Generator Fuel Consumption Test

A recent thread on fuel consumption of generators sparked my interest in doing a controlled specific fuel consumption test on some portable generators. Being a retired engineer I LOVE testing stuff. And I don't know of anybody who has ever done it. There's a lot of claims out there by manufacturers, but how accurate are they?

I called a friend who has a Yamaha EF3000iSE inverter gen that he uses for his camper. And I got an old worn out Generac GP3250 we're going to test. The Generac is in poor shape as it has about 4,000 hours on it. The valve guides are worn out and it burns a lot of oil. But it starts and runs on the first pull yet. I wish I had a newer one to test, but it's all I got available for now.

It's a cold windy day here and we needed a shop project anyway.

I don't where the proper place is on the forum to post the test information on standby or portable gens. This seemed like the logical section of the forum since these generators are most times used for off-grid backup, or for folks who have grid power, standby when the grid fails.

My friend is bringing his Yamaha to my shop this afternoon, then we're going to proceed to play with them :D
--
Chris
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Comments

  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    You're gonna be surprised at how far they've come with the inverter type that allow the engine to spool down to near idle for lighter loads. AND how quiet they can be! Just no comparison with the older ones that need to continuously roar along at 3600 RPM just to maintain 60Hz.
    My cousin has a 1000 watt Honda Inverter type, always starts first pull, EXTREMELY quiet for a generator and one litre of fuel usually keeps it whispering along for 8 hours at a time.
  • icarusicarus Solar Expert Posts: 5,241 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    It would be interesting to do this with a number of loading profiles.

    Load each genny with a similar load, say 1/3 (~1kw??) run for x hours.

    Then run with 2/3 ,and then full safe load ~80%.

    Using a heater with the full on so that the t-stat doesn't fool the load, maybe run the loads through a Kill-a-watt for cumulative total WH/litre for example.

    I will bet that the inverter wins hands down on the first, it gets closer on the second, and still wins on the final.

    Interesting test however.

    Tony
  • BB.BB. Super Moderators, Administrators Posts: 29,509 admin
    Re: Generator Fuel Consumption Test

    Personally, I would go with 1/4 load test (maybe even a 0 load test for calibration). For people running variable watt/type loads, I think that this is closer to real life. Only folks running heaters (and perhaps power factor corrected battery chargers) will be able to consistently pull 50% or more over long periods of time.

    At full load, I think this is less interesting. For the most part, generators are all pretty efficient at that level of power... And, frankly, I do not expect the inverter generators to do all that well at 100% load testing.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Generator Fuel Consumption Test

    The larger the generator, the more kWH's per gallon, if loaded greater then about 20%.

    A fixed, air cooled 3600 rpm generator uses a great deal of power for the flywheel air blower. This is a significant reason for fuel consumption flat lining below about 20% loading. Compression and values overhead goes up linearly with rpm where blower overhead goes up almost proportional to the square of rpm.

    Here are my test results.

    15 kW portable Generac. Regular gas, fixed 3600 rpm.

    No load , 0.8 gal/hr
    25% load, 3.75 kW, 1.0 gal/hour, 3.8 kWH's/gal.
    50% load, 7.5 kW, 1.3 gal/hour, 5.9 kWH's/gal.
    75% load, 11.25 kW, 1.6 gal/hour, 7.0 kWH's/gal.
    100% load, 15 kW, 1.8 gal/hour, 8.3 kWH's/gal.


    Yamaha EF3000is, regular gas, variable rpm, ECO control on.

    No load, 0.12 gal/hour.
    25% load, 0.7 kW, 0.17 gal/hour, 4.1 kWH's/gal.
    50% load, 1.4 kW, 0.32 gal/hour, 4.4 kWH's/gal.
    75% load, 2.1 kW, 0.47 gal/hour, 4.5 kWH's/gal.
    100% load, 2.8 kW, 0.60 gal/hour, 4.6 kWH's/gal.
  • BB.BB. Super Moderators, Administrators Posts: 29,509 admin
    Re: Generator Fuel Consumption Test

    Wow! Those Yamaha numbers are nice.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Fuel Consumption Test

    I found some dummy loads - a 750 watt automotive block heater. And I got a 240 volt 4,500 watt water heater element that I can drive with 120 volt power. The two of them combined should provide a close to 75% full load test. I'm measuring the power at the dummy loads with a Fluke tester.

