Generators, changing fuel type question. Gas to Propane

[Rams]

Looking at getting a 5 to 7K generator,    I know it's possible but, how feasible (cost to change over and using propane versus gasoline)  is it to change over from gas to propane.    One doesn't need to be nearly as concerned with propane going bad as with gas.

No experience with this so, I thought I'd ask the experts.

The reason:   I'm wanting to do a little RVing in the future and will no doubt need a generator.    I have extra propane tanks and am considering alternatives for power when in locations without an electrical power source.   You can only carry so much extension cord.       Enlighten me if you will.

[Bighead]

I would look a a company called Generac they make Propane generators.

[dreamaker]

There are kits out there, for tri fuel, for generators. You can use any of three fuels, what ever is available, your not stuck on one type. I have a Honda generator, and my next project will be tri fuel. I have been researching for a while. Its not one kit fits all, the kits are specific to the type of generator. I found some kits on EBay, look there.

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.Xtri+fuel+kits+for+generators&_nkw=tri+fuel+kits+for+generators&_sacat=0

[Master Blaster]

I would look a a company called Generac they make Propane generators.

Good advice, some of them are even set up to use either, switchable on the unit.

[Jess from VA]

I don't know a damn thing about it, but I'm also very interested.  

I need a generator several times a year, and a few times for 2-3 days constant.  I got a pretty decent overhead valve, cast iron sleeve, low oil shut off 5k (and set up a 220V back-wire to my house during a whole house heavy up).  However, despite my best efforts at draining it dry and the carb bowl (after each use), and only using fresh (ethanol polluted) gas, it has gotten gummed up several times and is unreliable and hard to start and shuts off regularly.  

The last time I really screwed my back up was pulling and pulling the starter rope, having it break, drilling out the rivets holding the rope-pull assembly, then having to wrap the rope for each pull.  Slipping and sliding in freezing rain in pitch dark.  Boy did I want to shoot that generator.

Added to that, I would love to keep a stock of gas, but that's out with ethanol crap, and if we get an area wide outage, then I cannot count on getting fresh fuel at local stations.  It is 10yo but has pretty low hours total running time.  I've been eying new and bigger ones, but foresee the same problems.

I know I should gas and run it periodically during long months of disuse, but who wants to do that, then having to drain the gas and bowl each time?

My brother got a giant propane setup on a concrete pad, with battery start, that self starts every month, but that was like $5-7K... but he is out in the sticks and loses power all the time where the expense may be justified.

Can full propane tanks be stored indefinitely?   And how long will a generator run on a std tank of propane?

[KG]

http://www.motorsnorkel.com
New website for UScarb
Sometimes it's cheaper to buy it already set up than buy a Genset and add a kit

Tri fuel works good if you have natural gas at home but there are other kits that use a regulator and drill a hole in your carb to install the propane jet. Some of the mods and kits you find online only work good with the Genset lightly loaded or heavy loaded. Will get some more info for you when I get home

[Wewaman]

Onan generators are what's in a lot of motor homes and they are quiet and propane.

[KY,Dave (AKA Misunderstood)]

I bought a small generator recently for short outages and made sure I got a propane unit. Reason being it will be used so little and gas would give gummed carb issues. Also in an emergency setting propane is easier to come by and transport safely. Happy with it so far.


They do make conversion kits as stated and here is an example

http://www.ebay.com/itm/like/161368768242?lpid=82&chn=ps

[Pepmyster]

I would look a a company called Generac they make Propane generators.
[/quote

 

[Rams]

I would look a a company called Generac they make Propane generators.

This sounds like some good advice.   I've heard very good reports about Onan and Honda brand generators.   Although I am aware of Generac, I honestly haven't heard good or bad about them.

But, buying one already set up for propane seems to make sense.    Thanks.  

Anyone else use a generator for RVing?    I'm told I can expect about 8 hours of use from a 20 lb. propane tank.    I have a couple of extra tanks and it seems to me to be a good way to put them to a good use.

Edited:  A couple of the reasons I'm not interested in a gas generator is that it's just another fuel that I would have to stock, I really don't want to have to be concerned with gasoline gumming up a carb.    Additionally, the RV is already propane dependent.    I considered a diesel generator due to I'm already using a diesel (Cummins) truck but, the weight of a diesel generator (even a small one) is significantly higher than those gas/propane versions.    Propane also seems to offer a much cleaner burning and longer lasting engine.      Seems like a no brainer to me but, as I said, this is not something I have much experience with.    

