Power Logging and Generator Hours

[ChrisOlson]

There's not really a balance of systems section on this board, so I guess I'll post this here.

Our power logs for YTD are attached in PDF format.

I was studying these logs and was a little disappointed.  One of my goals last year was to reduce the generator hours this year.  That hasn't happened.  If anything, we're putting more hours on the generator this year.  I think one of the problems is that we've gotten less conservative with our power usage in the home and if we want to run something we just turn it on.  The biggest chunk of gen hours was in Jan/Feb but when December gets here we'll easily put on another 100 hours.  We're going to go thru 500+ gallons of LP this year in the generator, which is alarming because the first year we put in our new system we burned less than half that - and I added more solar power in the Fall of 2011.

I don't have a way to measure kWh output of the generators, but I'm guessing our daily average usage approaches 30 kWh/day with the gen time figured in.

There's some things I could do to cut the gen hours.  One thing I see that happens in the winter time is that the bank has heavier loads on it 24 hours a day so in the morning it will be down in the low 24's on voltage, depending on what the wind turbines are doing.  We get up in the morning and make breakfast and the load from the coffee maker, toaster, electric range, etc., pulls the bank below the 2 hour low voltage auto-start timer for the generator.  So the gen starts and charges the bank up and then the solar and wind have nothing to do all day except maintain the bank.  I'm going to lower the voltage from 24.0 down to 23.8 for the two hour auto-start because that lower voltage in the morning is due to loads on the system, and not actual low SOC of the bank.

Even so, being we've gotten a little wasteful in our old age, we're not going back to the "old way" of living around how bright the sun is shining and how hard the wind is blowing to be able to do stuff.  So it appears to me that one of the things I'm going to do before winter is rip that LP generator out and install a new Kubota GL7000 diesel.  I don't care if LP gas is "eco friendly".  It ain't very damn efficient.
--
Chris

[bob g]

Chris

two suggestions,

1. get a GE digital kw/hr meter off of ebay or from austin international
they will set it up to read out anything you want.  it has a memory so you don't have to worry about losing your cummulative kw/hrs when the generator is down.

2. can you spell "cogeneration"?  in the winter harvest the waste heat from the generator engine can surely be put to good use, which in turn reduces the need of other fuel sources and reduces the cost per kw/hr of electricity generated.

if you did nothing but heat water, or divert the heat to space heating which would be easy enough, i think the amount of propane burned wouldn't hurt so much... actually probably make a significant difference in how you view the genset run times.

of course all this excess heat is less useful in the summer months unless you like lots of hot baths, showers or hot tub soaking?

getting back to the GE kw/meter , here is an example
not the one i use, but i bet it will do what you want.

http://www.ebay.com/itm/GE-Watthour-Meter-see-photo-/290655128946?pt=BI_Electrical_Equipment_Tools&hash=item43ac654d72

i would have to go check which model i have, the one i use
has over 200 different things it monitors and logs many of which
can be set to read out by toggling that little lever up front.

mine has the toggle lever which allows me to check iirc 6 different things, a magnetic reed switch which toggles through another screen, and in internal push momentary switch (i drilled a hole through the lexan cover to toggel it) which allows about another half dozen parameters to read out and scroll through.

every parameter imaginable is measurable and able to be displayed
for example volts per leg, amps, power factor, watts, kw/hr cummulative, watts surge/peak, half a dozen different kinds of distortion. etc. 

very accurate too

something to consider

bob g

[ChrisOlson]

I've been going to pick one of those up for awhile now (a kWh meter).  But another way to look at is is that the generator is going to run no matter what - be it for load start or low battery bank.  So whatever it generates is what it's going to do regardless.  The generator is an integral part of our system so we can enjoying living for a change instead of worrying about whether or not my wife can wash and dry a load of clothes.

The Kubota generator I want to get is liquid cooled so I can put a block heater in it to get it started in the winter.  I'm done with air-cooled generators.  That LP unit won't start in the winter anyway, even with a crankcase heater on it.  So we got a backup gasoline generator that will actually start.  So it hasn't been the best setup as far as generators go.

The Generac burns 1.1 gallons/hr @ 75% load and 1.5 gal/hr @ 100% load.  The Kubota only burn .65 gal/hr @ 100% load and it's 7 kw output instead of only 6 kW.  It's also twice as much money as the LP unit.  But it has glow plug pre-heat, and with the addition of a block heater, will start and run when the LP unit won't because there's not enough tank pressure to run it.

I'm not really that interested in a cogen system because it would be something else I'd have to mess around with.  And frankly the cooling system heat would be used to heat the generator shed up anyway to take the chill off in there, so it's already sort of a cogen system without the extra plumbing.

