C36 Alternator Upgrade

[MarkWood]

I am researching my options for upgrading my alternator to a higher output unit. I am hoping to find a compromise that will provide me with enough extra juice to make it worthwile, but doesn't reduce reliability or require any significant mod's. In other words, a bolt on affair.

Anyone out there have experience with this upgrade for their C36 with a Universal M35B Diesel?

Thanks in advance,

Mark Wood

[erps]

On the Catalina 34 International Association Website there are some nice write ups on Electrical upgrades including information on a 100 amp Alternator that will bolt right right on your engine with a single belt pulley. The alternator was built by a small outfit in either Minnesota or Wisconsin and cost about $120. Search for key words "Blue Circle" to find one of the discussions. Along with your higher capacity alternator, you'll want to buy a fancy three stage smart regulator. The regulator alone is an improvement over the stock dumb regulator in your current alternator.

[hellosailor]

Mark, how big is your battery bank & power draw?

The reason I ask, is because "bigger" isn't any use unless you can make good use of the power. It is fairly easy to have more alternator than you need, unless you've got a serious battery bank. Sometimes, a good external 3-stage regulator is all you need, along with upgraded cables and a better charge sensor (from the regulator to the batteries).

[MarkWood]

I have 2 gel batteries @ 225AH each in parralel as a house bank, and a dedicated starting battery. Our power needs are moderate. Mainly refrigeration, GPS Chartplotter, cabin and anchor lights, and the inverter for DVD's. All of which will be in more demand when we go cruising for 6 months in the Fall.

In addition to the alternator upgrade, I'm installing a Link 10 for monitoring.

Mark

[camaraderie]

Get a Balmar Bolt-on with an external 3 stage regulator like the ARS5 http://www.balmar.net/page67-ars5.html....or you will toast those gels. The link10 will serve you well.

[hellosailor]

Mark, assuming you really mean "gel" not "AGM"...Why did you choose gel??

2 x 225 AH = 450 AH and if used to 50% cycle, that's back to 225AH you'd need over about 5(?) hours at full acceptance rate.


225/5 = 45A from the alternator would provide full acceptance to the batteries, add whatever you need for lights & the reefer, and you can see how you may need less alternator than you'd think. But, the 3-stage regulator would still be a major improvement over any internal one.

[camaraderie]

HelloS...Actually Gels can be charged at 50% of rated amp hours or in this case up to 225Amps...at the right voltage during bulk charging. AGM's can be charged at full rated amp hours rate. Flooded are generally suggested to be charged at 25% rated amp hours though some argue that higher is OK.

As a practical matter a 100amp alternator will cut his engine charging time in half and so is quite worthwhile since one or two hours of charging every other day is a whole lot better than 4-5 hours. Geting into bigger alternators can require double belts and additional bracing to handle the load on the engine shaft bearings so I'd stick in the 100 amp range.

[hellosailor]

Cam-
Dunno about gels at all, but the conventional numbers for wet cells are 1/5thC and for AGMs 1/4C rate. How do you safely charge them faster than that? Gotta be a less-than-conventional charging protocol or tighter controls required, including thermal sensor?

Double belts are passe these days, v-belts in general are actually getting damned hard to find in stock. Ribbed belts will handle all the power--with just one belt and no constant need to even out the tension between two V's.

[camaraderie]

Hello...AGM's can be charged at their FULL rated capacity if you are in bulk mode and have a big honking alternator. Indeed Lifeline says UNLIMITED current during bulk charging!!!
Here's a reference so you know it is gospel:
Lifeline Marine Batteries - AGM Marine Battery & AGM RV Battery