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Replacement for Hitachi LR135-31 alternator?
"ray lunder" wrote
Ahoy, I could only find one technical reference for this which claims it's a 30 amp alternator. Could this be correct? I think it may be 35A but that is likely the standard alternator Yanmar used on even the 2-cyl engines. It's on a 12hp Yanmar one cylinder diesel and I'd like to charge my house batteries (220AH) and a 12v starting battery. If I'm beginning to understand these things I'm to look for an alternator which will produce 30% of my amp hour capacity. Since I'll probably charge the two systems separately I guess that's around 70 - 80 amps. Yanmar had an optional 55A Hitachi for my engine that with slight modification of the mounting bolt fits. This is what I have on our 2 cyl Yanmar and it seems to work fine with our 200AH bank plus starting battery. We don't have any fancy alternator regulator, but do have a Blue Seas ACR battery combiner so as to use the maximum output voltage (as opposed to a diode splitter). Don't oversize your alternator - That engine may be rated at 12HP, but I suspect at normal rpm, it would have a hard time making 10HP (BTW- I used to have that engine on an earlier boat). Check the engine power curve. The alternator may use up another ~2HP if the batteries are down leaving just ~8HP or less to drive the boat. For our 15 HP 2-cyl Yanmar, Yanmar recommend no more than 80A but I do know some who have installed 100A units - this can cause belt problems if the pulleys/belts are not rated for the power required. God Luck GBM |
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