    Before I came in the house for lunch I decided I'd better rebuild the cylinder head on that Generac. The valve stem to guide clearance is about .125". I got some sintered bronze guides for a Kohler diesel that will work. After lunch I'm going to pull the head on it, bore the guides and put the new bronze guides in it. Otherwise it will smoke us out of the shop :blush:

    --
    Chris
  • icarusicarus Solar Expert Posts: 5,241 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    Curious minds anxiously await your results

    T
  • FullpowerFullpower Solar Expert Posts: 69 ✭✭
    Re: Generator Fuel Consumption Test
    BB. wrote: »
    Wow! Those Yamaha numbers are nice.

    -Bill
    I disagree, the Yamaha seems to use near twice the fuel per Kilowatt hour.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Fuel Consumption Test
    Fullpower wrote: »
    I disagree, the Yamaha seems to use near twice the fuel per Kilowatt hour.

    Only above 50% load, which is just what one should expect.
    The inverter-gens are at their best during partial load conditions, which is what most people experience under typical conditions.

    The key is, as always, getting the right size gen for the loads.
    Loads; it's always about loads! :p
  • icarusicarus Solar Expert Posts: 5,241 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    I bet an Eu 1000 at 50% load would beat nearly all comers on a KWH/gallon.

    The point is, if you are needing a ~500 watt load, do it on a 1 kw genny rather than a 15 kw unit.

    T
  • BB.BB. Super Moderators, Administrators Posts: 29,509 admin
    Re: Generator Fuel Consumption Test

    Yea, I was looking at the 25% load numbers... From the Honda eu2000i, 1.1 gallon tank and 4 hours @ 100% and 9.6 hours at 25% (factory numbers):
    • 1,600 watts * 4 hours / 1.1 gallons = 5,820 Watt*Hours / gallon
    • 400 watts * 9.6 hours / 1.1 gallons = 3,500 Watt*Hours / gallon
    The old factory specs. were for ~15 hours at 400 Watts... Probably a bit on the optimistic side.

    Spec wise--even a cheap 3.5 or 5 kW genset will beat the Honda's (and other inverter generators) at 100% power.

    -Bill
    Near San Francisco California: 3.5kWatt Grid Tied Solar power system+small backup genset
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Fuel Consumption Test

    Well, this is what we came up with after I got the ancient Generac fixed so it don't smoke.

    As a side note, the valve seats and valve faces are junk on the Generac OHV engine. They're simply worn out and the head and valves should be replaced. I doubt it's long for this world - I'm guessing after putting new guides in it and lapping the valves so they seal again it's probably got 200 hours of life left in it before it burns the exhaust valve, or worse yet, drops the head off it into the cylinder.

    After roughly 4,000 hours on that thing the piston, rings and sleeve look like new yet.

    Anyway, we found a couple water heater elements, plus a block heater for loads. We disconnected the fuel supply to each one and ran it until it went dry. Then hooked up a funnel with a hose off it to feed the fuel to the engine. We dumped a measured 10 ounces of 91 octane premium pump gas with no ethanol in it into the funnel, started the generator and ran it against the clock driving the test load. The amps and volts was measured with my Fluke tester at the elements.

    I made a spreadsheet to do all the calculations and just entered the time the engine ran on the 10 ounces of fuel, and the volts and amps measured at the load.

    The outputs on the Generac are paralleled long ago so it'll put out the full the 27 amps it's rated at.

