Generators for Family Readiness – Part 1, by Greg X.

Many of us own a generator. But how much research did you do before purchasing yours? Generator system integration into you home power design is frequently a series of tradeoffs. I’m going to cover how generators work, potential design features, trade-offs, and strategic considerations. I actually own four generators of various capacities, fuel types, and features, each for slightly different purposes. I also work doing generator fleet maintenance.

Key Components

I like to break generators down into an alternator, and engine, a DC control system, an AC control system, a fuel system and a cooling system. Generator sets are typically powered with gasoline, diesel, natural gas or propane engines. The engines typically run at 1,800 RPM, 3,600 RPM, or are variable speed. The engines will be air cooled or liquid cooled. Alternators can be permanent magnet, brushless or they cnd bedesigns that use traditional brushes. The AC waveform can be made by the alternator or byan inverter/converter. The AC frequency can be created by the engine/alternator or by the inverter converter. The AC voltage can be controlled by a voltage regulator, the inverter/converter or by a circuit in the alternator. They can be pull-start or electric start. The generator manufacturing industry combines all these to create generator sets with different performance characteristics at different price points.

All the alternators rotate a magnetic field inside a set of wires (windings) to convert the rotating energy of the engine into electricity. The rotor is spun by the motor, and the stator is the stationary copper windings that produce the electricity. The best alternators are brushless with four sets of windings, the exciter stator, exciter rotor, and the rotor and stator windings. The voltage regulator (VR) sends a DC voltage to exciter stator which passes the energy electromagnetically to the rotor to create the rotating magnetic field. These alternators can produce high quality power, they can handle the stress of motor starting surges, and can last for tens of thousands of hours with simple bearing and diode replacement. They tend to be found in commercial generators.

A brush alternator still uses a voltage regulator, but passes the VR DC energy to the rotor via brushes. Brushes wear out, but power quality is still fairly good and brushes can be replaced. Inverter generators typically use an alternator that spins a permanent magnet as the rotor to create the voltage for the inverter. No brushes to wear. PMAs are typically smaller than other alternators, but require the inverter. Power quality is as good as the inverter. Consumer household generators may also contain a simple brushless alternator that uses an extra winding and capacitor in the rotor to somehow energize the rotor. They are reliable, inexpensive, but don’t regulate the voltage very well. My brushless consumer generator produces 129 VAC at zero load and steadily drops down to below 120 VAC by teh time it reaches 2/3 load.

I also have a generator with brushes and a voltage regulator. It produces 128-129 VAC all the time from zero to as much load as I could pull from it. The manufacturer told me they set the voltage high to allow for extension cord voltage line loss. The voltage regulator can be adjusted to a lower voltage, if that is what is wanted. I plan to order a spare pair of brushes. Voltage variability on the inverter will depend on the design of the inverters. I checked the two I own and one dropped about 4 Volts in the transition from zero load to ¾ load and the other dropped less than 2 Volts in the transition from zero load to ½ load.

If you have an alternator preference, then how do you tell what kind of alternator you are looking at? Go online and download the parts breakdown from the manufacturer’s or seller’s website. Find the alternator parts breakdown. If you see brushes in the figure or parts list for the figure you have an external voltage regulator. If you see two sets of windings on both the rotor and the stator, a diode pack on the rotor, and a voltage regulator in the set then you have a commercial brushless design. If you see a capacitor on the rotor and the generator set is very competitively priced, then you probably have a brushless design without the voltage regulator. Permanent magnet alternators are primarily found on the inverter generators. If all this sounds like Greek to you and you are particular find a friend who understands electricity and generators to assist you with investigating your choices. I should mention that I’ve phoned the original equipment manufacturers (OEMs) when sales people couldn’t answer my questions.

Engines and RPM

The higher the revolutions per minute (RPM), then the faster the engine will wear out, on any given fuel. Moving parts = wear with force adding to wear. This is even a good predictor of which parts will wear out in your engine. Most medium size commercial generator sets run at 1,800 RPM. A good 1,800 RPM commercial set with maintenance (especially oil changes) can run for 10,000 hours. There are small diesels typically of less than 20 HP that can run at 3,600 RPM which reduces size and weight, but 3,600 RPM is really pushing a diesel. We typically replace our 3,600 RPM diesel engines at lower hours than in our 1,800 RPM generators.

