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Old 10-09-2013, 00:08   #106
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Re: 12vdc generators - any good ones out there?

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Originally Posted by Dockhead View Post
Check this out:

Microcogen.info/***/SOMRAD Forums - Index

You've gotten a lot of sound advice on here based on theory (don't overload the engine; derate engine sufficiently), and some sound advice based on experience (don't hope you'll get useful charging without external regulation, so figure in the cost of that when you decide whether this is worthwhile or not).

But only one guy on here I know -- Lloyd; goes by Flying Cloud -- has actually built a homebrew generator. Lloyd spent months or years building his, and he's a professional marine electrician. It would help you if he would chime in, I'm sure.

Here's another place to talk to people who have actually done it: Microcogen.info/***/SOMRAD Forums - Index. Very interesting site; I wasted some time on it last night. One thing you can gather from the conversations of dozens of people who have actually built generators, is that it is not a trivial matter to get the engine sized right and get the pulley ratios right.

From that site, I also learned more than I ever thought there was to know about how alternators work. Very cool.
Dude:

I've been chiming in hear, for a year or 2....seems, noone takes me serious.

Now, don't you let the cat out of the bag.

Lloyd
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Old 10-09-2013, 02:18   #107
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Re: 12vdc generators - any good ones out there?

PbiJim, A couple of years ago I sorta buolt a DC using a kubota Mini Series for a project that went nowhere ( and I now cant get any more marinisation components) . I never finished teh control electronics as the project was killed.

I learned a few things

Firstly you need about twice the engine power above the charging power. Secondly i found mounting large case high power alternators awkward. driving them off the front with a serpentine belt was difficult to get the "wrap needed"

Next time around , Id direct drive a low rev alternator like the EcoTech , using a flexible shaft coupling , the only issue I personally have is Id prefer two alternators for redundancy and this is awkward as Ive not seen any co-axial units. Id like to experiment with the BMW/Land Rover water cooled alt too as well, though users report they arnt the most reliable.

I know in your case you want a small one , so the design decisions are different. Ive played with the little lombardini/kohler engines , which I actually think are superior to the EA330 kubota.

The big issue I have with EA330 systems is they drive it very hard to get the power , primarily because there is no convenient engine size just up from that engine.

Dave
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Old 10-09-2013, 11:05   #108
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Re: 12vdc generators - any good ones out there?

Quote:
Originally Posted by Dockhead View Post
Check this out:

Microcogen.info/***/SOMRAD Forums - Index

You've gotten a lot of sound advice on here based on theory (don't overload the engine; derate engine sufficiently), and some sound advice based on experience (don't hope you'll get useful charging without external regulation, so figure in the cost of that when you decide whether this is worthwhile or not).

But only one guy on here I know -- Lloyd; goes by Flying Cloud -- has actually built a homebrew generator. Lloyd spent months or years building his, and he's a professional marine electrician. It would help you if he would chime in, I'm sure.

Here's another place to talk to people who have actually done it: Microcogen.info/***/SOMRAD Forums - Index. Very interesting site; I wasted some time on it last night. One thing you can gather from the conversations of dozens of people who have actually built generators, is that it is not a trivial matter to get the engine sized right and get the pulley ratios right.

From that site, I also learned more than I ever thought there was to know about how alternators work. Very cool.
I've built 3 DC generators. All based on Kubota diesel engines. One was a 13hp two cylinder. Two of the units had a watermaker pump as well as large alternator. All worked out pretty well. The one problem I had was the 13 hp Kubota was a non flywheel version. it had bad vibration at certain rpms. Kind of a harmonic vibration thing, not a huge rattle. It actually cracked the welded aluminum frame once and split a custom made V pulley in two! The two little 6hp units were sweet, took up the space of a large fender. I had an Aircraft style vernier control throttle, after the charge cycle would drop down in amps from max output, I could just dial it down to an rpm that was almost no noise at all. Just a great sweet spot in those engines at low rpm. Fuel usage was so low it was pretty much not measurable.
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Old 23-09-2013, 13:32   #109
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Re: 12vdc generators - any good ones out there?

