Choosing the Right Backup Generator

honda generatorOkay...I'll admit it.  I'm all about energy independence, and fuel powered generators are totally dependent on some source of fuel.

However, even an energy independent homesteader should have a good backup generator on hand, and then use it as little as possible.  How so?

Generators and Energy Independence?

It's a principle called redundancy.  Another way of wording it is, "Don't put all your eggs in one basket".  The point is that no matter how well you have set up your solar, hydro, or wind power system, things can go wrong.  And when things go wrong, you need a backup.

Cloudy winter weather is the factor that most often causes folks to run a generator.  You see, we live in an area that has very cloudy winters.  And even with an oversized solar system, it's challenging to make 100% of your power from the sun up here.  A fuel powered generator gives us a relatively inexpensive way to supplement our solar power production during those really dark and cloudy 2 or 3 winter months.

And the generator also enables us to live with a much smaller (and less expensive) system than we would need if 100% of our winter power had to come from the sun.  If you can afford that size of system, sweet!  We would too if we could (and we keep working in that direction).  But if not, then a generator is your key to maintaining a normal lifestyle when your small solar array isn't keeping up.

And remember, in a properly designed system, you'll only be running the generator for several hours every week to 10 days.  Many folks don't even run their generator that often.  It just depends on how sunny the weather is, how much power you are using, and what size of solar array you have.

For me, running a fuel powered generator is treated as a luxury that I don't have to have.  In other words, if for some reason I could no longer buy fuel, even during the darkest part of the winter my solar panels would produce enough power to run the things I need.  And for 9 months out of the year, I'd be living completely normally.

Our goal for being off the grid has been to produce all of our power from renewable sources (solar, hydro, wind, wood gas, steam, hydrogen, etc) and not rely on fuel sources that must be purchased (gasoline, diesel, propane, etc).  But particularly in northern climates, it takes time to achieve that unless one has a bundle of money up front to invest in a very large renewable energy system.  Because of this, many people getting started with renewable energy begin with a small basic system and build up from there as budget allows.  Many times this initial system is not "renewable" energy but rather "alternative" energy as it involves the use of a fuel powered generator, to a greater or lesser extent.

Starting With a Small Basic System

When finances are tight, I suggest taking your off grid transition in steps.  The first step is what I call the Small Basic System and a generator plays an important role in this type of system.

The smallest and most basic system consists of a battery bank with an inverter/charger that uses AC electricity from a fuel powered generator to charge the DC batteries and then converts the DC power from the batteries into AC that is useable in the house.  This arrangement means the generator is only running periodically to charge the batteries rather than running continuously whenever power is needed.

As soon as the owner is able to afford it, renewable charging sources are added and perhaps a larger battery bank installed.  Once enough renewable sources are added, the generator is used less and less until it takes on the role of only a backup power source.

How to Choose The Best Generator For YOU

When deciding which generator to purchase, there were a number of items I took into account (not necessarily in order of importance):

  • Fuel Type
  • Mobility
  • Power Production
  • Cleanliness of Electricity
  • Fuel Efficiency
  • Price vs Durability vs Amount of Use

Fuel Type
Other than the durability issue, there are other factors to consider when choosing which fuel type.  Diesel engines have been successfully run on a variety of different fluids, including vegetable oil, hydraulic fluid, and used engine oil.  There is a process involved in preparing it for use, but it is very nice to have other options that could be less expensive or easier to get during hard times.  Diesel is also less volatile and doesn’t spoil as easily.

While I took all these issues into account, the conclusion I came to was that in my situation, they didn’t overcome the first issue mentioned above.  However, for some people it might.

Mobility
Gasoline generators are often more portable than a heavy duty Diesel unit.  If your generator needs repair that you can’t handle at home, it is much easier to move a 5 kW Honda than an 8 kW Diesel, unless you have the equipment to do the job easily.  Maybe not a major factor for me, but still something to take into account.  On the other hand, you probably won’t be needing to have your Diesel repaired if you take care of it.

Power Production
For generator size, I chose to go with 5 kW.  Too small and you won’t be able to use the valuable run time of the generator to multitask and accomplish all your big energy consuming projects while charging the batteries.  Too large and the unit will not only be overly expensive, but may also use a lot of fuel while wasting much unused electricity.  So for me, 5kW is a good compromise.  For many, a little larger may provide an extra margin of power.  And it can be difficult to find good Diesel generators smaller than 8 kW.

