Generators

[wct097]

Figured it was worth it's own thread.

I like the idea of having a standby generator for my next home. Need to do some more research, but I'm thinking one of the LP/NG varieties will work nicely depending on NG availability.

The thing I like about the LP option is that it allows you to function without the NG infrastructure working. Not sure how reliable that is, but in an extended emergency situation, I imagine it could be as problematic as the electric grid.... especially if there is an earthquake or supply chain interruption.

LP, on the other hand, would require a truck to come out to refill the tank during an outage. That could be an issue in most emergency situations. I wonder what kind of runtime you can get on a typical home installation.

The best of both worlds, I suppose, would be to run off of NG with the option of switching fuels to an on-site LP tank. Not sure if that's possible or not.

From what I'm reading, a 20kw standby unit would probably run two a/c units simultaneously for a 3k sq ft house.

 

[abqtj]

Here's a fine specimen

12 KW military generator

 

[BobKid]

LP is only going to give you 3-4 days between refills if you're running close to full load. Good for short outages, but a problem if it drags into a week or more.

 

[eysdan]

We have a Generac 20 KVA generator and it has served us well. It is LP, but we have a 1000 gallon tank as well. SAD has one too, but I can't remember how big. It got us through a three day power outage without any issues.

 

[whiskey tango]

Deezuhl FTW!! Lulz.

 

[serfur1]

it's not that hard, P=V*I, your voltage is 120v or 220v for dryer or A/C. Take the fridge load, 120v*Amps, your A/C load, figure in a few hundred watts for lighting, a KW for powering computers/Tv/chargers etc. and you'll have the size that you need. you may have to turn on the large things one at a time since motors can pull 3 times their rated current on startup.

the other thing you can do is a residential power load study,
Using a stopwatch while watching for the black mark on the meter's disk, measure the time it takes for one or more disk rotations. If the disk is rotating rapidly, better accuracy will be attained if you time more than one rotation.

Finally, take the three values and use the equation below to calculate the watts seen by the electric meter.

Here is an example calculation. From the meter's face, Kh = 7.2. The time measured for 5 rotations of the disk was 24 seconds. Thus, Rev = 5 and T = 24 seconds.

watts = (Kh * Rev * 3600) / T

Watts = (7.2 * 5 * 3600) / 24

Watts = 5400

Turn everything on that you would want to run during an outage and you'll know exactly what you'll need in terms of sizing. This is the MOST effective way to determine the load as it's based on actual load usage.

 

[Aged Punk Shredder]

my gas one has worked perfectly ever since we got it. The power grid has not been down more than 30 minutes at a time since I bought the thing from my parents a couple of years ago

 

[SAD]

We have a Generac 20 KVA generator and it has served us well. It is LP, but we have a 1000 gallon tank as well. SAD has one too, but I can't remember how big. It got us through a three day power outage without any issues.

Yup... 10K watt generac..

BTW... It's dual fuel. NG or LP. To switch it, there's a simple dipswitch on the carb.

Ours runs on NG.

Before the NG line was run out to the side of the house, I tested it on LP using a grill tank

 

[SAD]

LP... I wonder what kind of runtime you can get on a typical home installation....

You can find the specs online... But generally expect to consume between 1/2 gallon to 1 gallon per hour.

 

[wct097]

Yup... 10K watt generac..

BTW... It's dual fuel. NG or LP. To switch it, there's a simple dipswitch on the carb.

Ours runs on NG.

Before the NG line was run out to the side of the house, I tested it on LP using a grill tank

Nice. After this outage, I'm purchasing a used 5500w portable gas powered unit to keep handy for the TH and/or family members that are in need.

When the time comes to build or buy, the next house will have a proper standby generator that can run everything. Since I'm looking for a more rural setting, I'm expecting that we'll end up having to go the LP route. DEZUL would be cool, but I'm not sure how reasonable that is in a rural residential setting.

 

[wct097]

SAD, what kind of maintenance do you have to do with that unit? I'm assuming you have a weekly test/lube run set up. What about oil changes and that sort of thing? Is yours air cooled?