It turns out that UL has something to say on this subject -

http://newboatbuilders.com/docs/UL1112.pdf

I find the information about alternator RPM useful. I find the mechanical requirement that an alternator be capable of holding a person standing on them to be a bit surprising.

With a little luck, I may find the time to actually build a prototype in early November.
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Old 23-09-2013, 13:40   #110
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Re: 12vdc generators - any good ones out there?

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Id like to experiment with the BMW/Land Rover water cooled alt too as well, though users report they arnt the most reliable.
Dave, don't bother. I've replaced two of these on my Range Rover, despite the undemanding automotive job. I think I can safely say that they are carp.
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Old 25-10-2013, 17:01   #111
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Re: 12vdc generators - any good ones out there?

Today I took delivery of a little 34cc 1.1hp 4-stroke motor. I also ordered some shivs & a belt. Now, I just need to get a cheap alternator & the project will be on schedule for it's anticipated early November start.
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Old 25-10-2013, 18:04   #112
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Re: 12vdc generators - any good ones out there?

I may go Delco instead of Bosch on the alternator - http://www.delcoremy.com/Documents/E...ion-Guide.aspx
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Old 26-10-2013, 10:42   #113
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Re: 12vdc generators - any good ones out there?

sounds like fun. Dont go too large on the alternator...1.1 hp aint gonna handle much! I know a 100 amp (putting out about 85-90 to start) lugged a 6 hp Kubota down pretty well....
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Old 26-10-2013, 10:43   #114
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Re: 12vdc generators - any good ones out there?

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Dave, don't bother. I've replaced two of these on my Range Rover, despite the undemanding automotive job. I think I can safely say that they are carp.
Leave it to the Birish to use Carp... I would have used Tuna!
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Old 24-11-2013, 05:23   #115
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Re: 12vdc generators - any good ones out there?

I wonder has anyone thought of using the motor from a yamaha 9.9 4 stroke electric start outboard with a large alternator attached?

I have one laying around that the bottom half is shot, but the motor runs fine.
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Old 24-11-2013, 06:10   #116
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Re: 12vdc generators - any good ones out there?

How are you going to cool it with no bottom end?

David
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Old 24-11-2013, 06:36   #117
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Re: 12vdc generators - any good ones out there?

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How are you going to cool it with no bottom end?

David
Surely it wouldn't be hard to run a 12 v pump - not as if its a huge water flow.
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Old 24-11-2013, 09:23   #118
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Re: 12vdc generators - any good ones out there?

the cooling issue is the toughest with all of them. If you can find a way to provide a water port IN and OUT to exhaust it may work.
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Old 24-11-2013, 12:06   #119
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Re: 12vdc generators - any good ones out there?

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I wonder has anyone thought of using the motor from a yamaha 9.9 4 stroke electric start outboard with a large alternator attached?

I have one laying around that the bottom half is shot, but the motor runs fine.
Westerbeke has a generator using the power-head of a 4 cycle outboard engine, but its a AC belt driven gen.

Lloyd
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Old 05-08-2014, 18:05   #120
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Re: 12vdc generators - any good ones out there?

We're going back quite a few years here, but in '92 I took off in my 26' Kaiser and single-handed from Ft. Lauderdale to Mexico, Belize and the Rio Dulce in Guatemala. I had no inboard engine to twirl an alternator so I bought a Generac 1000W generator and plugged a car battery charger into it to keep my batteries topped off. That damn thing was LOUD! The new Hondas and others simply purr, but that old Generac growled. It was so bad that for the nine months I was gone I'd fill the tank about half way, start it up, hop in the dinghy and return after the fuel had run out and tranquility prevailed in the anchorage once more. It did an adequate job and I only had to do this every third or fourth day. Got up with the sunrise and went to bed not too long after sunset, so things worked out fine.
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