Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Rate Thread Display Modes
Old 03-02-2013, 18:46   #1
Registered User
 
rcmpegasus's Avatar

Join Date: Sep 2008
Location: San Diego & Port Townsend
Boat: Formosa 51 Ketch
Posts: 143
Images: 1
Send a message via Skype™ to rcmpegasus
Will 200 amp alternator work on Lehman 120hp

I am looking at putting a 200 amp alternator on my Lehman 120. Will use or react size double belts etc.. Question is will this adversely effect the water pump or crank shaft with the load ? I have been running a 120 amp alternator or last 6 years and it was fine.
__________________

__________________
Bob Mathews
S/V Pegasus
rcmpegasus is offline   Reply With Quote
Old 03-02-2013, 19:08   #2
Senior Cruiser
 
delmarrey's Avatar

Cruisers Forum Supporter

Join Date: Mar 2003
Location: Now in Blaine, WA
Boat: Modified Choate 40
Posts: 10,702
Images: 122
Re: Will 200 amp alternator work on Lehman 120hp

Use a double belt, it should be fine. Just get a 40% wrap on the alt pulley.
__________________

__________________
Faithful are the Wounds of a Friend, but the Kisses of the Enemy are Deceitful! ........
A nation of sheep breeds a government of wolves!

Unprepared boaters, end up as floatsum!.......
delmarrey is offline   Reply With Quote
Old 03-02-2013, 20:10   #3
Moderator
 
sailorchic34's Avatar

Cruisers Forum Supporter

Join Date: Feb 2011
Location: SF Bay Area
Boat: Islander 34
Posts: 4,812
Re: Will 200 amp alternator work on Lehman 120hp

Side loading on the water pump could be an issue. You will need 2 belts or a wide. Me I would set it up as separate from the water pump, so side loading of the water pump was a non issue.
__________________
sailorchic34 is offline   Reply With Quote
Old 03-02-2013, 21:01   #4
cruiser

Join Date: Dec 2011
Location: Key West FL - Burlington VT
Boat: O'day 32 CC Ketch
Posts: 493
Re: Will 200 amp alternator work on Lehman 120hp

Do a serp belt conversion and you will gain tons more belt torque with way less side load issues. and less dust, its why every auto maker has gone to serp belts. The serp belt kits are a grand, maybe scrap this whole plan and get more/any solar. Why run the main? Charging off the main is allmost old tech at this point.
__________________
RabidRabbit is offline   Reply With Quote
Old 04-02-2013, 04:14   #5
Registered User
 
GrowleyMonster's Avatar

Join Date: Dec 2012
Location: New Orleans
Boat: 1976 Cal 2-27
Posts: 1,298
Re: Will 200 amp alternator work on Lehman 120hp

Solar is wonderful if your load is small. Kinda gets cumbersome if you are running air conditioning, microwave, electric stove, etc.
__________________
GrowleyMonster
1976 Cal 2-27, MR WIGGLES
Now with clean, dependable electric propulsion!
GrowleyMonster is offline   Reply With Quote
Old 04-02-2013, 04:55   #6
Registered User
 
delatbabel's Avatar

Join Date: Oct 2012
Location: Sydney NSW Australia
Posts: 113
Re: Will 200 amp alternator work on Lehman 120hp

If you're running air conditioning, microwave, electric stove, etc, then perhaps you should be living in a house, not on a boat.
__________________
delatbabel is offline   Reply With Quote
Old 04-02-2013, 05:13   #7
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 8,524
Images: 14
Re: Will 200 amp alternator work on Lehman 120hp

Do you have any battery charging monitoring devices? I just wonder if your current 120 AH is really putting out a full charge for very long or does it taper off quickly down to say 40AH. If so won't a 200 AH alternator just do the same. On a much smaller scale we notice our 60 AH alternator starts at 40AH and then drop quickly down to less than 20 AH, so bigger won't put in any more as the batteries are charged up.

Pete
__________________
Moody 31 - April Lass
Pete7 is offline   Reply With Quote
Old 04-02-2013, 06:04   #8
Senior Cruiser
 
Blue Stocking's Avatar

Cruisers Forum Supporter

Join Date: Dec 2008
Location: St. Georges, Bda
Boat: Rhodes Reliant 41ft
Posts: 4,114
Re: Will 200 amp alternator work on Lehman 120hp

Bob, I obtained a double pulley from a truck supplier, carefully drilled mounting holes, and bolted it directly to the static balancer on the crankshaft. 135A Amptec, no problem in 14 yrs.
__________________
so many projects--so little time !!
Blue Stocking is offline   Reply With Quote
Old 04-02-2013, 06:06   #9
Registered User
 
rcmpegasus's Avatar

Join Date: Sep 2008
Location: San Diego & Port Townsend
Boat: Formosa 51 Ketch
Posts: 143
Images: 1
Send a message via Skype™ to rcmpegasus
I have several battery monitoring devices, Link battery monitor, Blue Power Panel for Victron multiplus, seperate amp meters for each panel. Old alternator would start at about 110 and drop as expected over time.

