Possible Upgrade in Alternator

[cptbraine40]

iboat experts,

1992 Mercruiser 3.0 (lx)
Alpha One, Gen 2 outdrive
Battery: Duralast dual purpose 29 series battery

I just put a bigger battery into this boat and was thinking about upgrading the alternator. It currently has the older mando (65amp I think) alternator and I am look at upgrading to Delco Marine 3-Wire 110 AMP. Here are my questions:

1. Is this even possible with the current wiring layout?
2. If it is possible, do I need to get larger battery cables to handle to increased amp?
3. Again, if possible, is there anything that I need to be aware of.

Thank you for any assistance you can provide for me. Oh, my current alternator is ok, I just like updating items on my boat and doing preventative measures on it (alternator is probably 10 years or older).

cptbraine31
"Lead me, follow me, or get out of my way"

 

[Volphin]

Re: Possible Upgrade in Alternator

That upgrade is plug and play. But remember, the amperage rating of the alternator is simply what the max output is, based on what it senses the need to be. I upgraded to the same one from my 55A, which I dunked in a full bilge and effectively fried. LOL

 

[cptbraine40]

Re: Possible Upgrade in Alternator

That is what I thought but I just wanted to be sure. I was not sure if my current battery cables would handle the increased amp. Like I said, the alternator I have now is fine, I just like to stay head of things during the off season and a 10 years old alternator gives me a worry when the summer kicks back up. Appreciate the input Volphin!!!!

 

[haulnazz15]

Re: Possible Upgrade in Alternator

I can't imagine it being necessary unless you have a lot of high-draw electronics (big stereo systems, etc) that require the bigger alternator to keep the battery up. Otherwise I'd just leave well enough alone.

 

[cptbraine40]

Re: Possible Upgrade in Alternator

I don't have anything that is drawing too much power. I have the larger 29 series battery and I just have a stereo, 4 6x9 speakers that I am pushing with a 400 watt amp. I guess I am just an overcautious type of person and I don't want to get left stranded on the lake.................it happened once...............and that was enough

 

[thumpar]

Re: Possible Upgrade in Alternator

It doesn't sound like you would use the extra amperage. Unless you plan to upgrade in electronics or need to charge a battery bank I would leave it alone.

 

[airshot]

Re: Possible Upgrade in Alternator

Rather than worry about the alternator and wiring just add a second battery. I have two, one strickly for starting and the other a 125 amp deep cycle that runs everything on the boat. I have never had to charge the big deep cycle more than once thru a season. I have the battery switch so I could charge it from the alternator but a small deep cycle charger is healthier for the deep cycle battery. Peace of mind knowing nothing is draining your start battery.

 

[thumpar]

Re: Possible Upgrade in Alternator

On my old boat I ran 2 batteries. One was a starting battery and the other a deep cycle. The deep cycle ran everything but the engine and trim. I used a battery isolator so that both would get charged but would prevent the starting battery from being drained when using the accessories. I just picked up another battery for the current boat and will be wiring it the same as the old one this spring.

 

[achris]

Re: Possible Upgrade in Alternator

65 Amps is way enough to run ANY size battery. In fact, you could put 4 batteries on that alternator and it would run just fine. The output rating of the alternator is the MAXIMUM current it will produce, and has absolutely nothing to do with the size of the battery you have. Most batteries only require a charge current of about 10-15 amps after starting. Yes you can put a new alternator on, but all you'll end up achieving is a lighter wallet...

Chris.......

 

[fishrdan]

Re: Possible Upgrade in Alternator

Agree with the others that say to add a second battery. And, add a Blue Seas ARC and battery switch so the second battery charges automatically.

65 Amps is way enough to run ANY size battery. In fact, you could put 4 batteries on that alternator and it would run just fine.

^^^Definitely. That 100(+) amp alternator could very well cook a single group 29 battery if the battery was discharged and taking a 100 amp charge rate, too much current.

Also, if you do install a 100 amp alternator you'll need to upgrade the + wire going from the alternator to the starter as the stock wire is too thin. I used 6ga wire when I added my 100 amp alternator, I'm recharge 2 deep cycle batteries, 4 total batts in the boat.

 

[KD4UPL]

Re: Possible Upgrade in Alternator

My boat has a 16 year old 55 amp alt.
I have a stereo with amp and subwoofer on my boat. I also regularly run my electric cooler. The alt. does just fine.
I think it would be a waste of money to upgrade something that is working fine and doesn't need upgrading.

 

[cptbraine40]

Re: Possible Upgrade in Alternator

Great, I really appreciate all of the input. I would love to put 2 batteries in my boat but I honestly don't have the compartment space for it, that is why I went with a larger 29 series battery. I did put a Marine Priority Start to the battery to be sure that I don't drain the battery too low. I am gonig to follow everyone's advice......................forget a new alternator at this time............thanks for the $100.00 savings