Choosing the Right Battery for Your Motorized Fishing Kayak and Accessories

Modern fishing kayaks have rapidly evolved to incorporate sonar and i-pilot Kota trolling motor technology. Choosing how you power these electronics is a very important decision.

so let’s discuss how to choose the right battery to power your fishing electronics and power your electric-powered kayak.

The following is an experience sharing from a fisherman:

First, you have to decide whether or not you’re shopping for a battery for your fish finder, to power your lights and other electronics on your boat, or if you’re looking for something to power your i-pilot or minn kota motor. You need to decide between sealed lead acid batteries and lithium iron phosphate batteries which are the two dominant batteries that anglers are using to power their kayaks.

The 12V sealed lead acid battery weighs about 3 times heavier than lithium. The lithium battery is very lightweight. that’s one of the big advantages.

Lithium is just how light it is and fishing kayaks are already getting heavier and heavier and having to transport a heavy battery can make a big difference especially when you’re powering an autopilot.

A sealed lead acid 100amp hour battery is going to average around 60 pounds whereas the lithium is only going to weigh right around 30. now the major disadvantage of lithium is that they’re quite a bit more expensive anywhere from three to five times more expensive than a sealed lead acid battery. So the initial investment up front is much higher, but you gain many advantages with lithium batteries.

First, the cost per cycle ends up being about half of what it would be if you ran sealed lead acid additionally out of each charge a lithium battery is going to give you a better life than on a single charge.

So most kayak systems are running on 12 volts systems and on a sealed lead acid battery down to about 30 percent of its charge it stops outputting enough volts to keep your electronics going and if you’re running a trolling motor, you’ll see the performance of that trolling motor decline as the voltage declines whereas, on a lithium battery, you’ll get 12-volt output all the way down to about 10 percent of its capacity so you’re gonna get more time on the water on a single charge.

Now let’s talk about how much battery you need to power your fishing electronics or your motor. So we’ll start with the sonar since that is probably the most common electronics accessory that most kayak anglers are going to have on their kayak and they need power and the major influence there is the size of your screen.

So I’ve run both helix fives and typically if you have a size five-inch screen or less, you’re going to be drawing on average about a half of an amp per hour or less. So that helps guide your battery buying decisions. If you have a seven-inch screen or greater, you’re going to be consuming closer to one amp per hour. I've checked on my Helix 7 it’s about 0.8 amps per hour which means with a 12-amp hour battery, I’m going to get approximately 10 to 12 hours on the water depending on if I have a sealed lead acid battery or if I have a lithium battery. I’m gonna need to recharge almost daily if I’m running my Helix seven on a 12Ah battery, whereas if I’m on my Helix 5 then I will be able to go out and do two full days of fishing on it pretty easily and not have to worry about recharging.

So think about that in terms of your battery usage, if you’re somebody who goes on long road trips and doesn’t want to have to recharge their battery or will be unable to recharge their battery, then if you have a smaller screen size you might be able to get away with a 12Ah 18Ah battery and get two to three days on the water, whereas if you’ve got a bigger screen size then you might be looking at either buying multiple batteries or even larger batteries than 12Ah you might be getting the 18Ah or 24Ah.

Let’s talk about the battery powering your trolling motors. So this is an autopilot so it’s powered by i-pilot. There’s also the minn kota 106 which has a slightly different motor for most anglers that are powering their minn kota and i-pilot kayaks they’re using 100Ah batteries. So that’s what’s recommended by me is at least 100Ah. If you’re just a pond hopper and you don’t have a lot of energy demands on your trolling motor, then maybe 50ah might make sense for you. But I think the vast majority of us are running 100Ah batteries or greater.

Now that being said be sure and check the dimensions of your lithium batteries. I have noticed there’s a lot less consistency in the lithium battery world on the size of the 100Ah batteries. A lot of the group 27 lithium batteries will fit easily into the battery box, but even some group 31 lithium will fit quite well in that box and that’s actually what I have in mind today you will also see quite a bit of variability in amperage, you’ll see some lithium batteries that have this group 27 size/ group 31 size that have up to 150Ah you might be wondering how are they squeezing so much more power into the same size battery and a lot of that has to do with the design of the cells inside the battery.

So the majority of lithium batteries especially those in the 100Ah range have cylindrical cells so they look just kind of like the batteries you buy at the store, they’re stacked inside those boxes but some of the higher amp hour lithium batteries use prismatic cells so these are almost like wafers or packages or pouches and they can pack a lot more because they’re square inside these square batteries. So the difficulty with those prismatic cells is that because they’re more tightly compressed in there, it can trap more heat more components have to be wired together, so there’s just more opportunity for failure. That being said there are a lot of great battery brands out there using prismatic that have very good customer service but you do have to be careful and watch those things and monitor make sure they’re not overheating.

Because they’re more prone to overheating and if there’s a failure in any individual one of those many hundreds of flat cells that are packed inside there then it will degrade the function of the battery itself. Whereas cylindrical cells they’re less prone to that failure and less prone to overheating the battery management system has an easier time managing heat in the battery and even if a single cell fails the performance of the battery won’t be greatly depleted whereas it might be more significantly impacted in the prismatic cell batteries. 

The prismatic cell batteries now when wiring up your kayaks for electronics on minn kota and autopilot kayaks you do not want to utilize the battery for your trolling motor as the same battery for your fish finder because it will create interference that will cause your fish finder to get a bunch of noise on it and it’ll make it much more difficult to use. So make sure you use separate power sources for your fish finders and your trolling motors. Now determining how much power you need for your autopilot or minn kota kayak, it‘s a much more difficult question to answer, this will all vary depending on your fishing style, where you fish, what type of conditions you plan to fish in how long you plan to be out on the water.

If you’re running sealed lead acid you have the advantage of having a battery display that shows the relative amount of charge left on the battery by pushing the test button on your minn Kota but those are not calibrated for lithium batteries. Lithium batteries tend to have a higher voltage output until later in their charge like I was talking about in the beginning. because of that battery readout isn’t accurate so it’s more difficult to ascertain how healthy your battery is when you’re out on the water. And that is why there are aftermarket lithium battery meters that you can attach to your battery box or somewhere on your kayak that will give you a readout of how healthy your lithium battery is. But for example, on mine, I actually have a little Bluetooth built into the battery itself and I can just hit that switch and turn on the Bluetooth and then I have an app on my phone that I can then bring up and check the health of my battery and it gives me the actual readout of remaining amp hours and I can also see what my current amp hour draw is.

So having that Bluetooth functionality has helped me out because now I can see in real-time what my remaining amp hours are, and what the current draw is off the battery I can also see my voltage, so I can adjust my behavior accordingly. Let’s say I’m in a rush somewhere and I crank the motor up to level setting 10, it’s gonna start to draw a lot more current from the battery. So I can moderate my behavior based on what the app is showing me is happening to my battery. If I’m a long way from the boat ramp I may not make it back at a level setting of 10 if I’ve drawn the battery down low enough but if I set it at a level of seven or five on the speed setting it considering reduces the draw off the battery and increased my range and I might be able to get back to the boat ramp that way without having use paddle. So having this Bluetooth capability has made a big difference for me and I know Tocopower’s smart lithium battery is doing well at this.

Otherwise, we hope you stay powered up there and catch fish.