Offgrid smaller house with 20kw generac on ng

wragged and wrong offgrid · December 2014

have moved to offgrid smaller house with 20kw generac on ng, how can I wire it to start from inside without using the transfer switch. we only have a small solar set up. we are only running 1000 and 2000w inverters. fried the 800 trying to do the n1 and n2 connection from the small inverter. any suggestions would help. can run the genset on manual with ext cord to house to run charger and vaccum, but would like to set it up on auto if possible. will be switching it to lpg next year

BB. · December 2014

Re: Offgrid smaller house with 20kw generac on ng

Welcome to the forum W&WO,

I am going to move your post to its own thread. It will make things easier and less confusing as the conversation continues.

I guess you are up in Canada somewhere? So, you are standard North American power. Are you using 120 VAC off grid or 120/240 split phase power?

And what brand/model of AC inverters are you (did you) use? If they are MSW (modified sine/square wave) units--They do not like having a ground bonded neutral (and a grounded battery bank). This can effectively create a dead short through the inverter.

Second--A question on your AC power connections. In general, you cannot connect the output of an AC inverter to AC mains or AC backup power.

For inverters that have an AC input for grid/generator power (usually inverter-generators that are basically uninterruptable power supplies (UPS's) with AC inverter and AC battery charger), they generally are pretty easy to connect the AC input to your backup genset.

Some AC inverter-chargers are "sensitive" to input AC voltage and frequency--If your genset AC frequency and/or voltage wanders too much, the AC inverter-charger may drop the generator input and run from battery bank.

Otherwise, if you do not have an AC input, the simplest is to use a transfer switch. The Generac probably has a very fancy automated AC transfer switch.

Or you can get manual transfer switches, or relay based transfer switches (not too much money).

In any case, probably need to know more about your power needs and present setup.

Is the solar power system for backup power (you are AC grid/utility connected) and this is for emergency power? You are moving off grid to save money/get away from the utility?

Natural Gas and no utility power is not very common... Are you running propane?

For a smaller off grid power system, a smaller genset will probably be much more fuel efficient (you can probably get away with a 2-3 kWatt genset and use 1/10th the fuel).

-Bill

oil pan 4 · December 2014

Re: Offgrid smaller house with 20kw generac on ng

Why are you going to switch to propane?

wragged and wrong offgrid · December 2014

Re: Offgrid smaller house with 20kw generac on ng

eventully will wood cookstove that will heat the house. the generac will run on propane also. the wiring is very old in this house and we have switched to 12v lighting and use the inverters for our ac needs. thanks to all who responded

wragged and wrong offgrid · December 2014

Re: Offgrid smaller house with 20kw generac on ng

as I said the wiring in this house is old and not up to code so we didn't get utility hooked up but there is ng running to the house and since we had already paid for the generac we hooked it up minus the generac transfer switch as there is no ac panel to hook it to. I also have a 2600 gas genset but gas is fairly exspensive here in mjd saskatchewan

Cariboocoot · December 2014

Re: Offgrid smaller house with 20kw generac on ng

I hate to say it but it sounds like you are in for some major expenditure. Wiring that is not up to code for utility power isn't any better for inverter power and is even worse for low Voltage (which draws more current for a given amount of Watts).

Now if this is just a case of the main service panel being 100 Amp or less and no longer allowed, that's different. But if the wiring is actually bad, get rid of it.

Otherwise it is a matter of needing further details on the equipment used. Some speculation:

You have some low-dollar inverters (only) which you run AC load from via built-in outlets?
You wish to start the generator remotely, either manually or automatically, to power loads and/or battery charger as needed?
I'm not sure what the Generac demands for remote start; that is usually model specific. If it had an autostart transfer switch which detected a loss of utility power, started the gen, and switched loads over - that could be 'fooled' into operating the same way from an inverter (providing it is a sine wave inverter).

In short we really need all the details to figure out what you want to do and how best to do it.

BB. · December 2014

Re: Offgrid smaller house with 20kw generac on ng

What is the price of Natural Gas in your area?

From this answer:

http://answers.generac.com/answers/1506-en_us/product/20kw/generac-power-systems-20kw-6730-questions-answers/questions.htm?page=2

You will want to contact your fuel supplier directly to discuss the cost of operation based on the consumption rates. The volume and pressure required for the 20kW unit at full load utilizing natural gas is 294,000 BTU/hr with 5-7” of water column. When operating at half load, natural gas consumption is 206,000 BTU/hr.

