Amp rating of OEM 5.0L alternator

harojs

Petty Officer 3rd Class
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Aug 28, 2016
Messages
84
5.0FLPMDA

I'm doing the Blue Sea "Add-A-Battery" ACR installation and I need to determine alternator size.

I am still running the stock OEM alternator.

Is it typically a 65A alternator for the 5.0FLPMDA ?

-John
 

Fun Times

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May 16, 2009
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8,776
Are there any stickers on your alternator that has any info like amps, part number etc.?
What year is the boat?
Sort of hard to tell what you may have exactly as Volvo offered two amp sizes in the repair manual but the manual didn't say what amp fits what engine model, etc..

Volvo has a 51 and 65 amp alternator within the ford MD manual....Looking up the early Volvo part numbers seems to show the 51 amp size or close to it at 55A as the most common....The high output would be 65A.....All the aftermarket alternators are all over the amp size range from 51 amps to 105+ amps depending on where you search.

http://www.volvopentastore.com/Alte...on_id.981139476--store_id.366--view_id.783292

http://boatinfo.no/lib/volvo/manuals/md_elect.html#/92

3853853
https://bpi.ebasicpower.com/shop/om...ystem/alternators/alternator-omc-cobra-51-amp
5.0FLPMDA1993190
5.0FLPMDA1994190
5.8FLPMDA1994230
5.8FLPMDA1993230

https://maxrules.com/fixvolvoalternator.html
FITS V8 FORD 5.0L & 5.8L
55 AMP, SINGLE GROOVE PULLEY, 3-WIRE
(GROUND WIRE CONNECTS TO NUT ON BACK,
NOT SHOWN), TACH LEAD, INTERNAL REGULATED
RED wire = Sensor, PURPLE wire = Exciter
REPL VOLVO # 3860769, 3853853, 3854809, 3854182,
3850927, 3857298,

I'd only guess it's 51 amps but the following link on page 3-4 offers a way to test your alternator to see what it's putting out if the specifications are that critical for what you're doing...., http://boatinfo.no/lib/volvo/manuals/md_elect.html#/74
 

alldodge

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Staff member
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Mar 8, 2009
Messages
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Assuming the question comes from determining the wire and/or fuse size, I would suggest using 65A for the the install. This will provide lowest voltage drop for wires and the fuse size even if 10 amp larger will still protect.
 

harojs

Petty Officer 3rd Class
Joined
Aug 28, 2016
Messages
84
Thanks all, I needed amp rating to spec a Blue Sea Systems ACR switch. Since the choice of kits was 65A or 120A, I went with the 120A. Switch is a bit larger physically which is good also for us older guys.
 
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