
- How much voltage does my fish finder need to operate?
- How many amp-hours (hours of use) will the batteries deliver?
- How much space and access do I have for mounting the power source?
- How much do I want to spend?
Probably the easiest way to go is to use rechargeable AA batteries that you can buy just about anywhere. Most of the fish finders that are appropriate for use on a kayak are designed for 12 volt marine batteries, and will operate within a range of 10 - 15 volts, so an array of eight AA batteries should work perfectly. Eight AA rechargeable batteries will typically deliver a little over 10 volts to the fish finder (usually about 1.3 volts per rechargeable battery, as opposed to 1.5 volts per carbon or alkaline battery). In fact, the fish finder I use on my kayaks requires at least 10 volts to operate, and with 8 AA batteries I am getting about 11 volts. As far as running time is concerned, my fish finder has a current drain of 180 milliamps (ma) every hour. Since I am using 2500 ma batteries, in "theory" I should get 13 hours of use from my fish finder before having to recharge the batteries. In reality, after about 4 - 6 hours the voltage output will drop below where the fish finder will operate. This setup is the smallest and lightest way to go, can usually be purchased (8 batteries and charger) for $20 - $30, but will give the shortest running time.
You can also use one larger, rechargeable battery for your fish finder kayak installation. There are many options, from home alarm panel backup batteries, to deer hunting auto-feeder batteries, to general purpose hobby batteries. Cabelas has a popular rechargeable battery that delivers 12 volts and 8 amps. The primary benefit of a larger battery is a much longer running time between charges. The main drawback is the larger size and weight of the battery. The Cabelas battery and charger is $30, which is an average price.
Now that you are all powered up, don't forget to check back for the next installment: mounting options.
Good Paddling
The Kayak Sportsman