Propane conversion, is it worth it?

[Rat407]

We are looking at getting a generator. Thing is the ones out there that are propane are either not large enough in watts or to expensive for the larger ones. Was considering getting what we want in the right size wattage and then getting a propane conversion kit from US conversions. Anyone have any experience in this area? Is it worth it and reliable? I like the fact of never having to worry about fuel going bad. Thanks

 

[Fordiesel69]

Question......do you have natural gas near your generator site?

 

[Rat407]

No unfortunately. The town has NG but they want an outrageous amount of $$$ to bring it down our street to our house.

 

[JTK]

How big do you need to go? You'll blow through some serious bottled propane with something larger than 5000 watts or so.

I've seen some imported propane powered smaller gen sets for fairly reasonable, but like said, in this realm, you're going to get more watts per fuel unit with gasoline.

Joel

 

[Fordiesel69]

There are a few requirments to do a proper conversion. My personal beleif is to buy a diesel and learn it well so you can do the upkeep. The fuel will last a very long time with a biocide and a simple additive. If it is an older diesel with a mechanical injection pump, it will not care too much if the fuel is a year old.

Now if you make your selection on a generator, you will need to supply the model and engine info. During the automatic startup, there may need to be an enrichment solenoid on the venturi to increase propane deleivery at starup. Adding this wire may be needed. Also during shutdown the venturi needs to shut off with the ignition. It can all be done but you need to have some electrical / wiring skills.

Lastly the large propane tank needs to be located somewhere safe, and per your local codes. You need to size the propane tank according to a full week runtime minimum.

There are pro;s and cons to all fuel types. If we have a major grid failure, you will not be able to obtain any fuel types unless you have a planned reserve. If there comes a day of an EMP attack, any intergrated circuit components will be fried. This is why I favor the old skool electromechanical control system on a generator. Typical outages should be planned for one week. Keep this in mind when picking a generator.

Another thing to consider is air cooled vs water cooled. Air cooled at extended periods will require makup oil requiring you to shut down and restart. Just some things to keep in mind.

 

[AandPDan]

I've did the conversion on a 5000 watt Tecumseh powered generator about 7 years ago. It works great. It runs VERY smoothly compared to gas and have had no problems whatsoever.

Saying that, think hard about how big a generator you need first. In my case I run the basics. I don't keep it running overnight, I'll usually shut it down about 12. The house stays warm and the food cold. I'll fire it up a few times throughout the day to warm things up, cook meals, etc. I don't see the need to burn up fuel when not needed because I've had those week long outages. I average about 7-8 hours running time a day

FYI, I burn about the same as when it ran on gas, maybe 1 gallon an hour when heavily loaded.

The small barbecue sized tanks will work OK when it's warm out but when it gets cold, you'll need something bigger for the vaporization.

The beauty of it is that, before I got the big tank, I could always "swap" propane grill tanks even when the stores didn't have power to run their gasoline pumps.

 

[Donald]

I was considering a conversion but picked up a used Winco propane generator for $500. Its one heavy duty monster. The conversion is about $300 I think.

One thing I read in a boating magazine, (yes they have an outboard that runs on propane) is that engines made to run on propane only (or really maybe propane or NG) have a higher compression ratio and don't suffer the loss of power when you do a conversion. I assume the tri-fuel generators have the same problem. This sounds true but I have not verified it.

I am using 100 lb tanks and have one and will get one more.

The lack of maint with respect to stale gas is the main reason.

If my lawnmower does not start in the spring, no big deal I will fool with it. But if the generator does not start do you want to fool with it in the dark and cold. And it needs to be fixed right now. You can't wait and pick up a part tomorrow.

 

[Food Scientist]

Originally Posted By: Fordiesel69
There are pro;s and cons to all fuel types. If we have a major grid failure, you will not be able to obtain any fuel types unless you have a planned reserve. If there comes a day of an EMP attack, any intergrated circuit components will be fried. This is why I favor the old skool electromechanical control system on a generator. Typical outages should be planned for one week. Keep this in mind when picking a generator.


What are you going to need the generator for if we have an EMP attack? I don't think my refrigerator, AC, heater or microwave will work after an attack.

 

[bullwinkle]

Microwave no-but I bet the others could be hard wired to just turn off and on with a switch if the circuitry is cooked.

 

[Fordiesel69]

Originally Posted By: SVTCobra
Originally Posted By: Fordiesel69
There are pro;s and cons to all fuel types. If we have a major grid failure, you will not be able to obtain any fuel types unless you have a planned reserve. If there comes a day of an EMP attack, any intergrated circuit components will be fried. This is why I favor the old skool electromechanical control system on a generator. Typical outages should be planned for one week. Keep this in mind when picking a generator.


What are you going to need the generator for if we have an EMP attack? I don't think my refrigerator, AC, heater or microwave will work after an attack.


Anything with micrchips will be junk. But any old skool electromechanicals will be fine. Like a washing machine with a rotating timer, a refrigerator with a temp probe thermostat, or an old stove & oven with turn dials. Anything digital will be a lost cause.

 

[Rat407]

I'm looking at just being able to keep our two deep freezes going and two fridges. That is basically it. No need for major comfort that we can for see. I was thinking on the lines of a 7000 watt would be fine. The propane one from Generac is only 3250 watts. I don't think that would be enough for what we wanted to do. I'm under the impression a little bigger than needed is a good way to go.