I dunno.  With LP pushing $1.90/gallon and I can get off-road dyed red diesel fuel for $3.20/gallon, the diesel would cost only about 85% per hour in fuel cost compared to the LP.  It's probably what we should've gotten in the first place, but we didn't.
--
Chris

[keithturtle]

It's probably what we should've gotten in the first place, but we didn't.

Hindsight is 20/20.  Thanks for sharing

Turtle

[ChrisOlson]

Hindsight is 20/20.  Thanks for sharing

It sure is.  I'm not dead set on a Kubota - I've also looked at the Cummins QD8000
http://www.cumminsonan.com/cm/products/diesel

The Cummins is a $14,000 generator, which is over double what the Kubota GL7000 costs.  But generators are one of those things where you get what you pay for.  And I hate to buy a Kubota and then say hindsight is 20/20 and I should've bought a Cummins.
--
Chris

[bob g]

Chris
i am interested
what engine is the cummins unit using?

and do you have a link as to its construction

14k bucks for a 7200 watt generator (continuous at sea level) seems a bit much, however that really depends on the quality of the component parts, the engine being a significant component.

for 14k bucks or even 7k bucks (the price of the kubota) i would bet a decent diy'er out to compete with that quite handily.

oh yes, and if you have any fuel consumption numbers that would be good too.

bob g

[bob g]

ok, i found the spec sheet, don't know how i missed it.

looks like the cummins uses a kubota 3 cylinder engine
so the engine reliability will be the same whether you buy a cummins
generator or a kubota generator, at least for the most part?

the fuel efficiency is decent, but certainly not great in my opinion.

again have you considered building your own?

if not, why not?

bob g

[highwater]

hey bob g, and others.
been hanging around for long time.
bob knows me from one of his forums.

I have one of these meters.
din rail mount.

downside is each time incoming power is disconnected it will click a tenth on you.
the spec sheet I have at home says anyway.
The current spec sheet avaliable, does not mention this however.
I think I have the pdf saved. will look

Randall

https://www.asi-ez.com/member/x166-kWh-Meter-DIN-Rail-Mount-Compact.asp

[ChrisOlson]

what engine is the cummins unit using?

It's got a 3 cylinder liquid cooled 29 cubic inch Kubota diesel in it.  The nice thing about the Cummins unit is the electronics and world class service, parts and support.  Cummins Power Generation's worldwide headquarters and service/parts center (Cummins N-Power) is located only 85 miles from us in Minneapolis, MN and they have service trucks that are better equipped than most large shops that will show right up at your place to fix a genset.

It is also an inverter generator so it puts out super-clean power and has "ecothrottle" like the Honda inverter units so when the load reduces the engine throttles back and still maintains frequency and voltage with the reduced load.  This is a very important consideration when charging batteries with an off-grid genset and inverter chargers, and can save a lot of fuel.

It is also a standard two-wire start, G/S stop unit, which integrates nicely with an off-grid system with standard generator controllers.

Cummins Power Generation is the largest manufacturer of standby and prime power diesel and natural gas generator sets on earth.  When you buy a Cummins you don't have to worry about it if it breaks - they got people and a worldwide network to keep their stuff going that is second to none.

The Kubota GL7000 has none of this stuff - and it's a lot cheaper.  Like I said - you get what you pay for.
--
Chris

[bob g]

Chris
at the risk of devils advocate

first i would agree cummins provides excellent  world class service and parts supply.

now the question

their unit drives a pm alternator, is converted to dc via a rectifer, then converted again to 60hz pure sine wave via the inverter, (@power factor unity), the result of which you then take into your inverter charger, to charge a battery bank, in order to later take the power from the battery bank, to power the inverter, to provide 60hz power to your loads?

the overall efficiency has got to be world class dreadful?

have you considered skipping a few conversion steps, by
simply driving a high efficiency battery charging alternator to directly charge the batteries?

in my opinion, the cummins is the most over hyped unit of its type i have ever seen!  really!

and i am not trying to be combative, but for 14grand it ought to be much more efficient than what cummins is presenting here?

my first clue is how they rate this product, it is rated as an 8kwatt generator, but looking down further that is an intermittent rating, continuous is 90% or 7200 watts, or rather 7200 kva because the inverter is rated at a power factor of unity? so maybe with a .9pf you have 6300 watts of actual capability at sea level?

at right at 1gallon per hour consumption at full load, is outside of any efficient offering by any serious company i know of in this class of machine.

so clearly there is something else that makes this desirable to you?

i realize this discussion is off topic to your original post intent, however this is something i have an interest in and as such am always interested in what other see in other units as desirable.  especially when we are talking 14 grand for the real capabilities here..

so yes i am interested in what interests you about this product.

thanks
bob g

[bob g]

hiya Randall/highwater

small world huh?

thanks for the link, that looks like a nice useful unit and especially good for those that are heavily into the din mounting system...

