Some of you might have heard about the storms that came through Omaha, Nebraska yesterday. 100+ mile an hour winds, hail, heavy rain. So the power was out for 26 hours. Which wasnt bad because gives me an excuse to oull out the lanterns and radio and relax. My 20 month was less than thrilled about it. So was my wife.

So Im looking at generator but dont know where to start. I would like to be able to power the fridge and some other stuff. Maybe the AC? How would this work?? Is it even possible? I would like a portable one if that matters. I also would not like to spend and arm and a leg. $600- $700 would be good....

Thanks for any info you can give me.

We bought a Champion 3500w (which my daughter and her husband now have. Long story). Bought it new for under $400, later found it in an auto parts store in Montana for less than $300. Don't know if it would power your A/C, but it should handle everything else. Noise rating as low as a Honda, supposed to be a copy of the Honda engine...

Hi Hardsted,


The Honda EU2000i has a pure sine wave inverter so can be used with senstive equipment such as computers, TV etc. They are reasonably quiet as well for a portable generator, which can be very important in a domestic situation.

http://www.hondapowerequipment.com/produ...delid=EU2000IAN

Thats helpful, thanks.

Knowing nothing about generators, how exactly would I plug stuff in? I just unplug my fridge and run an extension cord to the generator?

How could I operate my A/C?
IS there something specific I should look for? Minimum wattage?

The Homestead Generator
Rich “Raspy” Shawver

From time to time the questions come up about the selection of a homestead generator. Should it be gasoline, diesel or what about a multi-fueled option? How much capacity do I need? What Bells and whistles should be added? What about the noise?

Power generators are designed to produce 60 cycle AC. This is your common household power from the power company. To accomplish this they normally run at 3600 RPM, 1800 RPM or 900 RPM. Obviously the slower the system operates the less stress it is subjected to. Therefore the longer it will be expected to last.

For the prime mover of the system comes in 2 flavors. These are the standard gasoline and the diesel internal combustion engines. Multi-fuel systems are modifications of either of these 2 basic engines. Both work on similar principals. Fuel is sprayed into a cylinder with air. The fuel air mixture is then compressed. This mixture is the ignited to produce the power. The difference comes in how ignition is accomplished. The gas engine uses an electrically fired spark plug. The diesel engine, while initially uses a glow plug to get things started, relies upon compression to fire. There is the turbine engine but these are almost not known when it comes to generators. There is also the Wankle, which is a cross between a piston and turbine engine. These have almost become museum pieces.

In this respect the gasoline engine has the advantage. Aside from running on gasoline they can be modified to run on LP, Propane and Natural Gas commercial fuels. They can also function on homemade fuels of Alcohol, Wood Gas and Methane. The problem with multi-fuel operations is that to operate of different fuels require major changes in timing and fuel flow and air requirements for each fuel. To make the engine operate on several fuels in consecutive operations requires compromises. These compromises make the engine less efficient regardless of the fuel used. Additionally the modification piles extra complexity onto the system.

The diesel engine runs on commercial diesel. And function on homemade fuels of almost any vegetable oil with little or no modification. Yes, that means if you run out of fuel in a diesel powered vehicle you can walk into a grocery store, buy a couple of gallons of expensive cooking oil, pour it in the tank re-fire and drive away. The major problem with these fuels is they are temperature sensitive. The colder it get the thicker the fuel becomes. Often below freezing it becomes too thick to flow. This requires either a system to keep the fuel warm in cold weather. Or to store the fuel where it is not subjected to lowered temperatures. There is even a methane production advocate named John Fry that modified an old diesel to run on methane to power his farm.

One area where the 2 types diverge is in reliability and longevity. The most common gas powered generators are the small [5000 watt range] portable generators. While nicely portable they are only designed for intermittent use. They operate at 3600 RPM too fast, too annoyingly loud and way too short-lived. Even the larger models still tend to be of the higher RPM variety. Most diesel generators are designed to operate at 1800 RPM and a few can be found that run at 900 RPM. Diesels have better torque [power at slow speed] characteristics at lower RPMs than gas engines. Consider engine life in vehicles. Typically gas engines last an average of about 100,000 miles. Sure there are those that last to over 200,000 but have needed major overhauls to reach that. Not to mention that they need regular tune ups. These represent down time and the expense of parts especially spark plugs. Conversely diesels need little more than minor maintenance at 100,000 and usually last much, much longer. Ask any long haul trucker how many 100,000’s trucks average. A million miles is more the rule rather than the exception with little more than oil and filter changes. Diesels not having the need of an ignition [sparking system] have fewer parts to go wrong.

