Choosing a good generator

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  • westbranch
    westbranch Solar Expert Posts: 5,183 ✭✭✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »
    I finally had to have a guy that knows how to build a coal bed and get it going to come over and show me how to do it. :blush:
    --
    Chris

    And the secret is??
     
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  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »
    Our furnace is "dual fuel" - it also has the shaker grates in it to burn anthracite coal. Anthracite is the cleanest burning fossil fuel known to man.

    I brought up the coal thing because for folks looking for a backup heat source for their home, or even supplemental in really cold weather to cut your LP or natural gas bill, they make some REALLY nice little stoker stoves designed to burn rice or pea anthracite. It's a heat source that can be run off most small 120 volt inverters or generators (to run a stoker or circulating fan) without taking much power.

    Anthracite stores indefinitely, never gets bugs or pests in it, never rots, and does not absorb moisture or get wet. And you can store tremendous amount of BTU's in a small space. We get it in 40 lbs plastic sacks like this:

    Attachment not found.

    And there's no flame when it burns. It just glows. If you have a wood furnace rated for it (extremely high firebox temperature) it will turn a 80,000 BTU wood furnace into a 125,000 BTU.

    Attachment not found.

    If you have never burned it before, you're in for an education. When I first tried it I became convinced that I may as well go outside and gather up some field rocks and try to get those to burn because I'd have just as much luck as I was having with the anthracite. But once you learn how tend a coal bed and get it going, I think it's safer and cleaner than wood.
    --
    Chris
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    westbranch wrote: »
    And the secret is??

    Anthracite coal doesn't start to burn until it get to 2,600 degrees F (1,400° C) and it has to be held there for two hours to get it to light.

    The first thing you do is open the windows in the house and let a nice -20F winter breeze blow thru. Because you ain't never seen the amount of heat you're about to see in the next four hours.

    You light a hardwood fire using oak or maple. Nothing else works because it don't burn hot enough to light anthracite. You need to burn the fire down to hot coals left and you need a thick enough bed of hardwood coals in there to last for at least an hour once you start adding anthracite. And they have to be glowing with full draft on.

    You add the anthracite in one layer over the top of the coals and then wait. It will take an hour and you'll start to see the edges of some of the coal chunks starting to glow. You wait until that first layer is glowing all the way thru, then add another layer. Repeat and wait until all the coal is glowing. Then a third layer, and then a fourth.

    You now have a coal bed but it is very fragile because there's no ash in the bottom yet. Do NOT light a anthracite fire in a wood stove not designed for it - it will melt the grates and bottom right of most wood stoves. The combustion temperature of anthracite is around 4,900° F once it gets burning. The initial bed has to burn at full draft for at least four hours to get a protective layer of ash on the bottom of the bed. Your furnace will be running at a jacket temperature of 1,000-1,200° F during this time.

    When you have an established bed you can cut the draft to it and it will stay burning and your furnace will run at 500-600°F jacket temp.

    Coal stoves or furnaces have shaker grates. When you refire it you open the draft and let the whole bed get burning again at full glow. Then shake your bed down until you get some glowing pieces falling into the ash pan. Don't shake it too much or you'll lose all your ash. Don't shake it enough and you'll choke the air off to the fire and it will quit. You add anthracite in layers like you did the first time. And get it all burning good before cutting the draft again and putting it on "slow burn".

    Stokers tend themselves and you just have to empty the ash pan. Furnaces like we got (non-stoker) have to be manually fired. But once a day firing in really cold weather is all it takes.
    --
    Chris
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »
    If you have never burned it before, you're in for an education. When I first tried it I became convinced that I may as well go outside and gather up some field rocks and try to get those to burn because I'd have just as much luck as I was having with the anthracite. But once you learn how tend a coal bed and get it going, I think it's safer and cleaner than wood.
    --
    Chris

    Just less renewable. :cry:
    But sometimes you have to take what you can get and balance the pro's and con's. :-)
    SMA SB 3000, old BP panels.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    inetdog wrote: »
    Just less renewable. :-(
    But sometimes you have to take what you can get and balance the pro's and con's.

