Close Menu
    Facebook X (Twitter) Instagram
    Friday, May 30
    Trending
    • Best 5 Kayak Racks for GMC Envoy
    • Best 5 Kayak Racks for GMC Acadia
    • Best 5 Kayak Racks for GMC Yukon
    • Best 5 Kayak Racks for Subaru Legacy
    • Best 5 Kayak Racks for Subaru WRX
    • Best 5 Kayak Racks for Toyota Tundra
    • Best 5 Kayak Racks for Chevy Trailblazer
    • Best 5 Kayak Racks for Nissan Versa
    Facebook X (Twitter) Instagram
    Kayak Manual
    Subscribe
    • Home
      1. About
      2. Kayak Types
      3. Inflatable Kayaks
      4. Budget Kayak
      5. Folding Kayaks
      6. Kayak for Rapids
      7. Kayaks for Kids
      8. Sit-In Kayaks
      9. Sit-On-Top Kayaks
      10. Tandem Kayaks
      11. Touring Kayaks
      12. View All

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More
    • Contact
      • Write for Us
    • Privacy Policy
      • Disclaimer
      • Corrections Policy
      • Verification Fact Checking Policy
      • Unnamed Sources Policy
      • Diversity Policy
      • Mission Coverage Priorities Policy
    • Categories
      1. Best Products
      2. Canoe
      3. fishing
      4. kayak
      5. Paddles
      6. Paddle Float
      7. Paddle Leashes
      8. pump
      9. rafting
      10. Roof Rack
      11. Roof Rack Cross Bars
      12. Roof Rack Pads
      13. View All

      Best 5 Kayak Paddle Leashes

      March 23, 2025
      Read More

      Best 5 Waterproof Backpacks for Kayaking

      April 26, 2025
      Read More

      Best Bed Racks for Chevrolet Silverado

      March 3, 2023
      Read More

      Best 5 Kayak Racks for Kia Optima

      April 12, 2025
      Read More

      Anatomy of a Paddle Stroke

      March 3, 2023
      Read More

      Your Guide to Canoeing

      December 25, 2022
      Read More

      The Best Way to Load a Canoe Onto Your Roof Racks

      December 14, 2022
      Read More

      How to Outfit a Canoe for Fly Fishing

      December 6, 2022
      Read More

      How to Size a 12 Volt Battery

      May 22, 2023
      Read More

      Gear Up For Fall Kayak Fishing

      March 23, 2023
      Read More

      How to Fish in a Kayak in Texas

      January 3, 2023
      Read More

      How to Install a Rod Holder

      December 25, 2022
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More

      Best 5 Kayak Racks for Subaru WRX

      May 9, 2025
      Read More

      Best 5 Kayak Racks for Toyota Tundra

      April 27, 2025
      Read More

      Best 5 Kayak Racks for Chevy Trailblazer

      April 26, 2025
      Read More

      Difference between inflatable and foam paddle float?

      October 14, 2023
      Read More

      Do You Really Need Paddle Leashes?

      May 1, 2024
      Read More

      Best 5 Kayak Paddle Leashes

      March 23, 2025
      Read More

      Best 5 Kayak Paddle Floats

      October 14, 2023
      Read More

      Difference between inflatable and foam paddle float?

      October 14, 2023
      Read More

      Best 5 Kayak Paddle Floats

      October 14, 2023
      Read More

      Do You Really Need Paddle Leashes?

      May 1, 2024
      Read More

      Best 5 Kayak Paddle Leashes

      March 23, 2025
      Read More

      Your Guide to Built-in pump

      May 1, 2024
      Read More

      Whitewater Rafting Basics

      December 14, 2022
      Read More

      What to Wear Whitewater Rafting

      December 14, 2022
      Read More

      Paddling vs. Rowing a Whitewater Raft

      December 14, 2022
      Read More

      How do you use a foam roof rack for a kayak?