Cleanliness of Electricity
Low end generators often have cheap electrical parts that produce poor quality electricity.  This can not only be hard on equipment, but can also increase the amount of time required to charge one’s batteries.  Because of complicated reasons that only an electrical engineer would fully understand, poor quality electricity cannot push as much charging power out of a charger as good quality sine wave electricity.  Companies such as Honda and Yamaha have come out with generators equipped with an inverter so that  they can produce pure sine wave electricity.  This is a very nice feature, but it also comes with a price tag.  Many of the good Diesel generators have quality electrical components that produce clean electricity, so cheaper gas models would be the main culprits to be concerned about.  I have heard of “Honda” generators being sold by large chain stores that do indeed have a Honda engine, but the electrical components are greatly inferior to the “full” Honda models.  Buyer beware!  If it looks too good to be true, it probably is.

Fuel Efficiency
Diesels generally win here, but gasoline models with inverters built in (to produce sine wave electricity) are often able to lower RPMs to run only as fast as needed to produce the amount of power you are consuming at that moment.  That means fuel savings and less wear and tear on the engine.  We compared two large generator’s fuel cost to operate.  One was Diesel and the other was propane.  The Diesel won hands down.  But that was years ago and with the price of fuel fluctuating the way it is, who knows what it would be now.

Price vs Durability vs Amount of Use
If I had an unlimited budget and could easily afford the best and most durable generator, then I probably would have chosen a different model.  But since I am on a limited budget, the price was certainly a major factor in the decision.  On the other hand, I am a firm believer in not buying “junk”.  It ends up wasting more money in the long-run.  So for me, a deciding factor in this dilemma was the amount of use the generator would get.  Since I will only be running it periodically during a few months of the year, it could take many years to wear out a good average generator, if properly maintained.  If, on the other hand, I it would be used in a generator only application which would require extensive use, I would go for the most durable unit I could afford.

So far, we have been talking theory, but what does this mean in real life?  A good quality Honda gasoline generator, for instance, I would consider to be in the “good average” generator class.  It is good quality and reliable and if taken care of can last for many years under the kind of intermittent use I would be giving it.  For the high-end very durable end of the spectrum, I would go with a good quality Diesel generator made by Kubota or Isuzu or similar brand.

The Final Verdict (for me)

So you are probably wondering which generator I ended up going with.  Pleas bear in mind that what I chose is NOT necessarily what would be best for you.  Your needs and circumstances may be different.  But here's what I chose and why I chose it...

A good Kubota Diesel would have been my first choice.  A Honda inverter model (such as EU6500is) would have been my second choice.  But when I plugged in the price vs durability vs amount of use dimension, I changed my mind.  My final choice was a Honda EM5000SX.  No, it isn’t an inverter model producing pure sine wave electricity, but since it is a 2011 model, it has an updated voltage regulator (iAVR) and other features that reportedly produce fairly clean electricity.  When running hooked up to my system, the charger is producing full power.  And I have yet to find a piece of sophisticated electronics that don't "like" my generator.  Works for me!

And as far as fuel efficiency, I am sure it uses more than an inverter model and probably more than a comparable Diesel, but its only .75 gal./hour at its full rated load and slightly more than .5 gal./hour at half load.  Not as good as my Dad’s 12kW Diesel (.5 gal/hour at 5-8 kW) but still pretty good.

 

question1-trans  What type of generator have you had good service from?
(let me know by commenting below)

20 Comments

  • Avatar

    Mike Sexsmith

    Reply Reply June 16, 2015

    Hi Nick, First of all, let me say thank you for the battery article you did. It helped me pick out something longer-lasting than the Trojan L-16s I have been using. I ordered a nice 938 AH battery that should arrive next week.

    We have been using a Honda EUi 6500 Generator for almost six years now with no trouble whatsoever. First two years we ran gasoline, but then I sent the carburetor in to US Carburetor for modification to run on Propane. I also switched over to 100% synthetic oil at the same time & sure glad I did! Oil stays very clean & goes much longer between oil changes. It also starts very easy,even down to zero degrees was no problem... We have about 500 hrs on the generator now, so averaging about 90 hrs per winter... It was a good choice that I would make again! Take care, thanks for all your hard work! Mike Sexsmith

    • Avatar

      Jess

      Reply Reply January 8, 2018

      Thank you for your comments. I am just starting. I purchased a Onan diesel 7500 generator that came off a 2002 Rv that burnt down. The generator was mounted in the front of the rv and pulled out to work on it so it was not burnt in the fire. IT is the quiet one with a 3 cylinder cummins engine.

      My questions are. what do I need to hook up to it in order to charge and to run power? Is all that in the generator or was those needed items located in the RV?