 

[itguy08]

Originally Posted By: Rat407
I'm looking at just being able to keep our two deep freezes going and two fridges. That is basically it. No need for major comfort that we can for see. I was thinking on the lines of a 7000 watt would be fine. The propane one from Generac is only 3250 watts. I don't think that would be enough for what we wanted to do. I'm under the impression a little bigger than needed is a good way to go.


You could probably get by with a 2500 or 3000 watt unit depending on what the usage of you appliances is - check the nameplates for watts used. During one of the hurricanes last year a friend lent us a Honda EU2500i.

We ran the following all at once:
1. Full Size Refrigerator
2. Dorm Size Fridge
3. Freezer
4. FIOS Box
5. 2 Laptops
6. Coffeemaker (only after all the others were started)

We even ran the microwave on it after we disconnected everything.

That being said, I got a 5.5k unit as I wanted to be able to run a couple space heaters in the winter just in case.

Also don't underestimate comfort. It would be nice to be able to run at least a fan or small AC unit. I know when we were on generator in the summer we had no fans and it was the worst sleep I ever had - hot and sticky.

If you're going with gas or propane/natural gas I'd just get something that is a little larger than what your calculations are. That way you have some growth and can run even more if you do some basic load management.

Just a note about propane - be prepared to have a couple 100lb tanks on hand as 20lb BBQ ones will go quick. Looking at Home Depot the 7kw one they have will go 8 hours on a 20lb tank @ 50%. A 8.75kw one from Harbor Freight will go 12 hours @ 50%. Maintaining gas isn't that hard - Sta Bil + MMO and rotate in the car every 6 months. Run it every month when cutting grass with a couple space heaters attached.

 

[morris]

i ran propane once. the bigest thing is the price difference from gas and propane. it will cost you 15-20% hp. cause the propane is a gas as it goes in, taking up space that is needed for air. but if you must run propane use marvel mystery oil. check out this. www.ampcolubes.com i use the st400. just put MMO in and leave it.

 

[JimPghPA]

To OP, You have to take a close look at how many BTUs you will burn through, and how much Propane that is.

The Generac Propane unit probably would be best used with a large external tank, because the larger the tank the better it can absorb heat from ambient to make up for the latent cooling from the liquid propane turning into gas within the tank.

If you are going to go with Propane you probably want to keep the generator small so you stock enough Propane to run it long enough.

I know someone who looked into using propane for a stand-by automatic gen-set and found out that the tank size (or tanks if using more than one), were unrealistic. They went with natural gas.

RAT407, do you have oil heat? If so there is a heating oil that can burn like diesel, and will work in a diesel gen-set.

Most diesel gen-sets run at 1800 RPMs (half the RPMs of gas) and last a lot longer, and cost much more.

If you go with a larger gen-set and it is not an inverter type, then it will probably be one that runs at 3600 RPMs ALL THE TIME and a larger unit will consume more fuel even if it is not running near full load.

An inverter gen-set cost more, but changes the RPMs so it runs slower when lightly loaded. Inverter gen-sets consume much less fuel, and in general are quiet. They are also more expensive. I do not think there are any inverter gen-sets large enough to do a whole house.

There is also the problem about electric codes. Some areas require limit the number of circuits that the gen-set can run if it is below a specific size.

 

[JimPghPA]

BTW, Propane is heavier than air. If you get a leak it will flow down-hill, and accumulate anywhere there is an area for it to do so. This can result in an explosion. There are gas detectors that will sound an alarm, some are multi-gas, others are specifically for one gas. It has been a while since I looked for one, I think Fisher Scientific sells some, and may-be Graingers ,or McMaster-Carr.

 

[SteveSRT8]

Like in the old daze when all our trucks had a propane tank on board. When you entered the warehouse in the morning you NEVER switched on any lights until you carefully sniffed your way around first!!!

 

[Donald]

Originally Posted By: Rat407
I'm looking at just being able to keep our two deep freezes going and two fridges. That is basically it. No need for major comfort that we can for see. I was thinking on the lines of a 7000 watt would be fine. The propane one from Generac is only 3250 watts. I don't think that would be enough for what we wanted to do. I'm under the impression a little bigger than needed is a good way to go.


You need to get a peak hold clamp-on AC ammeter and measure each one, both startup and running. You can make sure they each start individually. Also you probably should add say 25% to each one to cover the defrost cycle which is an electric coil in the walls of the refrig or freezer.

 

[tig1]

Stick with gasoline.

 

[Rat407]

I guess if I wanted to I could tap into our 500 gallon propane tank that we use for heat. Then it wouldn't be an issue with running out of fuel. We have a tankless water heater that uses the gas during the summer and that is it. We want to get a gas stove when we remodel the kitchen next year. If the dryer ever goes out we will probably upgrade to a gas dryer as well.

Thanks for all the help, it is greatly appreciated.

 

[JR]

I have a coleman 3.75kw tecumsrh 5.5hp enduro ohv that is slated to get ng/lpg conversion. it has a 5gallon boat tank for supply and requires fuel three times a day. it runs 24/7 when in black out. most hours are 80+% load.

ken