    The way I look at it, there's usually a considerable amount of fossil fuels that get burnt making wood too. Wood is carbon neutral if you leave the energy expenditures out it takes to make it. But it's my opinion that anthracite is an under-utilized fuel source for home heating. It's only mined in a couple places in the US, and I don't know how much reserves there are of it in other places in the world. But if you compare it to wood burning furnaces that heat water (outdoor hot water stoves), anthracite is definitely more friendly to the environment than those are.
    --
    Chris
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    BB. wrote: »

    As far as I know, the catalytic wood burning stove was a response to air pollution rules (completely burn smoke and fuel). There are stoves that meet the EPA requirements without catalysts (when I check this a few years ago). There are some drawbacks to catalytic wood stoves (besides keeping a minimum amount of fire/air for cat. to work, I believe wet/green/wood with lots of sap causes issues too).

    -Bill

    Both catalytic and non catalytic EPA approved stoves burn very cleanly. We have a non catalytic EPA stove and it is sometimes difficult to tell from looking at the stove pipe outside whether a fire is burning or not.

    EPA approved stoves depend on secondary burning of hot wood gas and particulates. Non catalytic types depend on a baffle creating a longer path for secondary combustion to occur.

    As far as burning unseasoned or wet wood I think the issue with either type of stove (and for older pre EPA approval stoves) is water vapor cools the gas preventing complete secondary combustion. This also encourages creosote formation in chimneys/stove pipes.

    From an energy independence perspective, the downside of living surrounded by Douglas Fir/Cedar forest is that shading from trees can be an issue for PV- and wind power is out of the question. :cry:

    The upside is that I will never have to worry about finding a way to heat my home. 8)

    If wood is readily available, woodstoves are a fantastically simple, reliable way to heat your home - even in the coldest climates. The energy content of different woods varies. Doug fir is ok but does not compare to the energy in Eastern hardwoods. When I lived in Northern Vermont one load of seasoned maple in the wood stove would keep our place tee-shirt comfortable throught the night in -20 degree F temps.

    It sounds like anthracite coal is even much better. I remember traveling in northern England and Scotland years ago where many people burned coal for heat. I guess when most of your tress are gone, coal becomes king. Where I am, surrounded by millions of acres of Doug Fir forest - coal wouldn't make much sense.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »
    T It's only mined in a couple places in the US, and I don't know how much reserves there are of it in other places in the world.
    --
    Chris

    That is the problem in a nutshell. It is expensive and in short supply. It is the true instance of "clean coal".
    SMA SB 3000, old BP panels.
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Choosing a good generator

    sidetracks are ok for a spell, but let's get back to the topic.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    mtdoc wrote: »
    It sounds like anthracite coal is even much better. I remember traveling in northern England and Scotland years ago where many people burned coal for heat. I guess when most of your tress are gone, coal becomes king. Where I am, surrounded by millions of acres of Doug Fir forest - coal wouldn't make much sense.

    You can burn pine in the non-catalyst furnaces. It says in the manual not to burn it in ours because there is emissions from the sap that will plug the catalyst. I've still thown some pine in it from time to time - but usually just one chunk if the furnace has burned down and we need a quick re-heat. The pine burns really hot and gives off a lot of heat in a short time, getting the jacket temp of the furnace back up to 350-400 degrees where it's supposed to be.

    Most of the coal that's burned for home heating these days is still "soft coal". Otherwise known as "powerplant coal". You can get anthracite delivered in some places in Pennsylvania in bulk by the truck load. But almost everyplace else it is sold in 40 lbs plastic sacks. We buy it by the one ton pallet. I just bought a pallet last week because the last pallet we bought two years ago had only one bag left. We paid $255 for one ton.

    Anthracite has 25 million BTU/ton. If you compare it to heating oil to get the same BTU would cost about 150% more at today's prices. LP is 244% more for the same BTU. Natural gas is 124% more for the same BTU. So I think it's still a really good buy.
    --
    Chris
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Choosing a good generator
    niel wrote: »
    sidetracks are ok for a spell, but let's get back to the topic.

    Like running the good generator on coal gas? :-)
    SMA SB 3000, old BP panels.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    niel wrote: »
    sidetracks are ok for a spell, but let's get back to the topic.

    Niel - sorry. It was my fault. I guess I just elaborated on some of the options I see for backup heating that wouldn't take a big generator to operate in an emergency situation.
    --
    Chris
  • niel
    niel Solar Expert Posts: 10,300 ✭✭✭✭
    Re: Choosing a good generator
    inetdog wrote: »
    Like running the good generator on coal gas? :-)

    even that would be a sidetrack.;)

    you guys can continue on a dedicated thread if you would like.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator

    It's kind of all related though. Like the OP said, he has natural gas so was trying to decide what type of generator would be the best for backup power. But I think Sandy is a good example of what can happen when folks need backup power. A lot of furnaces require 240 volt power. In reality most folks can get by in an emergency with a little EU2000 or 3000 and it will run all the critical stuff, including lights. But not usually the furnace.