At ~$1.20 per 100,000 BTU at my house, that would cost ~$2.40 to $3.60 per hour. 24 hour per day power would be ~$57.60 per day minimum.

That is, in my humble opinion, a huge cost.

See if you can get a temporary (construction) power drop on your property (permits, any installation costs, etc.).

You play with an energy calculator to get it to match your billing units:

http://www.abraxasenergy.com/energy-resources/toolbox/conversion-calculators/energy/

206,000 BTU ~ 5.3 CuMeters (per hour at 50% or 10 kWatt or less load!!!!)

Read your meter after 1-2 hours of run time, and verify the amount of gas you are using. Don't wait for 30 day billing cycle. You may be horrified with a >>$1,000 CAND natural gas bill.

-Bill

wragged and wrong offgrid · December 2014

Re: Offgrid smaller house with 20kw generac on ng

sorry if I asked in the wrong forum but we are offgrid and want to be self sufficient. have 400w of solar and 1000w wind turbine power and we only run either genset if we need big power. I don't need 240 ac and don't plan to . our range is propane and also our on demand hot water. that is why we will be switching to propane. have to gut the house and redo insulation, also have tand g pine to redo interior with. our power needs are not that great house is only 600sq ft. was just looking for a way to start the generac remotely when we do need it. it has two 120 outlets on it that we just plug ext cord into. we are not using the power from inside it. had so why not use it.

Cariboocoot · December 2014

Re: Offgrid smaller house with 20kw generac on ng

wragged and wrong offgrid wrote: »

sorry if I asked in the wrong forum but we are offgrid and want to be self sufficient. have 400w of solar and 1000w wind turbine power and we only run either genset if we need big power. I don't need 240 ac and don't plan to . our range is propane and also our on demand hot water. that is why we will be switching to propane. have to gut the house and redo insulation, also have tand g pine to redo interior with. our power needs are not that great house is only 600sq ft. was just looking for a way to start the generac remotely when we do need it

Starting the Generac remotely can be done if it is an easy-start when you're not remote. In other words if it is automatic choke and all you have to do is turn the ignition on and push start. Basically you just wire in remote switches to do the same function. If it has a manual choke or other warm-up device it can be a bit more difficult.

Everything else you say makes perfect sense, even if it is a personal choice rather than an economic one. Sorry people started going on about cost numbers instead of trying to focus on the question you asked.

I have an off-grid cabin that is similar to what you have: no 240 VAC (except for the septic pump and that is handled via as-needed transformer), propane on-demand hot water and stove, and wood heat. My system is somewhat larger than yours (more PV, no wind turbine) and runs a full size refrigerator, water pump, and the satellite Internet connection. Due to the location it is not viable year-around though.

BB. · December 2014

Re: Offgrid smaller house with 20kw generac on ng

Not arguing wanting to be off grid... Just saying that a 20 kWatt genset is HUGE and EXPENSIVE to run.

You said that the 2.6 kWatt genset was expensive--The 20 kWatt can be 10x the cost of the smaller genset (perhaps only 5x the cost depending on the prices of gasoline vs ng vs propane).

Yes--You cause use a genset only when needed--And the prices of fuel will be a bit less. But, at this point, I fear you have gone more expensive rather than less.

A 2kWatt Honda eu2000i which runs ~4-10 hours per gallon of gasoline (~1,600 to 400 watt or less leads) vs the 20 kWatt genset which would run on ~2-4 gallons per hour equivalent in gasoline.

I moved your original post to its own thread so we can discuss just your needs. Not a problem. Bits and Bytes are cheap these days.

A 400 Watt system with a ~250 AH battery @ 12 volt battery bank would be a fine system for a small/energy efficient place (lights, computer, small water pump, etc.). If that is all you need, then that is great. (that is something like a 600 Watt AC inverter land).

If you need more power (aka a 2,000 Watt AC inverter), then you should really have a larger battery bank and solar array to support that size of inverter.

What are your power needs (peak watts, average watts, watt*Hours per day or Amp*Hour per day @ xy volts, etc.)? What other equipment do you have today (size/voltage of battery bank--I may have missed it)?