200 amp alternator is primarily to support the running of the 40 gal per hour water maker, it uses 19 amps of 110AC, which is inverted out of the battery bank. I have substantial solar (1200W) but having a big alternator could be a big saver on getting the bank back up after making water. Don't plan on using the main engine just for charging, only for when underway. At anchor would be solar or if insufficient running my small generator.

Battery bank is 8 Odyssey 1800 battery's with 214 amp-hrs each. 1700 amp-hrs total.
__________________
Bob Mathews
S/V Pegasus
rcmpegasus is offline   Reply With Quote
Old 04-02-2013, 07:26   #10
Registered User
 
GrowleyMonster's Avatar

Join Date: Dec 2012
Location: New Orleans
Boat: 1976 Cal 2-27
Posts: 1,298
Re: Will 200 amp alternator work on Lehman 120hp

Quote:
Originally Posted by delatbabel View Post
If you're running air conditioning, microwave, electric stove, etc, then perhaps you should be living in a house, not on a boat.
Perhaps. But the fact remains that some folks live on their boats and don't mind paying for the amenities normally found only in a house. If it were not so, genset makers would have a hard time staying in business.
__________________
GrowleyMonster
1976 Cal 2-27, MR WIGGLES
Now with clean, dependable electric propulsion!
GrowleyMonster is offline   Reply With Quote
Old 04-02-2013, 07:27   #11
cruiser

Join Date: Dec 2011
Location: Key West FL - Burlington VT
Boat: O'day 32 CC Ketch
Posts: 493
Re: Will 200 amp alternator work on Lehman 120hp

Nice, I want your battery bank. Well you've got solar covered, have you thought about a serp belt set up? I really like them, its worlds better than V belts. My westerbeke is super hard on belts, lots of dust and adjusting several times a year. If you look at any make of car and find the year split where they went from 3 or 4 v belts to 1 serp belt the next year the mantaince is 10 times lower, and side loading is reduced greatly. Just a thought, not cheap though. I guess it depends on if you have ever veiwed your belts as a hassle.
__________________
RabidRabbit is offline   Reply With Quote
Old 04-02-2013, 07:30   #12
cruiser

Join Date: Dec 2011
Location: Key West FL - Burlington VT
Boat: O'day 32 CC Ketch
Posts: 493
Re: Will 200 amp alternator work on Lehman 120hp

My tiny boat has A/C. I dont use it much, but if I'm sick of sweating, it's there.
__________________
RabidRabbit is offline   Reply With Quote
Old 04-02-2013, 07:43   #13
Moderator Emeritus
 
David M's Avatar

Cruisers Forum Supporter

Join Date: Sep 2007
Location: San Francisco Bay
Boat: research vessel
Posts: 10,150
Re: Will 200 amp alternator work on Lehman 120hp

Check with Lehman, the dealership or a mechanic that is familiar with doing this. I wouldn't want to make a guess that is wrong and prematurely wear out bearings or burn up belts. Don't assume that all serpentine belts can handle the load.

You might also consider a clutched PTO off the engine for something that is going to draw that amount of horsepower.
__________________
David

Life begins where land ends.
David M is offline   Reply With Quote
Old 04-02-2013, 08:22   #14
cruiser

Join Date: Dec 2011
Location: Key West FL - Burlington VT
Boat: O'day 32 CC Ketch
Posts: 493
Re: Will 200 amp alternator work on Lehman 120hp

There are several different widths of serp belts, large trucks and semi's use a wide belt allmost twice as wide as the 2 smaller sizes seen on auto's. This isnt something that could be cobbed together easily, most likely it would be i kit form, made to handle aux. reefer and large frame alternators. So I would assume that it could handle the loads, But asking the manufacture would be obvious.
__________________
RabidRabbit is offline   Reply With Quote
Old 05-02-2013, 20:24   #15
Registered User
 
rcmpegasus's Avatar

Join Date: Sep 2008
Location: San Diego & Port Townsend
Boat: Formosa 51 Ketch
Posts: 143
Images: 1
Send a message via Skype™ to rcmpegasus
I've looked into serpent belts. Cruisero keeps saying they se coming out with a kit, but have not seen it yet. If you have to manufacture yourself it's kind of pricey. I'll call American Diesel and get a read.
__________________

__________________
Bob Mathews
S/V Pegasus
rcmpegasus is offline   Reply With Quote
Reply

Tags
alternator

Thread Tools
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off




Copyright 2002- Social Knowledge, LLC All Rights Reserved.

All times are GMT -7. The time now is 02:12.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2017, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.