 

[SAD]

SAD, what kind of maintenance do you have to do with that unit? I'm assuming you have a weekly test/lube run set up. What about oil changes and that sort of thing? Is yours air cooled?

Air cooled. To get to a water cooled unit, you're talking big wattage and mega $$ (comparatively speaking of course).

Only maintenance is change oil once a year.... Check oil level every so often.

The computer runs a weekly exercise cycle on Wednesdays for 12 minutes at around lunch time.

 

[wct097]

Air cooled. To get to a water cooled unit, you're talking big wattage and mega $$ (comparatively speaking of course).

Only maintenance is change oil once a year.... Check oil level every so often.

The computer runs a weekly exercise cycle on Wednesdays for 12 minutes at around lunch time.

I'm thinking that for a home based unit, the air cooled would be preferable given the inherent maintenance of a water cooled unit. I'm assuming the oil change is pretty straightforward. Does it have a standard 12v starting battery?

Our 200kw and 100kw units at work run weekly for an hour or two on Tuesday mornings at 9am, but we have a contract for regular maintenance. At home, I'd be doing all of the maintenance.

 

[Jays89YJ]

I would go with a diesel unit and cycle fuel through our trucks throughout the year.

 

[miwico]

Yup... 10K watt generac..

BTW... It's dual fuel. NG or LP. To switch it, there's a simple dipswitch on the carb.

Ours runs on NG.

Before the NG line was run out to the side of the house, I tested it on LP using a grill tank

Fire your electrician.

 

[SAD]

Fire your electrician.

Can't. My wife likes having sex with him.

 

[SAD]

I'm thinking that for a home based unit, the air cooled would be preferable given the inherent maintenance of a water cooled unit. I'm assuming the oil change is pretty straightforward. Does it have a standard 12v starting battery?

Our 200kw and 100kw units at work run weekly for an hour or two on Tuesday mornings at 9am, but we have a contract for regular maintenance. At home, I'd be doing all of the maintenance.

Yup. Standard 12v starting battery. Controller board has a charging thingy on it.

My neighbor had a 25k water cooled unit. Its ****ing loud. If mine and his are running and I'm on my back porch, I can hear his over mine. And his lot is 600-800 feet away.

 

[Hubjeep]

Deezuhl FTW!! Lulz.

Diesel units are 4X the cost and rarely ever used in modern home standby as they are noisy and diesel longevity is not really needed since it is a standby unit.

SITB and main house are powered by a 12KW 4-cyl air-cooled Onan diesel (installed in 1992), there is no auto transfer switch, that would have been another $5K on top of the $12K generator. Today I would go with a Kohler RESA unit, made in the USA, both air cooled, and "clean" power, transfer switch sold separately.

BTW, taking random amperage checks the 12KW was at about 1/3 load most of the time with 3 refrigerators, three oil burner heads, etc. I only run one central A/C unit, besides that everything else is on, including the hot tub heater. It really doesn't take much to power a house, in this case two.

14KW
14RESA - Kohler - Kohler 14RESA 14kW Residential Generator - LP Vapor or Natural Gas

Add $1K for the 20KW
20RESA - Kohler - Kohler 20RESA 20kW Residential Generator - LP Vapor or Natural Gas

Fire your electrician.

X2. Pitch on that underground service entrance.

 

[wct097]

Why Kohler over Generac or Briggs & Stratton?

Our new 200kw and 100kw DEZUL generators at work are Kohler and have handled this outage like a champ.

 

[Hubjeep]

Why Kohler over Generac or Briggs & Stratton?

Our new 200kw and 100kw DEZUL generators at work are Kohler and have handled this outage like a champ.

Kohler and Onan are known to basically be the two best generators out there. Kohler RESA units are priced about $1K over the Generac (other companies probably have that too). Kohler unit has a $50 optional network connection to check status of the generator from any computer. My relative wants a home standby unit, going with an RESA unit.

B&S is relatively new to home standby, they use their Vanguard (great) engines, not sure who makes their generator heads though. Generac has been around a while, not the best reputation, though their recent home standby units have had fairly good reviews.