Power for your FF/GPS?

Thanks to everyone with all the greata replies, I've looked all weekend and decided to order one from Cabala's. I've got the box and water sealed in. I'm deciding where to put it now. Everything will be ready by the 13th of June to nail some Rockfish.

I use a motorcycle battery purchased from Kragen and two dry sacks purchased from Harbor Freight. The battery is heavy but it works fine. Also my battery is mounted outside my yak exposed and the dry sacks do their job.