Cat 3208TA alternator wiring to external regulator

[Portage_Bay]

So my CAT 3208T/A are rated at 52amps. So 104 amps total. Not enough?

I don't know what engine RPM you cruise at. I'm running 3208s and keep the RPM down for a quiet fuel efficient ride 1400 - 1600. With the house bank discharged from a winter night on the hook I'll see something on the order of 27 AMPs output from the alternator charging the house bank. Current set up one feeds the house bank, one feeds the start bank.

If I were to convert them to external regulation and tie both into the house bank that's still a low charge rate. My plans are for 100 AMP alts and intelligent external regulation to send the output from both alternators to the house bank. After I get a bunch of other more pressing projects done and paid for.

Regarding 104 AMPs not being enough. Yes, it will charge the house bank. From my reading, I'm far from an expert, the most efficient charge rate for FLA batts, which is what I have, is 25% of the 20 Hr rate. My arithmetic works out to 165 AMPs at a 50% SOC. So two 100 AMP alts working together have a chance of meeting that charge rate.

A clear explanation can be found here ElectroMaaX FAQ. I had been hoping to use Rod Collinn's alternators but he's not yet recovered from his stroke and his store remains closed. Now considering ElectroMaaX's gear.

 

[FF]

Many boats have 4or more batts that make the house bank.

If there is a rotary switch to switch the house into 2 banks , with 100a alts it is quicker to charge each bank at 100a,rather than hope one alt does not fool the other into a slower charge rate.

 

[Osprey69]

Tom, they were 52a when new, and that was the max output at speed.

Lee-Niceville makes a bolt-in 110a alternator that can be easily converted to external regulation.

Does that fit in the tight footprint of the 3208's alternator brackets?

 

[Scottwb96]

Not sure about a 110a version, but Leece-Neville does make a 90a drop-in. That just BARELY fits... Part # 8MR2070TA - 110-603
You will definitely still want to have it converted to externally regulated. I am using Wakespeed (2 units networked together) WS500 in my setup.

There is also an old Balmar 150a alt that was a perfect fit as well. That's what I have on my port engine. It's no longer available from what I have been told, but if you could find one, you could probably have it rebuilt.

 

[Alaskan Sea-Duction]

Keep in mind that the wiring for the alternator has its limits with regard to max amps.

 

[Hookmeup]

Wal-Mart Prestolite Leece-Neville 105 A replacement

I just got a new 105 A Prestolite Leece Neville alternator from Wal-Mart $245. I was able to cut the wires inside the regulator to the field and push them through unused holes to be connected to a Balmar regulator. I had to trim the 1\4 inch output terminals to same length as the old 50 A originals.other dimensions seem exactly the same as the original 50A unit.
I previously had replaced the other engine alternator with a Balmar Series 6 costing $650 that I had to modify to avoid the rear plastic cover at the top interfering with the manifold. I also used the shortest belt I could get on to maximize clearance of the new units with the manifold.
I used the belt management setting to limit max output to 80% but that will be a lot better than the 27A I got from the original units.
I'm keeping the old units as spare having modified them to have field wires outside the alternator regulator case. I don't think you could push these old units much above 35-40 A for anything but short duration use.