propane or gas generator?

Hi Folks,

One of the accessories I'll definitely be installing at the new homestead is a generator. I need to be able to at least run the water pump and depending on my fortunes in the next year or so might invest in something large enough to run at least one of the AC units (just because the power is out doesn't mean it's cold out! in this case AC will mean as much to survival as heat in other climates)

I'm trying to get some information about propane vs gas generators. There are several good dual fuel propane/natural gas generators on the market. While the gas is still on they could be run from that and switched over to propane if the gas is turned off due to a larger natural disaster or flooding or what have you.

Propane can be stored for a long time in good tanks. Although the initial cost to install those tanks would be higher than just getting a few gas cans, I really don't like the idea of having a garage full of stabilized gasoline!

The downside of propane is that gas is readily available. Even in the case of natural disaster it might still be gotten more easily than propane. So I would need to store more propane at even larger expense.

However, the propane generator would never have to have it's carburetor stripped after putting old gas in it and having it totally gummed up. So I think it would be more likely to work when needed.

Does anyone have experience with gas/propane generators and have any wisdom to share?

Or, knowing as I do the flashlight logic of this group will you all simply advise me to get one of each

Thanks,

Have you thought of using diesel? It stores very well. How many watts are you thinking of? If you are going to run a water heater, you might need a 10k+.

I work in the generator service field & your LP/Nat gas combo is a good choice. VERY seldom is natural shut off. If the situation is so bad that you can't get natural gas, you may not be able to get any kind of fuel. Diesel is OK, but the cost of the gen is much higher, & you still have a problem with fuel storage. Not as bad as gasoline, but still a problem. TX

LP or Nat gas is the way to go. You don't have to get a huge 500 lb tank. A friend of mine runs his 10k on 100lb tanks he can fill himself at the local co-op. He said he can run about 7/24 straight on 100lbs. He has three 100lb tanks. As you already thought of you can store them pretty much indefinitely, while diesel is good for about a year and gas is good for 1/2 year. Yes both will go longer, but I would hate to run bad fuel through a genset and have it fail tight when you need it most. I whish I had gone the LP route, I end up storing about 30 gal of gas and then dumping it in my older car every six months and getting new gas for the tanks, it works but it is a pain.

Umm, diesel doesn't really go bad much. The reason gas goes bad is it loses some of the dissolved gasses that help it start. It will still run, but be harder to start. Diesel doesn't have those dissolved gasses and the shelf life is something like 10-15 years (and will work past that). Diesel and kerosene are almost the same thing, and kerosene has a shelflife of around 20-30 years. I know somebody whose grandparents use some 47 year old kerosene in a heater and lamp when the power goes out, they refuse to let their granddaughter buy them newer stuff. You really don't have to worry about diesel as it isn't very volatile (which means it is safe to store, it won't explode from vapors). The diesel we are running in our tractor at the farm is about 4 years old now, and it starts like a champ, even when it is 15 degrees out.

Spud

The problem with diesel is microbes can live in it and you can actually get to many growing and then you have a real problem. It is less of a problem if you don't have fuel injectors, but without injectors, the engine is less efficient. Large diesel truck could burn just about anything and keep going, but smaller diesels have much smaller intakes so it might be more of an issue. You can buy additives to kill them. We ran in to this problem with sailboats using small Yanmar or Kubota engines. Again I would choose diesel over gasoline, but I would choose LP over either of them. Also if you live in a cold climate you need to worry about jelling with diesel. Many modern engines have automatic glow plugs and can start at -50F but not if the fuel is thicker then jelly. If you do live somewhere cold just make sure to get you diesel during the winter, then it will have the anti jelling already in it, or add some Power Service winter formula, in the white bottle.

