Back up generator advice needed

[47sawdust]

I want to purchase a back up power unit.What I have in mind is 5-6kw,1800 rpm water cooled diesel.
I know most folks use propane but I prefer not to go that route.Any suggestions would be appreciated.
Central Maine diesel has some affordable units,but I know nothing of their build quality.Marine diesel generators are a possibility but a little spendy.
Thanks,Mick

[scsmith42]

Find some local generator service companies and see if they have any good, used take-outs.

My local guy frequently has low hour, good used units that were removed from service.  Local telecom sites, etc, may exceed their generator capacity when they upgrade their equipment.  This means that their old, perfectly good units are replaced with higher capacity ones.

[Klicker]

What ever you get every couple of months start it up and let it run. This kips it working and fresh gas or fuel in it. Rod

[Coltbodi]

Since you have that Kubota you could look into a pto driven generator. It's one less engine to keep running, but it does tie up your tractor when the lights go out. But you can get a bigger unit for less money since you aren't buying the motor with it.

[woodmaker]

I went with diesel too.I'm not sure what you want to run,but if you want whole house capability ,5-6k might be a little small.I had a 5 k gas,and it worked well for lights etc,but wasn't big enough for well pump and furnace at the same time. Three years ago,I bought a used 12 k at the local generator installers open house. I set it up to run off my heating oil tank for the furnace,and this past week,it had it's first good test.We lost power for 36 hrs,and after sorting out some fuel line issues,(I put a ball valve in the suction line to prevent drain -back when changing filters;it allowed air to get in the suction line,then into the filters) we had good ,reliable  power,and actually used very little fuel

[Runningalucas]

We've had a 12kw kubota with a main 200 amp transfer switch.  Our power does go out a couple times a year during winter; usually no more than a couple days max. 

Gotta be careful to not wet stack it; usually we'll actually increase the load by just turning on the electric heat.

[47sawdust]

Thanks for the response.We have gravity feed water,wood heat with a Rinnai propane heater for backup,so as long as we don't use the dryer,no big demands.
I'm doing some research on used light tower generators.The Magnum mlt 3060 has either a Kubota or Mitsubishi 3cyl,1800 rpm motor driving a Marathon 1800 rpm 6kw gen head.Some have extremely high hours,but I found a unit i Mass. with 445 hours.110 and 240 outlet.
They seem like a good fit for my situation.I thought about the pto unit,but I like the idea of the self contained and trailered feature of these light towers.Just take the lights off and put it in a small shed.The unit I looked at yesterday was very quiet.
What does the "wet stack it" mean?

[thecfarm]

I have not started looking yet.
Kinda think I would like a PTO one. No rebuilding of the carb,which had to be done,on my generator that came off the Mayflower. I had not used it for more than 10 years.It works good,6000 watts. Sucks down the fuel.    I just plug it into to the side of the house,flick 6 switches in the basement and I can run the furnace,water pump,a few lights and a few outlets.

[North River Energy]

Out of curiosity, why the objection to propane?

[petefrom bearswamp]

x2

[47sawdust]

Why not propane? We use $400.00 of propane a year.I would have to get bigger tanks or tank to support the genset.
The trailer feature works well in my application.
I'm open to ideas.I'm just more at ease with the small diesel generator.

[Runningalucas]

http://www.ckpower.com/wet-stacking-avoid/

Wet stacking, or I 'think' it's also referred to as Carmelization.  It's where you run a diesel without the load necessary to make sure the temps are where they should be at.  Without the proper load, the generator will build a lot of carbon up in the cylinders, and onward.

When sizing the diesel generator, you're gonna need to make sure it's loaded sufficiently. 

[WV Sawmiller]

47,

   Personal opinions but how much more would it cost to get a bigger tank? How responsive is your gas company to just refilling existing tanks more often if needed? Keep in mind you'd likely need them to come refill during power outages and emergency conditions. But that is also the conditions you will be out running around trying to find diesel unless you already have a big tank you are comfortable will support you during emergencies.

   I am lucky - I have natural gas. I bought and installed a 17 KVA Guardian genset. Six years ago we had a derrechio storm with hurricane force winds which knocked out power to the surrounding 5 states. Our power was out for 11 days. My genset has an ATS and cranked itself 10 seconds after the outage and ran for 11 days. The only time it was off was once for me to change the oil and a couple times to check the oil. No real maintenance required. Cranks itself weekly and runs 10-12 minutes to charge the battery. While we lost power we did not lose natural gas - I have never lost both at the same time in the 27+ years we have lived here. My neighbors were making daily trips to our one local gas station with power (genset) to run their pumps and waiting in line up to an hour to get the $20 limit/ration of gas to run their small gensets. Others drove up to 100 miles down into VA to find fuel.  Neighbors brought food up to put in our freezer and extra reefer and to take showers since without power they had no water from their wells.

