Electricity question

[Sdspeed]

Originally Posted by beef78

I am thinking about adding a new fish finder to my kayak and instead of buying a new 12 volt, just buying another 6 volt and putting them in parallel to extend battery life. And when I decide not to take my fish finder, I can still run my bait tank on 6 volt.

Wouldn't you want them in series so you'd have 12 volts for the FF and a separate 6 volt line for the bait tank? May require a diode in the line to the bait tank?