Generator fuel consumption?

Blackcherry04

Re: Generator fuel consumption?

It is possible to Convert a FX model to a G model by changing the Boards. I have seen it posted on the Outback site. The poster sent theirs in to Outback, I have no idea what all is involved or if it can be done in the field like the rest of service or the cost. It is possible with a new Inverter , they might swap it. It's probably not cost effective any other way. Then there is that other problem, you don't know if your generator would work with it.

vtmaps

Re: Generator fuel consumption?

jcheil wrote: »

Dang, I didn't realize that the G model could be used off-grid in that way. I "just" bought the VFX3648

BUT... the GVFX demands tighter regulation of the generator. You may need an inverter generator (or other tightly regulated generator) if you want to do gen support with the GVFX. If the GVFX doesn't like your generator it will drop it and put the whole load on your batteries. The VFX is more forgiving of loosely regulated generators.

Interestingly, Outback makes a GVFX model with a "LA" suffix that works OK with most generators and the poorly regulated grid in many parts of Latin America. The "LA" models are not UL approved and not sold in the US or Canada.

--vtMaps

Cariboocoot

Re: Generator fuel consumption?

Funny, I thought you could reprogram a GVFX to give it wider acceptance range for input power. It would be bloody useless even as a GTI if you couldn't.

Blackcherry04

Re: Generator fuel consumption?

vtmaps wrote: »

Interestingly, Outback makes a GVFX model with a "LA" suffix that works OK with most generators and the poorly regulated grid in many parts of Latin America. The "LA" models are not UL approved and not sold in the US or Canada.

--vtMaps

The one thing that makes me a little shaky about the " LA " model is that it is listed with a 127 V ac output and not knowing if it's adjustable within that limit. say from 110 -127 V then it would be ok, but you still do not know about the HZ limits, say 55 - 65 hz. just do not know.

Blackcherry04

Re: Generator fuel consumption?

Cariboocoot wrote: »

Funny, I thought you could reprogram a GVFX to give it wider acceptance range for input power. It would be bloody useless even as a GTI if you couldn't.

It is adjustable but within certain limits. This I never had a reason to test, the Honda has no issues with it.

Cariboocoot

Re: Generator fuel consumption?

Blackcherry04 wrote: »

It is adjustable but within certain limits. This I never had a reason to test, the Honda has no issues with it.

Could you take a look at the programming for us and see just how wide-ranging those limits are?

Of course there's nothing like buying quality components (i.e. the Honda inverter-gen) all-around to make sure everything works. People who buy cheap stuff get poor results.

Blackcherry04

Re: Generator fuel consumption?

Cariboocoot wrote: »

Could you take a look at the programming for us and see just how wide-ranging those limits are?

Of course there's nothing like buying quality components (i.e. the Honda inverter-gen) all-around to make sure everything works. People who buy cheap stuff get poor results.

I can, but I don't have it here and won't be down to the lake till Saturday. I have a suspicion that it may be something in the input that might not be adjustable within the GTI U 1741 standard, it drops.

Here is a link to the programming guide, it has the specifications for U 1741 and the variables on the Inverter on page 24. I don't know if it tells the whole story.

http://www.affordable-solar.com/site/doc/Doc_GTFX20AND20GVFX20Inverter-Charger_REV_A_20080507135432.pdf

Here is where a issue may be. The Hz limit's are not adjustable, with a standard generator the Hz and voltage are coupled with the RPM but not with a Inverter Generator, there no way even though the voltage has a large adjustment to keep HZ within in limits ( 1.3 hz ) . Some AVR's may be able to keep it that tight, my 20 kw can within 2-3% and the loads are small and the governor is pretty good.

Attachment not found.

.

RCinFLA

Re: Generator fuel consumption?

For locking on a generator, and staying locked on a generator, it is not only the freq tracking range but also the tracking rate of the feedback loop that follows the change. (the phase lock loop bandwidth).

Any grid freq change is a very, very, slow slew rate, measured in tens of minutes at the worst. A generator on the other hand can have a few Hz's change in freq in less then a second due to surge A.C. load when something suddenly loads its output. (hear the engine RPM bog down for a moment).

An inverter-generator not running in ECO mode (full speed) has the best chance of maintaining freq and voltage across a moderate surge. When in ECO mode (engine speed modulation based on load demand) there is a clipping of the peaks of the sine-wave when a surge appears, as the engine slews to a higher RPM to handle the new load, which will also cause a connected inverter to release from the generator.

mike95490

Re: Generator fuel consumption?