Thanks

[LandElephant]

I've got a 5.5 k propane generator in my rv and love it. You always have fuel because you use propane for your hot water heater, heater, and stove. It's quieter and doesn't tear up the lub oil. I get about 7 days out of a 30 lb bottle when needed.

Had a gas generator in my first rv and hated it.

Charlie Morse
Land Elephant

[Jess from VA]

There are lots of multi-fuel generators for sale, and of course conversion to propane kits for regular gas generators.  Then there are propane-only generators.  So I have more questions.

Are the multi-fuel generators (and conversion kits) some kind of compromise that are not as good propane-only generators (assuming you are planning to use propane all the time anyway)?  

Are the propane-only generators better at what they do (like in the carburetor function) than multi-fuel generators?

Is the only difference in the propane-only generators from multi-fuel generators a gas tank (I mean besides a switch mechanism between fuel types)?  Some of the propane-only generators look a lot smaller than multi-fuel, besides not having a gas tank.

For my purpose, I don't need (or want) gasoline function at all (to gum up) if I can stock up on full propane tanks.  Do full propane tanks last a long time, or forever (unlike gas)?

Propane run generators of any type are not going to get gummed up from long disuse like gas generators, are they?

I have natural gas in my home, but do not see any economical way to pipe it out to the shed I keep and run my generator in.  My heavy gauge flexible extension to run power from the generator in the shed to the back of my 200 amp service box in the house is about 35 feet.  Some asshole probably wants me to grease the County palm with the expense of a permit for this too.  (I would not do this myself, it would be done to code for safety and insurance purposes, and I suppose no reputable contractor would risk his business license without a permit anyway)

[Hook#3287]

I've no experience with tri-fuel. Can't help there.

Onan makes excellent generators and are the preferred RV brand.  Quiet.

Honda has the best portables, pretty sure most are gas.  Also very quiet.

Generac seems to have concentrated on the home "back up power" market.  My neighbor has one and it runs on propane, starts up once a week to test itself and re-charge the batteries.  Comes on automatically when ever the power goes out. Not very quiet, but when the lights go out, who cares. We both have 500 gal under ground propane tanks and I've got a 7K Generac I haven't got to hooking up yet. 

Now, when the power quits, I roll out my Honda powered 5K and plug in the wire I had my Electrician buddy hook up.  I can go to my box and flip the breakers I don't need.  Out here in the boonies, I run my own well pump and that sucks up a lot of juice so I've got to watch that, but it works good.  Never had a problem starting it, it's a Honda , second or third pull, it fires.

If I had access to natural gas, that's the route I'd go.  I'd definitely pay the freight for that.  No filling tanks and having them hanging around, having to swap them when they run out.

Propane lasts forever, as far as I've heard, at least I've never heard other wise.  It's a gas under pressure, so what goes bad?  I've had propane in my 500 gal tank for 3-4 years as it's only used for cooking and hot water.

[Jess from VA]

If I had decided to live in my house forever after, I might look into an expensive, permanent auto propane setup, or pipe natural gas to an outdoor generator, but I may very well sell out in a few years and don't want to invest thousands in this project.  I'd plan to take my generator with me when I left.

Another question is, for unit of power or energy produced, is gas or propane significantly different in cost? (And I think 4 bux a gallon for gasoline is more realistic than 2 bux, in the long run.  My thinking is for increased reliability of both the machine and the storage of fuel, and relatively rare need for a generator, paying double the price for energy is worth it.   

[Rams]

Jess,
May I suggest that you enquire with a plumber as to what it would cost to run a line with a valve out to your shed for that generator.    You might be surprised at what it costs.    I know if I had access to natural gas, I'd plumb it into everything that could use it.

Charlie,
Check your PMs please.

Ron

[Jess from VA]

I may do that Ron. (problem is thru and under a bunch of concrete)

And I guess I am going to have to call the gas company (or a few others) to get my answers to questions about propane generators.