    Just more to think about. Good luck in your decision and search.

[47sawdust]

WV Sawmiller,
You're points are well taken.I will have a conversation with my propane company.Our present account is set up where they only come fill the tank when it reaches 20%.It takes us 14 months to get to that point.That's 2- 120 gallon tanks.
Our domestic hot water is heated by solar in the summer and wood stove water jacket in the winter which is supplemented by a 40 gallon propane heater.We cook with gas as well,although the wood cook stove does much of the work.No furnace,no water pump.
The longest we've been down in the 40 years I've lived here was 3 days.The diesel just seemed the cheapest to get into,$3k for working 6kw genset.Perhaps my thinking is flawed and I need to do more homework.Thanks for all the input.

[Kbeitz]

I have not started looking yet.
Kinda think I would like a PTO one. No rebuilding of the carb,which had to be done,on my generator that came off the Mayflower. I had not used it for more than 10 years.It works good,6000 watts. Sucks down the fuel.    I just plug it into to the side of the house,flick 6 switches in the basement and I can run the furnace,water pump,a few lights and a few outlets.

Why not turn you old gen-set into a PTO gen set.
I have done this to many generators .
It's not even a problem with the one with a tapered shaft.



 

[gspren]

  Reading this now has me thinking which usually costs me $$. I have a welder/generator with a 20 HP Honda engine that puts out 10K as a generator. I very seldom do any welding so it sits way too long between uses although I try to start it occasionally. I have a Kubota BX 2670 that would probably run a 10-12K pto generator and take up less room plus less maintenance and probably on less fuel. Any one use a pto gen on a little Kubota?

[thecfarm]

Kbeitz,you are a cleaver one. Reminds me of my FIL.

[woodmaker]

I chose diesel over propane because I always have diesel fuel around,(skid tank for equipment,loaders ,dozers, dump trucks etc.) but would have to depend on someone else to bring me propane.I'm sure in an emergency,their bigger customers would get higher priority than a small residential customer .My feeling is "the fewer people i have to depend on in an emergency,the happier I am". I can always move diesel with a tank in my pickup,cant do that efficiently with propane. Just my thoughts

[WV Sawmiller]

47,

   If you have not ruled them out entirely for other reasons, if just pricing I'd check on the propane gensets. I checked Home Depot and a 20KVA was under $5K and a 9KVA was under $3K. Sounds like you may find they are much cheaper than diesel and less maintenance once you get one.

    I first saw them while we were building the Embassy in Haitii and was impressed with how small and quiet they were and since I have natural gas I opted for that. I think I paid around $3k for mine delivered and have a friend from the local electric company who installed it for me.

   Everybody's situation is different as to needs, equipment experience, availability of various types of fuel, etc. All this needs to be considered in making such a purchase. I will say I love my genset and knowing 10 seconds after prime power fails mine cranks and shifts power to local. During my 11 day use 6 years ago I think my natural gas bill went up less than my electric bill decreased.

[Kbeitz]

If you like auctions and like to tinker you can save lots of cash...
I got a total of $50.00 in my 5kw system.



 



 



 



 



 



 

[North River Energy]

Mick,
A number of years ago, I bought a barely used Onan CCK 4k propane unit complete with switchgear off Craigslist. Might have paid 700, but I forget, which means it probably cost even less.  It's enough to keep the furnace circulators running, and I can run the shallow well pump as needed with a little creative plugging and toggling. Have been using the larger propane tanks from the local hardware store, and those work fine unless it's really cold, when they have a tendency to ice up.

After this last storm, I called our propane supplier to find out what it would cost to get a larger dedicated tank to deal with the icing problem. I assumed the minimal gas consumption would require a monthly tank rent, but no. Since the account already involves gas for cooking and shop heat, there will be no extra monthly charge for the tank. Game on.

Hopefully your distributor has a similar policy.

Despite being reliant on a gas supplier, the 'no fouling' nature of propane gives it a distinct advantage for instant on, standby use. Or at least that's my opinion, having thrashed about with a number of gasoline powered units.
.

If I had to power something full time, I'd go with diesel. If I needed universal portability, then I'd use gasoline. For instant reliable emergency power, it's hard to beat propane.

[woodmaker]

kbeitz,I wish my generator enclosure looked as nice as yours!

