Re: 12V Charger
I think the short life of dynamo charged batteries was down to the battery technology not the (voltage regulated) dynamo. The charging voltage of the dynamo could be adjusted (or fiddled with, of course) and could drift off, though.
Give or take the ambient temperature, about 14.4V is right for a one off charge, terminated when the battery is full; 13.8V is float voltage which can be applied indefinitely to keep it full.
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