(for those that are not familiar with it.)
that DIN system has a huge installed base, and there is tons of cool stuff made to work together with it, much stuff in surplus arena too.



bob g

[ChrisOlson]

have you considered skipping a few conversion steps, by
simply driving a high efficiency battery charging alternator to directly charge the batteries?

No.  One of the main things our generator is used for is peak load management.  Our inverters start the generator when excessive loads occur and they sync with the generator and use both the generator and inverters to supply power to the loads.  This is how we can have electric clothes dryer, my wife's induction 240 volt range, and I can run a full machine shop, etc., and run it off-grid.  You can't do that with a battery charging outfit.  You'd need WAAAY bigger inverters than we got to make it happen.

With our setup we can use moderately sized inverters and a moderately sized generator and run very large loads that rival what you can do on grid power.

so yes i am interested in what interests you about this product.

• reliable starting (I have Kubota diesels in my Bobcat skid steer loaders and am very familiar with them)
• more fuel efficient than our EcoGen
• it is diesel and I contract 30,000 gallons of off-road diesel fuel per year so I get a very good price on it compared to propane
• it is a very quiet running unit - this is for our house and when it starts I don't want to know about it
• super clean power output (my wife's range is all electronic and does fine on the inverters but error codes sometimes on genset power)
• world class service and support from a company I trust and worked for for 19 years

Unlike most people who live off-grid and consider it a "sin" to run the generator - we run ours all the time.  I already bought one generator that I've grown increasingly unhappy with as time goes on.  I won't make that mistake twice in a row.
--
Chris

[bob g]

Chris

can you see what presents some confusion here, on the one hand you state you are unhappy with the amount of gen run time you are experiencing, and on the other you state it is an integral part of your power generation design?

looks like if it is to be seen as part of the design, then run time is of no real concern, rather is should be seen as an indicator of how well the balance of your system design is at providing for your loads?

now to address some of your points

 "   reliable starting (I have Kubota diesels in my Bobcat skid steer loaders and am very familiar with them)" 

can't find fault here, seems reasonable to use what you are comfortable with as far as the engine choice.

   
" more fuel efficient than our EcoGen"

will take your word for that, i have no experience with an ecogen.

   " it is diesel and I contract 30,000 gallons of off-road diesel fuel per year so I get a very good price on it compared to propane"

no problem here, either, if you are going to burn fuel you might as well avail yourself to the best value

   " it is a very quiet running unit - this is for our house and when it starts I don't want to know about it"

Quiet is cool, and i can understand the desirable nature, can you put a value on that part of the cummins genset?  if all else was equal, then how much of the extra cost would you attribute to noise reduction?

    "super clean power output (my wife's range is all electronic and does fine on the inverters but error codes sometimes on genset power)"

agree'd, but shouldn't any inverter generator have similar qualities of power generated?

   " world class service and support from a company I trust and worked for for 19 years"

i guess that has a value, but if the unit is all that and a bag of chips, then presumably you won't be needing much of that world class service and support?  the 19 years notwithstanding.

what i am drilling down to is this,

from my perspective and based on what i know of gensets in this class
14 grand is a butt load of money, at as you say twice the cost of the average genset in this class, so... naturally one would want to know what the extra expense is buying him. most especially given the efficiency of the unit is nothing to write home about. if you are running significant hours, as you say, then i am left to wonder what the calculus you used to consider this cummins unit.

so far it would appear that for the extra 7 grand it is assumed to be quieter than the average unit (taking your word for it, or rather cummins word for it), and cummins service quality which is only really if you expect the unit to be problematic.

"Unlike most people who live off-grid and consider it a "sin" to run the generator - we run ours all the time.  I already bought one generator that I've grown increasingly unhappy with as time goes on.  I won't make that mistake twice in a row."

that seems reasonable to me, no sense in repeating mistakes.
refresh my memory, what generator are you using that you are unhappy with? what fuel does it burn? what kwatt output is it? is it an inverter generator?  what was its first costs? and what problems that required service have you had with it, that having a company like cummins might have avoided?

just trying to see what the comparisons are here, to see if it is apples to apples or nearly so, rather than crab apples to pineapples.  in other words its hardly a comparison if one is comparing a propane fired aircooled single cylinder engine driven capacitor regulated chinese unit with a 3 cylinder water cooled diesel driven pm alternator driving a pure sine wave inverter that is assembled here in the states by a local company.

what it comes down to is trying to quantify exactly what you the user see's as value in a genset?

don't get me wrong, i am a strong proponent of the use of a genset, i think one has to assume a genset is going to be a reality for the vast majority of offgrid applications and as such ought to be as well designed and matched to the application as is humanly possible. the goal being its operation in an environmentally responsible and fuel efficient manner as is possible also.  to me the issue relating to noise abatement and quality of service provided by the manufacture are of secondary importance, mainly because the former is something that can be addressed by placement and secondary enclosures such as a generator room, and as far as the latter one would assume that a quality built unit that is maintained properly ought not have issues that one would need factory support for in significant amounts.

