which generator/s for motorhome project?

[jesusgatos]

Like the title says, I'm building an M109 motorhome conversion and I need to figure out what generator/s I'm going to use. Figured that I ought to look into mil-surplus stuff before I buy anything. Hoping I can explain a little bit about what I need, and then get some input about what I ought to be on the hunt for.

I've put a lot of thought/effort into keeping my electrical needs in the motorhome to a minimum. Radiant heating, AC runs off the engine, no microwave or other real high-draw electrical appliances, etc. As far as the motorhome goes, I don't need much more than to be able to power the interior lights (which will probably be LED), computer (also serve as TV & stereo), fridge, fantastic vent/fan, misc. water pumps, etc. I'm also planning on installing 12V car-stereo speakers throughout the vehicle, but nothing crazy.

I'm probably going to replace the generator on the engine with Wolverine Tech's 12/24V dual alternator setup. I think his 12V alternator puts out about 200W, and I will use that to charge the house batteries. At least while the engine is running.

Something like a Honda EU2000i (or two) mounted up in the cabover rack would be another nice, quiet, power source. If I go this route, I'll probably just buy one for now, and then see if I really even need a second one. I do like the idea of being able to run them in parallel though.

The enclosed trailer that I'm pulling behind Mah Deuce is going to be stuffed full of all my tools (MIG-welder, electric/hydraulic tubing bender, drills, grinders, etc.), along with my bikes, and other toys. The MIG welder is the most demanding electrical load, and Miller told me that I'll need about a 6500W generator to get full power out of it. The generator doesn't necessarily need to put out 220V, but a lot of the generators I've seen in this category can/do.

Long-term plans also include solar panels, which will cover the majority of the roof of the M109 box.

I'll also be able to connect to shore-power, but don't imagine that I'll make use of that very often.

I've already got a 3000W pure-sine inverter installed in the truck, and I'm going to use 6V deep-cycle golfcart batteries of some sort for storage. Not sure how big this battery bank will be yet. Depends on $ and how much space the water tanks take up. But there will probably be at least ten 6V batteries mounted somewhere in/on the truck, and there will be another, larger, bank of batteries in the trailer.

So that's a quick overview. I guess what I'm wondering is whether there are any military surplus generators that might be particularly well-suited to either of these applications (small 2000-3000W generator for the truck & larger 6500W+ generator for the trailer).

I'm thinking that the little Honda EU2000i's might be hard to beat. Not wild about the idea of having to carry gasoline on the truck, but it's not that big of a deal. I'll be carrying plenty of gasoline in the trailer (for the dirtbikes), and would only need to transfer fuel to a small tank on the truck. If I end up putting one of the larger civilian generators on/in the trailer, that will probably need to be gasoline too. Just because all the non-surplus diesel generators I've seen are REALLY expensive.

Are the mil-surplus generators diesel-only or multifuel? Multifuel would be a LOT more appealing because I wasn't planning on having a pure-diesel tank, and I'll be running Mah Deuce on anything/everything. I will have a VERY good fuel filtration/processing system onboard though, so contaminants should be much of an issue. If a generator require is diesel-only, that's just one more type of fuel that I'll have to carry, and I would prefer to keep things as flexible as possible.

 

[mdlbldrmatt135]

The Mil surplus ones are Gas OR Diesel, there's no Multi's that I'm aware of. The gas are mostly 3 and 5 KW units and the diesel are 3kw on up. The welder in the link doesn't take AC power direct...... it's Operates on open-circuit voltage and voltage: 14 – 48 VDC/110 Max OCV.

 

[SCSG-G4]

Military diesel generators are not small or light. A 5kw (Mep002A) is about 700-900 pounds, and the smaller ones run 400+ pounds. There are civilian diesel generators that are much lighter. The thing to look for is slower than 3600 rpm, which is what the gasoline and many small diesel units go at. I'm working on a 5kw set that is run by a belt drive, so the generator part runs at 3600 while the motor does 2200 rpm. Military units run at 1800 rpm, which is even better. "Made in China" units will not last as long in operation as other units from what I have read. YMMV.

 

[Earth]

I'm thinking the way to go here is with an APU. They are gaining much favor in the civilian world. The military has been surplussing some but they are without controls. (good thread going on making a control panel) You could have heat, ac and power, use the truck batts and fuel tank. charge the batts, block heat the engine, and other cool stuff.

 

[ken]

My sudjestion would be the MEP-016B. It's rated for 3KW and can run 220V. It should be more than you'll need. As with other military equipment it's underrated. Mine burns about 1 quart of diesel per hour at 75%load. Holds about 2 gallons and will run 8 hours easy on a tank.It's made by onan. The bad part is it's a 2 pole genset and so runs at 3600PRM. You could tie the 24V side into the truck batteries and elemenate the battery.

