Did I make a mistake?

[jlp0217]

My engine (Perkins 4.236) has 2 alternaters which I replaced last summer. I also removed the 2 to 3 Diode pack and replaced with ACRs. Late last fall I decided to replace the new alternators' internal regulation with a Balmar 612 Dual. I'm now wondering if that was the right choice. The alternators are driven by different sized pulleys on the engine, making the alternators turn at different speeds. Don't ask me why - that's apparently just the way Jeanneau did it. Balmar doesn't discuss it in their manual, but they do stress that the alternators should be on the same engine. I don't see what difference that would make other than two engines wouldn't necessarily be running at the same speed, or maybe not even both running.
My understanding is that the regulator drives the field of both regulators the same - is that ok when they're not turning the same speed?

PS. I haven't yet moved the regulator's ground wires from the alternator to the battery as suggested. Its on my to-do list. I presume I could use a single #10 wire and jumper the 2 terminals on the regulator, or would the jumper even be needed? Both alternators output go to the house bank. Distance is about 15 feet, #2 wire.

One more question - Balmar's manual said to attach the altermator temp sensors to a case bolt, but the terminal provided is way to large - do any alternators have case bolts that large?
Anyway, I attached the sensors to the side of the alternator with a large hose clamp. Just looking for an OK on that.

Jim

 

[whatfiero]

Good lookin alts

I assume the alternators serve two different loads the one with the smaller primary pulley prob feeds house bank and larger starting bank as long as the can never be connected in parallel . The design is most likely to get the house bank charged up faster and just maintain the starting bank. Remember that the amp and voltage are directly related and go up with the speed that it's turning. Temp sensor usually bolts to a big ground lug on back of alternator

 

[Maine Sail]

Not a big fan of driving two alts with one regulator unless they are;

A) Set up identically

B) Both charging the same bank

I generally prefer the redundancy of two separate alternator systems, when you have that ability, and you do with two alternators.

 

[jlp0217]

Yes, (or no to whatfiero) the alts are connected in parallel to the house bank. Jeanneau had them isolated with the diode pack but that's gone. Guess I should pose the question to Balmar, but what happens with output when 2 alts are driven with the same field voltage, but are spinning at different speeds? Can I just remove the 2nd cable from the 612Duel and just get anther 612, or would I have to get 2 612s?
The house bank is 3 Lifeline 4D AGMs so they have no trouble sucking all the current the alts can produce.