    So do you buy a big 12 kW standby natural gas generator so you can run those big items, then have the gas shut off like they did in New York? Or do you buy a little EU3000 and have a backup heating source for your home that doesn't require the main heating unit to run? That can be a critical decision in choosing an emergency generator if you live in a cold climate.
    --
    Chris
  • swmspam
    swmspam Solar Expert Posts: 57 ✭✭
    Re: Choosing a good generator
    swmspam wrote: »
    Back to the fundamental needs: (1) electricity and (2) heat.

    Therefore, I've narrowed down my solutions sets:

    1. Gasoline generator + get a new furnace with a heat pump (use electricity for heating needs)
    2. Liquid-cooled gasoline or diesel generator + water pipes + indoors radiator (move the generator's waste heat indoors)
    3. Liquid-cooled diesel generator indoors + cogeneration (move everything indoors)

    Going back to the OP "Choosing a good generator" ... here is my conclusion:

    Considerations of Choosing a Generator for Backup and Emergency Electricity (battery charging and general usage):
    1. When Hurricane Sandy hit, natural gas went down with the electrical grid. The assumption is natural gas can fail and I should reply on my own fuel stored on-site.
    2. Gasoline is more ubiquitous and easy to obtain than Diesel (for me). Although Diesel has advantages, gasoline is preferred because of availability.
    3. Stationary generators are usually designed for natural gas or Diesel. Portable generators are mostly gasoline and can be equally reliable. Plus they are portable. If kept outdoors, a simple generator shed can house a portable unit and it can pretend to be stationary.
    4. Fuel efficiency is especially important if relying on stored fuel.
    5. Inverter generators have excellent fuel economy for variable loads. For battery charging, standard generators are better. However, the round-trip efficiency of charging batteries makes up for the difference. It is approximately the same to run an inverter generator in the background than intermittently running a battery charger then discharging the batteries between. Plus, the inverter generators are more flexible and portable, which may be important in emergency situations.
    6. 48VDC battery charging generators are rare and expensive. Most are stationary systems for telecommunications installations and use natural gas.
    7. 240VAC split-phase generators can cooperate with grid-tie inverters in "generator support mode", where the inverter can add its own 8kW to the generator. If using a 6kW generator, then the aggregate power of an 8kW inverter operating in generator support mode can deliver 14kW (not that I'd need that).
    8. Noise control is important. Some Honda and Yamaha portable units have noise performance comparable to stationary units. A quiet portable (inverter) generator in a shed would be even quieter.
    9. Honda generators have excellent reputations for noise, reliability, and efficiency. Yamahas have similar reputations.

    Solution: Honda EU6500iS with dual-fuel conversion kit. Build a generator shed that can breakdown and store in my garage that can assemble quickly when needed. This generator is legendary for noise, reliability, fuel efficiency, and high-quality electrical output. It is the only Honda inverter generator with 240VAC split-phase output. This generator has a prime power specifications (unusual for consumer portable units), which means it can run continually at a derated power to recharge a large battery bank. Dealers, parts, and repairs are readily available. The dual-fuel conversion kit allows natural gas operation (if available) to preserve my gasoline storage. If the natural gas fails, the generator can operate from my fuel storage. At a price point of $4000, the EU6400iS is one of the most expensive gasoline generators on the market and comparable to a good natural gas stationary unit (ones with non-Chinese engines).

    Thank you everybody for the massive amounts of experience and knowledge. This thread is far from over, though. There are too many generator selection issues that extend beyond this conclusion. This thread revealed that I still have a heating problem. If natural gas fails, a good generator is not going to heat my house. I could use an electric space heater for a short time until I burn all my gasoline, and then what? My solutions are an indoors cogeneration unit or a wood/coal furnace. We'll see where the equations end up. DTO (Data Trumps Opinion)!
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator

    On your generator shed, and since this may be fitting here for a portable taking the place of a stationary - here is some photos of our Honda standby generator shed that you may enjoy:
    https://picasaweb.google.com/110979388690716770927/HondaGenerator

    All a stationary generator is is a portable without wheels and fuel tank with a sound attenuated enclosure for it. The ventilated sound attenuated enclosure is really easy to build. Our relatively noisy EM4000SX is as quiet at full load in this enclosure as an idling EU3000 would be sitting in the back yard. The generator, in hot weather, actually runs cooler in this enclosure with a constant flow of air over the whole unit than it does sitting out in the sun in free air. I had to put a duct stat in there to regulate the internal temp of the enclosure in really cold weather.