In recent years natural gas generators have become the rage. Yet these are suspect in regards to longevity in my opinion. They are in essence modified gasoline engines with the same problems. Also because they use a pressurized gas instead of a liquid fuel they require a sealed system. Tolerances need to be much tighter to operate well. In internal combustion engines the fuel can act as a lubricant. This is very good in a diesel, poor in a gas engine and almost nonexistent in a natural gas system. So which do you think will give you less problems and last longer. I have heard reports that there are problems with even the higher end units in regards to life expectancy.

First conclusion is that diesel driven generators are a more viable option for a long-term homestead power system.

Sizing the system

To do this you really need to determine 3 separate figures.
1) Minimum needs
2) Average needs
3) Peak or Maximum needs.

Adding up the power requirements of the equipment in each category does this. Generators are rated in watts or rather 1000 of watts or Kilowatts. To find these values you need to read the appliance’s nameplate. Some list the amount in watts, which makes it easy. Others list the amount in Amps. To convert Amps to watts you multiply amps times the voltage to get watts. Most common electrical equipment runs on 120 volts although some use 240 volts. Example: 5 amps at 120 volts equal 600 watts.

Minimum need items are things like lighting, refrigeration, heating or cooling, ventilation and communications. This amount can be reduced from the combined amount by running this equipment sequentially. Average is self-explanatory. Peak is the largest single load or combination of loads that will be expected to be run and start at any one time. You might want to add a fudge factor to be on the safe side. It is better to have a little extra than not quite enough.

For efficient operation a generator should be loaded between 70 to 90 percent. Less the system is not as stable or being used effectively. The upper 10 % are to allow for the surge when a load is started. Also generators last longer and run better if used for a period of time rather than in a series of short runs. The most wear and tear is during the start up.

The generator is selected to meet the desired usage. Usually this is the minimum for emergency conditions or the average requirements of the homestead. This can sometimes be accomplished better by having 2 generators. Either one to meet minimum to average usage needs or combined to full fill any greater demands for longer-term use. Additionally each can be used as a backup to the other during maintenance or repair. Also as a source of spare parts if both are the same.

What bells and whistles are available?

Auto-start. This automatically starts the generator upon a power failure.

Transfer switch. This is a switch that shifts from commercial power lines to the generator and back. This is a safety feature to keep the generator from feeding the commercial grid. This feedback could cause an injury or worse to linemen repairing the cause of the initial failure. These come in manual or automatic. The automatic type switch the power after the generator comes up to speed.

Remote start. This is a nice feature for periodic running and testing or in place of an auto-start or in the case auto-start fails. It saves a trip to where the generator is located.

Remote monitoring stations. Several stations can be set up for convenience of knowing the status of the generator. These gauges would entail information such as if it were running, speed, various critical temperatures, oil pressure and even fuel tank level. These stations can even be fitted with alarms if parameters get out of operational ranges.

Paralleling meter. When more than one generator is used at the same time to supply the same distribution system this is mandatory equipment. In AC electricity the voltage rises to a peak positive voltage and dips to an equal negative voltage in a series of smooth curves. [Alternating current] When hooking 2 or more generators together the switch has to be closed as close to possible when these rising and fallings match. The purposes of the meter is to measure the difference between the 2 machines it shows when they are in sync and when the switch can be closed safely.

Battery bank. To greatly improve the systems efficiency a battery bank is a welcome addition. When the generator is running at lower than capacity it can be used to charge the bank. Which in turn can supply power when the generator is not on line. It can also store energy from alternate sources such as wind, water or solar systems. The battery can also have remote monitoring and controls incorporated with the generator stations. Depending on how it is wired the bank can operate at almost any desired DC voltage. The output of the battery bank can be dealt in 3 different ways.