its these last two factors that i find interesting, where you are clearly capable of providing for both noise abatement and service for a genset, i am left to wonder why you would pay a premium to avoid both? and also have a unit that burns about 20-25% more fuel than is necessary?

again, please don't take offense with my questioning, i am just trying to get an appreciation for your viewpoint, and your experience living as you are living, where you are living, given your abilities and resources.

just trying to determine if the difference's are perceived or real, if that makes sense.

thanks
bob g

[ChrisOlson]

Like I said earlier, my goal last year was to reduce the hours put on our genset.  That didn't happen.  Mostly because we have grown to enjoy having all the power we need "on-tap" any time we want it.  We used to live on 10 kWh per day - now we use 25-30 per day.

We have a Generac EcoGen and it is LPG fueled.  It has had various problems, including low voltage output, oil pressure sensor failed, two generator belts failed, it won't start at temps below 10°F.  It's on its third "brain box" right now because of low voltage problems.  Admittedly it was a new concept for Generac when we got it, and I've given Generac enough time to sort out the bugs and get it fixed.  However, Generac does not fix ANYTHING on units they have out in the field and they know have faulty parts in them, on their own.  The generator has to break or be rendered inoperable and then they come out and say, "Oh yeah - that's been updated."

I've had it with this s&*t.  If there's an update on a Cummins genset they will contact you and arrange to have one of those service trucks come out and update it BEFORE it breaks.

The efficiency of an inverter generator is less than a conventional at full load by a small amount (loss in the inverter).  I actually tested a bunch of different generators about a year ago and did a measured fuel consumption test on each one at various loads.  You can look up the results, which I posted on this forum someplace.  While the inverter units didn't fare as well at full loads, they are equal or better at partial loads where they start idling down while providing the same 60Hz power that a conventional unit has to maintain rpm for.  So I fully understand the tradeoffs and looking only at full load fuel consumption is deceiving.

From the standpoint of the Kubota GL7000 vs the Cummins QD8000 - if I want a Kubota generator I have to order it.  Once I order it I own it.  I won't buy one online and the dealer does not stock them, nor does he stock any parts for them.  I can call Cummins N-Power and have a QD8000 here this afternoon on a rental basis and try it out for a week, or a month, or whatever I want.  If I decide to buy it after a week they will tear up the rental contract on it.  Cummins N-Power stocks every part for the QD8000, including complete generators.  I can call Cummins N-Power and have a 2 MW semi-trailer mounted Cummins diesel rental genset sitting in my yard inside 4 hours if I want.  These guys are the pros:
http://www.cumminsnpower.com/

We already have a 250kW Cummins prime power genset that powers our grain handling system, and it "just works".  That set cost us $68K when we bought it.  We could've bought cheaper generators for that application too.  But if that generator breaks when we're in the middle of harvest we are SCREWED so we bought it from Cummins N-Power because they would be at our place with a complete replacement generator inside 4 hours if it ever went down.

So do I save the money and get a cheaper unit, or buy the best there is?
--
Chris

[highwater]

I found the spec sheet that I mentioned on the din rail meter.

https://www.asi-ez.com/literature/applications/

All the way to the bottom: publication #AN004
go to page 5 of 8
first heading: Counter operation


Randall

[ChrisOlson]

Well, it turns out Cummins N-Power has the QD8000 in stock for $10,514 outright, with a Cummins Power Command remote monitoring panel and Cummins ATS switchgear.  If I'm interested in one they'll bring it out and install it (which I have to pay for), and I get to try it out on a rental basis for up to two months.  If I like it I can buy it and the rental contract is void.  If I don't like it, I just pay for the hours on it and they'll come get it.

The Kubota dealer couldn't match that deal.  I have to pay for the generator upfront if I buy a Kubota, before they will even order it.  And it takes "up to two weeks" to get one - and if I don't like it they won't take it back.  And they won't deliver it and install it.  And if it has a problem I have to load it up and haul it to the dealer to get it fixed.  They don't stock any parts for one but they can get parts overnight if I want to pay the freight charge.  It comes with no remote monitoring panel but I can get a no-name Chinese-built transfer switch with it (optional).

