I will be using my Humminbird Helix 5 SI on a Kayak so I got a light weight battery to run it. After checking the Current draw with full backlight, and everything at max, it was only using a max of 460mA so this battery I'm getting should last me 8 to 9 hrs, and 7 at the advertised 615mA current draw. (dropping some knowledge for folks who are thinking about getting this particular FF, and wondering what battery to use) So I ended up getting this battery kit: https://www.austinka...Pack.html?last= It has recieved good reviews on different sites.