Battery Location

I have a 1648 Crestliner Jon Boat. I am planning for a deck extension up front and trolling motor. I currently have 1 battery in the rear of the boat, and was looking to add another. Do you guys think I should put the new battery by the old one at the rear, or towards the front/middle under the new deck. I was wondering if it would be too much weight up front with a deck and trolling motor. The rear has a 25hp motor, a 6 gallon gas tank, and the old battery.

It shouldn't be too much weight. On my 1642 I had 2 group 27 batteries up front with my 24v trolling motor and it was no problem.