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Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1

Converting generator to propane?

A 4000 w max I'm not sure if I can do tri-fuel but want I wanted to know is wont the propane has a little less energy then fuel so my max ratings go down?

Having said that for a 20lb tank with say a 70% load I wonder what the runtime would be?



davidg
Good Bye My Friend
Premium,MVM
join:2002-06-15
none

my 5kw Dayton LP genny will ice up a 20# bottle in about 20 minutes under half load. you may want to either tie 2 tanks together or buy a larger tank. you can get up to a 100# tank and take it to have it filled. If you live in town and have access to natural gas that may be a better option, no fuel to store.
--
Lack of Preparation on YOUR Part does NOT Constitute an Emergency on Mine!



Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1

Well were I will be using it at no propane.. and since I will be down for about a week or so if I get fuel I'd need to get about 15 gal min..

Now as for natural gas, the tie in point is at the meter? The whole reason why I'm asking was I was watching a youtube video last night and one person was thinking of doing the same because after the huricane it was hard to get fuel for at least 2 weeks.. but no one was buying any propane tanks.
--
It's NOT Ni-kon It's NE-KON!




LG is NOT Lifes Good It's Lucky Goldstar!



cowboyro
Premium
join:2000-10-11
Shelton, CT

1 recommendation

reply to Subaru

Calculate energy output vs energy content of the fuel and figure a ~20% efficiency of the generator.
20lbs of fuel will store 21600*20 = 432000BTU
Burn at 20% -> 86400BTU equivalent electricity.
Heat equivalent is 3413BTU/kWh -> 25.3kWh produced.
Based on a 2800W load you'd get 9hrs give or take.



ITICharlie1
Premium
join:2003-01-22
St. Louis MO
reply to Subaru

Read through this as I am doing the same thing shortly...

»Convert from gasoline to tri-fuel
--
Don't let my reality hinder your imagination!



SwedishRider
Rider on the Storm
Premium
join:2006-01-11
not Sweden
kudos:1
reply to davidg

said by davidg:

my 5kw Dayton LP genny will ice up a 20# bottle in about 20 minutes under half load. you may want to either tie 2 tanks together or buy a larger tank. you can get up to a 100# tank and take it to have it filled. If you live in town and have access to natural gas that may be a better option, no fuel to store.

Ganging tanks is a good option, but if you have a whole house propane tank(100 gal to 1000 gal), that's the best option. A large source of local fuel on site makes a run-out far less likely. The downside of natural gas is if it's shut off for safety reasons... which unfortunately happened in some areas post-Sandy. Those folks were in as bad shape as the no generator crowd.


cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7
reply to Subaru

said by Subaru:

Having said that for a 20lb tank with say a 70% load I wonder what the runtime would be?

It's not a matter of what the runtime would be, but what the tank will provide.

It takes approximately 2HP for every 1000 watts of energy. For each HP, 10,000 BTUs of fuel are required. So 4000 watts at 70% load equals 2800 watts. And 2800 watts * 20,000 BTUs per 1000 watts equals 56,000 BTUs. That's your fuel consumption per hour.

If you look here, the vaporization rate for a 20lb tank at 60 degrees is only 24000. So you'd either have to drop your fuel consumption by half, or only run it for half of an hour (if that). On a 30 degree morning like today, that 24000 BTUs/hr drops to 15,700 BTUs/hr. Even a 100 pound tank would struggle to keep up in cold weather. You can cheat a little and get a tank warmer that can help boost vaporization, but at a cost of additional fuel.


Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1

the propane would be for summer only, in the winter I would have natural gas.. I should of been a little clearer on that..

however having said that for the short 1-2 weeks I need the generator outdoors in the summer (July) I'm thinking gas would be better off for that, for winter back home I can do natural gas but I don't see much on the way of a hook up.. I assume the line has a outlet.



cdru
Go Colts
Premium,MVM
join:2003-05-14
Fort Wayne, IN
kudos:7

said by Subaru:

however having said that for the short 1-2 weeks I need the generator outdoors in the summer (July) I'm thinking gas would be better off for that

During that period are you using the generator for potential emergency power? Or to power things at a job site, cabin in the woods, etc? If it's the latter, I'd probably just use gas. As long as a natural disaster doesn't happen right when you need it, gas is usually pretty easy to come by. Filling up multiple 5 gallon gas cans that would be used over the course of a few weeks of decent usage also isn't that much of an inconvenience. Where natural gas or propane are nice is when you'll be running for a prolonged period (less refills), during supply shortages, or infrequent usage (gas doesn't keep as long).


Subaru
1-3-2-4
Premium
join:2001-05-31
Greenwich, CT
kudos:1

Nope just a job site


ncbill
Premium
join:2007-01-23
Winston Salem, NC
reply to Subaru

buy a couple of 100# tanks, have them filled, gang them together at the site.

if this is temporary I'd stick with gasoline instead.