| Author |
Message |
Johnny (4.174.103.43)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 6:38 pm: | |
Does anyone make a dedicated 12V genset? Or do I have to build my own?
Also, will a 3000W genset run 2 typical Coleman or Dometic 13,500BTU roof A/C units?
And can someone please tell me what, exactly, is the problem everyone has with Generac? |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 8:39 pm: | |
1. Yes.
2. No.
3. It's a cheap piece of junk.
HTH :-)
-Sean |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 8:42 pm: | |
Oops,
Just to clarify my answer to #1 -- "Yes" there are commercially available 12vdc generators. "No" you won't have to make your own, unless the specs (or the price) do not suit you.
-Sean |
Johnny (4.174.103.43)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 8:52 pm: | |
"can someone please tell me what, exactly, is the problem everyone has with Generac?" |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 9:21 pm: | |
Johnny,
OK, without being flippant any further, Generac makes a very low-end unit. I have not disassembled one, so it's hard to be specific about what corners they've cut to make their price point, but, based on past experience with failure rates, they fail consistently sooner than any other (major) brands. It has never been in my best interest to repair one, so I've never torn one down afterwards to see exactly why. But, based on experience with other equipment, I could venture these guesses:
-Cheap, inferior bearings.
-Poor winding techniques leading to insulation rub-through on the windings.
-Ineffective, "set-screw" type freqency and voltage "regulation" (if it can be called that) on the older units.
And that's for the 1800rpm ones --- I wouldn't give you a plugged nickel, so to speak, for a 3600rpm unit (Generac's or anyone elses) except for a real short-term-use type of situation.
Nowadays, I think they're using the John Deere engine, which has gotten quite good, so that aspect should be OK.
Bear in mind that Generac does not really market their product for continuous use -- these are really standby generators. If that's your usage pattern, you may be quite happy with one. Most conversions, though, use their gensets far more often than standby generators are designed for.
-Sean |
Johnny (4.174.103.43)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 9:32 pm: | |
Well, if I do this right, most of the time I'll be on the batteries (4 golf cart T105's), only using the genset to top them off every few days.
You're saying the Generac problem is in the genhead, not the engine?
Are there any inverters out there capable of powering a 120V roof A/C unit, that don't cost more than my truck? |
Johnny (4.174.103.43)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, April 18, 2004 - 9:33 pm: | |
One more: who makes the 12V gensets, & are there any I should stay away from? |
Sean Welsh (Sean) (64.81.73.194)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 19, 2004 - 12:02 am: | |
Johnny,
WRT Generac -- yes, the head is actually made by Generac, and, AFAIK, that's the main problem. They have used various engines and have done OK to worse-than-mediocre jobs integrating them. The current Deere powerplant, IMHO, is a good engine choice.
Yes, there are good inverters that will run a roof air. I don't know how much you paid for your truck -- I bought an inverter that will run two roof airs for $1,900.
WRT 12v gensets: I don't have a list, but most home wind generators and many hydraulic ones are 12vdc. Also, there is a mil-spec genset that is adjustable from 14-30vdc, and these come up on eBay fairly frequently.
If you want to DIY, which is probably cheaper, here's a good article to start:
http://www.homepower.com/files/mark8.pdf
--Sean |
Peter Aduskevich (Slowslowpete) (206.216.216.54)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 19, 2004 - 12:21 am: | |
Met a guy at a rest stop who had a 12 Volt genset. It had a 2cyl. Kubota for power. He said he purchased it from Cummins in the 80,s. It was made for trucks to heat and cool them. Inverter was inside. The rest had the usual under the cab enclosure. |
Phil Dumpster (24.16.243.37)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 19, 2004 - 2:11 am: | |
I have a Generac 10Kw generator I use to run things in my off-grid shop.
It has a two cylinder Briggs engine, something like 20 horsepower or so, and Generac's own head.
I would never put such a unit into an RV for use on a regular basis. It's noisy, vibrates, and is far too maintenance intensive for a built-in application.
If you want a build a 12 volt generator, a 5 horse lawnmower engine with an additional flywheel (from a Suburu or Toyota) driving a 140 amp truck alternator equipped with a three stage regulator would work well for charging house batteries. With a diode bridge from a three-phase "buzz box" replacing the diodes in the alternator and a rheostat to regulate the field of the alternator, it would also make an OK stick welder.
For a bigger generator, you could use an engine from a small car, such as the Volkswagen 1.5/1.6 liter diesels and the Suzuki 3 cylinder 1.0 liter gas engine as used in the Geo Metro. Both can be had for cheap, and at 1800 RPM produce around 25 horsepower to drive the generator head(s) of your choice. Both are water cooled, which can be used for a number of things, preheating the main engine and heating the interior of the bus for two of them. |
FAST FRED (63.234.23.111)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 19, 2004 - 6:09 am: | |
Panda , a German firm makes great DC gen sets , but with marine pricing .
To run a air cond from 12V will require a GOOD inverter , Big Trace Sine wave or any oone of the newer competition.
Can you just use 2 air cond?
A 12V unit for on the road , and a 120V for campsites?
FAST FRED |
Johnny (4.174.67.60)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, April 19, 2004 - 7:59 pm: | |
Actually, Fred, I think I may have found a 12V air conditioner...but at 9500BTU, I'd probably need three, which means I'd need a fricking huge alternater to run them.
Which is certainly doable. |
Buswarrior (Buswarrior) (64.229.212.58)
Rating: N/A
Votes: 0 (Vote!) | | Posted on Wednesday, April 28, 2004 - 8:47 pm: | |
Johnny,
I'd stay a long way away from Generac.
We have two 8k diesel models in a mobile command post with somewhere close to 2000 hours each over the last 12 years.
(Low hours on your mobile command post is a good thing: means not a lot of trouble, right?)
They have been a constant source of trouble on the electric side. There is no part of them that hasn't had to be changed out at least twice. Boards gone, windings grounded, poles lost.
The diesel engines have been pretty good, they run, but they are louder than neccessary, the rad mounts have broken on both, tipping the rads into the fans, the starters have been replaced.
The joke is that if both of them are actually running at the same time, one of them won't be the next time someone goes out to run them up.
Not good for the decision makers who just write off the whole idea of a mobile command post as a huge sink hole for funds and, as a breed, unreliable.
Ask around the jobbers to see which generators they NEVER SEE, they are likely the ones that keep running.
happy coaching!
buswarrior |
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