standby generators

kaiser715

kaiser715

Doing hard time
Joined
Jun 1, 2006
Location
7, Pocket, NC
With the new house build, I have been planning to put in a standby generator.

Original plan, up until today, was to put in a small one -- 7.5kw -- just to power the most essential circuits (using their 8 slot subpanel style transfer switch). Fridge, freezer, alarm, video, septic pump/alarm as the highest priority items. Then I was going to do a manual connect and switch for my big Diesel genset, that would pretty much run everything as needed.

After talking with the electrician, I am thinking about changing up....basically the time cost, etc of installing the 8-circuit panel (and disconnect/interlock for the diesel), vs a service entrance rated ATS (200amps) for the whole house.

Thoughts right now are a 20-22kw that would run my heat pump (2 stage, 4ton) and most everything as needed (but obviously, not all at one time). (Would lock out the 15k resistance aux heat strips when under generator power).

Biggest downside I see is increased fuel consumption -- 1gph vs 2gph of LP at half load.

Cost is a wash because I would sell the Diesel.

Thoughts?
 
Go big or go home. Go big for yo home.
 
Do it once and realize it was the right decision when it's 5 degrees blowing snow and you just go over and flip the light switch on when all your neighbors are outta power and trying to get their generators going and keeping fuel for them


Sent from my iPhone using Tapatalk
 
One thing I didn't address....

We are planning to do some traveling in the future. May have house sitters -- they'd love the power if it came to be needed....but if the house was sitting empty, I'd hate to have the generator run 24x7 for a week if we are stuck out west or somewhere while a hurricane or snowstorm has power out for a few days here. 1st the propane bill that would come, and 2nd, wear and tear on the generator when it would really only need to run a couple or three hours out of six to keep the fridge and freezer safe, or the pipes from freezing. It would be a bit much to ask someone to go out 4x per day and run the generator for a couple of hours...might as well have a manual.

I see where the manufacturers have setups where you can view the status over Internet or cell, but not control it (stop/start). At least not affordably. I guess could rig up something to trick it by feeding fake power input to the sense circuit. Have a timer set up for 2 on/2 off....cut fuel consumption in half that way....
 
We have very (very) similar homes/land. I too was going to go with a 20+kw standby but only have a 150 gal propane tank that is only for the gas logs. Then I did the math on fuel consumption. A 22kw at 50% is 2.5-3 gal per hour... Figure you run it 18 hrs per day for a 3 day period, that's right at 150gal and a lot of damn money. I've got a UPS on the desktop computer as well as the routers/cameras and an 8k gas generator I can run if needed otherwise I feel like I would be wasting a huge amount of money. Just my opinion.
 
I think you would be better served to have gas heat then have a genset run the heat. And unless it's a major storm (which you should know about before hand) you shouldn't have a long term power outage while out of town. A newer freezer should stay cold enough to not cause you any issues
 
braxton357 said:
We have very (very) similar homes/land. I too was going to go with a 20+kw standby but only have a 150 gal propane tank that is only for the gas logs. Then I did the math on fuel consumption. A 22kw at 50% is 2.5-3 gal per hour... Figure you run it 18 hrs per day for a 3 day period, that's right at 150gal and a lot of damn money. I've got a UPS on the desktop computer as well as the routers/cameras and an 8k gas generator I can run if needed otherwise I feel like I would be wasting a huge amount of money. Just my opinion.
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I figure at about 2gph, call it 50 gallons per 24 hours. At two bucks a gallon, $100 per day. If it ran 5 days unattended until it could be managed...that's still cheaper that the food that's in the fridge/freezer. I think $500 burned up unattended would be worst-case. If we were there, I'd run as needed if a long-term event, not 24/7.

Have you run the ups for any time? Most, unless it's a long-run ups, are good for 10-15 minutes, even with no load attached. Less time if they have any age on them at all.
 
BTW....I am listening, and am open to discussion and ideas.... just didn't want it to sound like I am dead set on a 22k now.
 
@Ron is the generator expert. Maybe he will chime in a little. :)

We have systems at work that are pretty simple and have a user interface panel that can be operated locally or remotely via your phone. You can monitor and control most any parameter you wish. It's really not that expensive. Ours is hooked up to dolor panels and low voltage DC power but 120V systems are available as well. This would be an option if you wanted to start or shut down even if you are 2,000 miles away. You could also receive alarms for whatever you desire, like startup alarm, low fuel, low oil pressure, whatever.
 
Yep @Ron helped me with my generator decision.

For me, I was thinking about a whole house 20kw (I too have a 5 ton heat pump) with an automatic transfer switch. What royally fubared my plans was trying to run natural gas from one side of my house to the other or run wire from one side of the house to the other (gas is on front right side of house, panel is on back left). The idea of an auto feature was appealing, but after I got quotes of $15k - $20k, it wasn't worth it. I have a portable 8kw now that I have to manually hook up, but it runs everything except the heat pump so we re happy.
 
BigClay said:
but it runs everything except the heat pump so we re happy.
Click to expand...

For a house you moved into? Yes...I agree 100% but even then....power goes out because of a brown-out or summer storm, and it's 96 degrees, you're gonna want that AC if it takes days to restore power. Thankfully we've never HAD to deal with a summer outage in my hood...just prolonged winter (ice) outages. And I'm grateful for my gaspack unit that serves the bottom floor and gas water heater so we have heat and hot water when we don't have power.

But I'm likely to build something in the future (like Kaiser) and planning ahead for a generator myself. I will likely go with a 20kw so I can at least have AC/heat/hot water/lights for extended periods if need be.
 
