Emergency Home Generator

Jeffy...that pic you posted looks alot like my 90,000 watt'er

Most of the cheap stuff sold by the big box stores is made "just for them" and of a lower quality just so it can be sold at a low price. Very few items are of the same quality as those sold by a hardware store or lawnmower shop. They asked Karchner to make a pressure washer for them. They had to sell for $99.00. Karchner had so many problems with those units that it hurt their reputation. They refused to renew the contract. Bob

Choosing an emergency power system includes many variables- here's a few:

-Peak load capacity (starting big motors, running resistive loads like electric water heaters, dryers, lots of lighting, etc)

-Fuel consumption curve (some are very thrifty at low power, but generally speaking, a larger generator's BASE FUEL CONSUMPTION is higher than a small unit).

-Fuel availability, storage, and turnover (as noted above, gasoline and diesel are easy to buy, propane lasts forever, natural gas comes in a pipe...)

-Initial Cost (your source, and wether you opt for used or new, and features)

-Convenience (auto start and transfer, manual start, etc)

-Noise level (high-speed, high power, air cooled louder than low speed, low power, water cooling)

-Long-term durability (not only in operation, but under non-use circumstances).


Here at my place, I have MANY generators, and they're all used for a variety of purposes.  I have several engine-driven welders with AC capability, and while they do a fine job of providing electricity, they're first-and-foremost intended for welding, so the AC power output vs. fuel consumption is nowhere near that of a dedicated generating plant.  That said, I HAVE provided emergency power to friends and neighbors with welder-gens, and it made 'em happy regardless.

A REAL standby generating system is just that... always ready.  That means you know it will always be capable of starting up quickly, and putting power to your property up to your expectations.  Since everyone's expectations are different, there's many different ways of defining 'best'.  Keep in mind, though, that the GENERATOR is nothing more than what the word says-  a generator.  To have emergency power, you need to have an Emergency Power System... which is to say, an understanding of what you NEED, a fair idea of what you want, and a thorough understanding of the ramifications of both.  In short, YOU need to know what your power demand IS, what parts of it are CRITICAL, and then, determine what it will take not only to provide that power, but to keep it fueled, functional, and in good maintenance, and you need to be able to safely remove the desired loads from utility connection, and feed them by the generating system.  You could have a whole-service transfer switch, a dedicated 'critical loads' transfer panel, or use a backfeed system (and there ARE legal ways to backfeed, but it requires proper interlocks) or simply enough, just string in extension cords.

I won't tell you how to do it, but I'll tell you what I have for an emergency power system, and try to explain WHY.

I have three generating plants, a rack of 12v batteries, a 120vac inverter, two 1000 gallon propane tanks, three 125 gallon propane tanks, one backfeed breaker interlock system, one 3-unit generator selection panel, and one whole-property transfer switch.  With exception of ONE Square-D breaker interlock kit, NONE of it was purchased new, and I have about $4000 total invested in it all.

My situation is simple-  we live on a 3-mile long gravel road not far from city limits, but it's a single-ended distribution line with several areas subject to blowing/drifting snow and very exposed to high winds.  We typically see 5-6 small outages (less that 24 hours) a year, and typically one or two extended outages (a week or so), during mid-winter, to early spring.   During our outages, it is normal that large quantities of utility customers are without power in the cities, and for the long outages, it's most frequent that the road is too iced and drifted for traffic to get anywhere near the problem areas.  Since there's only a small handful of people on this end of the line, we're we're usually quite a ways down the pecking order to get power restored.  This means we need to be prepared not only to provide our own power, we also need to have everything else necessary on hand for a snow-in.

Compared to utility power, running a generator to power your home is incredibly expensive.  You're burning fuel to run an engine that, in most generators, has to spin at governed speed, and uses a certain amount of fuel just to do it... and up to a certain point, there's no penalty for applying more load.  Eventually, you reach a point where the generator starts pulling mechanical load, so the engine's fueling rate rises by virtue of the governor holding frequency steady.

It is for this reason that my 35kw powerplant' 331ci 6-cylinder Hercules only gets put to work when we REALLY need power-  like... I need to run machine tools in my shop, or we need to run the electric range or dryer, or stove, or air-compressors, or welders... or a cyclotron...  I never run the big monster without having a load on it, because base fuel consumption is well over a gallon-an-hour.  Nice thing is, it's a 1200rpm machine, so when she's running, it has a nice, low PURRR.  It was built in '58 for the Civil Aeronautics Administration...