A good indicator of engine life, independent of fuel, is the cylinder wall material. We have small diesels at work with aluminum blocks and cylinder walls that wear out quickly. Buy cast iron if you can. Our larger diesels have cast iron blocks and/or cast-iron cylinder liners. They are known for their long lives and they can be rebuilt. Engine noise is typically less at 1,800 RPM versus 3,600 RPM reducing sound attenuation cost or requirements. Running at 1,800 RPM does increase the cost of the engine, since a bigger engine is required to produce the required engine HP at the lower RPM. In the 1970s, Onan made RV generators than ran at 1,800 RPM. They were big, heavy, but they just ran no matter what the conditions. They were tough. Their newer ones run at 3,600 RPM, are smaller, lighter, but they aren’t as robust nor tolerant to high temperatures.

Fuel and engine types

If efficiency is your primary consideration, then purchase diesel engines. They operate at higher cylinder pressures that enable them to operate more efficiently than gasoline engines. If upfront cost is the primary consideration, gasoline or one of the gasoline/propane engines will be much less expensive. If life cycle cost is the primary consideration, then you need to determine operating hours over estimated life, estimate fuel costs for different types of fuels, examine specific generator fuel consumption data, and the cost of different engine types from which the cheapest alternative can be calculated. If engine life is the primary consideration, then choose an 1,800 RPM generator, whether it be diesel or propane.

Another consideration for the infrequent generator user is keeping your fuel fresh. What kind of fuel do you have around the house? Can you rotate through the fuel that you have in storage? I have propane for heat and all my vehicles run on gasoline so my generators run on gasoline or propane. My vehicle fuel storage has the dual purpose of running my generators. Gasoline must be rotated, even with preservatives, which limits how much gasoline I can store. Propane can last 30 years in a tank. I chose to purchase two generators that can run on gasoline or propane to increase how much fuel I can store without increasing how much fuel I have to rotate.

I have a 500-gallon propane tank in the ground for house heat.  I’ve also accumulated 20-pound tanks and I’ve purchased 100-pound tanks. With a bug out place, I would install a couple thousand gallons of propane storage, probably over time, as funds allow. The portable tanks were purchased, filled and stored. Typically, the larger the propane tank the more cost effective it is to store propane. The problem with big tanks is moving them if you sell your property, though I’ve read that propane companies can pump your tank out. Propane tanks can also be buried reducing the risk of losing your fuel supply from incoming bullets. Propane is less energy dense than gasoline, but it burns cleaner.

(To be concluded tomorrow, in Part 2.)




27 Comments

  1. As my power requirements are minimal, two 1984 Honda EM500 500 watt generators have charged my batteries for several years. They cost $100 each, and although not as fuel efficient as the newer generation inverter type, however the difference in price, more than makes up the difference. With the difference in price of $800.00, I can buy fuel for winter consumption that is about 50 gallons per year for next 16 years. Mine burn about the same about of fuel as a modern 1000 watt Honda, about .6 gallons will run about 6 hours with a 50% load. It completely charges a 220 ampere hour 6 volt battery pair that has a 50% depth of discharge, with a 20 amp battery charger in less than 6 hours. It turns out that this combination of generator, charger, and battery bank size is the most fuel efficient system. In other words it is a ideal match up of components that provides enough power for a laptop and lights for 16 hours a day that consumes the least amount of fuel.

    Putting on the engineer’s cap, we can extrapolate with confidence that a modern 1000 watt Honda generator could be as fuel efficient, if two 20 amp chargers were used to charge four 6 volt batteries, and that a 2000 watt Honda could charge at least eight 6 volt batteries with four 20 amp chargers. If we replace two 20 amp chargers, we could cut the number of chargers needed in half. However 20 amp charges are common, and less expensive, and with four 20 amp chargers we have redundant redundancy, and peace of mind. If we loose one 20 amp charger, we would have to use 25% more fuel, instead of 50% more fuel, if we lost one of two 40 amp chargers. Of course with 4 times the power requirement, comes 4 times the fuel needed, or about 200 gallons for 4 laptops running 16 hours a day, and lighting for 4 people for approximately 5 months during a long dark winter with little sun. If the number of hours that 4 laptops is cut in half, then roughly half of 200 gallons would be needed. Full size laptops use no more than 100 watts per hour, no more than 5 amps at 19 vdc when running complicated software, or graphics and gaming etc. A notebook uses less than half that, and a Raspberry, about 1/4th.

