Power Logging and Generator Hours

[ChrisOlson]

I just got off the phone with an engineer at the plant in Minneapolis and he recommends that the engine be maintained at operating temperature for on-demand full load starting.  This is pretty standard with mission critical standby gensets like used in hospitals and so on so the generator can go to full rated power within 5 seconds of cranking (same as with Peak Load Management).

As I said earlier, while air-cooled engines can take this abuse, liquid cooled diesels cannot as it will severely shorten its life having that done to it several times a day all thru the winter.

For low bank timed starts, the inverter warms it up for 2 minutes.  But for Peak Load, it goes to work immediately - at full load - within 5 seconds after the inverter senses correct voltage and freq and syncs with it.

He had to consult with another engineer and they are estimating 375 watts on an electric block heater for the Kubota 770 to maintain it at operating temp at ambient temps below -20.  That's 9 kWh/day which is unacceptable for an off-grid installation.

That pretty much shot the diesel unit right there.  If we lived anyplace but in the cold north a diesel would work.
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Chris

[bob g]

Chris

because my work is focused on cogeneration, and i test and plan to use a diesel this is how plan to address the problem of cold weather startups

glow plug of course,

and i plan on the automation to startup the coolant pumps and recirculate heated water from the domestic loop storage tanks back through the engine to warm up it up prior to restart... i am not sure yet what length of time is necessary to put sufficient heat back into the engine yet... i am thinking perhaps a minute maybe longer,, only time will tell.

one scheme would call for just getting enough heat into the unit to provide for an easy startup, and then allow the engine to run at low speed setting (1200rpm) while powering a 1500watt heater that is screwed into the coolant at the cylinder plate... because of the rather limited amount of coolant in the block before the tstat opens,  i am thinking that even on a very cold morning an additional 1 minute of run time at 1500watts loading and 1500watts of heating ought to get the unit warmed up sufficiently to then allow the unit to go to full 1800rpm
and close the contactor to bring the AC generator on line.

i am also seriously thinking of a southward facing double glazed wall and a very thick dark concrete floor to absorb some solar heat gain during the day to temper the room over night so that maybe it doesn't get as cold as it would had i just put together a light duty shed with no attention to solar gain or insulation.

as for the chinese honda clones... so far i have tried out a couple of them, and been very happy with what i got.

nice little engine's that are low in cost and more than adequate for the intended purpose.  unbelievably quiet too!

bob g

[DamonHD]

Chris: could you use some sort of heat pump or other CoP >> 1 mechanism to provide the low-grade heat to the engine block: maybe you could reduce the electrical load to as little as 1kWh/d, eg about what my fridge/freezer uses, but effectively inside out, to keep it 10C+ above ambient in winter?  I wonder if you actually *could* use a freezer's reject heat to to this?

Rgds

Damon

[ChrisOlson]

Chris: could you use some sort of heat pump or other CoP

I don't know - I suppose it would be possible.  Hospitals usually use the heating system for the hospital to keep their generators warm in the winter.  Others use electric block heaters to keep them warm, but four 2,000 watt block heaters on a 500 kW genset consume a lot of energy.

So I just don't know.  It's something I have to deal with before winter.  But how I'm going to address it is not decided yet.

Edit:
Looking at the requirements, gasoline is going to be the easiest, most reliable and most convenient for us.  It might not be the most fuel efficient but practicality has to be considered too.  I just can't see the sense (for us) to going to the extremes of putting in an elaborate (or high energy consumption) heating system just to use a diesel generator, as much as that's the way I'd like to go.  But the northern Wisconsin/northern Minnesota area is the coldest area in the 48 contiguous states for average winter-time temps and I have to factor that in.

Also it should be considered that the gasoline generators of today are considerably more efficient than the old twin-cylinder horizontally opposed Onan and Kohler gas units that gave the gasoline fueled generators of yesteryear a bad reputation for fuel economy.
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Chris

[ChrisOlson]

because my work is focused on cogeneration, and i test and plan to use a diesel this is how plan to address the problem of cold weather startups

Bob, it's somewhat amazing talking to the two engineers this morning about getting a QD8000 started at 30 below.  They looked at it as a non-issue - just put a block heater on it - problem solved.

