Review by Jeremy L. Peake for Humminbird 7700281 GCBK Portable Gel-Cell Battery and Charger
Rating:
Not much to say. It’s a gel cell battery that works like you would expect. Got it for a Humminbird Piranhamax 170 to install in my kayak. Has enough capacity to run the sonar for a long time with full back light (12 hours and I still hadn’t hit the 11 volt mark).

I could have probably went with a smaller battery, as this one seems almost like overkill.

If you want lots of capacity for a gray scale fish finder, you can’t go wrong here.