    If you’d rather add extra photo voltaic panels, buy them immediately as the inexpensive ones are supplied by China. I might buy directly from Renology, or Windy Nation rather than Amazon, as Amazon may not be able to ship in time, or it’s work force may get sick with the virus. The clock is ticking loudly now.

    1. I have been pricing a propane generator here at my farm. The propane company wants to see a 500 gallon tank. I pre buy 500 gallons a year and it is workable at that amount, with scheduled fill ups.. Currently I have a rented 300 gallon tank. The generator is a 22kw Generac model sold by the propane company and installed by their contract electricians. For a 22KW system, battery, with 500 gallon tank and installation the cost is $7,577. After reading this article it has become clear that I don’t know anything about what I am considering buying. Solar panels, not very efficient here, 5kw system is about $14,000. I don’t think 5kw would do what is needed.

      1. I’ve found how little power one actually needs. Electricity is one of the things we do not really need all that much of if we are set up right. However, it is most important for pumping water. It is cheaper for long term sustainability to invest in methods that reduces consumption, and dependence. A 10Kw generator will run most 220V well pumps. Find ways to reduce water consumption, and less fuel will be used. 15 gallons of water per person per day is adequate if you have an out house. This includes bathing. Pump it to a cistern and shut it down. Water for the garden might be provided with a PV direct solar water pump in the summer, and saves propane for the winter for the main well pump. Water for the garden may be needed in hundreds of gallons per day. This would consume lots of propane or gasoline, and if your 220vac well pump or generator fails, you may not have water for your garden. A PV direct pump (solar) for a summer garden, that also pumps water for the house, not only saves huge amount of fuel, but also provides redundancy. The ‘solar’ pump can be installed above the 220 pump, as it usually would not draw down the well faster than the well replenishes itself. Also make a self fill bail to haul water out of the well by hand. Simple and easy to make. Lots of You Tube videos on that.

        Btw, an antique oil lamp that is properly designed, not a modern knock off, with the wick trimmed, will put out almost as much light as a Coleman lantern.

        1. “I’ve found how little power one actually needs. Electricity is one of the things we do not really need all that much of if we are set up right. However, it is most important for pumping water. It is cheaper for long term sustainability to invest in methods that reduces consumption, and dependence.”

          Tunnel Rabbit is a true self-reliant prepper if there ever was one. If we really think that TEOTWAWKI is a possibility someday, then it seems to my way of thinking that we should be gearing our mindset to Tunnel Rabbit’s words. But, that’s just me.

          I have a puny little 3 KW grid-tied solar system but in the process of seeing just how little electricity I could get by with, I end up selling most of my production back to the co-op and I average using just 95 kWh per month. A third of that is for the refrigerator, which I could easily do without if I needed to. Another third is for the computer/electronics which I could also do without or greatly reduce by switching to a solar-charged laptop, and the other third is for pumping water, lights, and assorted shop tools. I’m hoping to cut the grid tie this year.

          Most of us are going to have to make a lot of huge uncomfortable adjustments if the SHTF. To my way of thinking, the purpose of living a self-reliant lifestyle is so that I won’t have to make many adjustments. But that’s just me. I love the adventure of it, and the independence. But, understandably, most people would find it very inconvenient.

          1. St. Funogas,

            Thank you for the endorsement. I am busted as I’m indeed hard core. I know how to go into the woods, and be just fine But I’m getting old. Once the net is no longer available to myself, then my power requirement during the winter is near zero. At that point, my small solar system will support the only thing needed for security, radios, and batteries for night vision devices and MURS Dakota Alert sensors. At that point I really do not even need a battery bank either. I’ve also lived without refrigeration for years, but currently do have a frig. It is a luxury. Save the propane for emergency heating and cooking. I am well stocked up, and no longer need money. This means I can self isolate.

            I would encourage folks to take St. Funogas’s attitude towards all this inconvenience, and see it as an adventure, a field training exercise, and not as a horrible inconvenience, but a pursuit of Independence, and freedom. If we could only get rid of property taxes….