I have a Kohler 15kw machine... has a 4-cylinder Waukesha engine on it, again, 1200rpm, water cooled... made in '42, was originally use on a navy ship.  It uses about a gallon-and-a-half an hour under full load, but more like a gallon an hour at minimum load.  It will carry all the basic house loads (sump pumps, furnace blower, well pump, refrigerators) as well as a few more loads (either dryer or stove, and if she picks carefully, perhaps the dishwasher, but definately the basic outdoor floodlights, garage doors, etc.

During cold winter nights, I don't like leaving the bigger generators running... uses too much fuel for keeping the critical loads powered... so I have a 6.5kw military genset (type PE-197) which uses a whole lot less fuel.  It's powered by a Hercules ZXB liquid-cooled four cylinder, and also fuel'd by propane.  It will power both sump pumps, the well pump, the computer network, 2-way radios, and the Dish TV system just fine, but not much more.  Like the Kohler, it was made during WW2.

All three of these units have a few key things in common:

1) they can all be electrically started from batteries
2) they all feature MAGNETOs, and HAND CRANKS, so having a dead battery does NOT keep it from being started. (yes, they all start very well with cranks)
3) They're all liquid cooled, low speed machines.
4) They're all seven times tougher than anything one could buy today
5) All easily serviced, with a minimum of special parts, no complicated electronics
6) They're all set up and ready to operate from WITHIN a building... so if something takes one down, I'm not working out in the cold rainy-snow trying to get it fired up again.

Liquid cooling is a very important feature to me-  partially because of the long life afforded by liquid cooled engines, but moreso because I'm very sensitive to the cost of operation.  A generator burns about twice as much liquid fuel, as what is available at the generator's output leads.  This means the REST of the energy burned (fuel quantity) is going strictly to waste... exhaust heat, ambient heat, and noise.  Because of this, when you run a generator, and power a furnace, you're burning LOTS of fuel for the result you get.

My generators not only generate electric power to run the furnace, they DISABLE the gas-valve on the furnace, and heat the house using coolant from the generators... I circulate the generator engine's coolant flow into the house, and that keeps everybody warm and safe.  On cold winter nights, I can just leave that itty-bitty bugger running, and even though it may not be carrying much electrical load, it's providing heat to the house, and spinning the furnace blower... so at least I'm not burning propane in BOTH.

I don't automatically transfer my generators, nor do I automatically exercise 'em.  I do all of it MANUALLY.  Nothing wrong with doing it automatically, but keep in mind- if you're gone, and the power goes out, the generator could start, and run, and burn up your entire fuel supply for nothing... and not power your house.  The other issue... modern electronics is VERY susceptible to damage from electrical storms.  My dad's Generac found a zero-value circumstance several years ago when lightning hit the utilty lines and blew out the control panel's microprocessor.  The generator started and ran fine, but would not goverrn, and would not generate.  Worse yet, it would NOT TURN OFF... only way to stop it, was for me to disconnect the fuel lockoff solenoid and let it run-to-stop.  eventually he got a replacement panel, and it cost something silly like...  $500 for a new microprocessor board.  Insult to injury, after going two days with no power, eh?

Okay, so I gotta wrap up and hit the bed, but that one guy back in back has his hand up, so one more question, go ahead...

Okay, yeah... that battery rack and inverters... yeah, I was gonna get to that.  There's sometimes when our power needs are about zippo.... like... in the early-mid fall... at night... would like to just shut the generators down.  Well, I can do that, and as long as nobody opens the fridge or goes more'n about a dozen flushes of the toilet, we'll be fine.  It's good, however, to be able to flip on some of the lightswitches in order to see what we're working on.

To make it cheap, simple, and effective, I use my boat batteries... I take 'em out of the boats every fall, and leave 'em on a low-power trickle/float charger all winter.  There's always one or two OTHERS on the rack, also charged and ready.  The inverter is a cheap one... mebbie $50 or so is all it took to get it...  I've wired that to a set of dedicated wires going into the house... and there's a bunch of electrical circuits tied in there... and in the sockets of all those lamps, are LED bulbs.  I can essentially turn the generators off, and run lighting as necessary, especially around the generators (so I can see 'em if I need to work on one to get it running).

my setup is not optimal for someone else, but it may give you some reasons to help understand why I do it this way.

