Originally Posted by Grahambda
Hi, I am in the process of upgrading my house batts to Agm super cycle total 940ah. I have twin 135ís in my DeFever 44 trawler. I want to upgrade the alternator on my starboard engine to dedicate to charging the house batts. Looking at the Balmar XT 250, should I add this as a second independent alternator and use twin v belts driving off the crankshaft alone, ( comes with complications and cost around install of brackets and tension bars and limited space) or go the easier route and replace the existing alternator and install a serpentine belt system.
Welcome thoughts and recommendations.
Graham, on my DF44, I charge a FLA 920Ah bank using a single 100 amp Balmar on each engine controlled by a Balmar Centerfielder. When depleted to 50% SOC, it takes about 5.5 hours to get to full charge, the same amount of time when charged through shore power from 50% SOC. You do not need an XT 270. Do not be seduced by the seemingly faster charge acceptance rates of AGMs. It is an illusion. At one time, I had thought of adding the Balmar XT 270 and went so far as to adding double-belt pulleys. Then, after doing the Great Loop with my existing Balmars, I learned that it was all a waste, at least to me. The pulleys are still there on one engine. They look pretty.
I suggest you get in touch with Ian McLoud, another DF44 owner. He installed an AGM bank on his boat of about 1,300 AH, as I recall. You can find him through the DeFever Cruisers website.