Funny.... I got out of service with a brand new electric dryer (one of the most expensive electrics to run), so I decided to use it till it broke before going gas.  The bastard is still kicking without a single hiccup 23 years later.  Course as a bachelor, I only run a couple loads a month.  Men don't own or separate delicates.  LOL

[Rams]

After doing a little internet research, I've found a few options.   All I'm gonna say is, my goodness they're proud of their product.   

[KG]

there are advantages and disadvantages to each type of fuel.
gasoline has more heat value than propane and natural gas.

A 7kw gasoline powered  generator that is switched to propane will be derated to about 6.2kw and natural gas will be even lower.

gasoline has storage issues it must be used before it goes stale and gums up the fuel system. even with stabilizers it only lasts so long. then there is running out in the middle of a emergency to find a gas station with power to buy fuel.

Propane is a gas and is stored in a steel cylinder and does not go bad. propane generators come in two options for fuel systems. Vapor withdrawal and liquid withdrawal. Vapor takes just the vapor propane from the top of the tank to feed the genset. Liquid withdrawal takes liquid propane from the tank and at the generator uses a converter to transform it to vapor most use exhaust heat or coolant heat for this process.
The advantage for a liquid system is more reliable fuel supply in cold weather as the low temps will decrease the vapor pressure in the tank. the downside of a vapor system is they put a chemical to make propane smell and oil to keep the tanks from rusting. It is rare and I've only seen it in Rv systems this oil and chemical will make a black thick syrup and will stop up the fuel system.

another downsize of propane and gasoline is the need to practice energy management. with limited amounts of fuel you want to only run whats needed and not run the generator 24hrs a day. even with a 500 gallon propane tank if the emergency lasts long enough all the available fuel will be reserved for important customers such as hospitals and life safety. During the Tornado emergency in Alabama the fuel services were only delivering to customer that would take 500 gallons of fuel at a time unless you paid a hefty fee. They could make more money at 2 or 3 large stops faster than 20 smaller deliveries and it was in places a 2 or 3 hour drive to find an area with power.
So you need to run it long enough to charge batteries, cool the fridge and run the heater then shut it down till needed again.

Natural gas the fuel that doesn't run out. WRONG if there is a large disaster such as a earthquake or large multi grid power outage they can and will shut down the natural gas supply. Broken pipes in an earthquake will cause fires and explosions and in a large power outage they will not be able to control the plants that control pressure and flow of gas.
The other issue with natural gas is having adequate supply. do you have enough pressure to your house. is the meter big enough to flow enough gas to run the generator and then you need a pipe big enough to flow the volume needed to power the engine.

That leaves diesel powered gensets. with a good tank and proper use of algaecide diesel fuel will last for years but it also falls into the availability to get fuel and power management issues as gas and propane.

You have to look into what use you want the generator for such as to power your RV or what disaster you are preparing for.

almost as important as what generator you want is how will you get the power into the house and how much power you need to run everything. there are automatic transfer switches for $$$ then you can get manual switches for less all the way down to smaller circuit breaker boxes with a plug to connect the generator to the stuff on that box these can be as cheap as $200. some power the house by connecting to a stove receptacle and back feeding the house this can be dangerous as you may overpower the generator or may send power back down the line and injure someone trying to restore power.

You can get a look at the different generator s here http://www.powersystems.cummins.com/generators/cummins-onan-gensets.html

[KG]

There is also the need to look at what you want to power. A cheap construction grade generator is good for powering power tools but not for delicate electronics.
Newer furnaces use control boards and during the last couple of disasters we found the power from the cheaper generators was not good enough to allow the heater run on generator power.

I would also look at the smaller units by Honda and Yamaha. Some have the capability to connect 2 generators together to raise the capacity. run one generator when needed and both when the load gets to much for one. this can save fuel and  you can also alternate which one is running to save on wear. they are also smaller and easy to load and move.

