I have a stock, 51 amp, alternator on my Universal M25XP diesel. I was thinking of putting a Balmour 70 amp alternator on it. I wondered if anyone had done this on either a Universal M25 or M25XP and if so could you use the same belt and belt configuration or did you need to upgrade that too because of the higher load. Thanks Goodwinds, Dave M s/v DAMWEGAS
Uprating Alternator
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Read This Artice On Upgrading A M25
I wrote this article when I owned my C-36 and this past spring purchased a C-310 and did the same exact upgrade to it. The only thing I did differently was to not use external regulation. The Leece Neville 8MR alternatro comes with a great built in voltage regulator so I stayed with it. The Balmar alternators are over priced and NOT a direct fit for the M25 and will require bracket modifications. I have used the 8MR series from Leece Neville twice and never had a problem! It charges my two 4D's on my 310 easily and I have no excess belt wear! Rod http://www.catalina36.org/site2004/Article_alternator-battery.htm
I wrote this article when I owned my C-36 and this past spring purchased a C-310 and did the same exact upgrade to it. The only thing I did differently was to not use external regulation. The Leece Neville 8MR alternatro comes with a great built in voltage regulator so I stayed with it. The Balmar alternators are over priced and NOT a direct fit for the M25 and will require bracket modifications. I have used the 8MR series from Leece Neville twice and never had a problem! It charges my two 4D's on my 310 easily and I have no excess belt wear! Rod http://www.catalina36.org/site2004/Article_alternator-battery.htm
Balmar upgrade on MX-25XPB
As part of an electrical system upgrade, I installed a Balmar 75 amp alternator on my C310 M-25 XPB (year 2000). I had to file a little bit of material off the cast lower bracket, about an eighth of an inch, to allow it to swing to the new position. I also had to select a new length belt. Nothing else was required. Took me an afternoon to complete. At the same time I added an “In Charge” three stage external regulator. Combined with a “Link 10” battery monitor I installed earlier, the charging of my batteries are no longer a mystery, and I have some control over the process.
As part of an electrical system upgrade, I installed a Balmar 75 amp alternator on my C310 M-25 XPB (year 2000). I had to file a little bit of material off the cast lower bracket, about an eighth of an inch, to allow it to swing to the new position. I also had to select a new length belt. Nothing else was required. Took me an afternoon to complete. At the same time I added an “In Charge” three stage external regulator. Combined with a “Link 10” battery monitor I installed earlier, the charging of my batteries are no longer a mystery, and I have some control over the process.
alt boost
Dave; Take your present alternator to a shop that specializes in trucks and buses and RVs. See if they can rebuild it and increase the amp output at the same time. It will be a direct drop-in replacement with minimal fuss. I did it with mine.
Dave; Take your present alternator to a shop that specializes in trucks and buses and RVs. See if they can rebuild it and increase the amp output at the same time. It will be a direct drop-in replacement with minimal fuss. I did it with mine.
Save your money.
Install a Balmar external regulator to put that 51 amps to work. You are limiting the input to the battery with the internal regulator. An external regulator directs full output to the battery until it is nearly full and then reduces the input to a topping charge. See http://www.balmar.net/page15-maxchargemain.html for more information. Jim
Install a Balmar external regulator to put that 51 amps to work. You are limiting the input to the battery with the internal regulator. An external regulator directs full output to the battery until it is nearly full and then reduces the input to a topping charge. See http://www.balmar.net/page15-maxchargemain.html for more information. Jim
Actually Dave That's Been Done
I tried that on my C-36 before I upgraded to the 90 amp. I burned out the 51 amp alternator in two weeks doing just that. The problem is if you have a lot of house bank the 51 amp takes far to long to charge it even with an external regulator. It made my 51 so hot for so long I could fry an egg on it and it finally gave up. I did have it rebuilt and kept it as a back up but with the stock regulator. This is when I sourced the Leece Neville 90 amp.. You can try and force the 51 to do the job but just have a back up alt ready... I suppose if your at a marina most of the time & plugged in the 51 might cut it but if your on a mooring it's borderline at best..
