Comparison Home Stand By Generators

[3930dave]

So honestly, how much money did fuel cost some of you to run the larger, whole house permanently installed generators for several days? I'm just curious how much fuel they tend to consume rather than guestimating with no real-world experience with these types of units.

I remember joking with one of the guys in Texas (Lou ?) on here about the running costs he posted for his whole-house system being a small price to pay to keep the wife happy. Might have been in the Your Last Generator Maintenance Run thread I started (?).

I'm nodding off here, or I'd go check. I think his was something like 20kw, Natgas.

Rgds, D.

 

[grsthegreat]

the air cooled units seem to stand up for many years AS LONG as the maint is done. mines 16 years old. but i change oil every year, new plugs every other year. keep a battery maintainer and heater on oil.

when we get power failures out here in the sticks...it could be days till its repaired. i never run the gen for more than a few hours on average. frig and freezer will last 24 hours if doors are kept shut. i turn it on when it gets dark, turn it off at bed time.

a liquid cooled unit is made to run continuously...whereas an air cooled isnt really designed for continuous duty. even generac recommends shutting it down if it doesnt HAVE to be running.

a 22KW generator can burn 3+ gal per hour under full load, maybe 2 g/h at 50% output. that can add up over a long outage.

personally, i could care less. i dont like to be left in the dark. i like my light. so do the neighbors that tend to show up at our doorstep during outages. out come the cards, fire place burning, TV on for the kids....everyone is happy.

heck...even my xmas lights are running.........

my current system isnt large enuf to encompass the basement (with sump pump). the new system will control everything. I have GAS heat (with elect ignition) gas water heater, gas cooktop. all require elect for ignition.

my current system is a small 100 amp subpanel isolated from the main panel. its an independent generator panel with indoor switch to start and stop generator (manual). then i flip one switch, and all breakers run off of generator. has 2 amp gauges also. nice system, just underpowered.

If i get the larger unit, this one will be relegated to the shop....so i can operate air compressor, roll up door, etc.

why not, its all paid for.

 

[K man]

I have a question for you grsthegreat seeing you install generators. Mine is on a automatic transfer swicth. When power goes off it transfer to the generator. Now if I turn the generator from auto to off. Then the power goes off and wait a few hours before turning the generator back on will that be hard on the generator or do any damage. I mean right now the generator goes through a warm up before starting and I think it is 5 second then it starts on 15 on automatic. If it is off do I just put it on auto and let go or not. Just curious cause I am new to this and have used it yet. It exercise runs for 13 minutes every week on Tuesday. Any input would be appreciate. I like you don't want it running all the time especially while sleeping or away.

 

[grsthegreat]

I have a question for you grsthegreat seeing you install generators. Mine is on a automatic transfer swicth. When power goes off it transfer to the generator. Now if I turn the generator from auto to off. Then the power goes off and wait a few hours before turning the generator back on will that be hard on the generator or do any damage. I mean right now the generator goes through a warm up before starting and I think it is 5 second then it starts on 15 on automatic. If it is off do I just put it on auto and let go or not. Just curious cause I am new to this and have used it yet. It exercise runs for 13 minutes every week on Tuesday. Any input would be appreciate. I like you don't want it running all the time especially while sleeping or away.

you have to do the following when shutting down a generator under load..
1. TURN off the 2 pole breaker that feeds the house load (located on side of generator)
2. let generator idle a minute or two.
3. turn off generator.



if power is still off when you want to turn generator back on,do the opposite
1. Make sure breakers are still off. turn generator switch back to auto.
2. after generator fires up, let it run for a minute or so
3. then turn the breaker back on.


ive attached a jpeg showing this with pics, its the one i give my customers (this site wont take the pdf file i have)





by the way..i didnt create this, someone else did. i found it online myself.

 

[kiotiken]

GRS, thanks. I don't let the generator run long periods either. After a few hours, if the sump isn't an issue (it's not for much of the year), I'll go out and switch it to the off position, especially if I'm going to bed or it comes on in the middle of the night. I never knew I should trip the breakers first.

 

[K man]

Thanks you so much grsthegreat for sharing the illustration. I saved for future use.

This next question is for when the generator is not running under load just on auto.

Now if I turn the switch to off form auto and leave it like that so the generator will not start right away when a black out occurs. Then I decide to start for an hour or so just to bring everything up.

1. I will turn off the 2 pole breaker on the side of the generator.
2. Start the generator, let warm up a few seconds
3. Turn on the 2 pole breaker and this should feed the house right.

Then just reverse what I did and let the generator cool, shut the generator off and then once the power is restored I just put it back on auto and turn the 2 pole breaker on again.
Thanks
Gilles

 

[doxford jim]

Even though my backup generator is diesel and cheaper to run than the propane unit, we only run it for a few hours at a time. The house is well insulated and does cool down over night to around 50F without power (with -30C weather), but it doesn't get to freeze. Don't have to worry about sump pumps, but try to be sensible with the generator use.
Since times like this would be considered an emergency, normal routines and electric usage would/should be tailored to reflect that.