      If there is someone that could guide me in this venture and, make it simple for a simpleton, it would be be greatly appreciated. thanks Jess

  • Avatar

    Johnny Gregory

    Reply Reply June 17, 2015

    Hi, Nick,
    Thanks for a good, well-thought out article which confirms my recent buying of an older Honda EX4500. I may look into updating its voltage regulator as you mentioned newer ones have. Good info.

  • Avatar

    Johnny Gregory

    Reply Reply June 17, 2015

    Hi, Nick,
    Thanks for yet another great article. It confirms my recent purchase of a used Honda EX4500. I will look at its year and see about upgrading its voltage regulator for cleaner electricity. It does seem to take longer to charge batteries using a generator and battery charger so maybe you're onto something there.

  • Avatar

    Kalon

    Reply Reply June 17, 2015

    Thanks Nick for the valuable info. Will be very helpful with our future purchase of a generator. Looking forward to future articles. Thanks again.

  • Avatar

    Donn Leiske

    Reply Reply June 18, 2015

    I just bought a dual fuel (gas and propane) generator from Costco. They have a sale until 7-5-15. 7k generator, electric start. Works great. $650. http://www.costco.com/Champion-7000W-Running--9000W-Peak-DUAL-FUEL-Generator-wElectric-Start.product.100112008.html

  • Avatar

    Paul Williams

    Reply Reply June 4, 2017

    I own this generator and am very happy with it. It is currently on sale at Costco this month.
    https://www.costco.com/Champion-7000W-Running--9000W-Peak-DUAL-FUEL-Generator-wElectric-Start.product.100220385.html

  • Avatar

    Barry Miller

    Reply Reply June 4, 2017

    Hi Nick, One item to take into account if choosing a diesel or gasoline powered generator is that as the sulfur has been reduced in most diesel products and with the addition of ethanol based product in gasoline, both of these supply sources are experiencing breakdown in the product quality/age much faster than we have seen in the past. If you are storing diesel or gasoline for extended periods of time with little volume of use, you may be setting yourselves up for product quality issues when the generator is needed the most. Having spent a career in the oil, gas and propane industries, I always recommend propane as a "best choice " for generators as you will not experience product breakdown, temperature cloud point issues or "gelling" , nor the water and moisture based issues with the new ethanol gasoline over long periods of storage . For a seldom used generator, propane as a fuel source is your best alternative in my opinion.
    As for generator size, I run (2) of the Honda 2000 inverters and utilize the factory supplied companion wire which allows me to turn both generators into one 4,000 watt inverter generator. It really gives me all open options to run a smaller 2kw on lighter loads or the 4kw which can also handle my well pumps (220 ) requirements while still having the inverter protection for all of my sensitive equipment.
    Just two extra ideas as to how and why I chose my systems that may be valuable to some of your readers. I enjoy all of your articles and have been a reader and supporter of yours for several years. Keep up the good work as you really provide good sources of ideas to all of us !
    Thank you.

    • Nick Meissner

      Nick Meissner

      Reply Reply June 4, 2017

      Hi Barry,

      That's a good point about fuel stability issues and propane. I use PRI-G to stabilize gas and PRI-D for Diesel. Have had amazing results with successful storage for years in hot humid conditions! But I totally agree that today's fuel is very volatile, which is where propane shines!

      Perhaps my view of propane is shaded by the difficulty I've had in finding quality propane generators for a good price. At least from what I've found, to get into a quality model, the price approaches or even surpasses that of a comparable Diesel model. Maybe I'm looking in the wrong places, but I have a hard time justifying the extra expenditure for a fuel hungry device that will be used so little and doesn't get me truly independent.

      But your point is well taken, that a generator which is used very little is even more susceptible to fuel degradation and issues. Just wish I could find high quality propane options that could be had for a price comparable to gasoline models (maybe I have a suspicious mind, but I'm wary of the aftermarket tri-fuel conversions and understand that in many cases they void the warranty). Any ideas?

      Thanks!

      • Avatar

        Barry Miller

        Reply Reply June 4, 2017

        I understand and agree with your concerns. I have always felt that most generator warranties are very short informally only several years on average and therefore not a great concern for my purposes. You are correct that you will void the warranty to convert to propane on many brands. Because I do all work myself, I have a better confidence level than most on the operations. For me , the fear of poor product quality on diesel and gasoline drove me to the propane generators. At my farm, I have the luxury of a 1000 gallon buried propane tank running a regulator vapor system to the generator as well as a liquid line hooked to a refilling station so that I can refill my own cylinders under any condition which allows me a greater flexibility of use. During my energy career, I have seen product degradation in diesel start in less than 30 days. The use of treatment is a must in diesel and gasoline for any extended storage tanks. Propane supply does take a lot of concerns of quality out of the picture however your trade off is the propane conversion concerns. I just have seen too many diesel generators that sit at people's homes and never get run and then when they need them the most, we as their fuel dealer are the bad guys because their product and tanks are degraded. It's a rough situation and very difficult to fully clean the tanks once this black slime and moisure situation is present within the supply tanks or cabarators. It's a trade off for certain.
        Thanks .