    Congrats on your choice of a EU6500! You chose a brand that's top-of-the-line stuff.

    On your backup heating issue - I would recommend forgetting the indoors cogen unit. After you see how much heat is actually available from routing it and exhausting it from an enclosure for a small generator you'll come to conclusion that the amount of heat generated by a small generator set does not even come close to meeting the BTU requirements of a home. Most of these small generators operate at 50,000-60,000 BTU input and roughly 20% of that is converted to electricity. That's not much left for heating a home.
    --
    Chris
  • Blackcherry04
    Blackcherry04 Solar Expert Posts: 2,490 ✭✭✭
    Re: Choosing a good generator

    I guess a lot depends on the disaster you plan for. In Sandy if you were close to the shore your generator would have to have been stored on the roof. If it's a flood, all your electrical components would go south. A tornado close enough could cause you some problems. My plan for another Ice Storm / Snow storm, the rest of it is out of my control.

    Side Note : Someone had their generator stolen last night in NJ. The thieves started a lawn mower and left it running so the Generator owner would not hear the generator stop and taken. I saw another one where they just sawed the handles off and left them and the chain around a tree.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Choosing a good generator
    swmspam wrote: »
    [*]240VAC split-phase generators can cooperate with grid-tie inverters in "generator support mode" , where the inverter can add its own 8kW to the generator. If using a 6kW generator, then the aggregate power of an 8kW inverter operating in generator support mode can deliver 14kW (not that I'd need that).

    Just to be clear, generator support mode is something usually found not in GT inverters but in off-grid or hybrid inverters. And few of them at that.
    SMA SB 3000, old BP panels.
  • swmspam
    swmspam Solar Expert Posts: 57 ✭✭
    Re: Choosing a good generator
    inetdog wrote: »
    Just to be clear, generator support mode is something usually found not in GT inverters but in off-grid or hybrid inverters. And few of them at that.

    Xantrex XW6048
    OutBack GS8048
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    swmspam wrote: »
    Xantrex XW6048
    OutBack GS8048

    Add to that Outback GVFX inverters - which will also do generator load support

    These are all "hybrid" aka grid interactive inverters - not strictly "grid tie". Picky, I know..:blush:
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    inetdog wrote: »
    Just to be clear, generator support mode is something usually found not in GT inverters but in off-grid or hybrid inverters. And few of them at that.

    Xantrex SW/XW, Outback GS8048, Sunnyisland, and Magnum is coming out with one called the MSH4024RE. That's all I know of that can do it. The Outback GVFX is usually way picky on input power for it to work with most generators. The ones that can do it reliably have dual AC inputs with one dedicated to gen power.
    --
    Chris
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »
    Xantrex SW/XW, Outback GS8048, Sunnyisland, and Magnum is coming out with one called the MSH4024RE. That's all I know of that can do it. The Outback GVFX is usually way picky on input power for it to work with most generators. The ones that can do it reliably have dual AC inputs with one dedicated to gen power.
    --
    Chris

    The GVFX and GTFX inverters are picky - they require inverter generator input. But with a quality inverter generator (eg Honda, Yamaha) I believe it does work reliably.

    I am told - that the Radian (GS8048 ) has the same boards at the GVFX inverters - not sure if this is true or not.
  • inetdog
    inetdog Solar Expert Posts: 3,123 ✭✭✭✭
    Re: Choosing a good generator
    mtdoc wrote: »
    Add to that Outback GVFX inverters - which will also do generator load support

    These are all "hybrid" aka grid interactive inverters - not strictly "grid tie". Picky, I know..:blush:

    Maybe it has changed, but from the current programming manual for GTFX and GVFX:
    Neither the GTFX nor the GVFX is designed to be used with a generator. They are strictly for grid-interactive usage

    To me this means that although they may have the ability to do pass through of generator power, they cannot do true "generator support" in which the output of the inverter is controlled so as to prevent back feeding of power into the generator under any and all load conditions.
    SMA SB 3000, old BP panels.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator

    We looked at getting a Radian and they told me the AC1 on it will only accept grid power and the AC2 is adjustable to accept generators running somewhat out of spec.