I told them, "no - not for me it's not."

I could tell by the hesitation on the phone that they're going "what"?

Just goes to show that off-grid needs are totally different than the mainstream.  The mainstream says "just plug it in" and if the power goes out it'll be warm and can come online immediately with no problem.  I understand that it takes a lot of energy input to keep a diesel engine warm in really cold weather - hell, even idling or running at partial load they don't make enough BTU's to warm up.  But "just plug it in" doesn't work all that well for us when "just plug it in" amounts to 1/3 of our total daily electrical consumption in the winter.
--
Chris

[Frank S]

Chris we built several geological logging vehicles at a company I worked for in the late 70s these were sent to Antarctica  The company had virtually every square inch of the engines coated in at that time an experimental thermal blanket of ceramic foam composite.
 To prep the engines we first installed 100s of short threaded studs then applied a spray coating of wax. over this dozens of 4mil thick plastic pieces were pressed in place then Nylon stud extenders were installed with protective sleeves, a gridwork of thin plastic separators were then used to serve as individual tile molds. after all of this the entire engine and accessories  was sprayed with 2 inches of the ceramic foam. Once the foam had cured each tile was removed  cleaned then re installed with nylon fasteners 
 Supposedly this was to allow the engines to maintain their operating temp at -60 for up to 3 days without any additional heat source other than the installed block heaters and not cause them to overheat when running.
 I never heard how things worked out because once they were shipped out I was moved to the department where we were building bodies for Sandia Labs

[birdhouse]

if you really wanna run diesel, dig a big ol hole and put 1000' of 1.25" pex in it with substantial copper leads on both sides.  yank the radiator, and put a constant running small pump. 

just an idea... 

what's your frost depth out of curiosity?

adam

[Frank S]

Chris ask the Engineers to write up a PQR for Antarctica

[Bruce S]

Chris ask the Engineers to write up a PQR for Antarctica

I want to read the IQ & OQ and see the validation matrix for that. Any sicqsicqma spreadsheet would acceptable too.
 

[bob g]

Chris
i can relate to your frustration when it come to having to educate
engineers on what is needed, when you are going to them for advise in the first place.

doesn't instill a lot of confidence does it?

this stock answer, "just plug it in" is akin to the old "replace it with a known good part" and i know you have heard that one before!

i don't want to plug in a known good part dammit!  i want to find out how this damn thing works, what made it fail, so that if it is proven the part i need to replace really needs replacing i have some assurance it won't fail again... that seems to be lost on some technical/engineering departments.

i don't know why i expect so much when i consider that every industry has these issues,  there are good mechanics and bad mechanics, good carpenters and bad ones, etc etc. so it stands to reason that there are good engineers as well as bad ones.

remember the old question

"what do you call a doctor that graduated at the bottom of his class?"

answer:  "doctor" 

and that about sums it all up.

probably good nasa had a higher grade of engineers on staff when apollo 13 needed some help getting the power requirements reduced and the power reboot sequence worked out...
can you imagine calling a part contractor and talking to their engineering dept,,, "oh just plug in a heater" or some similarly non useful response.

bob g

[Frank S]

I look at it this way. when I need something to meet specs for here in the heat, since almost everything electrical is sized for a max of 40C it sometimes takes us several phone calls . Emails and often even factory visits to get the design engineers to understand 50C ambient with at times as much as 60C should be considered normal operating conditions.
 When it comes to something like Chris's environment being off grid while at the same time requiring an on demand system not a 2 minute lag, also the prospect of a large energy load to be placed on an otherwise balanced system, just to be able to have a full uninterrupted on demand flip the switch just like anybody else can. Should not be too much to ask.
 Having them work up a case study with a working solution as if the generator was going to be used in the most remote area of this planet should not be too much to ask. Even if from say April to October the covers would be left open while during the cold months they would be closed. or shuttered to operate automatically without the need for a heavy energy load.
 I don't want to hear the words just plug it in ever come out of the mouths of my engineers. either work up a reasonable solution or go back to the design room and stay there until they can find one.