 

[buickanddeere]

GRS, thanks. I don't let the generator run long periods either. After a few hours, if the sump isn't an issue (it's not for much of the year), I'll go out and switch it to the off position, especially if I'm going to bed or it comes on in the middle of the night. I never knew I should trip the breakers first.

Open the breaker before shutting down the generator. The voltage and current surges as the generator winds down to death to electronics and starting relays in fridges etc.

 

[3930dave]

GRS, thanks. I don't let the generator run long periods either. After a few hours, if the sump isn't an issue (it's not for much of the year), I'll go out and switch it to the off position, especially if I'm going to bed or it comes on in the middle of the night. I never knew I should trip the breakers first.

Same goes for even tiny portable generators. Any decent portable gen manual will tell you to Start and Stop the generator with loads disconnected. There's getting to be enough electronics on the gens themselves, that you want to protect that end too.

I don't often admit in public to reading Manuals , but this is shocking stuff !

Rgds, D.

 

[3930dave]

the air cooled units seem to stand up for many years AS LONG as the maint is done. mines 16 years old. but i change oil every year, new plugs every other year. keep a battery maintainer and heater on oil.

I view oil changes on all equipment as important, but see air-cooled being esp. critical due to the elevated oil temperature.

What do you use during standby to heat the oil, one of those silicone glue-on pan heaters ?

Sump pumps seem to be the critical requirement, driving the purchase of auto-start/xfer systems.

Rgds, D.

 

[hr3]

So honestly, how much money did fuel cost some of you to run the larger, whole house permanently installed generators for several days? I'm just curious how much fuel they tend to consume rather than guestimating with no real-world experience with these types of units.

I have an 8kw auto standby system,, and use 1.5 gph under heavy use most times when it's running it about .75 gph. propane.. The last big storm we had I only had 10% in the tank "about 10 gal." lasted 3 days non stop..

 

[K man]

I have no idea cause since I installed my 11 kw Generac generator we haven't had a black out lol. The book says I would use 1.4 gph on 50% and 1.9 gph at 100% so I will have to wait and see when I use it.

 

[Jkott]

I have an 8kw auto standby system,, and use 1.5 gph under heavy use most times when it's running it about .75 gph. propane.. The last big storm we had I only had 10% in the tank "about 10 gal." lasted 3 days non stop..

.75*24*3=54 gallons not 10. 50 is about 10% of my 500 gallon propane tank. But at between $2 and 3/ gal, that three days of electricity cost well over $100. I suppose it's cheaper that a hotel room but generators are not cheap to run 24x7 unless you really need it.

 

[PHPaul]

Get a whole house auto transfer switch gen set. It will not cost much more than pto set up. In bed at 3 in the morning when power goes out. Wake up hear gen set running , go back to sleep no problems. No hooking up, putting fuel in and flipping breakers.
Whole house gen sets is one of those things I will never be without.

^^^This.

I have a 14KW propane fueled Kohler unit. I'm actually very pleased with how easy it is on fuel. I have a 120 gallon (250#) tank hooked to it and it has done weekly tests and three 4+ hour outages without dropping below 70% (80% is "full") in over a year.

 

[K man]

PHPaul consumption is very good. I can't wait to see how my 11kw measures up.

 

[Jkott]

^^^This. I have a 14KW propane fueled Kohler unit. I'm actually very pleased with how easy it is on fuel. I have a 120 gallon (250#) tank hooked to it and it has done weekly tests and three 4+ hour outages without dropping below 70% (80% is "full") in over a year.

120 gal of propane is actually 504 pounds. 10% of your little propane pig is about 12 gallons. How long were your generator tests? 10-15 min? That's 8 to 12 hours of no load running plus 12+ hours of load. Using a other ratings of roughly .75 gph with some load, that's 9 gallons for your outages. That leaves the other 3is hgallons for 12 hours of no load exercises. Seems about right since the gauges are only approximate and vary based on temp.

If comparing burn rates for gas vs propane, remember that propane only has 73% of the energy of a gallon of gasoline.

 

[K man]

If comparing burn rates for gas vs propane, remember that propane only has 73% of the energy of a gallon of gasoline.
True but the other factor is the quietness of the propane generator to the gas and also the emission, smell and the lugging of gallons of gasoline and extension cords. More convenient to have the generator hooked up to a propane cylinder. Maybe it cost more to operate a propane generator but to me it is worth it. I can sit back relax and enjoy the electricity.

 

[MossRoad]

Here's an interesting page on the pros and cons of different generators/fuels, etc... good read.
Generator Fuel, What Generator Fuel is Best

 

[K man]

Very informative website MossRoad so of what I have read I think propane generator is right for where I live on a mountain and very environmental safe, low and clean emission. Thanks

 

[Hunter29]

High speed 3600 RPM diesel engines normally have a 10,000 to 15,000 hour life expectancy with proper maintenance and service under most conditions..

Show me one...