            About your 3Kw system. In my book, that is plenty. Get ready to go off grid entirely by purchasing an MTTP charge controller rated for your system’s voltage of for a maximum of 150vdc, that can quickly charge two or more 6 volt deep cycle batteries. Run appliances during the day when the panels are producing, and gain a 30% increase in efficiency, and reduce the number of cycles on the batteries. Of course, more batteries is better, as it would not only provide more power, but because the depth of discharge can be greatly reduced, and so the batteries bank will last much longer. However the battery bank should be recharged fully by the end of the next day, and we need enough power from the panels to make sure that happens. In the North West, size the battery bank so that the rated output of the panels is collectively 2 to 4 watts, for every 1 amp hour of battery bank capacity. For example if all you have is two 6 volt batteries that are rated for 220 amp hours, have at least 44o to 880 watts worth of panels. Power consumption should ideally be limited to 25% depth of discharge, or about 12.5 to 12.4 vdc, or twice that for a 24 volt system. There will be times when the weather will not allow any sun to charge the batteries. During those times when depth of discharge must be deeper than 50%, or down to 12.1 vdc, and that is okay on rare occasions, that might last for a week or so. This why a small generator back up is good idea. There may also be an unexpected need for extra power to perform an emergency project. Older small generators are low compression, less expensive to purchase, and runs fine on old fuel. Ether may however be needed to get one going on old gas, and then it will run just fine. Usually all that is wrong with an old generator is that the carburetor needs to be cleaned out with carb spray. Old generators are easy to work on, but noisy. Just stack blocks, or rocks around it, and provide a roof.

            This is what I’ve learned running my own system in the cold dark NW, and includes a survivalist’s strategy of long term self sufficient living strategy. It differs from the guidelines usually recommended.
            I could get St. Funogas off grid at a low price, and at warp speed. Just ask!

      2. Jima,
        I believe diesel is a better way to go for a long term collapse. Diesel will be the most plentiful in bad times, as it will be produced in quantity for trains and large trucks, and it stores for a very long time. It is also not pressurized, and might be found and carried home in smaller quantities, and used in diesel tractors and trucks as well as the generator. Gasoline produces more energy than propane per gallon about 20% more. Diesel produces a bit more energy than gasoline. Propane is more popular for a variety of reasons, but it is not as practical. Diesel generators might cost a bit more tho.

        1. G’day,
          We had a test run recently with the bushfires in our part of the country, diesel got sucked dry pretty quick (fire trucks, farmers trucks/tractors, commercial fishing boats, military trucks, prime movers (goods transport semi-trailers), earth moving equipment (for making fire breaks etc etc) fuel tankers didn’t come through whilst roads were blocked and fires closed highways.

          This was somewhere around 400km of coastline within a couple/few of linked (depending on fire status) “quarantine” zones (no travel over the mountain range bordering the coastline).

          Australia has these fuels commonly available at service stations E10 (ethanol), 95 and 98 octane unleaded, LPG and diesel.

          Before the end of week one (1) we were lucky to fuel up.
          One (out of the way station) was on its last dregs of diesel (gone by next day so no diesel in area), some (9 outlets within 40km radius) still had 95/98 (one or the other or not at all- 95 ran out before 98 probably due to price difference) most had E10, almost all had LPG…and remember people were trapped in the area so no one was expending great fuel reserves on “bugging out”.
          Diesel fluctuates in price between $1.42 to $1.68 per LITRE this year.

          1. merlin,
            Good to get a report from Down Under. We might see something similar here, except our personal vehicles run mostly on petrol, so we could run out of petrol first. I did get a chance to drive a 1990 diesel 4WD Hilux with a crew cab once in Brazil. Loved it. But we do not have any in this country. We got ‘jipped’. You gott’em and the Canadian’s gott’em, but we got stuck with the petrol version on account of some silly compliance law that required the removal of the necessary sulfur out of the fuel, making difficult for motors designed for it to meet diesel emissions certification, and still run without that lubrication. So the vast majority of our vehicles run on petrol. They should reserve the diesel for trains, and tractor trailer food delivering trucks, yet I doubt we’ll have that in place, before it is gone from local stations.
            We have few logging rigs, and lots of heavy equipment around here that will make for good alternative transportation, and few lucky ducks run diesel is their large pick ups.