The first method is straight DC. This requires a separate DC wiring system. A DC system works especially well for lighting. Many DC appliances can be acquired at recreational vehicle centers. Here is an interesting product. It is a variable output LED lighting Module.
http://www.techass.com/el/versalux/ulm/ulm.php?techass=3fe0092186fa2f45faefa96b753e0bbe

The second method is to use one large or a combination of several smaller inverters. Inverters are electronic modules that convert DC into AC.

The final option is the ultimate inverter. This is a motor generator setup. A DC motor drives a small AC generator. The advantage these have over the electronic inverters is longevity. These will last an extremely long time because of their simplicity. One interesting feature of this kind of set up is that it can operate in both directions. If the control circuits are adjusted the AC generator will act as a motor and a DC motor act as a DC generator. This can then be used to charge the batteries from the main generators.

Noise abatement and a few other issues.

If you run a generator in the basement or an attached garage it would not be long until it would drive you crazy. Not to say announcing its presents to the world for miles around. What is required is a separate powerhouse. This structure does not have to be close to a dwelling but it need not be far away either. The trick is to insulate it to contain the noise. The easiest way to this is to think of a root cellar like structure with a well-insulated door. Being situated below ground it uses the earth as a sonic as well as a temperature insulator. Since this also moderates temperature fuels such as diesel are not as effected if stored there. Also the negative effect of cold on the batteries will be minimized. If heating is required it will be minimal in nature.

Final Recommendations. The best engine I would suggest is a diesel. From what I previously stated you might think I would say 2 generators. Actually I would want 3. 2 mid sized units to supply the main power. Each capable of supplying the average power needs. Each can act as a backup for the other or combined to meet higher levels of need. The third would be a small portable gas generator. This is to take a power source to remote locations. Including a battery bank to increase efficiency. And a separate DC grid and a motor generator setup to supply AC from the battery and to charge the battery.

That's some good info on generators, thank's for posting it.

that is a ton if info....

Yeah, that is a great info source. Looking at Diesel generators, I understand they are more reliable as I already drive a diesel truck and while it would be easy enough on the fuel I just don't think Ill use it enough to worry about lasting forever. The price difference is also fairly large.

Raspy had a ton of great info. Just in case it was lost in all that information, I just wanted to highlight the point he made about making sure you understand the importance of not endangering other people by letting electricity flow from your home generator back onto the public power lines by plugging it into your home wiring.

Once you have the generator running, unplug the fridge or whatever and plug it into the generator via an extension cord. You may get away with one of the orange long extension cords commonly sold at Home Depot, etc., but I would recommend using one of the heavy duty ones, even though they are more expensive, as they can carry more power safely without overheating. Make sure they are rated for outdoor use.

Place the generator (if portable) in an area where the exhaust will not get into the house. Carbon monoxide can and will kill.

A/C uses a lot of power, and usually requires 220/240 volts. Given you budget, you may not find a generator that can handle that load and the other things in the house.

Prioritize your needs. Our priority is the fridge and freezer (for obvious reasons and storage of insulin), sump pump (to keep basement dry) and only then "comfort" items such as computer (internet) and a small tv radio (when the power goes out here, the phone, internet and cable tv manage to stay on: YMMV). We use oil lamps and battery powered lanterns for light. No A/C. I can also get the gas furnace running off the generator if heat is required, but that is a bit complex to do.

Read and follow the makers instructions for storage. You want it to work then next time, and if not stored properly, there is a good chance it will not start easily or at all.

Yeah, running the A/C is not really high on the list. I just thought if I had the power what the heck, right? BUt it will be a little complicated for me to figure out so it's not a big deal if that doesn't work out.

My priorities>

Fridge freezer
Cable Modem/ Router
Computer
Maybe a TV
Maybe some fans if its hot

Sounds very doable with a modest gas powered generator within your budget. Shop around and watch for sales.

Also, I should have mentioned, consider the size of the gas tank on the generator. Smaller generators have smaller gas tanks that may require refilling every couple of hours. You had a 26 hour outtage; how would it be to refill it 10 to 12 times? Consider models with a 5 gallon tank that will run maybe 8 or more hours on a tank.