    One other test we did after measuring the run time with two water heater elements, is that we hooked the generators back up to their fuel tanks. Then started them again and drove the two big heater elements. Then we plugged in my 3600 rpm bench grinder and tried to start it. The Generac leaned into it and started the bench grinder with no problem. The breaker kicked out on the Yamaha. It's all the Yamaha wants to start that bench grinder from a zero load condition. So the Generac has WAAAY more surge power than the Yamaha has. Not even on the same planet.

    I had to buy my friend some beer because he was looking pretty dejected after that old ancient Generac pretty much kicked his high-tech, high priced Yamaha's butt ;)

    The spreadsheet is below

    generator%252520test-1.jpg

    Edit: Adding my own comment---
    You can not convert shaft power directly to heat in SCR's and inverter electronics and expect to get any real efficiency from your generator, except at really light loads. If you like to start your generator, then kick back in a lounge chair with a cold brew and just watch it run, doing nothing, then an inverter gen is the one to get. But if you need real surge power and efficiency (most kWh/gallon of fuel burned), then it's hard to beat the conventional rotating field generator. The very slight difference at light loads is not enough to make up for the things you really buy a backup generator for. That's my opinion on it.

    OTOH, the Generac is noisy - REAL noisy. It is not even close to being a quiet machine. And it's output is "dirty" because the mechanical governor tends to surge a bit at light loads (I wouldn't doubt the governor is worn out in the unit I got too). But the Generac is also field serviceable, while the Yamaha is not. No matter what it is - brushes in the gen, AVR, or even the engine, the Generac can be fixed by the average person who's a little mechanically inclined. If something goes wrong with the Yamaha, might as well lug it back to the dealer because unless you're an electronics guru it's not going to work.
    --
    Chris
  • RCinFLARCinFLA Solar Expert Posts: 1,280 ✭✭✭
    Re: Generator Fuel Consumption Test

    For roughly equal wattage rating generators, a fixed rpm generator will win at loads above 25%. Above 25% loading, fuel consumption is much more linear to power output. ECO mode rpm peaks out at between 25% to 35% rated loading so you should be at near full rpm for all but maybe the lowest power test.

    The inverter output has a power loss of 5% to 12% depending on load but part of the loss is made up by three phase permanent magnet alternator will yield more electrical power per torque-rpm then a conventional single phase electrically field excited alternator.

    Comparing no load idle to surge starting current from an ECO mode rpm cutback is not a fair test. Most electric motors including most refrig compressors require ECO mode be turned off.
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Fuel Consumption Test
    RCinFLA wrote: »
    Comparing no load idle to surge starting current from an ECO mode rpm cutback is not a fair test.

    It is a fair test when you're using your Eco Throttle generator to run your bench grinder, plus some other loads. The reason I pointed it out is because if somebody has one and thinks they're going to run the 'fridge or freezer with it in a power outage situation, they're better off to buy a real generator.

    The other thing I should mention for somebody else that might test a GP3250 sometime, is that the one I got is an older one that doesn't have the 240 volt output. It has been parallel'd, which greatly enhances power efficiency of the generator.

    Example:
    If you connect a 10 amp load to one of the duplex plugs on the gen, the I^2R loss, assuming a 1.0 ohm resistance on that stator coil group, is 100 watts. Parallel the windings and now you deliver the same 10 amps to the load, but each stator coil group is now handling only 5 amps of the total load, for a loss of 25 watts per coil group, or 50 watts total loss.

    Voila! The generator is more power efficient. And that happens to be the case with this old Generac I tested.
    --
    Chris
  • icarusicarus Solar Expert Posts: 5,241 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    Chris,

    I appreciate you comment about a real vs other genny to start appliances. That said, I run into a situation every winter. My water line freezes solid in the lake when I am away. I built the system with semi conductor heat tape in the water line system. This requires that I run the genny for ~ 1/2 an hour once or twice a year depending on when I leave and for how long.

    The eu1000 won't start the heat tape due to large inrush current demand. I then parallel the 2 eu1000s plug in the heat tape. The two start it, and within a couple of seconds, I can unplug the second genny. In this case, a eu 2000 would do the trick, and I am not saving much fuel by using 2 rather than a bigger 1, but it allows me to use the 1000 for 99% of my loading over the rest of the year.