[ChrisOlson]

Adam, our average frost depth is 8 feet.  There has been years it's been more than that, however.

Reading Frank's description of arctic condition generators (which I have never seen this type of thing used) and all the other ideas - well, I think this illustrates the whole point.  Does a person go to those extremes just to use a diesel when you can install a gasoline unit and it "just works"?  I've been mulling this over in my head and a Honda EM6500 is looking really attractive.

I have used Honda's smaller generators with the iAVR in it and they put out clean power with 10 second surge capability, maintaining voltage and freq even though the engine lugs down, and I think everyone recognizes Honda quality.  I would, of course, like to try one out before I buy one and that's not going to happen.  But the Honda dealer that's only 10 miles from us does have one in stock.
--
Chris

[Frank S]

Chris you have to know this was in 1977 and when a customer stated his requirements the Engineering department took the approach that should something fail they wee the ones who had to go and fix it. That and the fact that not one of them had ever been  anywhere that it got colder than -5f in their lives I had just returned from Germany had had previously spent a winter just outside of   Reykjavik Iceland. There I was just a guy in his mid 20s who happened to apply for a welder's job who had happened to have been in one of the most gwdawfull places they had ever heard of. What they didn't know was Iceland is actually quite balmy compared to some other places I had visited it gets colder in Texas than some parts of Iceland normally does. Heck it was 10 times colder at Point Barrow the time I was there
 DO n't base you decision on any data I might toss out because all of it is older than this board and probably older than many of the guys on this board. I consider it possibly good for conversation or it might cause someone to do deeper research and that is about all. I've been lots of places done lots of things and most would be considered wrong by today's standards or technology.
 

[thirteen]

To me the better engineers are the ones that work with what they try to make. Or get things handed to them in peices. I worked with the son of a good engineer for about 8 months. He had sent his son to school for 5 years and when he graduated and got home he expected to have his own little office but John called me in the office and had me hand his kid gloves and a new shovel you should have seen the look on his face. I took him out to work with everyone. It was 2 months with every person on the job site from 2 months cleaning to 2 months roofing to 2 months wiring to the secretary's desk to 2 months painting and hanging sheetrock to cleaning the tiolets. He learned to operate loaders and poured cement and shoveled in the rain and shoveled the snow. He hated his dad for months but at the end he admitted he did learn and knows what and how things are done. I think he is in lives in Canada.

[ChrisOlson]

Yeah - they replaced the old power plant at South Pole Station back in 2001:
http://www.usatoday.com/weather/antarc/2001/2001-01-24-sp-new-generator.htm

They got new Cat 3512B's - three of them.  Before that they had three Cat 3412's that had been there since 1977 at the old Amundson-Scott Base:



The new gensets are used for heating the station as well as power.  That site has always fascinated me because it's about like living on a Mars base.  Except possibly way colder and more harsh than Mars.  There is no rescue from that place in the dead of winter, as Dr. Jerri Nielsen could attest to when she performed surgery on herself for cancer when she was stranded there in the winter of 1998.
--
Chris

[Frank S]

that new station was a marvel when they were building it to replace the old tin  and canvas shack quancet hut Hanger that housed a dozen separate research modules  the new one is designed to be raised on its stilts as needed to prevent snow entrapment.

[ChrisOlson]

I know.  I've long looked at that and thought seal it up a little better, add an oxygen supply to it and use nuclear reactors and solar panels for power instead of diesels and you got yourself a Mars base.
--
Chris

[Frank S]

Pretty much
 Here is all that I have been able to find on Steve's goop he came up with for that engine looks like some guy named David filed it as a composite panel
http://www.freepatentsonline.com/5849406.html[/i
 About halfway down you will find a reference  to low emissions engine by Steve and some other guy named Tom
 
 Makes more sense to me to see it used for what it is being used for than just  as an insulation on an engine since most cases removing heat is more of a problem than retaining heat.