    We use gen support to run all of our heavy 240 volt loads. If you want to push both the generator and inverter to maximum capacity for heavy surge loads (like I use my inverter with gen support for welding sometimes) the surge amps can sometimes approach upwards of 100 amps for 8-10 seconds. Most inverter generators won't deliver the surge for the time required and the inverter will spit them off.

    In order for gen support to work properly both the generator and the inverter's surge times have to be fairly well matched. As an example our Honda can deliver full 5 kVA for 10 seconds and the inverter can deliver about 10 kVA for 10 seconds. If you load the system to 15 kVA and the generator drops out of surge while the surge is still on the inverter will overload and shut down.
    --
    Chris
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »
    Most inverter generators won't deliver the surge for the time required and the inverter will spit them off.

    On Hondas you definitely need to have "eco mode" turned off for it to work and not spit the generator off. I assume the same is true for Yamahas , since it is that fuel saving mode that slows the response time to surges.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    mtdoc wrote: »
    On Hondas you definitely need to have "eco mode" turned off for it to work and not spit the generator off. I assume the same is true for Yamahas , since it is that fuel saving mode that slows the response time to surges.

    My experience with gen support, on at least the Trace/Xantrex SW's has been that you can set the maximum amps that the inverter will use from the generator during heavy loads. And you have to set that to the generator's prime power capacity. But the inverter expects that whatever you set that to, that it had darn well better be there when it wants it, plus 20%. When the microprocessors in there calculate all this out they have microseconds to decide what to do when a heavy load hits under surge - usually no more than one complete AC cycle. And the inverter responds by providing enough voltage increase to match the load based on that maximum amps setting that it expects to have help with, plus an additional 20% from the generator.

    If you only set that max amps setting to a lower setting of 80% of surge, you can't use the generator's full prime capacity on most inverter gens. This was one of the things that turned me off on a Cummins QD when we were looking at them.

    If both units are timed pretty well and they both drop out of maximum surge at the same time the power to your heavy load is automatically limited due to the "brownout" that occurs. And that lets them both recover. The generator will lug down, frequency will drop, voltage will drop, recovery takes place, hopefully the heavy surge load is done, and they both come back still working together. A generator that can't cut the mustard and hold minimum voltage and freq during that "brownout" will get spit off and then the inverter goes into immediate overload and shuts down because its transformers and FET's are already hot.

    For most things that don't have surge load, they're fine - my wife's range, clothes dryer, etc. But if one of those things is running and the well pump starts you'd better have a generator will balls or your power will go out.

    I am adding this because I wanted to make sure I am providing the right information for folks considering a generator for use on an inverter than has generator support. And this may only apply to Xantrex SW's - I don't know that. When I came in the house tonight my wife was doing laundry so I quick snapped a photo of the load amps on the inverter. This is with normal loads going in the house plus the clothes dryer going - right around 50 amps:

    Attachment not found.

    I watched it for a bit because the washing machine was in a spin cycle and it was going to fill up with water for the rinse, and this will start the well pump. I couldn't catch it with a photo but I saw 100-something surge amps when the well pump started (2 hp deep well pump @ 330' head). The inverter uses full surge amps from the generator as priority, and only fills in the difference during surge. I had my Fluke clamp-on on the AC line coming from the generator to verify this and it hit 42 amps, then dropped back to 30 amps after the pump was started and running.

    Part of the nice thing with a inverter with gen support is being able to run these big loads with a small generator. But don't scrimp on generator surge capacity if you intend to use this type of setup, because it won't work. If your generator gets spit off and the inverter has to take over the full load, the power will go out.
    --
    Chris
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »

    Part of the nice thing with a inverter with gen support is being able to run these big loads with a small generator. But don't scrimp on generator surge capacity if you intend to use this type of setup, because it won't work. If your generator gets spit off and the inverter has to take over the full load, the power will go out.
    --
    Chris


    I don't have extensive experience with this but I have tested it with my eu2000, GVFX3648 and 1 hp septic pump. The septic pump is 240V and run off my single GVFX inverter with an Outback PSX 240 auto transformer. It has a very high inrush current - cant remember exactly how high - (I did measure it once) . While running , it draws about 15 amps at 120 V from the inverter.

    With one of my eu2000is running through my Midnite epanel/gvfx3648 set up, supplying a couple of hundred watts of baseline loads and supplying the battery charger at 10 amps 120 VAC , the load support kicks in to support the septic pump load just fine without kicking off the generator- as long as eco-mode is off, With eco mode on the generator gets kicked off (but the inverter continues just fine - no lights out).