[Robert]

I have a 17k backup gen at the house that runs on natural gas. It also has the ability to change the fuel flick the switch and now you can run on propane with a power boost also. Since its a Generac now Briggs and Straton it can be converted very easily to run on regular gas by changing the carb and maybe the intake manifold. Since Generac is in the market of selling their engines to all sorts of other applications parts are pretty readily available and easy to change since the configuration of their engines needs to change with the application. While diesel is the true standard in big gensets on smaller ones gas and propane are the norm. I like my natural gas one because of the issues of carbs and gas storage ruining or at least plugging up the jets. I let it sit for a month or two at a time and just go out flick the switch and it starts. After my experience with power outages and gensets I prefer natural gas or propane. I dont like the propane as much because of the problem of haveing a tank, refills and storage. But since most gensets made for one can run on either one its a easy backup for a natural gas genset. I would also say if things get so bad that the gas lines underground break then we are dealing with issues that even if you run a genset on gas you will have a hard time getting it and not using it for other purposes, which with the hurricane that happened here in Florida was a real issue. Cars especially your own car competes for the gas supply that you have on hand and that could be precious little. Gas stations did not have power to pump gas but the natural gas was still flowing. The same could be said of diesel also so when the tank runs out you better have secured a new fuel supply. If you do a search there are many sites that offer conversion kits for generators but like I said Generac already offers engines with all kinds of configurations and you can pick and choose the parts to make a true tri fuel generator. This in my way of thinking was one reason I settled for my Generac. Runs on natural flick the switch propane change the carb and you can run on gas.

  Since you are speaking of a small generator and mobility might be a issue I would run in on propane since space for tanks really wont be a problem and they can run long enough on one tank not to make it a problem. There is no genset run on gasoline that does not take extra care when stored to make sure it starts when needed even one in a motor home. This is the biggest failure of gensets improper shutdown and long term storage.

  As for the mechanical end of switching fuels the engine doesn't care which fuel it burns. With the exception of power output of the engine. Natural gas has the least btu, next is propane and gas has the most. It translates to power output with the bigger units being cut by 1 to 2 kw running the different fuels. But the cylinder wash from gas and corrosion that can occur with gasoline is virtually eliminated with natural or propane. Since the btu difference the only change needed from natural to propane is the size of the jets used to meter the fuels. Natural gas will use a bigger jet size than propane but still use the same delivery system. As long as the pressure regulator limits the pressure into the engine to the same level as natural gas. Gasoline will use different carbs because of the different fuel requirements liquid not vapor. Also as a side bonus engines run on natural gas and propane will experience less oil dilution than those run on gasoline. This translates into lower maintenance and longer times between oil changes and less mechanical wear. Another consideration is natural gas and propane generators have less pollution in the exhaust than gas or diesel also. They run cleaner and exhaust smell becomes slightly less of a issue.

 Natural gas supplies are not a real problem in most areas and once plumbed with natural gas on a house run as much as you can off it. I have a outdoor grill in natural gas and its so nice not to have to deal with the tanks and wondering if you have enough gas to cook. The other thing is sometimes you may have to run a pressure regulator to the other consumers such as stove cook top because the natural gas genset to run properly may require a higher pressure from the gas main than the rest of the appliances. Reason being gas is usually supplied after the meter at a low pressure. So for big consumers and long runs require higher pressures to keep them supplied while small consumers require little pressure so you put a regulator in line for the small consumers and run the main line at a slightly higher level.

As for the problems with dirty power put out by most small and inexpensive gensets its can be a problem although not as big as it once was. Electronics today are manufactured to run a pretty wide range of power supplies and will accept pretty wide range of voltage and hz. It will bother some but if you run ac or other high demand appliances you will have to power accordingly with a much larger generator than you would use only because startup on ac is pretty high.

https://www.propanecarbs.com/tri_fuel_kits.html
http://www.propane-generators.com/

I know this is all more information than you wanted but I have included a couple of links to sites that make kits for trifuel conversion. The manufacturers of most gensets will also offer kits for the conversion of their brand specific needs.

A lot of motorhomes and some boats use Onan gensets and I have personally found them to be a little problematic and only offer parts available through their dealers. This along with size and space allocation for a genset is another consideration in a motorhome. Onan is usually pretty expensive also compared to a standard genset but the size and power output along with the configuration to mount one of these into a motorhome makes it a point of convenience. Noise and exhaust considerations make them also easier to use.

