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Thorsten Koch avatar image
Thorsten Koch asked

2 batteries on a boat with MPPT 75/15 and a 150W solar panel

How to best connect 2 batteries on a boat with 12v auto charger in the game and battery switch (1,2, 1&2 and off). Guess I will need some sort of a relay or diode?


Thanks for any hint.

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Thorsten Koch avatar image Thorsten Koch commented ·

OK, sounds like easy to do, I was planing to put a relay in so either the solar or the automatic charger is connected so I would not have voltage on the cable outside if the Solar is not connected and the charger is plugged in or the batteries are on.


Thanks

Thorsten

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JohnC avatar image
JohnC answered ·

Hi Thorsten. You could just parallel in the mppt to the autocharger outputs. They'll each control their output by V, and if you want solar to take priority, just back off the autocharger V-settings (if you can) to a little lower than the mppt's.

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