I've seen these microbes completely clog a fuel filter. Then if they get past that, they'll clog the injectors. You'll also need a good water seperator, as water will damage the injection pump. Diesel does have a "cetane" rateing, which is simular to the octane rateing in gasoline. It does deminish with time. If NG is available, that, with LP backup, is the only way to go. The reason you see so many diesel generators is due to OSHA's requirement for a backup fuel for anything other than diesel. NG/LP is still better, but then you get into the problem of how much LP you can store for your particular zoneing laws. TX

Propane and/or natural gas is a great way to go for a permanent generator. Be sure to change the oil at the proper intervals regardless of what the oil looks like. LNG/NG dosen't darken the oil or cause it to smell but still thins the oil and can caues loss of lubrication. One of our FD generators was a dual fuel LNG/NG, best of both worlds even though it never produced maximum engine power. Didn't matter, voltage was regulated and clean. Diesel is a great way to go in either a permanent or portable setup but you have to run it at least 20 min/mnth, better yet every week. Regardless of the fuel have a battery conditioner and a transfer switch properly installed.

The mention of the transfer switch beings up another question. Even if I buy a big whopping one, it will not be able to run all the high power loads necessary at once. However, I would like to connect it up to everything so that I can switch between, for example, the water heater or the AC.

Having to manually switch circuit breakers on and off to keep it within it's load doesn't sound like something that the code is going to be sympathetic to. Is there anyway to do something like that? I can't imagine that the desire to do something similar is uncommon.

Thanks for all the great info everybody. I had thought about diesel as well, but rejected it due to the really high cost. I didn't know that it would become a bacterial culture!

Does anyone know if it's possible to add a second muffler on any of these things to make them a little quieter? When the power is out the sound of a running generator is very obvious to everyone who doesn't have one...

You could get a whole house x-fer switch, the full 200 amps. then just feed the non-grid side with the generator. The problem as you are aware is you probably won't have a 200A genset. I wired my house myself so I choose a bunch of outlets and other key item like fridge and freezer. They are feed from my inverters which in turn are feed from a 30A 240 breaker in the main panel. The inverters could start/stop the genset, but my poor old genset doesn't have that option. So you could go that route also, but that wouldn't get your water heater or AC. They do make a manual 200A main that can choose either grid or "something else", it is manual, but far cheaper and that way you can turn off the other items that you don't need to make sure not to overload your genset.

As for the muffler, you could have someone weld you up auto muffler in place of the small one, it does wonders. I also have heard a number of people who bury a 55 gallon drum, then use 1 ½ pipe from the genset to the bottom of the drum, then fill the drum with those white washed small round stones. I just used a tractor muffler on mine and it is tolerable now.

You can run a secondary panel from the gen side of the transfer switch. If your switch is manual this is no big deal. If your switch is magnetic (automatic) it is more difficult. A simple solution is to hire an electrical contractor who specializes in aux power and give him a blank check. Ha. I am sure there are plenty of online sources for plans.
Diesel grows algea. A sterilant can be added once a year to control it.
Generator noise is a problem. If you are thinking about a small air cooled genset much of the noise comes from the engine itself not just exhaust. You can add about any mufler you want as long as you don't add back pressure. Water cooled engines are much quieter. Next would be an enclosure. Of course air flow must be designed around your genset, not built before you decide what to buy. The slower the engine turns the quieter and more expensive the genset. RV gensets in big motorhomes are quiet mainly because they turn at 1800 rpm rather than 3600 rpm like most small portables. The enclosure helps but mostly it is the slower rpm. Small diesel gensets, maybe 25KW, on a trailer and meant for long life are very quiet. You will pay about a fifty cents for each watt.
If you need a generator for business (or home) and expect to use it much you probably won't be happy with the $500.00 Costco type. Very loud and poorly made. Cheap bushings in the generator instead of bearings, etc.
Good luck. Bill

2dogs' post pretty well sums it up in a nutshell. I would say Bill definately works with power plants. Without more info such as what generator you're getting or total load, you've got about all the info we can provide. TX

Oh 2Dogs brought up a very important point. The 1800 RPM gensets are much quieter and last much, much longer. They also tend to be water-cooled, which again makes them more quite and reliable in the long run.