        • Avatar

          Mrs P

          Reply Reply June 5, 2017

          Thank you to both Mr Nick n Mr Barry for all the detailed info about generators, I have learned such much more!... I have been looking to acquire a generator as well!...my question is what brand name is best quality/performance:durability for a propane generator?...thank you for your reply.

    • Avatar

      Emily

      Reply Reply November 13, 2017

      Hi Barry & Nick - Would an 8HP propane generator run more QUIETLY than an 8HP gasoline version? Thanks for such a great thread. 🙂

  • Avatar

    Joe

    Reply Reply June 4, 2017

    We've been using our Honda EU6500i inverter generator since 2008 and are very happy with it. We bought it for our last country home that was on grid but experienced multi-day grid power outages every winter(3-5 days were common). The EU6500i gave us the 220 power we needed to run our well pump and a properly installed transfer switch allowed us to power the rest of the house. We were vigilant about rotating our 20 gallon fuel supply so that stored gas was never over 30-40 days old. In the winter, I would increase fuel storage ahead of forecast major winter storms.

    When we bought that home, it originally came with an off brand budget generator with a modified sign wave(dirty power). Certain electronic devices in the home would not function properly on modified sign wave power. After doing much research which led to the purchase of the Honda EU6500i, I was pleased to see that the clean inverter power meant that we were able to enjoy full functionality of our home electronic devices as well as having a much, much quieter generator.

    We are very close to breaking ground on our totally off-grid home on a new property. We will continue to use our Honda generator for those cloudy winter periods where we may need to periodically bring the battery bank up to a full charge. We would like to look at diesel or propane options but in order to spread out expenses, we'll continue using our very reliable Honda EU6500i in the short term. Once we gain some experience with our new off grid system, we'll reevaluate the generator issue and see if we need to make changes.

    I agree with the points made that proper fuel rotation or storage additives are a vital but often neglected part of managing a back-up generator. I label each fuel can with the date it was filled so I know when it's time rotate it out. Also, we all must consider the potential for future uncertainties where fuel may be difficult to obtain and have a plan to cope with that possibility. Choosing the right generator is a very individual choice since each person will have their own unique needs and circumstances. Thanks for giving us your thoughts Nick and giving us this forum to discuss our experiences.

  • Avatar

    Jeff M.

    Reply Reply June 4, 2017

    I know this is rather long but it's full of information. You are welcome to use it, edit it or not print it at all.
    I bought a new Coleman 5KW generator with a 10HP Tacumseh engine, (Which is out of business now.), from Sam's club in 1998 while living in Florida. Even with all the storms there, we actually never used it. We moved into a new manufactured home in West Virginia in the summer of 2001 and it took 3 weeks to get our power hooked up. We ran that generator 24 / 7 for those 3 weeks to run fans, freezer, refrigerator, window A/C, TV's for the kids and ourselves ect. Gas was $.69 a gallon so fuel cost wasn't an issue then. I went through 12 Qts. of oil for 20 oil changes in that time but it was well worth it. At 1/2 load, it would run 12 hours on a 5 gallon tank of gas. Where we are, we can't get natural gas without paying for a main trunk line too. That generator ran everything that we needed then and it had a fairly clean signal. I hooked it up from the 240 VAC twist lock plug out through into the meter box on the house so it would drive both sides of the breaker box and the house at 120VAC each. The only place where we ran into trouble was if the freezer and fridge were both running when I turned on the coffee pot. The voltage and frequency regulation was strictly by the engine speed governor. If I lugged the engine below the full governor speed, the AC frequency would drop below 60HZ as would the voltage drop below 120VAC. Both are really hard on compressors, motors and electronics. I went crazy for years when the power went off, running around the house with a volt meter whenever my wife would cook meals using 2 or 3 hot plates or I wanted coffee. If we shut everything off, we could even make a tank of hot water as it was a 240VAC X 3.5KW tank. About 7 years ago, I inherited a moderate sum of money with which I bought a good used car and a new Troy Bilt generator. About the same time, I was scheduled for another back surgery and knew that I wouldn't be able to pull start that 10HP engine anymore. I bought a larger 7KW unit as it was the smallest one available to me with electric start. It has a 5 minute overload capacity of 10.3KW, and has better regulation than the Coleman unit had. It comes with a "wall wart", (transformer), trickle battery charger that the directions say to leave plugged in full time as it shuts itself off when the battery is fully charged. The Chinese made 12VDC X 18AH gel cell starter battery finally died after 6 years. Lowe's, where I bought the unit, wanted $95.00 for an exact replacement. I was able to buy a 22AH physically identical, American made, replacement from Amazon.com for $44.00 plus free shipping. I have the unit's output wired into my house now through an isolation circuit so that when the power goes off, which it often does especially in the winter ice storms, all I have to do is flip a few switches to isolate my system from the mains and flip another to start the unit up. It's stored and ran in my DETACHED out building which I wired with 8 gauge copper wire into my main panel for this reason. NEVER, EVER run a generator in a garage or room that is attached to your house regardless of how well you think it's sealed as carbon monoxide can still seep into the living area unnoticed and kill you. My secret is your secret. MAINTENANCE! I change the oil spring and fall whether they run or not as motor oil will absorb moisture out of the ambient air. This combines with sulfur in the oil to make a weak sulfuric acid which is rough on aluminum engine parts and bronze crankshaft bushings. They run no more than 40 hours between oil changes. Good night, Jeff M.