            Please keep us advise. I find it very interesting.

        2. Mate, predominatley petrol here too, I’d hazard a guess 7 (maybe 8?) out of ten vehicles that pass our driveway are petrol powered.

          Additionally due to (amongst other reasons) service stations being closed some days because the staff were more concerned about saving their homes, friends/neighbours homes etc than attending “paid employment”.
          Maybe that’s the only reason stocks were not depleted within the first couple/few days, during which time queues were up to fifty vehicles long (as opposed to a busy day meaning at most a two (2) vehicle lineup, but those days aren’t common, we generally drive straight up to bowser).

          “Evacuation centres” were overflowing much more quickly than people expected.
          Happy to answer your questions if I can, ask Jim/Lily for my email.

          1. Hi Merlin,

            What is happening there will probably happen here. Today, this country begins to really fall apart. There is talk that the Federal government will take control of food delivery’s under guard, and rationing is probable as those in the supply chain do not show up for work and people go nuts. We are a lot less civil in this country. Guns and ammo are being sold like crazy in some cities. This is looking very grim indeed. I’m well prepared and in a very safe place.

            tunnelrabbit007@gmail.com

      3. I don’t own a whole house generator because of the potential fuel bill. I did the math once and the whole house set can burn quite a bit of fuel. Online a 22 kW generac was listed to consume 2.5 gal per hour at 1/2 load, or 11 kW. Powering a house you are likely to have a lower load, but even at say 1/4 load you would burn over 1 gal an hour or 168 gal in a week (24/7) at a cost of at least $250. Remember its oversized for a small number of high demand appliances so it burns more fuel. Then ponder the power going out while you are on vacation, the set runs for a week or longer, and you come home to a tank down 150 gallons. If you have a critical need for constant power, need power 24/7, need power for farm operations, go for it. Buy a large propane tank though, especially if you have frequent power outages, want to run the set after the SHTF, live in a hot area where A/C is essential, etc. I’m just going to throw away the content of my freezers if the power goes out while I’m on vacation, or maybe my son will come over and fire up a small generator to run the freezers for a couple hours each day. Your $7500 bill buys many freezers full of food. It really depends on your situation, needs, knowledge of electricity, etc. what works best for me may not work for you.

    1. John,
      I didn’t provide specific models or manufacturers initially because there are so many perfectly functional generators for sale. Follow the recommendations in the full article. Brands and models will depend on whether you need diesel or gasoline/propane. How many KW do you need? House or Business? How much money do you have to spend? Backup power or many hours a day? Auto-start or manual start? Consumer model or commercial? What kind of loads? Answers to all these questions affect who makes models for those capabilities.

      For all the generators recommend you stick with known engine manufacturers (see my choices below for a caveat to this). The engines have moving parts that wear out. A new diesel engine can be tens of millions to design and even gas engines require some skill and investment between metallurgy, emissions, etc. Briggs and Stratton, Honda, Kohler, Yanmar, Kubota, Cummins, there are alot of engine manufactures world wide. I know of a small manufacturer who ordered a small Yanmar diesel knock off engine from China. It was junk and unusable. I also know of manufacturers who fabricate high quality engines/generators in China.

      My first generator many years ago was a Porter cable generator with a Briggs and Stratton generator engine. I suspect Briggs and Stratton made it for Porter Cable but I don’t have proof. It has a good supply of parts and phenomenal motor starting. The constraining factor for consumer set motor starting is engine output, as the motor starting is so brief they minimally heat up the alternators. I suspect that the B&S Generator engine is designed to push out extra horsepower for short duration for the starting. I don’t know if they still make similarly designed consumer sets or not.

