Generator help please...

squerly

Supported Ben Carson
GOLD Site Supporter
I need to set up some backup power for the house I'm building. Obviously I don't have the option of Natural Gas being piped in from town so I'm going to have to go with Propane, Diesel, Gas or Batteries. I'm not really interested in making the investments in batteries every 8 years so I think that's out, at least for now.

Whatever fuel I decide on will have to be stored (in a larger tank) near the generator. Gas is pretty combustible and doesn't store well. So my money is on Propane or Diesel. I don't know much about propane and the research I've done (Google, etc.) indicates that propane is measured in cubic feet (I think) while diesel is stored in gallons.

Anyhow, does anyone have some guidance they can send my way? I want to run a 7-13 KW generator, preferably smaller than larger. How big of a tank will I need to keep a generator running (uninterrupted) for a couple of days? And what fuel should I use?
 

ki0ho

New member
GOLD Site Supporter
#1...run time...once you decide on the size gen set you want...read the specks on it KEEP in mind that most are rated in half load ....at full load the run time can be less than half.


#2....long term storage of fuel oil can be a problem...due to a fungus that can grow in diesel fuel.
most of the large units I installed were of the 10,000 KWS and up were diesel due to fuel comsumption requirements/and the larger ones in the Mega watt size were gas turbin driven

#3 LP can be stored almost for ever with no problems....much safer than gasoline......as for tank size figure your required run time....and loads....then double it

Please reconsider the smaller than larger route......Sit down with a wireman that knows his [or her] trade and figure your load requirements.....make a list of all elect loads and what you will want running at any one time.....keep in mind that motor loads require a hefty start up amperage..

Having seen your home going up I can not believe you will be happy with a 7-13 kw unit....
unless a large part of it ....like water heater, cloth dryer ,reffer, ect..is going to be on LP.
Your general contractor would be the first person I would point you to for help...He will no doubt know of the right person in your area to hook up with/ and PLEASE..keep in mind the cheepest bid is seldom the most economical!!!!!
 

FrancSevin

Proudly Deplorable
GOLD Site Supporter
What he said.

My advice is propane. It stores best and the unit runs quieter and cleaner than diesel or gasoline.
One suggestion, have the house wired so that essential appliances are on their own panel. Stove, fridge, well pump, furnace and essential lighting. Then you can size the gen for that load.
Set that sub panel up on an auto trip out switch from the main panel. The gen would start automatically from that switch and keep essentials powered up even if you weren't home.

Most likely you can get by with a 60 to 100 amp emergency load center on the Gen. Remember, not only initial costs but operation costs go up as you increase the size of the generator. More fuel consumption means a shorter cycle of power when you may need to stretch supplies. The question is, do you really need to run "everything?"

I have this system ready to install when I build the house. It has a 5500 watt gen for essentials. But my house is to be much smaller.

With a set up like that a 10KW would be more than sufficient. Just don't run the Hot tub.

I wouldn't discount a battery system of sorts either. For my TV and radios, I have a large deep cycle battery that charges on a trickle unit. It has a 450 amp inverter that runs the TV, charges cell phones and walkies for days. I also keep a small Solar panel (less than$50 bucks) to charge it if our power is out.

Battery, panel, wires and charger ,,,, less than $200 bucks
 

300 H and H

Bronze Member
GOLD Site Supporter
I think you need 20Kw, unless like Kioho says you run major appliances on propane. We get along fine here on 10Kw, but I turn off the water heater when we run it for days. We don't use the clothes drier either as it is 5Kw as is the water heater. So just those two things add up to 10Kw. I can run the water heater at night, if I need to, when we are not using much juice. If I had 20Kw, we could do what ever we want to, when we want to.....

For me diesel is the way to go with several thousand gallons around usually....

Regards, Kirk
 

bczoom

Super Moderator
Staff member
GOLD Site Supporter
What everyone else said plus one more thought.

What are your heat sources? Figuring ice storms are a major cause for outages, the temps can be cold when the power is out.

If you need to run electric heat, your generator has to get bigger. I burn wood so it's not an issue but my 15KW genset is not big enough to run my 5-ton heat pump.
 

Melensdad

Jerk in a Hawaiian Shirt & SNOWCAT Moderator
Staff member
GOLD Site Supporter
Not sure if it was mentioned, but if you go with Propane then please realize that propane needs expansion space inside the tank.

FOR EXAMPLE: if you size your tank based on what size you think you need, based on the fuel use of the generator you must understand that a 500# tank may actually hold about 400# of useable fuel (roughly based on 20% expansion space). So if you need 500# of fuel then you need a tank that is bigger than a 500# tank.
 