  • Avatar

    Jeff M.

    Reply Reply June 4, 2017

    There wasn't enough room to post this in my other comment but check this out. It may interest you. Jeff M.

    http://cyclonepower.com/

  • Avatar

    Ken

    Reply Reply June 5, 2017

    Interesting, Your comments and the comments of readers that follow.
    We have two 10 Kw Kohlers on propane.
    They are permanently installed in a room off our shop,
    are doubly muffled, low speed and can be called from our house.
    You are correct in saying the bigger the system the less you will use the genset.
    They get used more for heating the shop than for electricity.
    We do have grid here and I can buy a KwHr for 11 cents incremental cost.
    The low cost is compliments of the Grand Coolie Dam near us.
    To generate a KwHr by the gensets costs me 30 to 40 cents/KwHr depending on the price of propane.

    Appreciate your interesting page,
    Km

  • Avatar

    Allain

    Reply Reply June 5, 2017

    Hi everyone....my generator is a telecom genny that I picked up for $300...a 12 kW head mated to a 9.9 HP Deutz engine....it produces up to 6 kW with that engine....at 1800 rpm..all it needed is a voltage regulator and outlets....it is worth that much in scrap metal...this was a fun project...

  • Avatar

    Phil D

    Reply Reply July 3, 2017

    Hi Nick. An interesting article. My wife and I, now both retired and in our mid 70s have lived off grid fore 33 years. The first couple of years we used kerosene lamps and Coleman lanterns. Then we got a 650 watt, used Honda generator. Wow, bright lights and a TV. It lasted 4 or 5 years, with regular oil changes, being used every evening for a few hours. Next, I found a used 4500 watt gen. that put out full power out of one plug. I bought a 2000 watt Trace inverter-charger and a bank of 8 Trojan L 16s, which lasted 6 or 7 years. In the ensuing years we have gone through several battery banks and a couple of generators. Our current generator is a 12 K that I got used with 400 hours on the meter for 350 dollars. It now has 2800 hours on it. If I could do things over, I would certainly do things differently. There were no sites like yours in 1984. lol Plus we live payday to payday, and a solar set up was way out of the question. Now as we reach the age where we are starting to think about Old Folks homes, going full out solar makes no sense. I would like to go to at least some solar, but there are no solar sources here that I would trust to walk me through it. We live 50 miles from Portland Or. Also, we would have to cut down some big trees. Any way, it has been an adventure. I like reading about other people's experiences and who knows what the future holds.

  • Avatar

    BobM

    Reply Reply November 13, 2017

    There wasn't any mention of natural gas generators. While not mobile, and not cheap to install, I would like to hear any feedback. Thanks

  • Avatar

    john

    Reply Reply March 15, 2018

    Nick, I purchased a Generac 5k just before an October 2011 snow storm that knocked out power for 11 days. I would like to get a standalone nat gas unit down the road as the gasoline one is very thirsty, and the ethanol is just terrible to all my small power equip. I was glad i waited in line to get it as it came in handy for that storm as i used it to run the blower unit on my fireplace insert. I always store the generator with CAM2 100 octane leaded gas so the carb doesnt get gummed up. No matter what, everyone should periodically run their generator WITH SOMETHING HOOKED UP TO IT to exercise the commutators. Running the engine occaisionally (sic) is not enough. I use it for things like running my little table saw or electric pole saw out in the yard and I also changed the oil to synthetic.

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