-Bill

wragged and wrong offgrid · December 2014

Re: Offgrid smaller house with 20kw generac on ng

thank you for your understanding of my question, the generac has auto start, that uses voltage drop sensor or manual running. I see what you mean about the choke but the nexas controller on it needs more study to remove start logic elsewhere. thanks again

techntrek · December 2014

Re: Offgrid smaller house with 20kw generac on ng

I have a 12 kw Generac and a 3000 watt Honda inverter-generator. The Honda is WAY cheaper to operate and MUCH quieter than the Generac. Even with no load my Generac uses 1.5 gallons/hr of LPG. The Honda is about 0.15 gallons/hr of gasoline. Since you are only plugging extension cords into the Generac a 2000-3000 watt Honda or Yamaha inverter-generator will be much more suited for your needs. Sell the Generac and use the money for a Honda or Yamaha inverter-generator.

Trickle Charge · December 2014

Re: Offgrid smaller house with 20kw generac on ng

Here's my setup.
A 6kW Ecogen (240VAC) plumbed to a 400L propane tank with a Magnum Research inverter and AGS unit for remote start.

https://www.youtube.com/watch?v=Lgji4MiZV6U

oil pan 4 · December 2014

Re: Offgrid smaller house with 20kw generac on ng

Sounds like you should keep natural gas as your main fuel source and get some propane as a backup.

That's what I do. I have natural gas. But just in case I have two 40lb propane tanks I keep full and 2 radiant propane heaters.
In the last 3 or 4 years I have had to use my propane heat backup precisely zero times.
When I first moved into my current home the wall mounted NG heater broke and instead of using the NG stove for heat I fired up my propane radiant heater.

You could save so much money using natural gas over propane you could use the money you save to add big propane tank to add to your propane reserve each year.
If your appliances are propane and you have natural gas for some reason, to switch over most if not all appliances all you have to do is switch gas metering orifices. Only tools you need are adjustable wrench and hex keys.

But if you want to waste a ton of money buying propane so you can feel more "self sufficient" be my guest.

wragged and wrong offgrid · December 2014

Re: Offgrid smaller house with 20kw generac on ng

the old wall ng heater was the only thing here, I got my plumber to put a line to the generac. the other stuff I hooked up myself. we are on the outskirts of a small rural town and don't want any bills in the mail.lol we don't use the genset much, so I just thought to get rid of the ng bill, I would just switch everything to propane so I know what my costs are. the ng heater will be gone once we get the wood cookstove, lots of wood round here.lol

icarus · December 2014

Re: Offgrid smaller house with 20kw generac on ng

Changing from Nat to LP? Asside from the basic monthy charge to the utility, the price of fuel is about 1/2 for Nat Vs LP. I would never trade Nat of LP. Not to mention that it is pretty hard to run out of natural (in the short term anyway! )

Tony

Alaska Man · December 2014

Re: Offgrid smaller house with 20kw generac on ng

wragged and wrong offgrid wrote: »

the old wall ng heater was the only thing here, I got my plumber to put a line to the generac. the other stuff I hooked up myself. we are on the outskirts of a small rural town and don't want any bills in the mail.lol we don't use the genset much, so I just thought to get rid of the ng bill, I would just switch everything to propane so I know what my costs are. the ng heater will be gone once we get the wood cookstove, lots of wood round here.lol

Must be a brother from another mother.......... My whole purpose in life is to go down the mailbox and not have a bill in it. And that's what we have done and why we also chose to be off-grid.

We do however run a generator to charge the battery bank in the winter and even in the summer on rainy days. IMO 20KW genny is a monster to feed, NG PG or Gas. Sell it and get a smaller Inverter/Generator as others have suggested. You will save mucho denaro in short order.

oil pan 4 · December 2014

Re: Offgrid smaller house with 20kw generac on ng

You replace a NG bill with a much higher propane bill.
I thought about doing a propane conversion when living in Virginia back in 2008 when NG got expensive. I would save $20 a month during the summer and shell out $400 to $500 a month easy during winter (with NG it would be up a $200 bill maximum).

wragged and wrong offgrid · December 2014

Re: Offgrid smaller house with 20kw generac on ng

ok guys thanks for all the input and you all have a happy holiday season, clint and terryann from mid sk in canada

Offgrid smaller house with 20kw generac on ng

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