    Granted, it would make no sense to own a second genny for 20 minutes a year, but it sort of highlights my notion,, use the right tool for the job, ie, the proper sized genny, running a peak efficiency. Finally, there is something really nice about the inverter gennies with how quiet they are. I had an EX 1000 3600w non inverter, and with similar loads the noise from the the EX is considerable, while I cannot hear the EU out side on a 50' cord.

    Nice info on your tests,

    Tony
  • RandomJoeRandomJoe Solar Expert Posts: 472 ✭✭✭
    Re: Generator Fuel Consumption Test
    ChrisOlson wrote: »
    It is a fair test when you're using your Eco Throttle generator to run your bench grinder, plus some other loads. The reason I pointed it out is because if somebody has one and thinks they're going to run the 'fridge or freezer with it in a power outage situation, they're better off to buy a real generator.

    I've not done any careful testing, but based on my observations loading my EU2000i...

    It has little trouble starting my appliances - fridge and gas furnace being the primary ones I'm interested in - with the Eco Throttle on. There's a definite line voltage dip and a bit of oscillation of the engine as it tries to recover, but it does so quickly and the appliance doesn't seem to care. (I don't normally do this anyway, I've just tried it to see what would happen. Normally I get the generator running, let it warm up a few minutes, switch on loads, THEN turn on Eco and let it idle down.)

    The only item it *can't* start in Eco mode is the 9000 BTU portable AC unit. Frankly, I was surprised it could run the thing *at all*, so it really isn't a big deal to me. Flip off the Eco switch so the engine revs to full speed, start AC, then I can switch Eco back on and the engine still idles down a fair ways. (I also have a 9000 BTU mini-split in the back room - can't run that at all. When I tried, the engine just bogs down and the AC unit does nothing.)

    RCinFLA wrote:
    ECO mode rpm peaks out at between 25% to 35% rated loading so you should be at near full rpm for all but maybe the lowest power test.

    I haven't seen this with mine. Even at 1000-1200W the generator is audibly not at full speed. Switching the Eco mode off results in a definite increase in RPM (and noise). When I use the 800W portable AC as a test-load, it idles down considerably.

    Again, I've never tried to do any careful measurements so don't have actual numbers, just what I've heard from it while in use. I do know that one filling of the gas tank will last for many 1-hour test runs. (Haven't had a long-term outage yet.) I know it's a "no-no" but I tend to fill the tank once a year when I get fresh fuel (I add Stabil) and run on that the whole year. I don't test every month like I intend, but do generally get 6 tests / year... Hasn't run dry on me yet! Tried to run it dry once on purpose, got tired of waiting! :p
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Fuel Consumption Test

    Tony,

    Definitely, with all you say.

    MY comment on the inverter gen vs a "real" gen was meant to say that for most folks who will buy these generators for home backup power, they are not saving any fuel with the Eco Throttled inverter gen like the sales propaganda claims. The reason they buy them is to run critical stuff like a 'fridge, freezer and/or well pump. And in some cases to keep a furnace blower going. These are all inductive loads and a "real" generator is still the best to run them.

    Sure, you can buy a bigger inverter gen and run them. But a smaller rotating field gen will run them fine and save you fuel.

    It was interesting to see in our run tests yesterday how the efficiency of the Yamaha engine continues to improve with heavier loading and gains in rpm. I'd have to pull the engines off and run them on the dyno to actually measure it. But I know for a fact that the efficiency of the SCR's and inverter electronics goes south at heavier loads, and yet the efficiency of the Yamaha continued to improve with heavier loading. That only leaves the engine. Just another example of how the Eco Throttle actually hurts overall efficiency of the unit.

    We played with the Eco Throttle concept on Cummins NTC and KT-series 250-500 kW gensets back in the 80's and could never realize any actual gains in efficiency of the set. And yet today, the electrical efficiency of the generating unit has been reduced by bolting on electronics, and they strap on the Eco Throttle and market it as "saving fuel". It's all marketing, and the consumer believes it. When in reality, the only time you can save any fuel is when there's no or little load on that genset. And it's not very dang much.

