Choosing a Fish Finder Battery

Fish Finder Battery

So you have a fishing kayak and you’ve decided to install a new fish finder – then you realized you need a battery and you’re struggling with what size and type you’re going to need. Maybe you have a basic understanding of electrical gear or maybe you have no idea what it’s all about. Fear not! I’m here to help you find your way through the maze!

Fish Finder Battery

The best type of battery in my opinion is an AGM, or Absorbent Glass Mat battery. AGM batteries are an excellent way to power electronics and other accessories on a kayak because they won’t leak even if tipped upside-down. They perform best and last longest if not discharged more than 50%, followed by an immediate and complete recharge. This is why it is so important to select the right size battery for your sounder. Remember, using a battery that’s too small will limit its performance and life. The only difficulty with using a battery that’s too large is a little extra weight although performance will be excellent.

Things to remember when taking care of your AGM battery
• Do not discharge AGM batteries more than 50% for best long term performance to be safe
• Always fully recharge your AGM battery as soon as possible after a trip
• Always keep your AGM battery topped up when not in use
• Only ever use a smart charger with an AGM battery, they charge in stages and prevent overcharging


Gremlin 9X Fishing Kayak. 9 Foot, Raised Seat, Big Hatch. Bash Creeks with the Pocket Rocket.

Fish Finder Battery

Click image for more info.


What kind of deep cycle battery charger?
Choosing the right kind of battery charger is the first step in maintaining your battery’s health. Smart chargers are compatible with calcium, gel and AGM deep cycle batteries and can even detect the charge needed based on the battery’s voltage. Almost all 12v deep cycle battery chargers also come with reverse pulse technology that helps reduce internal impedance while on charge, as well as lowering the temperature. These chargers can be quite expensive, ranging from $180 – $400 depending on your needs.

How to work it all out.
Here is an example of the formula I have been using to calculate the size of battery needed for different gadgets. The idea is to keep from running your battery until it is dead during a normal day of use and reducing its life expectancy.

Lowrance Elite 4x Chirp colour sounder, average fishing trip duration of 6 hours
• From published specifications the sounder is rated to draw 0.25 amps.
• Multiply this by 6 hours on the water: 0.25A x 6 hours = 1.5Ah (amp hours) used.
• Since we don’t want to deplete more than 50% of the battery capacity we need to double the amount we’ve used 1.5Ah x 2 = 3Ah as the minimum battery size required to run the sounder for that amount of time.

Most kayakers will go for the compact 7Ah battery because they’re common and relatively inexpensive. They also have the advantage of allowing multiple uses without needing to be charged between sessions on the water – first day 1.5Ah used + second day 1.5Ah used = 3Ah used in total, which is still less than half the battery capacity.

So in conclusion – a 7Ah 12v AGM deep cycle battery will suit most anglers. And don’t forget to look after it by topping it up after use and not letting it discharge more than 50%

Happy Paddling!

At Dream Kayaks we have a full range of batteries for kayaks. Click here to check them out.

Looking for a new kayak? We have the best yaks on the planet!

Beast Kayak

by Jase Follent

Leave a Reply

Your email address will not be published. Required fields are marked *