Two things that can not be stated enough re portable generators.

Watch that exhaust, it will kill if it gets into your (or your neighbors) home.

Chain it down. Portables, 'specially during a long term outtage, have a nasty habit of walking away...

Thanks for the great info Raspy!

How difficult would it be to power a normal household natural gas furnace (fan, ignition, controls) with a portable gas generator?

My most common difficulty at our home would be a long-term power outage in the winter, therefore no heat in the house because the furnace would not run.

Mike

Mike,

I have done it successfully.

In theory, not hard, especially if you know what you are doing and don't mind a few minor violations of local codes.

A typical gas fired forced hot air heating system doesn't take much power to run. But every installation is different and the details get complex. Here is how I did it.

First, the system needs to be off line from the main breakers. Flip the breaker(s) that power the system to off.

Second, find an alternate way to get the power into the circuits you just isolated. In my local jurisdiction, the code calls for one standard outlet at the furnace, so this is easy.

Make a "make to male" adapter. Make sure and triple check that you do this correctly or there may be fireworks or damage to the system.

Run an extension cord to the furnace from the generator, plug one end of the male to male into the extension cord and the other into the outlet on the isolated furnace circuit. Your furnace, fans and controls should have power, and, after a brief "reset" time should come up and run and provide heat.

I have only done this in extreme conditions, when indoor temp got below 50 f., as there are conditions when the power you are injecting can leak our through the grounding system (which is not disconnected by throwing the breaker) and endanger the folks working to restore power.

I can't stress enough that every installation is different, and, depending on your skill/knowledge, the help of a friendly electrician on a non-attribution basis may be required.

Hi Bws48,

Thanks for the information. I am not an "electicial guy" at all so I would have an electrician do the installation.

Any idea how powerful a generator would be needed to make a normal household furnace operate?

Mike

If you use natural gas or propane to heat one of those vent less wall heaters would be a good heat source. I have seen them for as little as $150.00 in the off season. I have a friend that uses one and it heats most of his home, the furnace only kicks on, on the coldest of days.

You want to buy one that does not have a fan, this way it needs no electricity to heat.

I think they are close to 100% efficient.

My fridge is on a 20 amp breaker.
My gas furnace is also on a 20 amp breaker.

I have run the fridge OR the furnace on a 3000 watt generator (about a 25 amp generator if did the math right). I did not try, nor need to, run BOTH at the same time. The idea is to run one for a couple of hours, then switch to the other. If you need to power both at the same time, then you I think you need about a 5000 watt generator, for a 120 volt system (again, if I did the math right).

Hope this helps.

A couple of observations-I operated pet grooming trailers for 3 years. These trailers relied upon a propane-fueled onan generator. Lots of breakdowns. Replacement vehicles are diesel vans which have a bank of 12v batteries, a 90 amp alternator, and a 3KW inverter. Lots fewer breakdowns. Easier to get service on the parts that break, cuz the alternators and inverters are relatively easy, tho costly, to replace. This is a configuration used in FEMA and Red Cross disaster response vehicles.

The argument in fuel choice seems to me to hinge on fuel storage and availability. Locally, the electric power fails pretty often (village is suing power company for this lack of reliability) and natural gas has not failed so far. Large volume, long term storage of diesel or gasoline presents some problems in safety and loss of fuel quality over time. We chose a 5KW gas fueled permanent installation for back up power, and have good luck with it for 6 years; but, as raspy points out, the engine is still basically a lawn mower motor, and is not as reliable as a truck engine would be.

Hi Bws48m thanks for the information, that gives me an idea of the size of generator I would need.

BobS I like your thoughts on a gas fireplace for heating, I have promised my DW a fancy one of these with a mantle for in the living room, but decided to replace the siding on the house first. Only so much time and money!

I appreciate the replies fellas!

Mike

Mike, I seriously doubt that you'll need 20 amps to run a forced-air gas furnace. Mine is rated at 9 amps, and heats an old 1200 square foot farmhouse with capacity to spare.

