Design Stage for Off Grid Generator and Battery Shed

[ChugiakTinkerer]

I have settled on a tight, well-insulated shed for the generator. I can go with the propane light and get a long burn even from a 20 lb tank. According to my heat loss calculations, in the absence of any air exchanges a 7' x 7' x 7' insulated box will stay amazingly warm. But air is needed to keep the flame going so we'll see what the ultimate temperature delta will be. I'm thinking of having an air inlet with an adjustable damper so that I can regulate the flow of fresh cold air. The plan of course is to be out at the cabin as much as possible during the winter, so I don't envision the need for extended times of cold-weather heating while we are away. But if we get a deep chill for a few weeks I want to be able to keep the generator warm enough to start on demand, while we remain in town.

[The German]

Ok, where is your P-tank going to be located, inside the shed or outside,,,,,, you do know why I'm asking this right...... I'll leave it that for now.....
TG

[DRIFTER_016]

DRIFTER, I'm looking forward to seeing and reading about your install. Your cabin project has been inspirational.

I'm planning on ordering it for spring 2022 delivery so I can get it out to the cabin and get it installed that summer.

[ChugiakTinkerer]

Ok, where is your P-tank going to be located, inside the shed or outside,,,,,, you do know why I'm asking this right...... I'll leave it that for now.....
TG

Yeah, I thought about that. I'm planning on keeping the propane inside the shed. Outside at -40 and the propane won't vaporize.

The one good thing about all this overanalyzing at this stage is that I've realized I can go forth and build the shed without too much worry about heating it. The deep cold will be behind us by the time I have the gennie online. I can keep scratching my head about my numerous worries and come up with an ultimate solution by next winter.

[ChugiakTinkerer]

I'm planning on ordering it for spring 2022 delivery so I can get it out to the cabin and get it installed that summer.

i'm starting to wonder if I shouldn't adopt that schedule as well. I'll muddle through the next few weeks and let you know.

[homer]

You might try asking your questions on the NAWS solar forum. That's where I got al lot of info for my off grid power.

[The German]

Ok,,,,, Over thinking at this stage of the game, is not a bad thing, if you wanted the Tank outside and above ground,,,,,-[GOOGLE]- Propane Liquid Withdrawal Systems, this is the Design we used when we Built the Power Modules for Copper Valley Telecom in Glennallen, back in the day......
TG

[Iboondock]

I have settled on a tight, well-insulated shed for the generator. I can go with the propane light and get a long burn even from a 20 lb tank. According to my heat loss calculations, in the absence of any air exchanges a 7' x 7' x 7' insulated box will stay amazingly warm. But air is needed to keep the flame going so we'll see what the ultimate temperature delta will be. I'm thinking of having an air inlet with an adjustable damper so that I can regulate the flow of fresh cold air. The plan of course is to be out at the cabin as much as possible during the winter, so I don't envision the need for extended times of cold-weather heating while we are away. But if we get a deep chill for a few weeks I want to be able to keep the generator warm enough to start on demand, while we remain in town.

It's my experience that a generator is not going to be happy running in a space that tight., do you have a design in mind for ventilation when it's auto starting? Are you planning on having the generator, batteries, inverter, etc. all in the same space? If you're going to leave the system on, there will be some waste heat generated by the electronics, even at low idle, more while charging. And the batteries act as a thermal mass, something to keep in mind when you're calculating.

[homer]

Good point about air for the generator. My room is 8 x 16, and I have to latch the door open. I also have a flapper for the discharge air. Onan 4kw propane.

[The German]

CT,,,,, if you are considering Running the Generator on Propane Fuel,,,,, it need's to be the Correct Type of Propane for Internal-Combustion Engines, see attached...
TG

[ChugiakTinkerer]

Hey all, thanks for your ongoing input. A quick recap: Been reading NAWS forum. Still a newbie so lots more reading to go. I am now preferring the ide of keeping batteries in a separate insulated shed/housing. One fire would hopefully only take out one major asset and not two. Issue of keeping batteries warm isn't really a concern but I can address that later as needed. Generator shed will have an air intake, and maybe another for the generator itself. Also will have a drain hole to allow propane leaks to escape. I priced an 8 kW Northern Lights diesel generator and about choked. A big step down from that is a Honda EM 6500SX. About one third the price installed. Weighing costs and benefits of each. Interesting info on propane combustion engines. I haven't really gone far down that path, just due to the propane volumes needed. 10 miles from the road makes hauling fun. It's certainly proving to be a challenge to figure out what I'll need to keep the system "hot" through the dead of winter. Appreciate your perspectives. CT

[homer]

That Honda is not designed for an indoor installation. Most aren't. That's how I ended up with an onan. You might have to modify it.

[Iboondock]

I opted for a propane generator. It's located outside under a roof to keep the snow off. The coldest I've had to start it was -38, it ran fine for about an hour and then started to starve for fuel, a little heat to the tank fixed that . I added a tank heater that is powered only when the generator is running and haven't had fuel issues again down to -30 so far. I have three 100# bottle manifolded together. I have engine and battery heaters installed on the gen that I use to preheat when temps are below -20.

Over 7 years we've averaged 65 hrs of annual runtime, and fuel consumption averages about 1 gal/hr. We're 100% solar from mid January thru mid October. November and December are generator months.

If you're not going to keep the batteries warm, you need to derate the bank accordingly.

My opinion- If your property is a good solar site, add as much solar as practical, panels are cheap and going to get cheaper. At a minimum max out whatever charge controller you're considering for the system.

[ChugiakTinkerer]

I opted for a propane generator. It's located outside under a roof to keep the snow off. The coldest I've had to start it was -38, it ran fine for about an hour and then started to starve for fuel, a little heat to the tank fixed that . I added a tank heater that is powered only when the generator is running and haven't had fuel issues again down to -30 so far. I have three 100# bottle manifolded together. I have engine and battery heaters installed on the gen that I use to preheat when temps are below -20.

Over 7 years we've averaged 65 hrs of annual runtime, and fuel consumption averages about 1 gal/hr. We're 100% solar from mid January thru mid October. November and December are generator months.

If you're not going to keep the batteries warm, you need to derate the bank accordingly.

My opinion- If your property is a good solar site, add as much solar as practical, panels are cheap and going to get cheaper. At a minimum max out whatever charge controller you're considering for the system.

I'd appreciate more details on your solar and generator installations, if you don't mind.

[homer]

My details: My place is done in the high desert. It gets plenty cold -25* ,but plenty of sun. 2500 watts of panels, outback charge control, outback 3648 inverter. Onan 4kw propane. 8 x 16 insulated power room, in a barn. 8 6volt golf cart batteries. 48 volts system. 10 years so far.