Current storms are making work a bitch. I'll be glad to post more detailed thoughts later.
But in short,, new construction there is virtually no cost savings below a 22kw. Maybe $5-600 for a 12-16kw and it won't run half.

A 22kw will likely run your entire house. An lcr can be added to any big loads like a sump pump or pool pump if applicable.

Regarding lp remember not only consumption but also boil rate. If the wrong size/shape tank is selected you can suck a full tank dry. And have to wait 10 minutes for more boil off.
Don't let anyone try to sell you on lpl....lpv is the only choice around here.
 
I'm listening too, and in for more details. My wife has been wanting a whole home generator for a while now. We were only out for about 2 hours yesterday, but I expect we'll be purchasing one soon. My parents next door are still out, since 1:00 pm yesterday.

I was looking at 22kw generac.
 
SeMI off topic here but it's relevant. Anyone ever did a dual fuel conversion on a generator? If so which kit did you go with and how did it work on lp? I'm in the planning stages of our house and I was initially thinking about an automatic standby like you were talking about but I have all but changed my mind. I have a 7500w now and it does everything I need it to do except run the ac. I only care about ac when I sleep so I figure I'll just keep a window unit in the barn and use it in the bedroom at night. I would like to have the option of running the gen off lp seeing as I'll always have a few hundred gallons of lp in the tank. I don't want to have to rush to the store and fill up a bun ch of gas cans at the mention of a storm every time.

Also, you guys want to talk about fuel consumption. I bought a 200kw for work last week. At full load it burns thru 16gal of diesel per hr :eek:. I hope the fuel truck can run during extended outages!
 
Your home standby units (22kw and below) are natural gas/ lp dual fuel automatically.
 
awheelterd said:
Also, you guys want to talk about fuel consumption. I bought a 200kw for work last week. At full load it burns thru 16gal of diesel per hr :eek:. I hope the fuel truck can run during extended outages!
Click to expand...

And you didn't call me, jackass?
See if I ever burn chicken wings on a charcoal grill inside a hotel room with you again.

200kw is the bottom of my size range.
Delivered a 3,000 kw a couple weeks back. At 100% load it burns 269 gallons per hour.
 
I didn't read many of the above posts, but having a critical loads panel (100A or so) that is a sub panel from your MDP is also an option. If you backfeed your critical loads subpanel it would also backfeed to your MDP (if you choose to open the circuit), but you will need a whole house transfer switch after the meter to isolate the MDP from backfeeding up the line.
 
@Ron what's the trade in value of a 9yo 1mw with low hours? I bet it's sub 100. Need to upsize to a 1.3.
 
Could probably get 75-100 in the current market.
Maybe.

I know a few guys.

Problem is a 1mw is a 30l platform and a 1.5 is a 50l platform..they ain't fitting in the same hole.
 
Thinking out loud:

I wonder what the fuel consumption is of a 20kW at ~60% load is vs a 15kW at ~90-100% load.

Would you benefit in the long run in having a good load management system.

Or find out the range at the highest efficiency and keeping the genset there for the longest period possible.

On that note who are some good load management manufactures and where to find info on them?
 
Ron said:
And you didn't call me, jackass?
See if I ever burn chicken wings on a charcoal grill inside a hotel room with you again.

200kw is the bottom of my size range.
Delivered a 3,000 kw a couple weeks back. At 100% load it burns 269 gallons per hour.
Click to expand...

Lol! If I had been buying new you'd have been my first call. I got it used from a friend's company. It was too good of a deal to pass up. They has a twin pack 300 for a steal but it was just me than I needed.
kaiser715 said:
I just did an LP conversion on a military 3kw. Used this kit: http://www.ebay.com/itm/TRI-FUEL-PRO...72.m2749.l2649 They have other kits for specific setups, or generic.

Took about a half hour to set it up, 5 minutes of tinkering to get it running right. Super easy.

Awesome thanks

Click to expand...


Ron said:
Your home standby units (22kw and below) are natural gas/ lp dual fuel automatically.
Click to expand...
Yeah this is just a regular roll around briggs gen that I'm talking about. I'd like the orion of us g it elsewhere rather than having a dedicated unit
 
Futbalfantic said:
Thinking out loud:

I wonder what the fuel consumption is of a 20kW at ~60% load is vs a 15kW at ~90-100% load.

Would you benefit in the long run in having a good load management system.

Or find out the range at the highest efficiency and keeping the genset there for the longest period possible.

On that note who are some good load management manufactures and where to find info on them?
Click to expand...


The 16kw Generac uses 1.99 GPH at 50% load, and 3.57 GPH at 100% load.

The 22kw Generac uses 2.16 GPH at 50% load, and 3.67 GPH at 100% load.

So, the 22 might actually cost less to run than a 16....same house, 22kw would run at about 2/3's load, when the 16kw is running wide open.

Motor is the same CC, just the generator head/windings are different.

About 1k difference in cost between the two. After the first long power outage, after listening to the other half repeat incessantly "if we'd spent another thousand bucks, we'd have air conditioning right now"....it would be well worth the difference.

Drop down to an 11k and IIRC, the motor his about half the CC's, and IIRC, runs 1.16 GPH at 50%.
 
kaiser715 said:
The 16kw Generac uses 1.99 GPH at 50% load, and 3.57 GPH at 100% load.

The 22kw Generac uses 2.16 GPH at 50% load, and 3.67 GPH at 100% load.

Motor is the same CC, just the generator head/windings are different.

Drop down to an 11k and IIRC, the motor his about half the CC's, and IIRC, runs 1.16 GPH at 50%.
Click to expand...


So the 11k @ 100% is the same as the 22k @ 50%.

22k @ 50% uses 2.16 gph
What's the fuel consumption of the 11k @ 100%?
 
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