Automobile Alternator On A Yanmar?

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J

Joe Mullee

I was swapping emails with a Yanmar mechanic and asking him to recommend an alternator. I have a Yanmar 3GMF that is 22 years old and has the stock Hitachi 35 amp alternator. My batteries now consist of 300ah for the house bank and a seperate starter battery. He told me that many alternators would sufice in the 60-80 amp range and that I shouldn't rule out an automotive type. I'm still learning so I wanted to know what others thought about that suggestion. Thanks, Joe Mullee
 
G

Gary Wyngarden

Nigel Calder's recommendation . . .

is that the amp output of the alternator should be at least 25% of the amp hours in the battery bank it's charging. He also doesn't have many kind comments about automobile alternators since their effective output drops significantly as they heat up. That said, it probably depends a lot on how you use your boat. But if you have 300 ah in your house bank, you're probably doing a fair amount of cruising on the hook. I would also consider upgrading your voltage regulator to a three stage at the time you replace your alternator. Lots in the archives on this. Hope this helps. Gary Wyngarden S/V Wanderlust H37.5
 
Jun 2, 2004
5,802
Hunter 37-cutter, '79 41 23' 30"N 82 33' 20"W--------Huron, OH
Sounds wrong.

The obvious advantage of the Hitachi is that it will fit. It will have the double feet and not require any special mounting. It will be inexpensive because it will have a built in regulator. And I believe the windings are of marine wire, wire that is designed to resist the ravages of salt water. I have a 300Ah bank and upgraded to the 55-amp from the 35-amp, about $60 bucks on E-Bay. There is a difference. The 55 requires an additional wire for the exciter voltage. Easy to do with the right diagram. Money not an issue? Then buy a Balmar and their 3-stage regulator.
 
Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
Joe,

With a 300Ah battery bank you realy need a 100A alternator. Callthe folks at Balmar and they will set you up with EXACTLY what you need. DO NOT use an automobie alternator. Car alternators are not ignition protected. I know you have a diesel, so what? How about the propane line that run thru your boat, or the surveyer who notes it and the insurance company that cancles your policy for an essential deficiency. I now this is contrary to ABYC standards. I think it is against a CFR section or at least a USCG rule. Sorry to be blunt but this is a safety issue. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
100A with breaking the bank

Joe: Here is an option that will deliver 100A and will not break the bank. It can output as much as 70A @ 1200 RPM (if batteries are low). http://thefloridakeys.com/batteryshack/
 
Jun 2, 2004
3,507
Hunter 23.5 Fort Walton Yacht Club, Florida
Not Even a Consideration

You will hear from folks here that diesel does not ignite and it is not a safety issue. Diesel will ignite and yes not as quickly as gas but once ignited that would make little difference.
 
Jun 3, 2004
418
Island Packet Island Packet 29 West River, MD
Steve, What do you know about ...

that outfit? There is another website, www.yanmardiesel.com, that has a similiar alternator. They are also in the Keys. Looks like the same alternator. Anyway, do you have any first hand knowledge of these guys?
 
Dec 2, 2003
4,245
- - Seabeck WA
Guys, no diesel engine comes with an ignition

protected alternator. It's not needed. If you want to see what one looks like check out an atomic 4 or any gasoline powered vessel. They have a screen over the air vents of the alternator and the carburetor(s). It looks like something that would be used for keeping the bugs away while on the porch or in the hot tub.
 
Dec 2, 1999
15,184
Hunter Vision-36 Rio Vista, CA.
Roger Mummah has one

Joe: Roger Mummah of Endless Summer fame has one of these alternators and he swears by them. It does take another cable and a different belt, but may be worth the swap out of that is what you want. You may also be able to get a 75AMP Hitachi from one of the larger engines that would be a direct replacement.
 
Jun 4, 2004
94
Catalina 22 Cape Cod
Against USCG Regs to use Automotive . . .

Somewhere in my travels I came to understand that it is somewhat illegal to use standard automotive parts such as starters and alternators for a marine engine. The reason is that the standard stuff is not properly sealed for marine applications and will allow sparks to ignite engine compartment vapors. Marine equivalents of these parts will not ignite engine compartment vapors and therefore are safe to use in marine applications. Regards, Ted
 
Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
Fred,

I have to draw your attention the the A.B.Y.C. Standards. Section A-1.6.1 This section is relating to propane but is applicable to this discussion. "A-1.6.1 If LPG is provided on the boat, all electrical sources of ignition located in a compartment containing LPG appliances, cylinders, fittings, valves or regulators shall be ignition protected." When it comes to LPG I error on the side of caution. Just an oppinion. Pat McCartin Inland Marine Diesel Buford, Ga imd_ga@hotmail.com
 
Jun 5, 2004
242
None None Greater Cincinnati
Battery Shack

See link - though in the Keys, they will ship. They build their own high-amp (marine) alternators on frames that will fit on the standard marine engines. I know they have one for Yanmar - I just haven't purchased it yet. Much cheaper than the brand (Bomar???) carried by Worst Marine, or even Defender. Initial reports from people are that they are good. Can be internal or external regulation.
 
Dec 2, 2003
4,245
- - Seabeck WA
Pat

That brings up many old threads here on HOW. I've had propane on my H34 since she was new in '86. To follow the ABYC requirements,,, well I can't. It would be impossible. My boat is too small and built wrong. The coast guard liked my setup, several times. So did my surveyor. I like it too. And another point, when you smell that stuff, you WILL find the leak, long before you can blow up the boat by starting the engine. IMHO of coarse. :) P.S. There you go! My engine is not in the galley so I don't need to ignition protect it. Pretty silly huh?
 

p323ms

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May 24, 2004
341
Pearson 323 panama city
I bought a 45 amp GM type

Alternator for my pearson 323. The wife fried the original by turning the battery selector to off. we've been using it since last May with no problems. It is self exciting and self regulatng so all I did was run a wire to the battery selector switch. We don't motor that much usually a couple of hours over a weekend. It keeps the batteries charged. Again I broke the rules and use two deep cycle batteries for starting and house use. Tom
 
Feb 26, 2004
23,003
Catalina 34 224 Maple Bay, BC, Canada
Check the specs

Some our of our C34 members have been happy with Battery Shack products. Please note that they sell BOTH internally and externally regulated alternators. Scroll down on their website info. Stu
 
Jun 3, 2004
347
Hunter 30_74-83 Lake Lanier, GA
Fred,

Point taken. I'm just paranoid with LPG, and my lines run thru my engine compartment. Come to think about it every system has represantation in my engine room. Pat McCartin Inland Marine Diesel Buford, GA imd_ga@hotmail.com
 
Jan 18, 2004
221
Beneteau 321 Houston
Battery Shack and Balmar

First, stick with a marine certified alternator. I can tell you first hand that the expected life will be proportional to the cost, and failure on a car is not as problematic as failure 30 knots out to sea. As for Battery Shack alternators--I purchased an alternator from them for my Yanmar 3GM30. Was told it was an exact swap. Finally got it installed after several phone calls only to discover that there was no output. Removed the unit and had it tested at two separate places hoping that it simply was installed incorrectly. Both tests showed only trace output. In my frustration and desire to get back on the water, I purchased a Balmar 100AMP with a 3-stage regulator, installed in about 1 1/2 hours without modification except enlarge the cabling, and it worked perfectly. I have heard many good things about the Battery Shack, I guess I just got THE bad one for month or something. Good Luck! Jon McClain
 
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