9A x 120VAC = 1080 watts. In theory, a 1200 watt generator should be able to handle that (but nothing else). In practice, though, there's a big momentary current draw when the fan motor starts. If you read the fine print, you'll find a lot of generators rated at 1500 watts are in fact 1500 watt peak, and 1200 watt continuous. And 1200 watt generators are 1000 watt continuous, etc. Buyer beware.

BTW: a couple of gas fireplaces plus an efficient wood stove saved the day after my parents had a serious garage/house fire in -35C weather. All power was knocked out for two days, but with a bit of antifreeze in the traps and these heaters, we kept things from freezing up and causing more damage. The heaters were natural gas, and were the type that had didn't require electricity to run.

Yeah, 20 amps seemed high to me also, but I went and actually checked the breaker, which I had thought was 15 amps, and was surprised when I found the 20 amp breaker. My system covers about 2500 sq ft, which may account for a larger system and thus a more powerful fan. I suspect the breaker is larger to account for the power surge of the fan kicking in, but that just a guess.

In any case, best to see what is actually called for in actual application.

+1 on checking the continuous and surge power ratings. When my sump pump kicks on, there is a big surge and you can hear the generator react to the sudden load.

OK, I got off my lazy butt and checked my breaker panel, my furnace is on a 15 amp breaker.

Thanks,

Mike

Watts law, P= I times E

P= Watts
E= Volts
I= Amps


That means 120 volts times 15 amps comes to 1800 watts.
Honda recommends you don’t run their generators more then 80% for a constant duty. That means a 2300 watt generator would run your furnace. 80% of 2300 is 1840 watts. That’s just for the furnace, I’m sure you would want to run other things along with the furnace. Figure out total watts by using the formula above.

So... how easy would it be to build your own generator? I'm about ready to junk my car. It's got a 2.3 4 cyl that runs good. Are we talking a heavy duty alternator, battery bank, and a big inverter?

There are a lot of sites on the net with free plans that show you how to do this with lawn mower engines. But for the most part they are lower amperage output, and almost always 12-volts.

I thought about making one of these for camping / portable use till my brother bought a 2000-watt generator for $125.00. for that price it’s not worth the time to make one.

I’m sure it can be done on a larger scale with larger, higher output. But it may be more cost effective to buy a pre-made one for the higher output.


A 5000 watt inverter sells for several thousand dollars. So an inverter is not a practical part of a generator. You need to find some kind of motor or alternator that puts out your desired voltage & amperage.

A home brew 12V generator is more practical than is used to be because good inverters are cheaper than they used to be...and inverters in general are better than they used to be.

I was looking at inverters a few days ago, can’t remember who it’s made by but a 750-watt sine wave inverter was $1100.00

Still pricy compared to what a 750 watt generator would sell for.

My brother has a 2000 watt generator that cost $125.00, he bought it last winter. Yea it’s Chinese made, but I would make a guess that the inverters will also be made in China.

Thanks Bob, I had no clue how to do that conversion!

Mike

A 15 amp breaker is the standard size for house wiring in Canada. That doesn't mean the furnace actually draws 15 amps. It's always best to check the documentation or contact the manufacturer.

True sine wave inverters will still be expensive. Your brothers 2000 watt generator isn't likely a very clean source of power and I doubt it's true sine wave. If you don't need true sine wave you can get a 1500Watt (3000 peak) Xantrex inverter on Amazon for the same price...around $115. You can also cover the gap and get a 'modified' sine wave inverter which does a fine job as well.

There should be a name plate on your furnace. It will list the power requirements in either watts or amps.

Home built 12 V generators.
Home Brew Power
My homemade generator "Generax 1500"
Home Made Generator

Hi harstad, I too have been looking at this situation, we get a lot of power outages here in Cairns, cyclones, flooding etc and was tired of being without power for up to a week or so and this is what I did.

1. Figure out what you really want to run and add up all the watts.
2. Buy a generator that will handle the load to run everything including A/C (in my case a 6kva)
3. Figure out your power usage less your A/C and purchase a bank of AGM battries (may be only 2-3) a decent inverter a smart battery charger and a battery monitor, your battery bank should carry you for 3 to 4 days or so before needing to be charged, this will run lighting, fridge, computers, fans etc.
4. Get a sparky to install a power point in your electrical box and a change over switch, this insures no power goes back into the grid when you plug in your generator or running from the battery.