      May 1, 2024
      Read More

      Best Roof Rack Pads for Kayaks

      October 22, 2023
      Read More

      Best 5 Kayak Racks for Toyota Prius

      April 27, 2025
      Read More

      Best 6 Kayak Racks for Jeep Compass

      March 22, 2025
      Read More

      Best Roof Rack Pads for Kayaks

      October 22, 2023
      Read More

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025
      Read More

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
      Read More

      Best 5 Kayak Racks for Subaru Legacy

      May 9, 2025
      Read More
    • Best Kayak Rack
      Featured

      Best 5 Kayak Racks for GMC Envoy

      By Arthur MooreMay 10, 2025011 Mins Read
      Read More
      Recent

      Best 5 Kayak Racks for GMC Envoy

      May 10, 2025

      Best 5 Kayak Racks for GMC Acadia

      May 10, 2025

      Best 5 Kayak Racks for GMC Yukon

      May 10, 2025
    • Blog
    Kayak Manual
    Home » How to Size a 12 Volt Battery
    fishing

    How to Size a 12 Volt Battery

    ArthurBy ArthurMay 22, 2023No Comments7 Mins Read
    Facebook Twitter Pinterest LinkedIn Tumblr Email
    Share
    Facebook Twitter LinkedIn Pinterest Email

    As we evolve as kayak anglers it becomes our nature to want to upgrade.  We buy the new kayak and we want to trick it out with a bigger depth finder, lights, USB ports, etc.  All of which are great products to give you more functionality while out on the water, but with all of those upgrades our power demand also increases.  In this post I hope to give you an idea of the simple calculations you will need to size your battery as well as which types of batteries are the most commonly used on kayaks today.

    The first step in sizing your battery is understanding your TOTAL power demand.  In order to keep this as simple as possible we will work solely with the units Amps and Amp-hours.  Amps will be used to signify the current required by an electrical product, and Amp-hours will be used as the rate of the current draw from the electrical source.

    In my case for example, I have two products that will be drawing current from my battery on my kayak.  One is my depth finder which is a Lowrance Elite 9 TI and the other is my LED light kit from SuperNova Fishing Lights.  If I look up the power consumption numbers for both of these products I find the following…

    • Lowrance Elite 9TI: 0.9 Amps
    • Extreme LED light kit: 2.0 Amps

    So, adding these two together I have a total of 2.9 amps of current that I need to supply to these two products every hour.  Now if you look at a typical 12-volt battery they usually have the total amount of Amp-hours listed for it.  One would think then if I needed the battery to last a typical 7-hour long fishing trip that I would multiply 2.9 Amps by 7 hours giving me roughly 20.3 Amp-hours…then I would go out and buy a 12-volt 20 Amp-hour battery and I would be done, right?  The answer is unfortunately no as we live in an imperfect world and we are limited in some cases by the technology of the battery.  So, let’s go over the two typical styles of batteries that are most commonly used by kayak anglers and what equation to use in each case.

    1. SLA Batteries

    SLA batteries or sealed lead acid batteries are the most common style batteries that kayak anglers can purchase.  They are cheap and easy to find which are great characteristics, but like anything else in life it has its drawbacks…

    • In order to get the longest life out of your SLA battery it is recommended that you do not discharge the battery past 50%. As an example, if you have a 20 Amp-hour battery…you should not consume more than 10 Amp-hours as it can slowly degrade the battery which causes it to lose charging capacity and overall life.  Realistically we don’t always have a way of knowing how much we use on an average trip so the equation below will help us take this into account.
    • As we consume current from an SLA battery we start to experience a slow drop in voltage. Once the supply voltage gets low enough we eventually lose power to some of our electronics as they usually need a certain voltage to operate.  As an example, a depth finder’s transducer signal slowly becomes weaker as we experience a voltage drop which also causes a decrease in performance of certain products.
    • SLA batteries do not respond well to extreme cold or hot temperatures which also degrades the amount of battery life.
    • SLA battery amp-hour ratings are based on a 20-hour discharge time frame. So, if you have a 20 amp-hour battery discharging over 20 hours that comes to 1 amp per hour being taken from the battery.  If the electronics on your kayak take more than that in an hour then you also lose battery life during a fishing trip.

    Long story short, you can see that a lot of factors act against us using SLA batteries…but at the end of the day they are still the most cost-effective battery and should last you a full season if you take care of them.  In order to size your SLA battery, I recommend using the following equation below. It takes into account the issues we will run into above and should give you a conservative number to use when you purchase your battery.

    So, if I want to have my battery last a minimum 7 hours I need to use the following equation…

    Total fishing time (hours) x current consumed by electronics (amps) ÷ efficiency factor (0.7) = Battery current draw rating (amp-hours)

    7 hours (total fishing time) x 2.9 amps (current consumed by all electronics over 1 hour) ÷ 0.7 (efficiency factor) = **29.0 amp-hours

    **Note that this calculation does not take into account if you turn off electronics part way through a trip…I would recommend doing a calculation for each electronic component and their typical run time and at the end add up all of the separate amp-hours. Also, this equation does not take into account voltage drop which may cause your electronics to turn off…but overall this equation should be conservative enough to give you a ball park battery size**

    2. Lithium Batteries

    Let me just preface this by saying that not all Lithium batteries are the same across the board so your results may vary, however, Lithium Ion and LiFePo4 batteries are a much higher caliber battery and come at a premium price.  The reason they come at a higher price is because of their advantages over the typical SLA batteries.

