gallon=120,214 Btu
Stoichiometry Mass. . . . Vol. . . % by mass
Propane (LP)15.5 : 123.9 : 16.45%
Gasoline . . . . . . . . . . 14.7 : 1 — . . . . . . . . 6.8%

Per unit time both are ideally in the vapor state and the percentage fuel required is quite similar. The energy released per unit time from gasoline is higher by about 25%. Gasoline burns hotter than propane. In open air, a gasoline flame reaches peak temperatures of about 1,800°C to 2,000°C (3,300°F to 3,630°F), while a propane flame burns at approximately 1,960°C (3,560°F). Under pure oxygen, gasoline can reach over 3,000°C compared to propane's 2,820°C.


As for "dry" and "wet"....this is where that terminology comes from....When a formation holds mostly methane, it is referred to as a dry gas field. But most formations have a mixture of various hydrocarbons that all come to the surface as the well is produced. Wells that produce a lot of the other light hydrocarbons are called wet gas wells. These other light hydrocarbons include ethane, butane, natural gasoline and propane.

In natural gas processing plants, propane enters the plant as a component of the wet natural gas stream from natural gas and crude oil wells. When the raw, wet natural gas is cooled and pressurized in the plant, the heavier hydrocarbons (including ethane, propane, normal butane, isobutane, and natural gasoline) turn into liquids and separate from the natural gas stream. The mixed liquids, also referred to as Y-grade, are then refined and separated in a fractionator into purity products (products that are at least 90% of one type of hydrocarbon gas liquid [HGL]).

Oil refineries can produce propane in two stages of the crude oil refining process. The first refining process that yields propane is the atmospheric distillation column, where crude oil undergoes initial distillation. In modern, complex refineries, propane (and propylene) is also produced in fluid catalytic crackers (FCC). During this process, long-chain hydrocarbon molecules are cracked under high temperatures and pressures to break these molecules into lighter hydrocarbons that are more suitable for motor gasoline production. In addition to those gasoline blending products, the refinery crackers produce lighter molecules including propane, normal butane, isobutane, and their olefins.
 
Last edited:
Hello G.,

Years of military training and "country life" in general has taught me to prepare by using 2 to 3 levels of "backup".

Fortunately, we still have non-ethanol fuel and E-10 in my area, but E-15 is gradually being implemented. E-15 is just more trouble, and I think even the fuel injected small engines will have a hard time dealing with that stuff.
Why? What you think is irrelevant. What you can prove scientifically is relevant.
 
You have it well in hand it seems. Backup for Backup. The switchover works well but the Propane adjustment should be constant with no adjustment required. Propane has Less BTU energy than Gasoline. Burn temps are within 35°F of each other in the 3,450 F range. What IS damaging is using E-15 Gasoline in small engines as we are being forced to do in Canada.
Yes...there will be an adjustment unless you want to run lean with propane.
Stoichiometric ratio for propane is 15.5:1, gasoline is 14.7:1. The propane required per unit time is greater than gasoline therefore the orifice must be larger to pass the greater amount required. If injected, which I doubt it is, you'd need to adjust the PWM upward to admit more propane per injection event.
 
Back
Top