    It's kind of like diesel vs gasoline fueled cars in North America. If the entire US auto fleet was converted to diesel, there would be a glut of crude oil on the market overnight. Marketing has sold the gasoline fueled vehicles to the consumer over the years. My wife is Swedish, born and raised in Lungvi, Sweden, and we go to Europe a lot. In Europe almost half the vehicles sold are diesel. And their average fuel economy per passenger mile is better than double that of the North American market.

    All due to marketing. The price of gasoline in the North American market is artificially cheap. Engineers always like to build the best stuff and we'd have everybody driving diesels. But then marketing teams get involved and engineers are forced to build what the marketing teams think they can sell. And that's pretty much the story with everything you can buy - it's not the best that engineers can build. It's been designed to make you want to buy it.
    --
    Chris
  • mike95490mike95490 Solar Expert Posts: 8,373 ✭✭✭✭✭
    Re: Generator Fuel Consumption Test
    ChrisOlson wrote: »
    ...Then we plugged in my 3600 rpm bench grinder and tried to start it. The Generac leaned into it and started the bench grinder with no problem. The breaker kicked out on the Yamaha. It's all the Yamaha wants to start that bench grinder from a zero load condition. So the Generac has WAAAY more surge power than the Yamaha has. Not even on the same planet....

    That's an improper comparison. Like asking a 2 door car, to pull the same trailer that a 2 door Mack truck can pull.

    The large rotating mass of the Generac can give tremendous surge capacity, that no inverter generator can. But, there is a line of inverter generator that uses it's starter battery, as a booster battery for peak surges.

    I can stall my inv-gen (honeywell 2000) with the worm-drive saw every time, but now I just "blip" the trigger on it, a couple times till it's up to speed, then I can "hammer down" and cut anything the blade will handle. I can also put it into the truck myself, but my 5KW generac, needs 2 folks to lift it up. And with the inv-gen, I can hear my cell ring.
    Powerfab top of pole PV mount | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
    || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
    || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

    solar: http://tinyurl.com/LMR-Solar
    gen: http://tinyurl.com/LMR-Lister ,

  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Fuel Consumption Test

    If you ever bothered to read the instructions that come with the inverter-gen it specifically tells you to turn the eco-throttle OFF when starting heavy loads. Don't blame the machine if you don't use it right.

    Odd how this test doesn't line up with the real world experiences of so many of us who have used both types of generator. Maybe those Yamahas aren't so good; I don't know, I've never tested one.

    Most people use their gens with varying loads, as I've mentioned before. The majority of cases they run less than 50% of power potential which is where the I-G fuel economy shines, as mentioned before. As always you need to get the right generator for the job, as mentioned before.

    Implying that the inverter-generators are not "real" generators or that there is no fuel savings to be had with them is doing a disservice to both the generators and to anyone who might benefit from one. I'd hate to see someone go out and buy a big fixed RPM unit when all they need is a little inverter-generator. Those of us who have used both types for many years know the advantages and disadvantages of them.
  • icarusicarus Solar Expert Posts: 5,241 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    Here is another example. We have a ~550 watt running window A/C unit that we use on very hot, very still nights for a few hours a year. I bought it assuming I could run it on the Eu1000, and in fact I can. One has to be diligent in the starting sequence however. First, get the genny warm, turn off the eco throttle. Then kill all the other loads on the line, then turn the a/c unit on fan only, turn the t-stat to full cold. Once the fan is running full speed, switch to low cool, run for a minute or so, and switch to high cool.

    Then, as long as the t-stat never shuts the compressor down, it will run until the genny runs out of fuel. I can also dial back the eco throttle and the RPM drops to ~1/3, even giving me enough "head room" to run the ceiling fans and or a the lights.