      I wanted a gasoline/propane set next. I saw the Champion 7000W dual fuel at Costco. The price was right so I investigated. I downloaded the manual, looked over the parts breakdown, read about maintenance requirements in the manual, read the reviews, and called the company and talked with their technicians. The technicians gave me good answers. Sometimes they had to find a more skilled person (maybe a quick call to engineering) to answer the harder technical questions, but the answers were good. I was told they keep a store of spare parts here in the US, for what its worth, but important to me. The set has served me well. Later I purchased a 1800W inverter set and a 2800W inverter/propane set. Motor starting isn’t good on their inverter sets compared to a standard alternator, and the 2800 has trouble starting the camper A/C. For the price I was able to purchase multiple sets sizes that mainly run during infrequent power outages vs buying one honda. The cost of a propane honda 3k inverter gen would have bought all my generators. I exercise the sets with my yard trimmer, electric chain saw, and space heaters. I made tradeoffs. I also try to avoid paying a premium for a brand name unless there is a decided performance need or advantage. I took on some risk with that first set. I could have put a propane kit on my existing generator but I really wanted factory installed propane capability which limited my options.

  2. Beware that if you need to do ANY high frequency communications, an inverter generator will likely wipe out that capability while running with broadband radio frequency interference. There are solutions, but they are costly and require some engineering knowledge. Voltage-regulated generators are much quieter but still have some interference. Older style generators with only mechanical governors won’t have nearly as good voltage regulation…..but make only spark-ignition noise. BATTERIES can be charged and then used for HF communications after shutting down the broadband noise transmiters, as an alternative.

    1. Good point. I have an 1kw inverter little briefcase thing but it’s mostly for the fridge. The traditional 3600rpm thing hooked to the generator disconnect panel 2 phase for the pump also runs the house including the fridge just at a much higher gas rate. So we do that 8-10am and 6pm-8pm to get the deep freezers cycled after meal times.

      But the ham radio is 12V. I will not be running a power supply off a generator. I’ll just use the deep cycle battery from the chicken run fence charger for the ham radio.

    2. Is the inverter generator emitting HF radiation through the case or is there noise in the output waveform that causes interference to the radio? Could one put a Faraday cage around the generator to suppress the noise?

      1. Greg: it turns out to be a combination, but the biggest problem is that the inverter acts like a transmitter, and the extension cord like an end fed antenna.

        If you Google around, you will find some quality work that shows how to get around this problem, but it will set you back about $150. Look for people who have actually done careful studies.

    3. I have run radios directly off PV panels. A Baofeng only requires a 10 watt panel to transmit with 4 watts. I use a transformer in between. Here is an inexpensive, and fully adjustable power supply that can step down any voltage DC from 50vdc to any desired voltage lower to 1vdc at a maximum of 5 amps. It will maintain a minimum voltage by reducing current. And Current can be limited as well by varying the voltage. On paper, at 13.8vdc x 5 amps = 69 watts of power. I suspect a mobile could put out 50 watts or less, powered by a 100 watt PV panel in full sun that produces a maximum of 5.5 amps at 19vdc. Of course the radio would do well with only 10 to 25 watts out, and would be more reliable as solar conditions always change. A 100 watt panel would run a Baofeng in cloudy conditions. Set the Commo Window for high noon for best results.

  3. Very good information and advise. If you have some mechanical and electrical aptitude, the best thing to do is to get an older 240 Volt 1800 rpm Onan. They’re very reliable and darn near bullet proof, but they’re getting bought up. Also, there are a lot of MEP803a military generators available because of the many years of war in the middle east. They are 1800 rpm diesels and are very quiet…sounds like a car idling. I have some of each of the above, and I will tell you first hand that they put any box store generator to shame.

  4. A word of caution on the military MEP gensets. The larger ones, ie 10 kw and up are a nightmare to work on. There are so many safety devices on them, over voltage, under voltage, over frequency. under frequency, over temperature, oil pressure and all are tied together. trouble shooting was changing the control boxes out and they are hard to find and expensive. If you have one of these I recommend you disconnect all of these and add a Murphy Switch, this protects against low oil pressure and coolant overheating. After market universal voltage regulators are easy to install and cheap.

    1. If you are trying to troubleshoot a MEP-803 you can find the maintenance manual online, 9-6115-642-24 (it also contains a wiring diagram and schematic), and for parts 9-6115-642-24P. The 803 has circuits to protect the user and the generator set from damage. Potential sources for the black box control box parts are TRC in FL, and Afcon Products in CT. They will be expensive. You might need to study the wiring and bypass the circuits. Make sure there is a fuse on Q1/Q2 between the main alternator and the VR. It protect the alternator windings from a VR failure mode. The engine was made by lister petter, not sure of the manual number. There is a company in England that still makes the lister petter parts. Beware, all the DoD sets 15 kW and up will be three phase, 120/208 or 240/416.