These are the things that tend to sway my decisions - especially when I already spent well over $3,500 on a unit that's not even good for a boat anchor.
--
Chris

[Frank S]

Not that it would mean any sweat trickling down my nose either way but based on the stated availability, the after sales service which Cummins can offer in its form of rental or purchase mainly because of their network of worldwide distributions Having them do the install and run in plus going on contract for an extended warranty period almost guarantees you trouble free service or at the very least a low likelihood of being without power.
 You are your own utility company with only ONE customer. You do not have the option of telling yourself sorry we are experiencing technical difficulties all of our crews are working round the clock to restore your service,we will get to you as soon as we can.
the $10K price tag based on that aspect alone sounds like you are well on your way to having made up your mind.
 I know it would for me if I had a $10K battery bank to maintain 

[ChrisOlson]

Not that it would mean any sweat trickling down my nose either way but based on the stated availability, the after sales service which Cummins can offer in its form of rental or purchase mainly because of their network of worldwide distributions Having them do the install and run in plus going on contract for an extended warranty period almost guarantees you trouble free service or at the very least a low likelihood of being without power.

I'm not totally decided yet.  I know we have to do something before winter because I'm not going thru another winter with the generator we got.  When I found out the LP tank had been sucked almost dry a few days ago, and what they're now getting for LP to come fill it - and add to that all the problems we've had with it.........

If our Generac ever makes it out of warranty it would be a nightmare to keep it going.  The EcoGen was a new concept in off-grid generators but I don't enjoy being the "test bed" for a new product to get the bugs worked out of it.  When they shipped it out they didn't even have the wiring diagram right for the 240 volt conversion on it, and who knows how many people bought them and they only put out 219 volts.

The way I look at it, a person can try to save a nickel now to spend a dime later, and where does that get you in the end?  A nickel short.
--
Chris

[bob g]

Chris

just to refresh my memory, how large is your battery bank in kwatts?

bob g

[ChrisOlson]

57 kW.  Twenty four Rolls T12-250's.  24 volt.
--
Chris

[bob g]

57 kw, hmmm
are you sure the cummins 8000 series unit is large enough for the size of bank you are using?

i can see long hours of run time with the genset to recharge that battery bank should the clouds be thick and the windspeed low, and made much worse by the ongoing needs of your home?

interested in your thoughts on this matter

57kwatts, taken down to 50% SOC leaves 28kwatts to replace, factoring in battery efficiencies, and rounding off, lets say somewhere around 30kw/hrs needed to recharge... that of course without the home drawing more as you charge, and no other charging current coming in from elsewhere.

that 8000 series is probably good at getting 5kw back into the battery bank per hour, after all the conversion steps are accounted for , so it would appear that the genset could easily run a minimum of 6 hours per day?

and easily twice that on cloudy, calm days when life goes on with power demands of the home continuing?

what do you think?  is it large enough to do the job?

i guess it couldn't hurt to rent the thing for a couple months, run it through the paces, and just for testing cut off the solar and the wind generator input to see just how well the thing does under these conditions, how many hours it must run, and just how many gallons of fuel it consumes?

that is where renting or leasing from cummins makes a lot of sense, it might be that it proves to be right sized for your application, if not you would have a good idea just how much large a unit you might need to do the job and then buy it.

what do you think?

bob g

[ChrisOlson]

57 kw, hmmm
are you sure the cummins 8000 series unit is large enough for the size of bank you are using?

Yep.  The inverters only put out 240 amps and the 6 kW Generac can do that with no problem as long as the rest of our loads aren't too heavy.  If the generator starts because of the two hour auto-start timer (bank at 50% SOC) it takes the Generac, typically 7 hours to fully recover it back to a full bank.

The guys at N-Power told me the QD8000 will put out 7.5 kW continuous at 100 degrees F ambient temp and 1,000 ft elevation on 1 gallon/hr.  He said in cold weather below freezing it will deliver the same performance on .92 gal/hr.  So it actually has more "grunt" than the Generac to power loads and keep the chargers in the inverters at full amps during bulk.

The nice thing about the Cummins is that it will idle down once the bank goes into absorb and doesn't have to keep running at rated speed like the Generac does.  I think that will save a lot of fuel because at 50% load the guy at N-Power told me it will burn .6 gal/hr @ 3.8 kW output - he said they have measured many many of them and that's where they are at 1,000 ft elevation for performance.  The Generac burns 1.1 gallons/hr @ 50% load (~2,800 watts output).  .6 gal of off-road dyed red diesel is $1.92.  1.1 gallons of LP gas is $2.09.  So the cost per kWh in fuel for the QD8000 figures out to 50 cents/kWh @ 50% load.  For the Generac it's 75 cents/kWh @ 50% load.

The Generac's engine is a 530 cc twin cylinder, 2600 rpm and the generator is belt drive.  The Cummins has a 770cc three cylinder and can run up 3600 rpm, but it idles down and runs slower at lower loads.

That's why I think I'm going to try it.  They only charge me $22.50/hr rental if I don't like it, or it doesn't do what they claim.  So if I run it for 10 hours and decide to return it I'm only out $225.
--
Chris

[ChrisOlson]

that 8000 series is probably good at getting 5kw back into the battery bank per hour, after all the conversion steps are accounted for , so it would appear that the genset could easily run a minimum of 6 hours per day?