TiredRetired

Mr Lovable
SUPER Site Supporter
All sound advise here so nothing to add other than KiOho is spot on with the advice of sitting down with your GC and discussing your needs now while the house is being built.
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
my vote is for diesel you can add biocide to the fuel to prevent the bugs from growing lpg has its advantages they start easy and are quiet. on the down side my mother had one in her rv . she had a fuel delivery problem and couldn't find a generator guy who would work on it. the gas guys all said it was a problem with the generator they would only service the supply circuit, also if you are running cold you will only be able to use about 60 %of your tank before the product becomes too cold to vaporize. with diesel you can run it out and re start it the one problem wit diesel you should have an engine pre heater on it for reliable cold starts if you don't keep it in a warmed shack. just a few proes and cons. diesel is used here because lp is quite a bit more and you get more hours per gallon and yes lpg is sold in gallons as a gas it's measured in cubic feet like natural gas in the liquid state it's still measured in gallons.
 

FrancSevin

Proudly Deplorable
GOLD Site Supporter
SQUERLY, you do have an advantage on winter heat with your ground source cooling system. It will also work to heat the house in winter so I would suggest you keep that circulator fan in the priority circut loop.
 

Melensdad

Jerk in a Hawaiian Shirt & SNOWCAT Moderator
Staff member
GOLD Site Supporter
. . .wit diesel you should have an engine pre heater on it for reliable cold starts if you don't keep it in a warmed shack. . .
He is in North Carolina, I doubt he will need a pre-heater or a warmed shack for storage. I'm quite a bit north of him and we only worried about diesel when it dipped below 0 as the 'high' for more than a few days.

Typically we have weather that dips well below 0 as our low, but them comes back up during the day. I do use 'anti-gel' in my diesel tanks, and I used it in my diesel truck fleet, but its pretty rare that we gel our diesel. Seems like our winter temps are more moderate than they were 15 or 20 years ago, back then we had issues every winter. I've not had ANY issues in the last 5 years. I don't know what the winter temps are in North Carolina, but I suspect they don't have sustained weather that is cold enough to cause too much grief with diesel, especially if he uses a winter treatment.
 

squerly

Supported Ben Carson
GOLD Site Supporter
Thank you very much everyone, lots of good info/advice. Thanks again!
 

Snowtrac Nome

member formerly known as dds
GOLD Site Supporter
All except that part about cold weather operations. doesn't sound like it will be much help to you. I gave my 2 cents worth as that is out prime power out in the bush . the little generators with yanmar and Kubota engines work real well and just sip the fuel. the last consideration you should have is ventilation to your gen set when running especially if it's hot
 

cpttuna

New member
If you go with propane, are you going to get the propane or is the propane man coming to you? I have 2 40# tanks for my furnace out in the sticks in a small house. This is the max I thought I could handle by myself.
 

Dargo

Like a bad penny...
GOLD Site Supporter
Thank you very much everyone, lots of good info/advice. Thanks again!

Well, did ya get your genny all set up? If not, for better or worse, I now have several hundreds of hours into generator research, sizing, methods on deciding fuel choice and, unfortunately, plenty of experience of running on generator power for weeks at a time over the last couple of years. The super, super short version is that my generator serves me and my family so we can do absolutely everything on generator power that we can on grid power; including running 4 A/C units on hot days as well as running compressors and plasma cutters while the other full loads are on. Everything is automatic and I do nothing to go to generator power or back to utility power.

I probably had a dozen professionals out giving me their sizing recommendations (and not any two came up with the same size) and I did end up going with diesel which, after several years, I can say I'm glad I did. I've found with proper conditioners in the fuel I have no problem with 10 year old diesel fuel as long as it is treated as I mentioned and run through proper filters. I concerned myself so much with automatic heat wrap in case of cold starts and found that it is HIGHLY dependent upon what brand of diesel engine you have running your generator. I also discovered that it was worth it to go with the best Deep Sea electronics on the generator unit as well as the high end (and large - really large) automatic switch.

Oh, although it really wouldn't work out in my favor due to maintenance and wear costs, it is less expensive for me to run for 2 weeks in 100 degree heat with all A/C units humming and a large power draw than it is for 2 weeks doing so from the utilities. Again, that really doesn't work for the long haul due to the extreme costs for wear and tear as well as the additional maintenance. And, for reference, I currently have 600 amp service from the utility company. Although the wife and kids do not seem to care, that can make for rather substantial monthly utility bills. :hammer:
 

XeVfTEUtaAqJHTqq

Master of Distraction
Staff member
SUPER Site Supporter
I always try to plan for failure. Consider your back up options when getting everything wired in. An extra portable generator that can run the minimum (well and hot water) is always nice to have - just in case. My portable can run my Mig welder so it is useful for outside welding projects and other stuff where power cords are a pita to reach.
 

Dargo

Like a bad penny...
GOLD Site Supporter
I always try to plan for failure. Consider your back up options when getting everything wired in. An extra portable generator that can run the minimum (well and hot water) is always nice to have - just in case. My portable can run my Mig welder so it is useful for outside welding projects and other stuff where power cords are a pita to reach.

LOL! I'm going to use your post to help explain to my wife why I kept my little Honda 8,500 portable gas powered generator.
 

EastTexFrank

Well-known member
GOLD Site Supporter
LOL! I'm going to use your post to help explain to my wife why I kept my little Honda 8,500 portable gas powered generator.

"A Little 8500 Honda gas generator".

That in itself is bigger than both my gas generators put together never mind the monster that you have as your prime!!!!
 
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