    Again - no extensive experience but just a test I recently did and it worked! I've heard others say it works well for them as well. So of course YMMV. And Chris your situation of running an electric range, dryer or other very large loads is of course a different beast requiring larger inverter and generator. I think for your average situation with an occasional surge load that exceeds a small generators ability, it can work just fine with these GVFX inverters.
  • ChrisOlson
    ChrisOlson Banned Posts: 1,807 ✭✭
    Re: Choosing a good generator
    mtdoc wrote: »
    And Chris your situation of running an electric range, dryer or other very large loads is of course a different beast requiring larger inverter and generator I think for your average situation with an occasional surge load that exceeds a small generators ability, it can work just fine with these GVFX inverters.

    It very well may work fine, and we only know when people like you take the time to test it. That way folks have the information and it provides one more possibility for off-grid or emergency backup systems that people can use. The Outback inverter is a much more economical inverter than the big Xantrex and Radian ones. And the EU2000 is a much more economical generator than a big 5 or 6 kW that it would take to run your well pump in an emergency as standalone.

    So thanks for pointing out that it DOES work. Outback tech support told me it wouldn't.

    The surge, or inrush, amps to a well pump depends on the size of the motor only. For our 2 hp pump it is about 25 amps, which is 50 amps at the inverter. The running amps will depend on motor size, water pressure and head and ours is about 9 amps @ 240 volt, which takes about 18 amps from the inverter or 120 volt generator going thru the PSX-240.
    --
    Chris
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    inetdog wrote: »
    Maybe it has changed, but from the current programming manual for GTFX and GVFX:



    To me this means that although they may have the ability to do pass through of generator power, they cannot do true "generator support" in which the output of the inverter is controlled so as to prevent back feeding of power into the generator under any and all load conditions.

    There's an addendum to the manual that was added to mine that shipped with the inverter. I don't see it on their website. . I believe the ability was added later to the G inverters. I think it was promised for the non G inverters but never implemented.

    Outbacks documentation is terrible. Their manuals, especially for their inverter/chargers, FNDC and mate are poorly written and incomplete. The "current" programming manual for the GVFX inverters is from 2007. I believe the addendum about generator load support is from 2010. I will see if I can find it when I'm home again and post it.
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    ChrisOlson wrote: »
    So thanks for pointing out that it DOES work. Outback tech support told me it wouldn't.

    Chris, your situation, as I understand it may be a bit different in that you are running loads that exceed the ability of either your inverter or generator to run independently but which they can run when both are working together to support the load in an additive power output manner.

    In my situation, the inverter can run the load independently with no generator and is then able to support the small generator which alone cannot supply the load independently. Maybe that subtle difference is important - I'm not sure:confused::confused:

    When I get a chance, I'll try to do more testing on my system and see what the limitations are. For me this is only something that would come up with the occasional prolonged power outage and cloudy weather requiring generator battery charging.
  • mtdoc
    mtdoc Solar Expert Posts: 600 ✭✭
    Re: Choosing a good generator
    mtdoc wrote: »
    There's an addendum to the manual that was added to mine that shipped with the inverter. I don't see it on their website. . I believe the ability was added later to the G inverters. I think it was promised for the non G inverters but never implemented.

    Outbacks documentation is terrible. Their manuals, especially for their inverter/chargers, FNDC and mate are poorly written and incomplete. The "current" programming manual for the GVFX inverters is from 2007. I believe the addendum about generator load support is from 2010. I will see if I can find it when I'm home again and post it.


    I found this on the Outback website this from page 17 of the October 2010 manual for their smaller GFX (also grid interactive) inverter chargers: (LINK HERE)
    Grid/Generator Support
    A system display is required to control this feature. When this feature is enabled, the inverter limits
    the current draw from an AC source, augmenting it with additional current from the batteries when
    necessary. This helps prevent overloading a small AC breaker or generator during short-term use.
    Initially, the AC source current is used for both loads and battery charging. In the MATE system display, the
    ac1/grid limit or ac2/gen limit settings dictate the maximum AC draw. If the AC draw exceeds this setting,
    the inverter reduces its charge rate to give priority to the loads.
    The charge rate will be reduced as much as necessary to support the loads. If the loads equal the
    amperage setting, the charge rate will be zero.
    If the AC loads exceed the amperage setting, the charger will begin operating in reverse. It will take power
    from the batteries and use it to support the incoming AC current.

    This page is the same as the Addendum added to my GVFX3648 manual