Bob, even on a bad day we usually get 10 kWh or so from the wind and solar.

And remember that some of our heavy loads (that use the most kWh) are on-demand generator hours where it doesn't actually charge the batteries.  The generator starts to help out the inverters and batteries, then shuts off when the load drops below the Load Start threshold.

So in reality, starting with a full battery bank, it takes three days of really bad weather to get the bank down to 50% where the generator would have to make a long run to get the bank back up.  That's a really rare occurrence.

The more common starting event is when my wife turns on two big things at once - and I shouldn't always blame it on her because I use a fair amount of power in my shop too.  If I'm running the lathe and the air compressor starts with other normal stuff going that will cause the generator to start and run for 15 minutes minimum due to what is called "Load Start Amps" in the inverter menu.

But those intermittent runs allow us to run the really heavy draw stuff without sacking the bank.

And frankly, that is one thing that I don't like about a diesel unit is the (sometimes) 15-16 minute runs just for Load Start.  An air cooled gas generator is better suited to that type of abuse.

So I'm still up in the air over the whole thing.  Honda also makes a really nice 6.5kW gasoline fueled unit with their iAVR system:
http://powerequipment.honda.com/generators/models/em6500

The fuel consumption on the Honda is .9 gal/hr @ full load, .6 gal/hr @ 50% load.  Honda is another company I trust, and based on my experience with Honda generators I have no doubt this unit would last as long as a Cummins unit, and be just as reliable.  The Honda is also very quiet and they are easy to wire up for off-grid auto-start systems because they have a built-in plug and a remote cable that can be tied right into the gen controller - plus they have an auto-choke so it only requires a three-wire start setup.

A Honda EM6500 is 1/3 the cost of a Cummins QD8000, I know they will start at 20 below with no problem because I've used them and they will.  But the fuel cost would be more than diesel because I can't buy gasoline around here without paying the highway tax on it - although I can get the tax back on fuel that I run thru it when we file our income taxes at the end of the year.

Like I said, I'm really undecided.  I would like to try the QD8000.  I'd also like to try a Honda EM6500.  But I don't know anybody who has one that will let me use it to try it out.  And the Honda dealer does not have the cradle to grave support that you get from Cummins when you buy a generator.

I look at all this, and there's some things I could do to cap the generator hours at about 400 a year by making some different adjustments in the inverters.  350 gallons of gasoline thru a Honda generator in a year - when you look at it that's not that bad of a number when you consider that the damn thing is powering your home.  At $4/gallon that's $1,400 in a year, or $117/month.  That's more than a lot of folks with grid power spend on their entire electric bill in a month.  But for off-grid that's damned cheap if it starts in the dead of winter when it's needed, and is a reliable unit.
--
Chris

[bob g]

well i look forward to hearing about which ever generator you go
with, getting accurate real world info is hard to do. hard to do because folks get married to an idea and are either intentionally or unintentionally blinded, which either way skews the numbers.

i think we can trust what your experience turns out to be, and as such i am very interested in what the real numbers and reality turns out to be.

looking forward to updates

thanks
bob g

[ChrisOlson]

well i look forward to hearing about which ever generator you go
with, getting accurate real world info is hard to do. hard to do because folks get married to an idea and are either intentionally or unintentionally blinded, which either way skews the numbers.

I'll let you know what I decide.  I'm still weighing all the options.

There's only one fuel option that will start at temps under -20F without preheat or energy input, and that's gasoline.  When the starting problems with our Generac became apparent, and it also became obvious that Generac had no way to fix it, we bought a small 3kW Champion gasoline fueled unit for backup, and I have it hooked up to the inverters' grid input AC connections.

That Champion generator has proven to be as reliable as the sun rising every day.  It was easy to hook into the auto-start system as it has an auto-choke, so it only requires a three-wire start like a Honda.  We had a warm winter last year.  But during the one cold snap when it got down to -30F that generator started with no preheat at all.  It sits in a small generator shed alongside the Generac, and it's not heated in there and there's open screens to let the heat out - so if it's -30 outside, that little unit is thoroughly cold soaked to -30.

On the first two tries it started and quit but the inverter tries it six times before locking it out with a "Gen Failed To Start" error.  On the third try it started and kept running, so the inverter warmed it up for two minutes and put it work.  That's reliability.  When it's 30 below the last thing you really want to be doing is farting around with a generator that won't start.

If a diesel takes substantial energy input to keep it warm enough to start on-demand in temps below -20F, then whatever fuel savings there are in greater thermal efficiency can get easily eaten up in more generator run time just to replace the kWh it uses to keep itself warm.