[ChrisOlson]

Makes more sense to me to see it used for what it is being used for than just  as an insulation on an engine since most cases removing heat is more of a problem than retaining heat.

Well, there is some basis to using it on a liquid-cooled engine since most of the heat produced by the engine is lost in the exhaust, and pretty much the remainder thru the cooling system.  Once it is shut down it cools by convection and insulating the engine reduces the amount of heat lost.

But I have trouble believing that the insulation described would be very effective.  While it may help to keep an engine from "cold soaking" for several days, I see no way it could actually maintain engine temperature as would be required for an on-demand, cold crank to full rated power standby generator.  The 1.0 - 2.5 MW gensets that I worked with when I worked for Cummins, commonly used for standby power for high-rise buildings, large auditoriums, hospitals, etc., all use electric block heaters and the energy input to those is significant.  The generator has to be tested and certified to go from utility failure to rated standby power in the time the UPS can maintain power to critical circuits in the building, which is usually only 10 seconds.

For prime and peaking power units, the testing and certification is different since starting and stopping is scheduled well in advance.  So preheat is not an issue.

For us, the Load Start is a very important consideration because our inverters can only put out over rated power for a few minutes.  The generator has those few minutes to start, get its voltage and freq in spec so the inverter can sync with it, and transfer part of the loads to the generator (up to the max input amps entered in the menu for the generator) to reduce the load on the inverters back to below-rated output.  If the generator does not come online - our power goes out because the inverters shut down due to overload.

This is the single most important thing our generator does for us - battery charging is secondary.  And all last winter we had to be careful with loads to prevent a power outage due to the generator failing to start.  That defeats the whole purpose of the system, and one way or another I'm going to "fix" it with a generator that will start and can handle going to immediate full load without complaining.  That LP unit, even if it does start will sometimes bog out and quit due to low tank pressure in cold weather and it can't get enough fuel to it to maintain 10-14" WC at the regulator.

So it turns out LPG was a bad choice for us for a generator.  I guess that's what they mean when they say "live and learn".
--
Chris

[Frank S]

Like I said I don't know how well or even if Steve's idea worked He picked my head for what little it was worth but my only prior experience was how to start cold military diesel engines not how to keep the mat operating temps.As you know there is a whole world of difference.
 I am wondering out loud only if there might be a way to incorporate High cap pulse or slow discharge energy storage capacitors
http://www.amazing1.com/capacitor-chargers.htm
http://www.nrel.gov/vehiclesandfuels/energystorage/ultracapacitors.html
 to assist the invertedrs while the gen is coming online
 again loud thoughts only

[ChrisOlson]

I would imagine there are numerous ways, but all it really takes is a generator that starts.

Cummins also builds the QG (Quiet Gas) series generators that are gasoline fueled.  The QG7000 has a Onan EH65V v-twin engine with electronic fuel injection and full pressure lubrication:
http://www.cumminsonan.com/cm/products/gasoline/compare?gensetId=17&detail=true

And they are quiet - 69 db(A) @ 10 feet @ full load.  With a Power Command remote monitoring panel it is about double the price of a Honda EM6500SX.  Even though the Cummins QG7000 is a more powerful genset, I think the fuel consumption is very close to the same as the Honda unit.  The Honda EM6500's rated output is 5.5 kW which might leave us just a little short of what we have now.  The Cummins QG7000 is a little bit bigger than what we have now.
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Chris

[thirteen]

if it gets to cold to start a diesel but it will turn over soak a rag in gas and let it air out for a few seconds and hold it over the intake turn it over but take the rag off the second it turns over twice. Emergency start but it works. She will rattle for a few second and it will test out the engine with high rpms and high oil preasure. Not recomended but in an emergency things work. 13

[ChrisOlson]

Well, our system relies on an auto-start generator for load management.  Telling my wife she has to rush outside in 30 below weather to grab the gas rag and quick hold it over the air intake before the generator tries to start for load amps is going to get me some suspicious looks and probably a blunt statement about not knowing what the hell I'm doing.
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Chris

[smidy]

like i understand this generator will have some hours on it every day when it is cold? if so could you plumb the coolingwather to a storage tank and store heat and a smal cirkulationpump to cirkulate the wather trou the enginge and keep it almoust running hot 24/7 with just waste heat? of course you need a emergency radiator and pump if the storagetank get to hot. hope you undrstand my bad english.

