I am trying to decide on the best external regulator to use with a Beta 20 and any advice on ease of installation with the various systems. I used an "Aqualine Marine mod. 10-82 with my previous engine, but will be installing something new. Looking at a "Balmar ARS-5" or a "Sterling Power ProReg BW" (those are the 2 major players here in the US)
My batteries consist of 2 banks of Trojan T-105 batteries - each bank has 2 6-volt batteries wired in series so that each bank consists of 225 amps total for the 2 banks = 450 amps
I had thought of using a 120 amp alternator on the Beta 20, but am concerned about whether the engine handles this large alternator with only one belt. If I charge just one bank at a time (225 amps), it seems like the 75 amp alternator with a good external regulator should be plenty of power.
I suggest that you go with the 120 amp alternator. The wide polyvee belt (serpentine style) does transmit the power well.
The 75 amp alternator wont do what you want of it as it will need to be working at close to max all the time.
I also suggest looking at the Balmar 614 regulator and harness. I would however first test the engine and charging system with the standard internal regulator to get a base line of how the alternator actually charges. This way you can get a real world comparison to check if the external regulator actually does you any good or not.
