Friday, March 10, 2017

The Best Kayak Fish Finder Battery!

12v 10,000mah Lithium Battery vs. 12v 4amp SLA Battery

One of the most essential kayak accessories is a fish finder.  A fish finder allows you to a lot of knowledge on the water such as depth, water temp, structure, and even fish.  Some fish finders also have GPS features that can help keep you safe on the water.  These units range from 3-10 inches, I'm sure somebody has gone bigger but not that I have seen...yet.  The one trick with these units is on a kayak you need a power source that isn't as big as the yak!  Bass boats have the luxury of being able to hold multiple 12v 30-50 amp batteries.  In a kayak you need a battery that has a lot of power in a small size.  Currently there are two major options for batteries, Sealed lead Acid (SLA) batteries and Lithium batteries.

Now before we get into talking about the differences between SLA and lithium batteries, a very common question is what battery do I need?  What I say is to look at what that the amps per hour that particular unit draws.  This is usually estimated at the highest power draw.  This number can help give you an estimate of how many amps your battery needs to be.  The most common size is usually a 12v 8-10amp battery.  This seems to work well with both the smaller and bigger units.  Now to the differences in battery type.

The most common battery in the kayak industry is the SLA battery.  The one benefit of a SLA battery is that they are cheap!  Great deals for these batteries can be found and your kayak can be wired up for under $50.  With that does come some downfalls of SLA batteries.  The first downfall is they are big and heavy.  One 12v 10amp SLA battery can weigh up to 10lbs per battery.  Throwing 3 of three of these into your kayak, depending on the kayak can hurt the carrying capacity of the yak and throw off how the boat is trimmed in the water.  The second downfall is that SLA drastically lose power in cold weather.  If you fish in cold weather plan on bringing several batteries or not using the electronics.
12V 4amp SLA is large, bulky, and heavy
The final drawback of SLA batteries is their life cycle.  Many of these batteries are not deep cycle and aren't meant to be drained till dead.  Additionally as a SLA battery loses amps the voltage will drop.  For most fish finders when this voltage drops below 12V it is no longer usable until it is recharged.  Also don't expect many SLA batteries to last more than a few seasons.
      Positive: Lots of power for the money
      Negatives: Heavy, not good in cold, short shelf life, and the voltage can drop below 12V

The new upcoming batteries in the marine industry is Lithium batteries.  There are many different kinds that are up and coming such as Lithium Ion, Lithium Iron, and Lithium Phosphorous.  Basically they are very similar just different formulas to generate power.  The benefits to lithium batteries in kayaks are plenty.  The first is that they are very small and lightweight.  This crucial when weight is an issue on a kayak.  Plus with their small size they can be stashed anywhere.
12V 10,000mah is small, light, and powerful
Only around 5 in x 3 in x 1 inch and less than a pound.
The second is that they provide 12v until the battery is completely depleted meaning you will get 100% performance until the battery dies.  The third major benefit is that there is a lot less drain in cold weather compared to SLA.  The fourth benefit is that these batteries are good for hundreds to thousands of charges meaning less batteries to be bought.  Now for the downsides!  The first downside is the price, these batteries are SUPER expensive, meaning a large upfront cost.  The second downside is that some lithium batteries have a risk of fire but in recent years companies have taken many safety precautions to prevent this.
     Positives: Light, small, all 12V, no cold weather battery loss, and longer shelf life.
     Negatives: EXPENSIVE and must take precautions for battery safety

Now that was a lot!  So I am gonna give you my recommendation on what I have been using! I personally use an external laptop battery charging pack that has a 12v output.  I have had great success with these.  I own two and one will power my Garmin Echomap Chirp 73sv for about 5-6 hours.  I found it on amazon and it provides 12v with 10,000ma. here.  As long as you can crimp marine connectors you can wire it up!  Its super simple, but if you have any questions feel free to ask!
 It cost me in total around $120 and has held up through all the abuse I have put it through.  Additionally it has usb ports already wired into it for charging my phone and it has a built in draw cut off that keeps the battery from being overdrawn and shorting out.  You can find it

The upfront cost of lithium batteries can be very daunting but if you can swing the fee, there are major rewards with it. Bioenno and Nocqua that are directly marketed at kayak fisherman.  Also don't be afraid to rock a SLA battery if it fits your.  They are dirt cheap they get you out on the water.  I hope this helps answer any kayak electronic battery questions you might have.  If you have any questions shoot a comment below or message me on facebook and I can help in anyway possible!
Battery box, both batteries give me a combined 10-12 hours of power.
12v output port for powering and 12v input for charging.
 Plus there are many manufacturers such as

Thanks for reading along and Tight Lines,

Patrick "Pooti" Tharp


  1. Thanks for your post! The external laptop charging battery is a great idea. I have Garmin Striker 4 fish finder and was wondering if you can give more details on exactly how to connect the charging battery to power the fish finder. Thanks!

    1. All you do is splice the connector it comes with. This particular model comes with a small section of wires with a connector on both ends. I just cut open the wire and ether solder or marine connected the wires to the ff wires

  2. I have the same fish finder. How can you convert the adapters to plug into the finder?

    1. You just splice the wire that is connected to the connector

  3. How do you remove the internal battery and connect it to the finder? Bill Robbins

    1. No removing internal batteries is needed. I use the power pack as is. It has a 12v output and came with a double connector end cable (connector on both ends). Just cut that in half and wire into your fish finder batteries.

  4. Hey Patrick, apologies if this post goes up twice; thought it went through first but never saw anything. Anyways;
    Thanks first off for an informative post. I, like some others it seems, have some confusion about how to hook up the battery to your FF. The double ended 12v connector you used to splice in FF; when you cut open the jacket on that wire are there two wires inside (for +/-)? If so, are they generally labeled or color coded? If not, how did you determine polarity? Also, if there arent two wires, then where did you run your negative/black wire from your FF to? I purchased a 32,000 mah battery, similar to the one you show, and need to hook it up soon so Im hoping you have some more wonderful insight! Thank you in advance for your help! -Sam

  5. I'm wondering the same thing as the other guys. How do you join the wires when the fish fisher power has two wires, negative/positive, and the battery only has 1 output?

    1. That output is a DC barrel jack, which has two conductors - inner and outer connections. If you cut the end off of the cable, or cut it in half, inside you will find the two wires to connect to fish finder power.

  6. Just fair warning these batteries are deceivingly labeled and are NOT 10000mAh@12V and you're getting gouged. If you look at the Product Description portion of the Amazon listing you'll see this "- Capacity: 10000mAh / 37Wh". Ah is a number that can be fudged by changing voltage, Wh is a constant.

    37Wh%12V=3.08Ah. This can be verified here

    So where does the "10,000mAh" claim come from? If you take 37Wh and divide it by 10Ah you get 3.7V. 3.7 is the nominal voltage of the lithium cells that make up the battery. Technically I guess it's not lying, but it's pretty shady. $60 is by no means a good deal for a 12V 3Ah battery when you can get a 7Ah Dakota Lithium for $70.