[ChrisOlson]

like i understand this generator will have some hours on it every day when it is cold? if so could you plumb the coolingwather to a storage tank and store heat and a smal cirkulationpump to cirkulate the wather trou the enginge and keep it almoust running hot 24/7 with just waste heat? of course you need a emergency radiator and pump if the storagetank get to hot. hope you undrstand my bad english.

Yes, the generator will typically start at some point every day in the winter.  It sometimes doesn't run long, depending on the load condition that called for it to start.  But load amps in the winter can amount to maybe 1-2 hours per day on average.  Run time for battery charging can accumulate up to another 2 hours a day (averaged out over a month) in the winter - especially during December/January.

There are various methods that could be used to keep a genset engine warm enough to start.  But what I was told that for our setup where it is required to go to full load immediately after starting that the diesel unit I was looking at should be maintained at operating temperature.  It takes a lot of energy input to maintain even a small engine at operating temp in very cold weather.

I think I've weighed all those options, and considered the alternatives, and using a gasoline fueled unit, even though it may cost a few more dollars over a year's time to operate, is probably going to a better choice for us.

Most off-grid folks don't have a load management system like we have.  They just use the generator to charge the bank when the power doesn't come in from wind, solar or hydro.  The starting requirements for the generator are much different when you're using it for load management because it is coming online within a few seconds of a heavy load being applied to the system, specifically to meet that heavy load so the batteries and inverters don't have to handle it.  While it is a very nice and convenient thing to have, it is VERY hard on the genset because it requires it to start and go to full rated load, all within seconds.
--
Chris

[ChrisOlson]

I made a video of this phenomenon to show people how it works and what's required of the generator to make it work.

If it's 20 below zero F (or even colder) I don't think a cold diesel unit is going to either start on time, or be able to come up to full rated power like a gas unit can.  At least not without significant energy input to keep it warm.

Like I said in the video, I'm really leaning towards a Honda EM6500 at this point because I think it's a good generator with stable power output, and can do what's required without complaining about it.
--
Chris

[bob g]

can the honda or any gas genset actually startup and go to full throttle and full output upon a cold start in temperatures as low as 20 below?

i would fear scored cylinders and pistons

how do they manage to do that without scoring?

are they spec'd with very loose piston to wall clearance?

just curious

bob g

[ChrisOlson]

are they spec'd with very loose piston to wall clearance?

Yep.  Air-cooled engines are typically "loose" because they operate under such a wide range of temperatures.  The cylinder head temp on an air-cooled gas engine can approach 600 degrees F in hot weather.  Also they are "splash" (hydro-dynamically) lubricated (most of them anyway), so they can come up to full rated power and speed right after startup without any damage to the crank pin and rod.

The common everyday air-cooled lawnmower engines have been started and slam bang come up to 3,600 rpm since before Moby Dick was a minnow without any issues at all.  With modern synthetic 5W-30 lubricants extremely cold weather operation is no problem at all for these types of engines.

Spark ignition engines can take this kind of abuse time after time.  Diesel's can't because they're a true heat engine and you'll coke up injectors, collect unburned fuel in the fire cup in the piston, and stick the top ring in its land in short order unless it's all the way up to operating temperature.
--
Chris

[bob g]

the reason i ask is most lawnmowers are not started at 20-40below zero
and shoved into foot tall grass within seconds of startup.

i have no concern for brg lubrication, but i would be concerned about cylinder scoring,, that is why i ask.

bob g

[ChrisOlson]

i have no concern for brg lubrication, but i would be concerned about cylinder scoring,, that is why i ask.