[sawguy21]

'For instant reliable emergency power, it's hard to beat propane.' Natural gas if available or propane is really the way to go for clean reliable standby power. Contaminated or stale fuel is never an issue so extended storage is practical. Units like the one WV Sawmiller has can be equipped with oil and battery warmers that run off the utility power. If it is cold enough for the propane to freeze up that diesel ain't gonna start without some help.
If someone who can start the system is available when the power goes off the manual systems work but what if it is 100 above or 30 below when nobody is home for an extended period of time? The automatic systems really shine here. Just my .02Cdn, ymmv

[47sawdust]

NRE and the rest of the propane crowd,

I've about reached the tipping point.The experience of those who have gone before is important to listen too.Thanks for all your input.
A 15 year old Kohler 7kw unit with 169 hours is a possibility.Local Kohler dealer says it's an excellent unit Propane company says no problem,keep an eye on the tanks and refill when needed.

[gasman1075]

I sold and installed LP systems and LP generators for many years and am propane certified ( Master and Journeyman licenses ) and my only advice for sure is to buy a tank if you can and bigger is better. One gallon of LP nets you 92,516 BTU. A 7KW ( 144,000 btu ? ) burns about 1.5 GPH.  A 500 gallon tank vaporizes at about 634,000 BTU / hour at 20' F and A horizontal 500 gallon tank nets you about 400 +/- gallons of propane or about 283 hours of run time or 11 days at 24/7. When you use your generator the most your LP company probably doesn't have power either. They may have a 3 phase generator to run their LP plant ( load trucks etc. )  but most don't. I sell propane as well ( wholesale only ) and cover VT also. If you call me at the office 518-733-0101 I'll help if I can.

Thanks

Jack

[florida]

I've installed several 25W whole house systems that needed a 1000 gallon buried propane tank. My problem with propane is the $2400.00 of propane in the tank that may sit for 10 years between uses. That's a lot of money to keep tied up a long time. I've used my 6Kw Honda 3 times in 14 years and I live in a very active hurricane zone. The total run time for those 14 years is less than 120 hours. Diesel looks pretty good to me.

[WV Sawmiller]

    Florida makes a good point about the money tied up in the propane but since you already have and use propane and the local company indicates they can support you this may not be as much of a concern. It may be a factor for others considering setting up such a genset. If they can use the propane for other purposes such as hot water, heat, cooking, dryer, etc. they can help justify the cost. I love gas for these purposes too and find it much preferable to electric.  I'm extremely lucky with natural gas in that I don't have to pay for stored gas. I just pay for it as I use it.

    I put my genset in because of power outages in the winter due to local ice storms. The one time I really used it extensively turned out to be from 30 June-11 July during a freak summer storm. If I lived in Fla, where I was born and raised, I'd want one for hurricane back up. Anybody who lives in an area subject to dangerous storms of any kind that take out the power, especially those with any kind of health issues, should consider a whole house genset.

[Ljohnsaw]

I need a short run emergency generator.

I'm building a cabin off grid so I'm doing solar.  I have fire requirements that I have a sprinkler system to be installed.  I was planning on running a pump (~2hp?) capable of delivering ~30 gpm @ ~28-30 psi off my batteries for 10 minutes.  The county insists I have a auto start generator.  Since it will likely never be used (other than maybe to charge the batteries?), I'm thinking propane is the way to go.

So, what size generator and propane supply would be recommended?  I'm thinking a 5 gallon BBQ tank would be enough.

[47sawdust]

Well the deal will soon be done.I'm going to Hartford Ct. on Monday to pick up the Kohler unit.It is a 2002 model 169 hours,7kw, with a Kohler transfer switch.After installation the local Kohler dealer will service it twice a year.After installation,I will have $2600.00 in to it.
This feels like the right approach.
Thank you all for your help.
47sawdust

[sawguy21]

 8) Good choice

[plantman]

Just a couple of hints. Think carefully about where you're placing the generator. The noise can really keep you up at night so if it's possible to mount it in a box and some distance from the house , it's an advantage. Of course , if you're snowed in then you still have to be able to reach it.
Secondly, some small generators are not recommended for electronic appliances because the power they produce is not "clean". I guess that means it's not steady. I bought a Harbor Freight 4000W generator about 10 years ago and I'm very happy with it but it's only big enough for the essentials. I haven't used it hardly at all so I'm glad I didn't buy anything bigger. I always keep fuel stabilizer in it and run it every few months.

[WV Sawmiller]

Plantman,

   My first experience with gensets was in the USMC when they set my operation next to the generator farm. Not great. If the genset 47 is talking about is a Guardian type in the fiberglass case he may never know it is running. Mine cranks itself and runs every Sunday afternoon and most weeks I never hear or even know it is running. The first time I heard them was some when had in Haitii and that was a big deciding factor for me to buy one. I have never regretted it yet and I bet 47 doesn't either.

   A big congrats 47. I hope it does everything you need and want it to do.