For the most part a portable generator will do fine during power outages that usually don't last a week.
I didn't buy one to light up the whole town.
I use it to run a few circuits in the house.
I thought way ahead and have propane heat besides oil since I don't need electricy to run the propane and a propane cook top that also doesn't need electricity.
When the power is out for awhile it's not the end of the world.
A few circuits for a few lights and water is fine for me.
I know some of you can't live without a tv.

Dave, When you install that inter-lock kit I don't consider that back feeding. That's converting your panel into a transfer panel. 

And to keep it in an ALLIS frame-of-mind, I saw a Palmer generating plant, about 18kw or so, single-phase 240, gasoline carb AND propane mixer, out in the Wickenburg, Az area back in January... it was posted on Craigslist, and if I had the cash, it would've come home with me.  It had a very unique engine casting, like it WANTED to be a WD block, but wasn't... the governor location was wrong, but everything else looked okay.  My thought is that it was one of the BUDA variations.  Very neat, but alas, I had insufficient cash.  Would'a been the perfect backup mill for a die-hard Allis enthusiast.

http://www.interlockkit.com/

Oh, and for what it's worth-  one horsepower is the mathematical equivalent of 746 watts.  That means you need to multiply the number of KW by 1.34 to determine horsepower equivalent.

A 10kw generator needs AT LEAST 13.5hp coming in on the shaft to hit it's 'advertised' output...  but you'll be hard-pressed to find an engine that'll actually DO it, because of mechanical and electrical losses... primarily, heat (generators don't carry current without getting hot) and of course, the drag of a mechanical cooling fan to keep it from melting.  A 10kw generator with anything LESS than 15hp on tap, in my opinion, is incredibly optimistic, and not likely to survive long, nor capable of starting a big motor, if it actually CAN hit that number. 

When shopping for generators, look at how they're advertising it, and then compare it to others.  An Onan 5CCK generator turning at 1800rpm is rated for 5kw continuous duty, and has a twin cylinder engine that would be otherwise rated for 12hp at 1800, and 16hp at 3600rpm... and under those circumstances, will outlast several owners.

The Waukesha FC140 on my old Kohler 15kw plant was rated something like 24hp at 1200rpm, continuous duty, and given a 4-hour overload rating of 120%.

When you see generators labeled with terms like 'peak' or 'surge' rating, what they're doing is putting lipstick on a pig.  Look for 'duty cycle' at a given level.  When you see a 100% duty cycle rating, THEN you're looking at a realistically-rated machine.


Edited by DaveKamp - 03 Nov 2011 at 6:48pm

I've got a question for anyone that knows Onan generators.

Dusty- sounds like to me that your Onan's RV controls have a load-sensing control system... meaning, you have a switch inside the RV that 'enables' the generator to run, and when there's a load, it will allow it to run just fine, but if the load falls below a certain point, it shuts the generator down.

This is something you'd want to bring up with the Onan RV generator guys... Smokstak has a forum specifically for these, and you'll find that there's a few guys there that know the controls exceptionally well... and I'd be surprised if they didn't answer it with a why, AND a how-to defeat that function.

One test I'd do... is plug in a 75w lightbulb with the water heater and fridge, and see if it'll run that way.

Guys, thanks for confirming what I was thinking about watts per leg. 

 

Edited by Dave H - 04 Nov 2011 at 5:54am

"So if the building burns and the sprinkler pump emptys the tank and the milloin year flood comes at the same time we need to worry about the silo floating out of the ground."

Oh... almost, but here- I got it:

If the building burns, and the generator runs and empties the tank, all that water will flood your entire county, and then the generator will shake that silo out of the ground...

What a moron.  Just the kind of guy you'd want have around to throw water when the french-fry cooker catches on fire.

I had an inspection on one of my installations... inspector was talking to the Fire Chief about 'confined space', carbon monoxide, and explosion concerns... Chief asked me if there was 'anything combustable' down in the scale pit... I said "uh... it's a concrete pit, with concrete and steel scale decks"... he said "What's the flashpoint of concrete and steel?"  and smiled as he signed my paperwork.  <I like this guy!>