Solar panel to charge battery

[seanform]

Hello everyone. On my boat I have two batteries,one 100AH and one 125 AH. I would like to keep them (or at least one) constantly on charge with a solar panel. How much current does the solar panel need to be? 10x

[Verytricky]

Approximately 3w per 100AH unregulated.

This is to 'hold' a charge, and not to charge a battery.


Youy need to ensure that your battery can not 'charge' your solar pannel at night, as the losses there would negate putting on a pannel - so use a diode to restrict flow direction. If you exceed around 6w per 100ah you need to look at a regulator that turns off the charge when the battery is full. This assumes a battery in good working order. An old or damaged battery would probably require a higher charge, but dammage will occur if you consistantly overcharge a battery.



If you are using wind generation you need definately a regulator and a 'dump' to prevent damage to the electrics.