7 amps * 20% useage (Probably a lot of duty cycle but if you are in
weeds it may be close to 20%) * 2 downriggers * 8 hours of fishing =
22.4 Amp hours....

33 ah would mean you would run the unit down to almost nothing and it
would not last very long. It would also get real weak and slow at the
end of the day.

Take Bill's advice... go buy a group 27 deep cycle battery, a battery
box, some type of rubber rug (to keep it from sliding around and
breaking something) and you will need a 10 AMP automatic battery charger.

BTW... Why a separate battery? Your alternator can easily keep up with
this kind of draw while trolling.... is it a wiring thing?

I would suggest a second battery, switch, etc and run it off the main
engine battery leaving the second one for starting backup...



JJ wrote:
Hi again. I am installing 2 downriggers on my boat. I want to run them on a
separate battery. They draw 7amps each. What kind of battery do I need for
a full day of fishing ? Would a portable power pack (33 ah deep cycle) work
?

Thanks again for all the help.

JJ