When you need a generator its sometimes for real critical needs and like any mechanical thing it needs to be run, checked maintained on a regular basis. In backup gensets starting once a month and checking output is important, with gas this becomes a real maintenance nightmare which is the primary failure of most gensets. With natural or propane this operation becomes very simple without putting in gas then shutting it off then draining carb bowls, using store and start and wondering if next time the carb is plugged. Also since natural and propane do wash less oil off the surface of the cylinders the customary injection of oil into the cylinder on long term storage becomes less of a issue.

[Rams]

Some excellent information, thanks.   

[dreamaker]

Here is a lot of great information, but what is the point of the generator, lights out!!! So my thought is, if we have loss of power, I can use what is available for fuel, that is the point. So maybe the logic would be to have a couple of propane tanks and a tank of some gas, just in case there is no means to connect to natural gas. Another thing you may consider is a exhaust tube, people tend to keep the units in the garage. So safety first!!!

[Jess from VA]

Thanks guys.  

Consistent with points above,  propane is capable of producing 84,300 BTU’s per gallon, gasoline is capable of producing 114,000 BTU’s per gallon, and diesel is capable of producing 129,500 BTU’s per gallon.

So 1 gallon of propane only produces 74% of the energy that 1 gallon of gasoline can produce or 65% of the energy that 1 gallon of diesel can produce. So you would need 26% more propane to do the same amount of work as 1 gallon of gasoline, or 35% more propane to do the same amount of work as 1 gallon of diesel.  You should expect to go through more propane than you would gasoline or diesel in similarly sized engines. Roughly, 6 gallons of LP to 5 gallons of gasoline.

Decent charts.
http://www.propane-generators.com/propane_usage.php

Of course, energy use also depends on how much you are pulling to the run the house.  Even though my 5K gas will power most of what I want (gas furnace blower, two fridges, a few lights, but no AC, except it will run a small 600 window unit so I have one cool room) I always minimized all power use on generator (no coffee maker or microwave or other small hi draw stuff).  I also had some brown out issues in the past, so in addition to knocking out the main, I would knock everything off the box, then slowly bring back on all my 110 circuits, and none of my 220, and that solved the brownout.  I could run my TV and computer which are set up with double surge protection.  

Anyway, using a 5K watt propane generator at 50-60% draw looks like I might get 7-8 hrs run time from a 20lb tank.... maybe.  This is hard to get an answer to, and there are a lot of variables. EDIT:: FURTHER RESEARCH MAKES IT LOOKS LIKE A 20 LB TANK MAYBE GIVES FOUR HOURS ON A 5K GENERATOR.

And I have been reading some complaints of trouble staring a propane generator with cold propane tanks.  It looks like I would need to have 4-6 20lb tanks on hand minimum, but I sure don't like the idea of keeping them in the house (most of my power outages are from winter ice storms).  I suppose keeping one in the house to keep it warm would work, then in a power outage, bring the others in to warm them up before the first runs out would work.  

Something like these look about right.
http://www.electricgeneratorsdirect.com/power/5000-watt-propane-generators.html

Honda is always more.
http://www.generatorsales.com/order/Honda-5kw-Propane-Generator.asp?page=H04585

[Hoser]

i must be lucky, I have used my backup gen probly six times in the last five years, a couple times for days at a time.  I fill it with treated gas from the 30 gallons of E-10 I have stowed in my storage shed, replace what I use with E-10 and a can off berrymans. I suppose it may not start some day, but it hasn't happened yet.  It is wired to run the whole house and garage, 110 volt circuit only.  Hoser   ?  

[Jess from VA]

Both my gas generators (3500/5000) did well for at least 5 years, but at some point a few years later, despite my best efforts at draining the tank and bowl (changing plug and oil), and using fresh gas, they got gummed up and unreliable, and hard to start (with multiple broken ropes), and shut off every 20-30 minutes, and required expensive repair (I suck at small engines) which only lasted another two years before the same problems returned.  And I am unwilling to do the Chinese fire drill of adding gas, running, draining gas and bowl every few months as I probably should.


I'm pretty certain my current 5k gas (low total hours, 10+yo) could be made reliable again for a couple hundred bux (I did so before), but I am going to throw that money toward a propane generator.

It's a long way for me to get non-ethanol polluted gas.  

And, I cannot keep gas on hand period (treated or not, for 6-18 months), but I can keep propane on hand.  I am not dumping old gas in my bikes/car either (which I tend to keep tanks full anyway).