I use the generator as a back up and to charge my batteries and for those realy heavy days to run hot water and aircon thus keeping the cost and noise down running the genset full time. There is no cheap solution to this type of power supply so shop arround. Dont forget to run a generator once a month and put a good load on it and learn to look after those battery's, a lot of people let gensets sit in the garage for years without firing them up and wonder why they dont work!!! dito for the battery's you should get about 8 years from these IF you keep them charged correctly, this will insure a good working power supply when you realy need it most. This back up system did set me back a few K but what the hell when Sh*t did hit the fan my wife,kids and myself sailed through it comfortably.

Harstad and tonyb both provide great information.

At a previous home, we added a sub panel next to our primary electrical panel that would carry the load from our back up generator (B&S 7500w) to several critical loads needed in our house (well pump, refer, propane insert fan, several lights, etc.).

At our current home we added a 3.6kw solar system that we are backing up with an AGM battery bank (three sets of 48v or 12-12v batteries). This will allow our home almost normal use - except for luxury items like the A/C, garbage disposal, dishwasher, W/D. And, we can charge our batteries while providing power to our house with the back up generator that we brought with us. During several days of storms when there is no solar benefit, the back up generator should fully charge the batteries within a couple of hours giving us ample power for overnight without running the generator constantly.

It really depends on how much you want to invest into your home. A good generator with high quality extension cords (don't buy cheap ones as they don't carry loads nearly as well - read their specs! buy cords that will carry construction loads - power tools, etc.) can easily get you through a 72 hour dilemna provided you are conserving. Battery back ups can get expensive, but are a great safeguard whether tied to a solar system or charged by your power provider. Having the ability to charge your batteries during an outage with a generator is a plus too.

Regarding using your A/C during a power outage, I would say forget it! Unless you go crazy with an overkill back-up system you will not be able to carry the load. I've watched our 'net meter' go from selling power to our utility at 2.25kw per hour to buying 4.5kw per hour once the compressor on our A/C kicked on - a 6 to 7 KW swing. You will overload most standard generators or drain your battery back up in minutes if you try to run your A/C.

That's my 2 1/2 cents anyway.

Hi Hastard,

Go to this link and learn the A-Z on backup power, this guy is realy genuine and helps a lot of people, his site is very informative and you will get a lot out of it regarding generators, batteries etc.
Follow the link and go to Tech InfoFridge and Solar

Jumping in a bit late here, sorry for that.

Two thoughts on generators while the power is out:

1) For longer term there is also a psychological factor to those around you. The power went out here for a week at a time twice last year. During the day it wasn't really much to hear the generators running. After dark fell and we'd laid down to bed the only thing you could hear was the two generators in the neighborhood. After a few nights of being kept up by them it was easy to resent them. That's one more advantage of having them set up with batteries. The ability to still provide power to what you need without drawing as much unwanted attention.

2) It's possible to modify a chest freezer into a chest fridge that consumes about 0.1 kWh per day*. Making modifications like that may allow you to use a less expensive setup, run more devices or have more head room.

*http://www.mtbest.net/chest_fridge.html an example of a chest fridge.

The fact that your furnace is on a 15 amp breaker, does not mean that it consumes 15 amps, indeed the NEC requires that circuits supplying continous loads are not loaded to more than 80% capacity, therefore if instaled to code the furnace should draw 12 amps or less, probably a lot less.

The actual draw may be determined from the manufactuerers, or if cord and plug connected, by measurement.

Running whole house or central A/C is not normaly feasible from an an affordable portable generator. Such A/C is generally 208/240 volt and is not cord and plug connected.
A sufficiently large generator could of course run the whole house, including A/C,this would require a changeover panel between the meter and the main breaker panel, unless you have very considerable experience, this should be done by a licensed electrician.
A larger portable generator could be used to power a 120 volt cord and plug connected A/C unit, either of the throuh the window type, or the floor standing style that useing a flexi duct to remove the hot air.