  5. When it comes to generators, the smaller and simpler the better. Most important is to size the generator to feed your power needs. Oversizing a generator will only waste fuel, and in case of Diesels, possibly wet-stack. Running a 60kw generator to feed a 3kw load is an example.
    All my generators are diesel, since all my vehicles are diesels. I find the best generators are the military MEP’s from 10kw on down. These use relatively simple controls, most parts including aftermarket regulators are available. The smaller 2 and 3 kW units also have pull starters, so you wont have to worry about maintaining any batteries. The Mil manuals are excellent, and will allow you to troubleshoot and repair these gen sets.
    If you buy surplus generators, you should have some electrical and mechanical knowledge, otherwise you may wind up being disappointed. Hiring someone to repair or maintain your generator will be very costly. Lastly, stay away from any of the modern generators with all digital controls and digital control panels. While these are great when spares are available, repairing one of these in a TEOTWAWK
    I situation will be next to impossible. These digital panels frequently cost in excess of U$D 1K and have a delivery time of weeks to month. Keep it simple and reliable – KISS principle!

  6. RT ,,after 45 years off grid homesteading and ranching ,i agree with your assessment,my takes,, ,i prefere diesel power ,i have made my own fuel using waste deepfryer cooking oil from the quickstop gas station and have grown canola and pressed it for oil , running a gen set on it is a no brained to set up ,we also run trucks and farm tractors on it ,years ago we were in a bind money wise and ran everything on strait veg for five years till we got back on our feet ,now I’m not talking about biodiesel that takes outside inputs , we still have 30 55gal drums of oil stashed out back ,20year old oil is still useable if sealed and kept cool ,i opened a drum just last week that was that old and was going to dump it in the fire pit but it looked good so put it back in the stack (needed a drum for a project)as for gen sets all of mine came from industrial auctions ,all are 20,000 hr units the highest time unit I have was 9,000 hr one had under 2,000 hrs ,some came from light towers some were backup at job sights ,all have multiple voltage,(i like)
    A 4 light lighttower have 4.5 to 6 kw most likely ,the big three Japanese small diesel engines have a lot of interchangeable parts ,i like them ,, i know of a rebuild using parts from three different manufacturs, I also like the 100percent duty cycle ,, I run the shop with 25kw ,the house has 1cylinder 3kw 12v to the battery bank , for the well ,washing machine ,freezer ,and every thing at once a gen from a lighttower 6kw ,,remember that 100percent duty cycle,?
    The cost?the 25kw in a sound cabinet ,900dollars it looked new 2200hrs,,, light tower fresh off rental service 4 to 6 kw on a trailer ,800 to 1400 dollars each (we have 3)1400hrs to 4000hrs ,the one cylinders were from road warning signs , 12v to batteries to inverters ,run 24hrs on 2 gal,x2.5 to 3 kw cost 300 dollars each ,again 3 to 4 k ,,nice thing is on the electric side a heavy duty 100amp alt from a Chevy will work
    All are plug and play. All but the 25 came on nice trailers

    I encourage everyone to think out of the box

    1. It looks like you have the electrical side of things covered well and if you do, please share where/how you find these items if you feel comfortable in doing so. It might be a topic for an article submittal.

      My story….Several years ago I told a buddy, thinking I would get his assistance in searching for a low RPM Lister which he didn’t know about until I mentioned it. He found one and did an end run and bought it for himself. That was literally the last one that appeared in our area Craigslist. There is a lesson in that story! Take heed before responding.

      We are now OK with generator supplied power for home as I was able to get a deal on a 7kw diesel with .8 hrs on it along with our 5kw gasoline genset that we purchased new 25 years ago, however I would like to purchase a quiet economically priced small diesel AC/DC genset that is not terribly heavy for mobile operations.

  7. I have a kubota 14kw diesel 1800 rpm…consumes .7 gallon per hour …could of got bigger for just alittle more,but looked at fuel consumption..hooked to house with a frankenstein switch..I mean,how lazy do you have to be that you cant go outside to pull the switch from grid to gen power & turn the key on to fire the gen up. These automatic systems are not needed unless you’re on an iron lung or something .

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