[John Mc]

...some small generators are not recommended for electronic appliances because the power they produce is not "clean". I guess that means it's not steady.

Steady is one thing: it's important to have good voltage and frequency regulation. However, that is not the only factor. The waveform they generate also needs to be clean. The main measure of this is something called Total Harmonic Distortion (THD). For electronics, you want something below 5 or 6%. Cheap generators are often much higher. Even the entry level generators of some big name companies are awful in this regard (the Generac GP series comes to mind - they have something like 23% THD). Manufacturers who have bad THD ratings usually make it tough to find out the rating - you won't find it in their advertisements, and sometimes not even in their owners manuals. THD can to be higher the more heavily the generator is loaded, so make sure any spec you are given is the rating at full load. Further, poor THD performance is not limited to small generators. It happens across the size range.

If you are thinking "OK, I just wont run my TV or computer when running on a generator", think again. You may be kicking yourself if the electronic control system on your furnace won't come online when the power goes out and it's below zero out. (Older furnaces without the modern control systems are usually more tolerant of dirty power.)

[Ianab]

One of the small "Inverter" generators should be OK for electronics as they have built in electronics that regulate and smooth the power output. A larger conventional unit will usually smooth out if you have some steady "base load" like lights or a small electric heater running off it.

The little cheap generators are notoriously unstable, especially with a light or fluctuating load. Work OK to run a power drill or angle grinder out on the farm, or some lights etc, but you don't want to be plugging fancy electronics into them.

[sawguy21]

I am assuming your new to you unit is designed specifically for residential standby use, you will really appreciate it the first time the power goes off.. While not inverter clean, the power should be very close to what is supplied by the utility. The manufacturer will supply guidelines as to minimum distance from buildings as well as doors, windows and fresh air intakes. They are usually reasonably quiet in the weatherproof cabinet although you don't want it outside the bedroom wall.

[47sawdust]

The Kohler unit has an insulated enclosure.From what I was told the only time it ran was for weekly exercise.My propane company says the unit must be a minimum 10 feet from the tanks.In my case my electrical panel and tanks are in close proximity.If I'm 10 feet from the tanks I'm probably 20 feet from the panel.This location is on the opposite side of the house from our bedroom,easily accessible and flat (we don't have a lot of flat).I'm hoping for a smooth installation.

[Kbeitz]

I have a line conditioner on my gen-set.
You can get them cheap off E-bay...

[Roxie]

@Kbeitz, Cowboy Bob is NOT gonna be happy that you shared that picture of your generator cover.   :D  That is gorgeous! 

[John Mc]

Sawguy21 is right, most of the permanently mounted generators designed specifically for residential standby use produce power clean enough to run anything you want. You don't have to have inverter quality power (which generally beats the quality of the power company) to run sensitive equipment.

As far as power conditioners go, most I've seen focus on voltage regulation (i.e. keeping your 120/240 VAC right at 120/240) and surge suppression. I'm not sure what they do for THD or frequency stabilization, but there may be some out there that help with that.

[Don P]

We lost power for a day a couple of weeks ago when an F1 tornado hit about 5 miles away. It dropped a tree on our helper's mother's car while she was driving as it passed through, luckily she dove into the seat. Anyway, another friend who is now in her 70's and living alone had pulled out the whole house generator and had a little pull start unit put in. She fired it up and began hearing sizzling and popping in the house. She cooked a few things and burned up an outlet strip. I'm assuming someone jury rigged it to the transfer switch, I don't think she would or could run a suicide cord. We've talked briefly but I haven't seen what went on.
I'm guessing the little unit was making power or grounding differently than mains power. Any clues?

[John Mc]

Sizzling and popping makes me wonder if someone wired the plug wrong and delivered 240 into a 120 line?

[Don P]

I'll try to get a post mortem from the electrician. Where my mind was wandering to, on a portable generator with plugs and breakers there must be a ground-neutral bond at that panel? The house panel would also have a bond... and now my pea just sits there and says "so?", and I don't know.

[John Mc]

Well, you've got me going now, Don P. I know with some generators, you have to separate the ground to neutral bond before connecting it to your home (or maybe you have to connect it? I can't remember which.)  Generators designed to work on a job site are wired one way, and those designed to connect to a house are wired another. I can't remember the details, but I didn't remember the difference causing things to go snap-crackle-pop - unless there were other problems.

[Don P]

We're at the same place. A foggy memory of stories of those little generators not being able to just plug up to a panel because of a bonding problem. I think you would unbond ground from neutral in the generator panel and run 4 wires to the house panel, hot, hot, neutral, ground?

What happens in the double bonded scenario if there is a wire on the wrong screw somewhere in the house with something plugged into it?