There is no danger of cylinder scoring by running an air cooled engine at full load when it's bone cold.  Cylinder scoring is either caused by ring end gaps being too tight or lubrication breakdown from excessive heat.  The clearances and shape of the pistons in air-cooled engines are different than liquid cooled engines.

All areas of the piston do not expand the same; the top of the piston runs the hottest so it expands the most.  The skirt runs the coolest so it expands the least.   For this reason the diameter at top of the piston will normally be smaller, and the diameter at the bottom of the skirt will normally be a little larger than the  diameter at the top of the skirt.

Also,  the piston does not expand the same all the way around its circumference.  The diameter  measured across the piston pin will expand more than the diameter-measured perpendicular to the piston pin.  Therefore, liquid-cooled engines use cam ground pistons.  When the piston heats up to operating temperature it will be round.  If the piston were not cam ground, the piston to cylinder wall clearance would have to be extremely high when the engine was cold to allow for expansion, aka air-cooled engines, and it would not be round when at operating temperature.  This will cause piston slap and other problems in liquid cooled engines, when piston slap is "normal" in air-cooled units.

Air-cooled piston engines have been used in some of the highest horsepower applications on earth, operating in some of the most severe temperature extremes imaginable, in aircraft for 100 years.  They will survive and take abuse that no liquid-cooled engine can.
--
Chris

[bob g]

thanks for the tutorial on piston design, i am sure someone here learned something for the effort.

the thing i keep coming back to is this, i find it hard to believe that honda is ok with a cold start at 20 or more below zero, going to full throttle and full rated load within a few seconds of being first lit up.

i don't care what oil you want to use!

years ago i was tasked to find out why a quarter midget race car powered by a 500cc single cylinder honda could not finish an 8 lap race without scoring its cylinder...

the reason was the piston fit was too tight for the application, the car weighed in at about 3 times what the bike the engine came off of, the airflow was inadequate and the piston would very quickly out grow the bore.

it didn't score due to ring end gaps or the size of the piston head, it scored due to too little clearance between the barrel/body/skirt of the piston and the cylinder bore.  opening up the clearance to near .008" (about 3 times the honda spec) corrected the problem.

if you recall cummins diesels scoring cylinders on cold morning startups, wherein the driver would jump in, startup and haul ass out the gate would score the cylinder,, it was not due to ring gaps or piston head as cummins piston heads are decidedly smaller than the skirt diameter, it was scoring of the skirts and overheating of the liner which would burn the liner packing and you got antifreeze in the oil.

so unless you allow the honda to warm up a bit on a cold startup before you apply a full load my bet is you will run the very real risk of scoring.. i see no way around it with 20 or more below zero F.
the coefficient of expansion of the aluminum alloy vs that of the iron sleeved cylinder will certainly be a problem.

either that or the engines are set up with loose fitted pistons to start with, in which case maintaining piston sealing is problematic, so a compromise would have to be made. a compromise that would not enhance normal temperature longevity, so it is hard to imagine why honda would make that compromise in order to allow operation in sub zero climates under this sort of startup/load demand.

now what i would accept is honda might spec an engine for such use, with the understanding that the reduction in longevity is traded for the ability of abusing the $#|+ out of the engine with such a demanding startup.

there really is no reason that anyone should design a genset for this sort of duty other than for emergency backup power use.
this is why we see gensets sold surplus for pennies on the dollar that have less than 500 hours on them... it is well understood that the engines have had the living $#|+ demanded of them and as such have lost a significant amount of their lifespans.

personally i would never recommend to anyone in your position to design a system that would place this sort of startup requirement on a generator,, its just not good engineering in anyone's book!

the idea that you have to have power "Right now" is not reasonable, and i would refuse to sell you a unit to be used in such a manner. if cummins wants to do so, fine, they have deep pockets and they are charging twice what the machine ought to sell for anyway.

