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pianotuna's avatar
pianotuna
Nomad III
Mar 08, 2014

eco switch and fuel consumption

Hi,

We all know that inverter generators have an economy setting for low demand. Usually 1/4 of "full blast".

As demand goes up to say 50% does the eco switch allow the engine to run at 1/2 speed? Or does it rev up to as fast as it can go?

My Yamaha sIEB runs for 19 hours at 1/4 load and 7'55" full bore.

Will it run longer at 50% load? For example 9.5 hours?

What about at 1/3 load? Will it run for more than 12 hours?

8 Replies

  • Hi,

    Thanks all.

    The cold start up on the Yamaha 3000 iSEB will not allow eco mode until the generator has warmed up. That is possibly a good way to know, at least in winter time, when one can start to make it work hard.

    I think that Yamaha is telling porkies on their run times at full load. I.E. their times are, shall we say, "optimistic"?
  • BFL13 wrote:
    My Honda 3000 with eco off runs at so-called full blast, but then when I turn on a good load like my PowerMax 100a charger, the Honda grunts and seems to get a bit louder. How can that be if it is already at full?

    Once I get the 100a going I turn eco on and the noise drops some. After amps taper, the noise drops even more, till it is the same as with no load (not much noise)

    In eco, if you add a load (and the gen does not conk out!) the noise rises up to whatever and drops off again when load is reduced.

    If you do want to run a big load in eco then let the gen warm up first or it will conk out. Easier to just start with eco off and then turn eco on afterwards.


    The reason it gets louder is because when not in Eco and at high speed with no load, it takes less throttle to keep the rpms.
    When your AC kicks on and makes a load, the gen has to work harder and the throttle opens more, more power, louder.

    Like driving 55 with your truck, no trailer, vs with trailer at same speed. The truck will need more throttle and will be louder with the load.
  • Every make/model is probably different. The eu2000i has a maximum speed of 5,000 RPM. With the eco switch on, its idle speed is 3,000, and with eco off its idle speed is 4,300.
  • Inverter generators only run as fast as necessary for the load. More load = more speed = more fuel consumption.
    Lots of non-inverter generators also have an eco switch. These units operate differently. As soon as any load is placed on the gen. it throttles up to 3,600 RPM and stays there until the load goes away. Even in this situation, fuel usage will still increase with load. The more load the more fuel is necessary to maintain 3,600 RPM
  • I have a Honda 3000 and a 6500 and they only run as fast as they need to on eco
  • My Honda 3000 with eco off runs at so-called full blast, but then when I turn on a good load like my PowerMax 100a charger, the Honda grunts and seems to get a bit louder. How can that be if it is already at full?

    Once I get the 100a going I turn eco on and the noise drops some. After amps taper, the noise drops even more, till it is the same as with no load (not much noise)

    In eco, if you add a load (and the gen does not conk out!) the noise rises up to whatever and drops off again when load is reduced.

    If you do want to run a big load in eco then let the gen warm up first or it will conk out. Easier to just start with eco off and then turn eco on afterwards.
  • I've noticed my Yamaha 2000 throttle under eco mode isn't really "linear" with the load, but it's not as bad as "full blast" either.

    I use a 760 watt hotpot (about 50% load for the 1600 rated watts) to exercise the genset, and with eco mode on, when the thermostat on the pot kicks in, the generator idles up a bit, but not full-blast.

    My genset runs almost exclusively without eco mode, because it only runs to recharge my battery bank, and I want the full 120+ amps of charge current. When the charger exits high current mode, I switch to eco mode if neighbors are generating, or just shut it off if I'm the only one.
  • My Honda eu2000i only revs as high as it needs to, to maintain enough output. Unlike others, mine will start my 13500 dometic AC in economy mode at 85 degrees and 1500 ft. Ave not tested hotter or higher yet, but it will probably have to be in normal mode for summer.