The Champion is barely big enough to carry the house loads and trickle charge the batteries, and preheat that Generac to try to get it started.  And even if it does start chances are there's not enough tank pressure to keep it running at those temps.

Looking at my logs, the most hours get put on the genset from November to February.  The rest of the year is so minor that it's mostly not worth considering because it's mainly Load Start conditions where the set only runs for a short time.

These are all the things I have to consider.  And I am not even close to figuring it out yet.  Looking at it from purely a fuel efficiency standpoint, one can tend to get blinded like you say and forget that I might be back to Square One with a diesel genset in -30F weather - with a unit that won't start.
--
Chris

[bob g]

you certainly have some unique variables, the possible 30 below temperatures being a significant one.

does the little champion warm the generator room up at all at those low temperatures? or because the room is so large it really has no chance?

also does the kubota engine have glowplugs or other intake heater options? 

those low temperatures has not been something i have had to consider for the last 25 odd years or so, living west of the cascades in western washington, i can remember only one winter where the temps got down to double digits below zero for a week or a bit more. far more likely to have lows in the single digits above zero as the coldest again only for a week or so each winter..

now that i have relocated back to kansas, and with the abnormally warmer winters that folks tell me about, getting down into the teens is more common around here for the coldest.  however i just read in the paper that the coldest on record in kansas was one cold winter where the temps dipped to 40 below zero F.  many times over a one month period, and as we know if it did it once it can do it again.

therefore i too ought to keep in mind cold start issues, because i am convinced this area is well passed due for a really cold winter.

and no i don't want to be out screwing around with starting a block of ice that looks like it might have been a generator.  been there done that with frozen truck engine's with gelled fuel and so damned cold that even starting ether just goes "whump"  at best.

good luck

bob g

[ChrisOlson]

does the little champion warm the generator room up at all at those low temperatures? or because the room is so large it really has no chance?

It warms it to about 70 degrees inside the little shed.  The shed is small - about the size of the Generac's housing and I have the screens on it designed to only let out enough heat so it warms up nice in there even in the coldest temps.

Based on my experience doing that (and experimenting with the screens so the air-cooled unit gets up to proper operating temp in cold weather) I could do the same thing for a Honda EM6500 and it would be fine.

We can't put a permanently installed generator in a building here.  It has to be in an approved all-metal enclosure located at least 10 feet from any building (building codes and insurance).

Edit:
Bob, I forgot that you asked about the Kubota engine - it's a precup engine with glow plugs.  They will start pretty good down to about zero degrees.  And I have been able to get them started at 20 below in my skid steer loaders but it takes 2-3 timed cycles of the glow plugs and intermittent cranking to get the combustion chamber temp up to where it will start.

For reliable starting on a genset application it would require some form of external heat, preferably a block heater, so it would start for on-demand load management.  That is one thing about air-cooled gas engines - they can take that abuse in cold weather where it starts and goes to full load within a couple minutes.  That's pretty hard on diesels because of the pressures they operate at compared to low compression gas engines.
--
Chris

[Bruce S]

Chris;
That industrial engine is the little brother to the 1100cc that Max over in Mother Earth news used to build his 100mpg roadster.
My biggest worry with the diesel would be like the problems I had with the old 300tubro MB, the gel point of the fuel, but If I remember my Michigan days of using fuel oil burners, don't they change the mix to have more kerosene has temps get lower?
My fix was adding ULG to bring the gel point down.

[ChrisOlson]

Bruce, plugging fuel filters is not a problem even at 35 below with straight #2 fuel treated with Power Service fuel treatment.  With an in-tank fuel heater heated by the cooling system coolant you can go to 50 below with no problems.

Nobody blends #1 with #2 anymore for winter up here in the north because a 50% blend only lowers the CFPP (Cold Filter Plug Point) by about 25 degrees F.  Also, ULSD does not re-absorb wax once it drops out.  Power Service fuel treatment is used by all the fuel distributors up here now since it actually provides real cold weather reliability and fixes the wax dropout problem with ULSD.
--
Chris

[birdhouse]

i've been reading along this whole time... 

the cummins does sound like a winner, except for cold weather starting.  i'd be worried that when you need it to start, and the batteries are already low, that you'll suck even more out of them trying to get the diesel up to temp to start and thus recharge...

sounds like a never ending battle (vicious cycle) where you'll end up bringing out the champion 3000w on a regular basis just to get the cummins online...

i think you've basically concluded in previous posts, that:  in REALLY cold weather, the ONLY reliable genset is gasoline powered.   

that being said, the honda sounds like a winner to me.  reliable start EVERY time, a little more fuel cost, yet still pretty good support. 

i've been researching an auto start genset for my (much smaller) system, and i don't have quite as cold of weather as you, but that still throws diesel out in my books.  i'm pretty sure i'm gonna get that champion you speak of.  i get -10F on the rare occasion, but 0F fairly regularly. 

