Wrapping up the Kayak Project... Fish finder wiring Question

[Lipripper92592]

I mounted the battery in a starboard locking box in a Trident 15.
What kind of yak are you mounting it in?
Go the separate battery route. Look at the specifications on watt/amp hour draw for you FF unit, it's mostly likely around .5amps per hour.
You never want to draw a lead acid battery past down past 60% full charge. Meaning you will only get around 6 effect amp hours out of a 10 amp hour battery before you start to cause damage, ( sulfation, degradation of the plates, etc)
Run at least a ten amp hour for just the FF, unless you want to have your FF shut down in the afternoon if you start early.