RCinFLA wrote: »

.....An inverter-generator not running in ECO mode (full speed) has the best chance of maintaining freq and voltage across a moderate surge. When in ECO mode (engine speed modulation based on load demand) there is a clipping of the peaks of the sine-wave when a surge appears, as the engine slews to a higher RPM to handle the new load, which will also cause a connected inverter to release from the generator.

??? Huh ? Doesn't an inverter run at the same freq regardless? Inverter gens generate DC, which is fed to the inverter, which should be pretty stable. If the peaks get clippped off, won't the voltage sag cause the "connected inverter" to disconnect?

Blackcherry04

Re: Generator fuel consumption?

Most small Standard Generators I have had any dealings with were set up with no load setup output of 123-125 V output and that is 62 hz or so. Theory being at some point of a load it will pass through the 120 V @ 60 hz output. Most of the governors will react at some point of loading and bring it up to a reasonable output depending on their sensitivity to maintain constant a RPM. So, trying to use on on a G model Outback Inverter with 59.3 to 60.5 hz limits is doomed to fail no matter what you try to do with them.

Cariboocoot

Re: Generator fuel consumption?

And of course if you're using a large conventional generator it may not be loaded enough to fall out of the 'accepted range' of the inverter - nor enough to be economical.

I think the important lesson we learn here is that for small generators the inverter-gen type is best.

My VFX only drops the gen if there is a sudden drastic change in load, such as the water pump turning on. Other load variations are not large enough nor swift enough to exceed the eco-throttle's ability to keep up. A bit of planning keeps me ahead on this: start water pump, then connect generator. It will run it (even on eco setting) it just won't start it. Plus the VFX's charger ramps up from zero, so the gen never gets hit with maximum current to begin with from that (have to love the smooth operation of Outback chargers - the best there is).

Blackcherry04

Re: Generator fuel consumption?

Cariboocoot wrote: »

And of course if you're using a large conventional generator it may not be loaded enough to fall out of the 'accepted range' of the inverter - nor enough to be economical.

I think the important lesson we learn here is that for small generators the inverter-gen type is best.

So, True.

Even with Generator Support the Inverter WILL drop the generator if the loads exceeds the generator ability to maintain it's output. The Honda EU 2000 in ECO will drop at times when the load is sudden and exceeds it ability to ramp up. Like Coot said, if it's something you know is coming you turn the ECO off and all is fine.

I have modified one of My Honda's with a one shot timer that will pull the Honda out ECO throttle for a 10 sec period when triggered. Call it a pre-load step up. There is delay timer on the load that will hold the loads connect ( 5 sec ) while the Honda is ramping up. After the 10 seconds and all has stabilized the Generator drops back to the ECO mode.

RCinFLA

Re: Generator fuel consumption?

mike95490 wrote: »

??? Huh ? Doesn't an inverter run at the same freq regardless? Inverter gens generate DC, which is fed to the inverter, which should be pretty stable. If the peaks get clippped off, won't the voltage sag cause the "connected inverter" to disconnect?

Freq is not the probable with inverter-generators, yes freq stays constant. Problem is voltage slump while ECO mode speed control slews the engine rpm up to speed to meet the surge demand. The sine wave peaks clip off because the alternator cannot meet the current demand of the surge. The connected inverter disconnects because of AC not meeting minimum voltage.

As to the original thread title. The best way to go to minimize fuel consumption is to have AC inverter/battery system able to meet the peak surge current requirements then have a generator sized to meet the average power demand, even if gen disconnects from AC inverter during pump starting. Most gen's peak for their kWH's/gallon of fuel between 30% and 70% of kW rated loading. A 5kW gen with 500 watt average load is going to waste fuel. If your average power is about 300-500 watts, an inverter-gen in the 2kW range is a good choice.

Sometimes, depending if AC inverter response time is fast enough, by setting the inverter to limit maximum AC input current can prevent generator from slumping out causing a disconnect from AC inverter.

For emergency power during hurricanes, I have a Yamaha EF3000i as my 'trickle charger' and a 15kW Generac for spot use for hot water heater, HVAC, and battery recharging.

stmar

Re: Generator fuel consumption?

After all the input and reading countless reviews I went with the Honda EU2000. Big R, a local feed/ranch/sport store, actually had them on sale and they are a service center for Honda but I hope that will not be needed. Got it running with very little effort and I must say it is a quiet machine, ran a shop vac for a while to test it out. Now I am going to wire a plug, using an old wind generator circuit wiring that is no longer in use so I don't have to drill any more holes in the house, and take it to the inverter's gen ( AC-2) terminals. Basically I will have an extension cord wired in to the inverter so that all I have to do is plug it into the generator when needed. Thanks for all the input, now I have to concentrate on replacing the battery bank!!!