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:grin: I need to change the Alternator on my boat, because the one on it is the first type that Thornycroft fitted when they phased out dynamo's, the guy at Thornycroft recommends fitting a 36Amp one as that what the pulley system was designed to take, and he's says it's more than man enough for two 110Amp battery's, but all the sites I've checked say that it should have more Amps, one even says you need a 50Amp one just to charge a 85Amp battery, anyone have any input on this, or know where I can find more info,,

Regards Frank,,

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I thought that Jimbo! I may go for the larger one because I want to try and fit a third battery, so I have one for starting and two domestic, the new boat has an Engel fridge, so what with the little telly and lights I don't think one 110amp battery will be enough,,

Regards Frank,,,

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It will depend on how much you run obviously, but 36a does seem ather small, however if you fit a good regulater and splitter system it will at least ensure that it is giving it's full 36a and is distributed where it's needed.

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Hi Mowjo

Ideally your alternator (and charger) should be 20% of the total power of your batteries any more could boil leisure batteries. If you are grouping batteries together in parallel always match the amp/hour values.


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