    It just illustrates that there are work arounds for many thing. On another side note, my 5 kw lister diesel (talk about rotating mass to absorb any surge!) absolutely would not start my bench grinder. The lights would dim, the grinder would spin slowly and never get up to speed. It would run fine on other gennies, and since I ddin't much care (since we don't use it anymore except for fun now and again!) One day with nothing better to do I pondered the problem. It turned out that the line voltage was far enough off (low,,,~105 vac) that the voltage drop trying to start the grinder would never allow it to spin up. The engine speed never drops, as the freq. stays stable, just the voltage dropped. I simple moved the exciter resistor a bit on the coil, raising the idle voltage to ~225/112 vac, and voila the grinder started just fine. Cap start motor so I guess that is no surprise.

    Icarus

    Tony
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Fuel Consumption Test

    I may have gotten hold of a Honda EM4000 to test. It's not an inverter gen but it's another one I can add to my collection of data I intend to collect on various small generators. I know I can get a Yanmar YDG3700 diesel too, and test that, assuming the guy I know that's got it isn't using it at his hunting camp.

    I'm waiting for the guy to call me back after lunch on the Honda. I told his wife I wanted to borrow it for a few hours. Didn't tell her what I'm going to do with it. ;)

    I'm just going to collect some numbers so folks can see how various small generators perform. They can look at the numbers and decide for themselves what's going to work and what doesn't. The efficiency claims of inverter gens is pure marketing hype. Period. Granted, they have their place - they're nice for camping, they're nice and quiet, they have super clean output, and are typically lightweight and small. But the fact is, the best engineered products rarely succeed in the marketplace. The best marketed ones do. And probably better than 90% of consumers don't know the difference.

    If I can get hold of that Yanmar I"ll show you that a diesel, being a true heat engine with no intake throttling, will kick butt on them all because it can run at super lean air/fuel mixtures that won't even make a spark ignition engine sneeze.

    I got interested in this project because of the claims. But there's the facts - there have been no advancements in the thermodynamic efficiency of internal combustion recip engines in the last half century. And you cannot generate power out of thin air unless you use a wind turbine. No matter what marketing hype tries to convince you of, you are still dealing with the basic thermodynamic limitations of the design. You can throw a hemispherical, polyspherical, wedge, or whatever combustion chamber at the problem, change valve angles and size, head port length and angles, change valve lift and duration, ignition timing, throw electronics at it and try to gain better fuel control so you never run the engine too much on the rich side of stoichiometric .

    But in the end an Otto Cycle engine still wastes the vast majority of the heat of combustion by spitting it out the exhaust and the remainder is lost in the cooling system. The little bit that gets converted to mechanical power will never match the Diesel Cycle because the Otto Cycle efficiency depends on two things - compression ratio and specific heat ratio of the combustion gas.

    Until I see one of these inverter gens with a diesel on it, I won't buy one. Because I know what happens to the efficiency of a spark ignition engine at low mean piston speeds.

    When it comes to efficiency with generators, most people only know enough to look at the gal/hr fuel consumption. When they should be looking at how many watt-hours the thing makes per gallon of fuel. That's all.
    --
    Chris
  • ChrisOlsonChrisOlson Banned Posts: 1,807 ✭✭
    Re: Generator Fuel Consumption Test

    I guess my last post has been pulled for some reason, evidently because it contained some good information on why inverter gens are inherently less efficient than conventional revolving field generators.

    So I will decline to post any further information on my generator tests here. The information will be available on my website when I get more generators for testing. And it will include a Honda inverter gen when I can find one to add to the data. I know the folks at Northwest Honda pretty well and they may have a demo or rental unit I can get to test.
    --
    Chris
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Fuel Consumption Test

    Chris, you know why the post was pulled. You were informed of it. Don't try to make out like we're unfair here.
  • waynefromnscanadawaynefromnscanada Solar Expert Posts: 3,009 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    Implying that the inverter-generators are not "real" generators or that there is no fuel savings to be had with them is doing a disservice to both the generators and to anyone who might benefit from one. I'd hate to see someone go out and buy a big fixed RPM unit when all they need is a little inverter-generator. Those of us who have used both types for many years know the advantages and disadvantages of them.

