Solar for kayak

[old_rookie]

Originally Posted by PescadorPete

Here battery voltage versus current with a Hobie 12v bait tank pump, tank full of water:

12V --> 1.37A
11V --> 1.20A
10V --> 1.06A
9V --> 0.91A
8V --> 0.77A
7V --> 0.64A
6V --> 0.52A
5V --> 0.39A

On six volts, the pumps draws less current (so it uses less power) than at twelve volts. My experience has been a 6 volt battery last much longer that a 12 volt battery powering the pump.

I bet the motor/pump moves less water too. If the amount of water circulated is adequate, then it sounds like a good solution. But this idea doesn't work for other electronics such as FF or whatever that needs to run on 12V. Usually they have internal voltage converters to bring it down to 5VDC for the internal electronics run - but there could be other devices that still need 12VDC - like the display or sonar. So it is best to run those at the rated voltage.