I tried that on my C-36 before I upgraded to the 90 amp. I burned out the 51 amp alternator in two weeks doing just that. The problem is if you have a lot of house bank the 51 amp takes far to long to charge it even with an external regulator. It made my 51 so hot for so long I could fry an egg on it and it finally gave up. I did have it rebuilt and kept it as a back up but with the stock regulator. This is when I sourced the Leece Neville 90 amp.. You can try and force the 51 to do the job but just have a back up alt ready... I suppose if your at a marina most of the time & plugged in the 51 might cut it but if your on a mooring it's borderline at best..
JonW thanks for the picture,
now I see that gear driven raw water pump too. Just as described in another current thread.
now I see that gear driven raw water pump too. Just as described in another current thread.
Good ideas, Rod, a question?
Thanks for the discussion. A lot of good ideas. Rod, I tried to find the spec. on the internal regulator on the 8MR and could not. Does it seem to charge wide open then float when charged like a more sophiscated external regulator. I am just trying to get a feel for why you decided it was not worth the extra expense for an external on the second installation. Thanks Goodwinds, Dave M s/v DAMWEGAS
Thanks for the discussion. A lot of good ideas. Rod, I tried to find the spec. on the internal regulator on the 8MR and could not. Does it seem to charge wide open then float when charged like a more sophiscated external regulator. I am just trying to get a feel for why you decided it was not worth the extra expense for an external on the second installation. Thanks Goodwinds, Dave M s/v DAMWEGAS
I Went With Internal Regulation Because..
I had two failures with the Balmar ARS-4 regulator. Granted Balmar replaced the units both times but due to the poor reliability I decided to stick with the simplicity of the internal. The internal is basically a two stage regulator but it has an adjustment screw to dial in max output to match your batteries. My alternator shop guru actually talked me out of external regulation saying it is not necessary and cited numerous examples of situations where multi stage regulation is not used in deep cycle batteries. He services golf courses and told me that even the chargers at courses are two stage.... I ran my boat the entire season with internal regulation and had no problems at all it charged up quickly and my batteries tested fine at the end of the year.. Plus I can buy four new 6V batteries for less than the price of converting to external regulation. I buy new batteries every three season regardless of need anyway for peace of mind so why bother???? If your doing it for that extra few% of charge then I suggest over sizing your battery bank it's far cheaper.. I may have been suckered into it the first time around but not the second. My new motto KISS keep it simple stupid. I suppose if I were doing extended cruising for say two years I might consider external because but only because of the cost of batteries in other countries & the 24/7 use on them but for our 5 month season I don't think it really matters much...
I had two failures with the Balmar ARS-4 regulator. Granted Balmar replaced the units both times but due to the poor reliability I decided to stick with the simplicity of the internal. The internal is basically a two stage regulator but it has an adjustment screw to dial in max output to match your batteries. My alternator shop guru actually talked me out of external regulation saying it is not necessary and cited numerous examples of situations where multi stage regulation is not used in deep cycle batteries. He services golf courses and told me that even the chargers at courses are two stage.... I ran my boat the entire season with internal regulation and had no problems at all it charged up quickly and my batteries tested fine at the end of the year.. Plus I can buy four new 6V batteries for less than the price of converting to external regulation. I buy new batteries every three season regardless of need anyway for peace of mind so why bother???? If your doing it for that extra few% of charge then I suggest over sizing your battery bank it's far cheaper.. I may have been suckered into it the first time around but not the second. My new motto KISS keep it simple stupid. I suppose if I were doing extended cruising for say two years I might consider external because but only because of the cost of batteries in other countries & the 24/7 use on them but for our 5 month season I don't think it really matters much...
Here's A Link To The 8MR Series Alternator
Click the link to see the specs on the 8MR2069TA 90 amp alternator..
Click the link to see the specs on the 8MR2069TA 90 amp alternator..
Oh, One thing
Talk of different size alternators brings up something that might help. The output capacity of an alternator is determined by the stator. No other difference. I've never paid more than $14.00 for one. I've even been able to raise the capacity of my stock 69 Camaro alternator from the original 'high output' 37 amps to 100 now. Works really good again. (finally) They never had large watt stereos, electronic fuel injection and ignition when I bought it new.
Talk of different size alternators brings up something that might help. The output capacity of an alternator is determined by the stator. No other difference. I've never paid more than $14.00 for one. I've even been able to raise the capacity of my stock 69 Camaro alternator from the original 'high output' 37 amps to 100 now. Works really good again. (finally) They never had large watt stereos, electronic fuel injection and ignition when I bought it new.
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