    Couldn't have said it better Cariboocoot!
    Strange how every once in a while someone comes out of the woodwork who appears to either have an axe to grind, of is trying to appear a budding scientist pushing this or that idea, all the while being way off base.
    From seeing how well my cousins little Eu1000 works, how little fuel it sips and how extremely quiet it is, it's definitely what I'd be getting if I didn't have the little hydro. No question whatever! Just last night, not kidding, gave away my traditional 4400 watt gas gobbling generator. Never realized how much fuel it used till I spent some time at my cousin's camp with his Eu1000.
  • henry1henry1 Solar Expert Posts: 51 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    Thanks for the basic info on the Generator run times because of trying to figure out some of the basic time for battery chargering .I'm going to do a test run next week of the hours that the generator needs to charge my battery bank at the cabin and time it down to the min to see how much fuel that the unit use .
  • VicVic Solar Expert Posts: 2,970 ✭✭✭✭
    Re: Generator Fuel Consumption Test

    My $0.02,

    The generator that I use most, and has the most run-time at this off-grid location is the Honda EU-1000i. Quiet, fuel stingy, and almost always run it on Rco Throttle.

    In town, ran it for about 50 hours during two protracted power outages. It ran everytihing -- fridge, lights, TV, Hammie Radio etc, all on Eco. It easily started my fridge in Eco. And was very stingy on fuel for these outages.

    In addition, it is essentially impossible to find a "real generator" in its power class. Use it often to run a small sump-type pump to transfer water, to run a vehicle charger away from the main buildings, and for soldering in the field. It weighs about 31 Lbs wet, and is a comfprtable one-handed carry.

    The EU-2000 will start my worm-drive Skill saw. So this one can be used for light duty construction jobs.

    I could not imagine life here, without these two lil Hondas. Vic
    Off Grid - Two systems -- 4 SW+ 5548 Inverters, Surrette 4KS25 1280 AH [email protected], 11.1 KW STC PV, 4X MidNite Classic 150 w/ WBjrs, Beta KID on S-530s, MX-60s, MN Bkrs/Boxes.  25 KVA Polyphase Kubota diesel,  Honda Eu6500isa,  Eu3000is-es, Eu2000,  Eu1000 gensets.  Thanks Wind-Sun for this great Forum.
  • halfcrazyhalfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Generator Fuel Consumption Test

    From my experience if one needs a generator to run an absolute fixed load then buy a standard generator rated for 125% of the load at least. But most of us here do not have a standard steady load this is where the Inverter gennys shine. They will do much better when lightly loaded and that is where most generators spend there time.
  • Blackcherry04Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Generator Fuel Consumption Test

    Like everyone else with some trial and error you'll find out what works best for you. For me it's a Honda EU 2000, a 55A Iota charger and a 3000 watt inverter and a couple cheap golf cart batteries. You can run ECO all day long on a gallon of gas and still have plenty power to run about anything you want. Yes, there is conversion loss, but that's the price you pay. Would I be better off with a 3-4KW real Generator ?? Maybe, but I wouldn't enjoy it as much.

    I'v got a 20KW ( 2 Gallons a hour ) for some heavy lifting, but the little generator is hard to beat and I am willing to alter the way I do things for the payback.
  • CariboocootCariboocoot Banned Posts: 17,615 ✭✭
    Re: Generator Fuel Consumption Test

    The moderated post has been restored, albeit slightly edited.

    Regrettably Mr. Olson has decided not to participate in the forum due to differences of opinion over proper forum etiquette. Please not he was not banned. He was even invited to post a link to his generator test results; he declined.

    If you want people to respect your point of view, you have to respect theirs as well.
  • halfcrazyhalfcrazy Solar Expert Posts: 720 ✭✭✭
    Re: Generator Fuel Consumption Test

    This seems to be a trait of Mr Olsen on another board I frequent. It is a shame as he is a very brilliant man and can build darn near anything from nothing.
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