could you buy two hondas for the price of one cummins?  just something to think about...

adam

[Frank S]

Bird house I would doubt that Chris would be using power from his bank for starting the Gen the charging system of the gen would not be compatible with the charge voltage of his bank. nor would an automotive CCA designed battery be compatible with  a deep cycle bank
 For cold weather starting I had a system on my welding rig that pretty much cured that.
 My truck engine was a 1160 Cat Natural aspirated with a Murphy controls automatic block heater these were powered from the 3 8D batteries that ran my crane and winch. at that time I believe it was called the Yukon extreme. good for -45 as long as my fuel was not gelled ( that happened once my mistake) my truck would start
 My welder was a Hobart 400 amp Diesel with a Perkins  58 hp 3 cyl. it too had an automatic block heater plus the inductive intake heater. very similar to what Cummins came out with on their dodge diesels
 when I got ready to start my welder I just switched it on in cold - - - weather  I didn't even have to push the start button.
 One time I drove up to Montana to test out for a pipeline I hadn't started my welder in a couple of weeks and after I got to the job site it was several days that we had to wait around before we could test out.
 So there we sat in a motel In Bute with -30 to -40 with a snow storm blowing. Every day the rest of the hands would be out trying to start their Lincolns. some would but most wouldn't without being cabled t another. I never cranked my machine because my philosophy was I don't turn it over for less than an days work in the cold.
 Come the day for testing there were 40 hands lined up to test out for a 15 stick job It was colder than I ever want to be again. none of the gas rigs or diesel Lincolns would start. The  line boss walked up to me and said son you might as well head back to Texas I can't use a Hobart on my job because you can't  jump them from the Generator. and No diesel will ever be on any of my Lines.
 A asked him, if my machine will start on not more than the second try and I can jump 10 of those toy welders off at the same time will you at least allow me to test ? If I bust then it will be  me not my equipment that didn't get the job at least.
 OK if that brown Piece of railroad junk will even turn over I'l let you test. He had been stating in the same motel and knew that my machine had not even been turned over in several days.
  I flipped the switch and lit a cigarette stood there and drank my coffee you could hear 40 dying batteries in the back ground from grinding on overheated starters.
 A few seconds later my machine started to turn over and about the fifth piston that hit top dead center it busted off pretty soon the  smoke cleared up I casually tossed my leads on the ground and told 10 guy to clamp on. As soon as all had I spun both dials from minimum to Maxine a few seconds later there were 10 flat heads coughing to life . I spun the dials back down and the guys disconnected.
 I worked on that line in the heated  test tent making manifolds and turn backs for the duration of the job, and have yet to test out on any of his pipeline jobs
 Sorry for the hi jack but I just wanted to explain that cold can be overcome even as much as I hate being in it.

[ChrisOlson]

that being said, the honda sounds like a winner to me.  reliable start EVERY time, a little more fuel cost, yet still pretty good support.

When I weigh all the options, it really does look that way.

When it comes to the Champion vs the Honda in gasoline powered units - amazingly Champion Power Equipment has better support than Honda does and they are geared to the DIY'er.  If you have a warranty problem with your Champion generator, or even need some technical information, give Champion a call and you get to talk to somebody who actually knows the answer to your questions.

The engine on our Champion is a Honda clone and the unit is built in China.  But I can't fault it's quality.  Champion even re-designed their rocker arms and instead of the chincy stamped steel rockers that a Honda has in it (that DO wear out and have to be replaced), the Champion has cast iron rockers on a real rocker shaft.  The first time I adjusted the valves on it after breakin I was pleasantly surprised to see that so I took a pic of it with my cell phone:



So frankly, that Champion generator which I bought as a "cheap" backup has turned out be anything but "cheap".  It is easily on par with a Honda for reliability and quality IMHO.

FrankS - yes it would pull power from the batteries to keep a diesel warm for cold weather starting.  I don't know how many kWh/day would be required to keep a Cummins QD8000 warm enough for on-demand Peak Load Management in cold weather, but I'm going to find that out.  One of the engineers at the plant in Minneapolis will know.
--
Chris

[Frank S]

Chris my V8 cat in my truck had 4 heaters thermostatically connected the Murphy unit  installed by the previous owner of the truck took care of everything. I read on 1 of the heaters that it was 120 watt  I thought these were large for an engine  with a 10 gallon cooling system but apparently they did the trick I had 6 batteries on the truck 2 type 31 12v for engine start 3 8D Cat brand for the crane & winch and 1 type 31 for the welder
 2 Alts on the welder and 2 on the truck engine I could charge the crane/ winch batts by either the truck or the welder

 I was not thinking about you block heaters being connected to your bank but it would make sense but are your gen set/s started from the bank as well or do they have their own separate starting battery.