what battery ?

Matt,

What kind of Fish finder are you running with that battery and how many hours will it power up your fish finder for?  I've got a Lowrance Hook 5 which draws about an amp an hour, so I can go all day on my 8amp hour Cabelas battery.  I just upgraded to the Hook 7, and I'm guessing it will draw a bit more power, but I'm curious about the battery you have, as I'm sure it's a fraction of the weight of my battery.

Matt,

What kind of Fish finder are you running with that battery and how many hours will it power up your fish finder for?  I've got a Lowrance Hook 5 which draws about an amp an hour, so I can go all day on my 8amp hour Cabelas battery.  I just upgraded to the Hook 7, and I'm guessing it will draw a bit more power, but I'm curious about the battery you have, as I'm sure it's a fraction of the weight of my battery.

I just upgraded to the Hook2 7 myself (also upgrading my kayak to a 2019 Outback soon as well). I plan on using the same 12v, 10ah lithium battery with it but, as you said, probably won't get as many hours of use from it because of the larger screen drawing more power. How do you like the ff so far?

I've only used it so far in demo mode to adjust the settings to what I liked in the hook 5.  I also uploaded all of my waypoints into it.  I wasn't excited to have to buy a new ram mount but I am liking the wider screen.  Will be much easier on the eyes with split screen mode.

I'm waiting on the BerleyPro sunvisor I ordered for it to arrive.  They are the only company that make the molded sunvisor and they say it will cut down the glare on the screen, and allow you to run the fishfinder at lower brightness and lower power.

I will get it on the water soon, but I'm sure it will be great.

I made my battery box from a waterproof snap lock container
https://smile.amazon.com/gp/product/B0000AN4CK/ref=ppx_yo_dt_b_asin_title_o02_s00?ie=UTF8&psc=1
I just put the wires for my plug through the hole and covered it with goop.
I used this fuse holder with a 3A fuse.
https://smile.amazon.com/gp/product/B072F4F4Y3/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

I tied the battery box in place by tying a couple of pieces of old bicycle tire around my battery box and then running an adjustable bungee cord (the kind where you can pull it through and lock it in any place) through the tires. I then use the bungee to attach the box to the inside of the kayak. I tied it around where the scupper holes go through but you could tie it to any convenient spot. It holds the box in place above the bottom so it is never in water. It stays in place even when I load the kayak upside down on my car. I leave it in my kayak all the time and charge it by unscrewing the waterproof connector and screwing it into another connector attached to my charger. However, you can easily remove the whole box. Super cheap and easy.

I posted a description of the battery boxes I have made for 12 volt SLA batteries at https://www.northwestkayakanglers.com/index.php?topic=17734.msg191025#msg191025. The box is an inexpensive dry box which is available at Walmart, and it uses a panel-mounted 2-pin SAE connector to connect to either my fish finder or my recharger. I use the Fastex buckle strap to attach the battery box to the inside of my kayak, and it also provides a handle when I'm carrying the box around.

Note:  if you have an 8" circular hatch you don't need a battery box with the FPV power: 

Matt,

What kind of Fish finder are you running with that battery and how many hours will it power up your fish finder for?  I've got a Lowrance Hook 5 which draws about an amp an hour, so I can go all day on my 8amp hour Cabelas battery.  I just upgraded to the Hook 7, and I'm guessing it will draw a bit more power, but I'm curious about the battery you have, as I'm sure it's a fraction of the weight of my battery.

I have a Raymarine Dragonfly Pro 4 with GPS that I run all the time and full brightness most of the time. I have run it for two solid days fishing without issue. I am fairly sure that the stated capacity is unlikely if not impossible to be quite what it is stated as, but nevertheless it works fine for my usages. For a battery and charger at that weight I have been pleased with it.

how old r ur batteries?