you will never convince me, nor would anyone else in a similar installation that an automated system with an appropriate delay to provide for warmup before the load is applied is not acceptable.
there is no reason that you or your wife, could not wait the requisite amount of time needed to provide for such a warmup. the idea that you want to start a load of laundry "now" rather than having the washer start when the power is available a couple minutes later seems without merit to me.

now if you came to the table and said i must have this sort of performance because of my medical needs such as some sort of heart monitor, or similar thing that is mission critical, then i would say fine, lets build you a generator that will not only start reliably at 50 below zero but also take on a full rated load within a few seconds... but this is not the case!

i think sometimes we make unreasonable demands of a system and its components, and are unhappy with the cost, with the longevity or performance of the system in general or some component part when it fails to meet our "want" instead of our "need"

i guess i would not want to hear you come back here, bitching about honda in the event that on a very cold morning even though it started you scored the cylinder and damaged the engine trying to get a hot cup of coffee "right now" instead of waiting a couple minutes for it to warm up and stabilize first.

i would not see this as a fault with honda, i would attribute the failure to owner abuse!

hey, but thats just me
i have always been the poor guy that has to clean up the mess when folks abuse equipment, and it is never their fault it is always the POS equipment that is at fault, at least this is what they would have you believe.

bob g

[ChrisOlson]

there is no reason that you or your wife, could not wait the requisite amount of time needed to provide for such a warmup. the idea that you want to start a load of laundry "now" rather than having the washer start when the power is available a couple minutes later seems without merit to me.

We spent too many years waiting to wash a load of clothes or even vacuum the floors in the house until we got a sunny, windy day.  That might seem like the "hot tip" to somebody new to off-grid living.  But it gets really, really, REALLY old after about 5-6 years of doing it and living that way.

I made a mistake in picking a generator that won't start and run in cold weather and I'm going to remedy that one way or another.  And I'm not going to do it with a complicated cogen system with a lot of plumbing and wiring and tubes running to and fro from the generator.  It's going to be simple and reliable so it works without messing with it all the time.

My power logs showed me this last year that we're not going to reduce our gen hours below about 400 a year no matter what we do.  And when I look at this, the fuel cost is actually very minor in the big picture so there's no sense to going to extremes to have the most fuel efficient generator possible.  What we need is one that works every single time, no matter what the conditions are that its called upon to work in.

I've gone over this again and again in my mind, and even though diesel looks attractive because of efficiency and price, the cost difference is very minor compared to other fuels.  LP gas will not work - already Been There Done That.  The prime consideration is getting a unit that starts as reliably as the little Champion backup unit we got.  And that's not the brand of the generator, or the design - it's the fuel used.  Gasoline is the only one of the three fuels that does not have a problem flowing at 40 below zero without additives in it or heat applied to it.

So, considering the issues, and gasoline being the best option for cold weather, the only thing left to decide is what generator to get.

Frankly, I'm not even remotely worried about scoring cylinders in a Honda generator.  If it does, on some outside chance, it's got a three year warranty and Honda will cover it.  I have not seen a Honda GX-series engine that you can destroy as long as it's got oil in it and the air cleaner is on it.  There's a reason that 99% of the rental industry uses Honda engines on power equipment even though they are certainly not the cheapest.

We own our 500 gallon LPG tank, so once we got gas in it we own it and they won't take the gas back.  We finally ran that tank dry so now is the time to change generators.  If I wake up in the morning with a wild hair I'm going to drive to the Honda dealer and come home with a new EM6500.
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Chris

[smidy]

I'm also a bit woryed about full trottle/load from cold no mather wath fuel, but i came up with an idea that wont be hard on electricy load but will need fuel, dont know the english name on it so i'll give you som brands eberspächer and webasto there are more brands but this pop up, smal petrol/diesel burners usully used in thrucks around here to warm up the engine and cab in cold wheter. the truck i drive(mercedes econic 2633) have an eberspächer and it works great. in about -20 C it will heat the engine in one hour to about 50 C and warm up the cab. maybe that could be somthing to heat your engine in your generator, of corse it need to be liqid cooled engine then.