Join Date: Jul 2000
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I recently repowered with a new Yanmar 3GM which came with an internally regulated Hitachi 80amp alternator. The problem is that it puts out 14.4 volts, which over time, I hear, will fry my gel cell batteries. My old engine/alternator had external regulation which put out 13.8 volts, more in line with that recommended for gel batteries.
My question is this: Is there a simple inexpensive way to step down the voltage by adding resistance on the battery side of the alternator? I''m not wild about the idea of having my new alternator modified by a shop and/or spending money on new wet cell batteries, new alternator and/or a smart regulation system. My cruising consists mostly of weekends and an occasional week or two of vacation time, the rest of the time my boat sits on a mooring with all power off (except the bilge pump of course). I have very modest electrical usage, so I''d like to keep things simple and inexpensive.
In ‘This Old Boat’, Don Casey talks about a disconnect switch between the alternator and battery, I’m guessing why not a resistor? All comments welcome.