    • Lithium batteries can be discharged near 100% without causing damage to the battery or affecting the overall lifespan.
    • Lithium batteries are voltage stable and do not drop in voltage much if any when current is pulled from the battery.
    • Lithium batteries can tolerate extreme cold much better than SLA batteries but they do get hotter much more easily than an SLA battery causing stress on the individual cells inside of the battery which could degrade overall life of the battery…so keep them cool below 85 degrees if at all possible.
    • Lithium batteries are current stable and are not rated on a 20-hour scale like SLA batteries. The amp-hour rating is the amp-hour rating no matter the amount of current your electronics pull.
    • Lithium batteries can take 10 times more charging cycles than a normal SLA battery…but they do require specific chargers as to not overcharge the cells which can put stress to the battery and also degrade life just like heat will.
    • Lithium batteries of the same amp-hour rating as an SLA battery are much lighter offering you some weight savings on a kayak.

    Now, if I want to size a Lithium battery to power my electronics I will most likely use the following equation…

    Total fishing time (hours) x current consumed by electronics (amps) ÷ efficiency factor (0.97) = Battery current draw rating (amp-hours)

    7 hours (total fishing time) x 2.9 amps (current consumed by electronics) ÷ 0.97 (efficiency factor) = **20.92 amp-hours

    **Note that this calculation does not take into account if you turn off electronics part way through a trip…I would recommend doing a calculation for each electronic component and their typical run time and at the end add up all of the separate amp-hours**

    There is a lot more information that could have been covered in this post, but I figured if you understood the equations for both an SLA or Lithium battery above that it would give you a straight forward answer in how to size your battery.  I also hope that the points I have made help you decide what battery makes the most sense to use on your kayak based on your power needs and budget.

    Share. Facebook Twitter Pinterest LinkedIn Tumblr Email
    Previous ArticleKayak Fishing Tournament Practice 101
    Next Article Best Kayak Racks for Ford Ranger
    Arthur
    • Website

    Arthur G. Moore is a veteran paddler. He has over 10 years of whitewater kayaking experience in his kitty. When he was young, he used to love kayaking in rapid III and rapid IV but as time went on, he decided to concentrate mainly on covering long distances on a standard touring kayak. He is currently working as a senior editor for Kayak Manual.

    Related Posts

    Gear Up For Fall Kayak Fishing

    March 23, 2023
    Read More

    How to Fish in a Kayak in Texas

    January 3, 2023
    Read More

    How to Install a Rod Holder

    December 25, 2022
    Read More

    Comments are closed.

    Affiliate Disclaimer

    KayakManual.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com. As an Amazon Associate, We earn from qualified purchases.

    About Kayak Manual

    Kayak Manual is trying to help both beginners and seasoned kayakers to have a great time on the water by providing them with the most comprehensive and up-to-date information available about kayaking.

    We hope that this manual will provide you with all of the information that you need to get started kayaking or to improve your existing skills. In addition, we have included many helpful tips and resources that we hope you will find useful.

    Category
    • best (5)
    • Best Kayak Accessories (2)
    • Best Kayak Rack (17)
    • Canoe (20)
    • fishing (6)
    • kayak (619)
    • Paddle Float (2)
    • Paddle Leashes (2)
    • Paddles (1)
    • pump (1)
    • rafting (3)
    • Roof Rack (4)
    • Roof Rack Pads (1)
    Latest Posts

    Best 5 Kayak Racks for GMC Envoy

    May 10, 2025

    Best 5 Kayak Racks for GMC Acadia

    May 10, 2025

    Best 5 Kayak Racks for GMC Yukon

    May 10, 2025

    Best 5 Kayak Racks for Subaru Legacy

    May 9, 2025
    Recent Posts
    • Best 5 Kayak Racks for GMC Envoy
    • Best 5 Kayak Racks for GMC Acadia
    • Best 5 Kayak Racks for GMC Yukon
    • Best 5 Kayak Racks for Subaru Legacy
    • Best 5 Kayak Racks for Subaru WRX
    • Best 5 Kayak Racks for Toyota Tundra
    Facebook X (Twitter) Instagram Pinterest
    © 2025 ThemeSphere. Designed by ThemeSphere.

    Type above and press Enter to search. Press Esc to cancel.