 

[jesusgatos]

The Mil surplus ones are Gas OR Diesel, there's no Multi's that I'm aware of. The gas are mostly 3 and 5 KW units and the diesel are 3kw on up. The welder in the link doesn't take AC power direct...... it's Operates on open-circuit voltage and voltage: 14 – 48 VDC/110 Max OCV.

Thanks. I wasn't sure about whether or not the diesel generators were multifuels. But how well do they handle WMO and WVO?

Military diesel generators are not small or light. A 5kw (Mep002A) is about 700-900 pounds, and the smaller ones run 400+ pounds. There are civilian diesel generators that are much lighter. The thing to look for is slower than 3600 rpm, which is what the gasoline and many small diesel units go at. I'm working on a 5kw set that is run by a belt drive, so the generator part runs at 3600 while the motor does 2200 rpm. Military units run at 1800 rpm, which is even better. "Made in China" units will not last as long in operation as other units from what I have read. YMMV.

No kidding. That sounds like a pretty big package for the power output.

I'm thinking the way to go here is with an APU. They are gaining much favor in the civilian world. The military has been surplussing some but they are without controls. (good thread going on making a control panel) You could have heat, ac and power, use the truck batts and fuel tank. charge the batts, block heat the engine, and other cool stuff.

Um, what's an APU? OK, just googled. It Auxiliary Power Unit. But what's so special about them? And why is keeping the RPM's under 3600 so important?

My sudjestion would be the MEP-016B. It's rated for 3KW and can run 220V. It should be more than you'll need. As with other military equipment it's underrated. Mine burns about 1 quart of diesel per hour at 75%load. Holds about 2 gallons and will run 8 hours easy on a tank.It's made by onan. The bad part is it's a 2 pole genset and so runs at 3600PRM. You could tie the 24V side into the truck batteries and elemenate the battery.

How big is it? How much does it weigh? How loud is it? How much do they cost?

 

[Earth]

In big rigs, the APU saves idle hours. You can heat/cool cab and sleeper, charge the batts, and pre-heat the block. Make pop corn and watch movies. Uses a small efficient diesel fired engine. uses the truck's fuel tank and batts to start. These are small compact little beauties that are made to mount on truck exteriors and supply power. I think one would work well in an M109 conversion. I plan to use one in mine--right up on the roof.

 

[jesusgatos]

In big rigs, the APU saves idle hours. You can heat/cool cab and sleeper, charge the batts, and pre-heat the block. Make pop corn and watch movies. Uses a small efficient diesel fired engine. uses the truck's fuel tank and batts to start. These are small compact little beauties that are made to mount on truck exteriors and supply power. I think one would work well in an M109 conversion. I plan to use one in mine--right up on the roof.

Are you saying that they can power a heater/AC, or are those built into the APU's? I've got heating and cooling covered (several times over), so while that sounds cool, I don't think I need that.

 

[Earth]

No, the unit POWERS a cab/sleeper heater/ac unit. And generates power. Look at them as nifty on board generators. You can see them on trucks mounted right next to the fuel tanks, where other trucks might have a tool box.

I have a flock of the MEP 002a gen sets. Awesome unit, but it's way to heavy and bulky to mount anywhere on an M109. You might also check out the generators they mount on RVs and horse trailers with living quarters. They're compact. And quiet.

 

[Isaac-1]

APU's are becoming popular in the trucking industry thanks to the ever spreading no-idling laws, and come in a variety of types. Some of the nicer ones couple a small diesel engine with a generator on one end and an air conditioning compressor, and a high output battery charging alternator on the other end, plus heat exchanger that is tied into the main engine's cooling system and cab heater. This allows truckers to live in comfort plus keep their engines pre-heated in winter, etc. Other's are nothing more than small diesel generators designed to fit under truck cabs.

As to the MEP units, I have a MEP-701a in my backyard to provide power to my shed which is a MEP-016B as mentioned above in an ASK housing, even in the ASK housing it is still loud, loud enough that I can't imagine sleeping in that shed while it is running. It weighs in at just over 500 pounds (I think the plain MEP-016B is around 350-375) These units are powered by a 3600 rpm Onan single cylinder engine that is only used in these generators, their 24V/400HZ cousins and a few other rare bits of military equipment such as portable air compressors, etc. There are 2 other variations on the MEP-016 family you may want to consider if parts availability is important to you, these are the MEP-016D (which is a MEP-016A/MEP-016C gasoline generator that has been retrofitted with a Yanmar 1 cylinder diesel) or the MEP-016E which is a a MEP-016B retrofitted with a Yanmar 1 cylinder diesel (note the Yanmar engines are somewhat lighter than the original Onans, and may be some what quieter)

Ike

p.s. the Yanmar retrofit, was a life extension program that started about 8-10 years ago

 

[Armada]

Like the title says, I'm building an M109 motorhome conversion and I need to figure out what generator/s I'm going to use. Figured that I ought to look into mil-surplus stuff before I buy anything. Hoping I can explain a little bit about what I need, and then get some input about what I ought to be on the hunt for.

Do a search. OPCOM did the same thing awhile back to his m109. He has great documentation on mounting a genset, etc. IIRC he used a civy generator due to its smaller size and quietness.

 

[joestewart]

I vote Onan CCK - a motor home generator. Find one for about $100. Cheap, quiet, reliable - only shortcoming I see in using it is the hassle of hauling gasoline and delivering it to the mounted unit.

 

[trentM37]

Went with a 8,000 watt propane, since heat/stove/hot water were propane. Also don't have to worry about fuel getting funky. Same size as most 5/6,000 watt gas units. Big enough to power my house needs if needed, and have wired house for this emergency use. Sometime will post build photos. Have used ideas found here, which I greatly appreciate. And added some of my own.

 

[m109guy]

Um, what's an APU? OK, just googled. It Auxiliary Power Unit. But what's so special about them? And why is keeping the RPM's under 3600 so important?

I believe he was talking about the style of generator I picked up (MEP-903C). You can read my thread on building the control panel here.

But like Mike stated, most military generator are heavy and not very small. While it might be cheaper to try the surplus route, a civi generator made for an RV would likely fit your needs better.

 

[davo727]

What size mig welder? Thats going to be the killer, I have a 7000 watt, 8000 surge and it wont run my miller 200 mig at all even at a low power setting.

 

[jesusgatos]

What size mig welder? Thats going to be the killer, I have a 7000 watt, 8000 surge and it wont run my miller 200 mig at all even at a low power setting.

The enclosed trailer that I'm pulling behind Mah Deuce is going to be stuffed full of all my tools (MIG-welder, electric/hydraulic tubing bender, drills, grinders, etc.), along with my bikes, and other toys. The MIG welder is the most demanding electrical load, and Miller told me that I'll need about a 6500W generator to get full power out of it. The generator doesn't necessarily need to put out 220V, but a lot of the generators I've seen in this category can/do.

The one in that link.

 

[davo727]

OK Sorry, I wonder if your miller dealer will let you demo one running it off a generator so you can verify it works...

 

[zout]

You can see a partial of the Onan gen set I used in both units overhead racks from my thread - here is a pic getting ready to install Dinger65's unit.

It can run the roof 13,000 ac unit plus a couple outlets - main purpose is to recharge batteries from the transfer switch and the inverter/charger

 

[jas67]

There are 2 other variations on the MEP-016 family you may want to consider if parts availability is important to you, these are the MEP-016D (which is a MEP-016A/MEP-016C gasoline generator that has been retrofitted with a Yanmar 1 cylinder diesel) or the MEP-016E which is a a MEP-016B retrofitted with a Yanmar 1 cylinder diesel (note the Yanmar engines are somewhat lighter than the original Onans, and may be some what quieter)

You occasionally see the (civilian) Yanmar generators for decent prices, used. New they're $2-4k depending on size, I've seen them as low as $400. The made them in 2kw, 3.5kw, and 5.5kw sizes.

The Yanmar civil units, and the MEP's Isaac mentioned above, are likely no quieter than the MEP-016B. I have a MEP-016E, it this thing is LOUD! I also have a china-made clone of the civilian Yanmar 3.5KW. I ran this one for 5 hours during a power outage on Tuesday evening (my MEP-016E has a problem with the 24VDC side of things). It (the yanmar clone) was fine during a winter outage, but it was 80 degrees, and quite humid, so we had the windows open and fans running. Even with the genset about 80 ft from the back door, we had to raise our voices to talk over the thing.

By contrast, i have the Honda EU2000i you mentioned (we using it camping -- it is 120V only, so we still need one of the diesels mentioned above to make 240V for the well-pump). You can darn near have a normal conversation 10' from the thing. No, it isn't diesel, but its fuel consumption will be even less than the 3KW diesels for the types of loads you are looking at.

I think that the APU's others have mentioned here would be the best (if not most expensive) solution. They are typically liquid-cooled 2 or 3 cylinder diesels (usually Kubotas or Yanmars), mounted in sound-insulating enclosures, and often have AC compressors on them too. You'd use far less fuel to get AC this way than to idle your deuce. Also, you can use the heat from the cooling system to heat your living space too. Because they're liquid-cooled, they can be quieted much better than any air cooled engine, as you don't have to try to get air into the engine to cool it. You can put the best, quietest muffler in the world on an air-cooled diesel, but you'll still get a lot of mechanical noise from the engine and injection pump. With a liquid-cooled engine, you can put all that in a soundproof enclosure.

As for your larger power needs for your welder and such, why not just use a diesel-powered welder, and than use the M109's generator for your other power needs?

 

[jesusgatos]

Thanks for all the feedback guys. Looks like I'm going to want an EU2000 in addition to whatever larger generator I might end up getting, so I'm going to work on getting one of those first and I'll continue looking into larger generators.