Learning About Trolling Motor Batteries
When it comes to picking out a trolling motor battery (ie. a deep cycle battery), you’re going to want to do your research because they are definitely not a “one-size-fits-all” product. An angler with a new fishing kayak does not need the same trolling motor battery as someone with a high-powered bass boat. Yes, they both need deep cycle marine batteries that accommodate a continuous draw of power from the trolling motor and/or fish finder, but there are more specs to dig into that will vary depending on the specific fishing application. And that is exactly what we’re going to do here – I’ll go over some of the basic specs of a trolling motor battery so that you can figure out which are the best battery options for you to consider.
Let’s use a hypothetical trolling motor battery here as an example – say you buy a trolling motor battery that lists the following specs: “12-volt battery, Marine, R.C. Minutes: 180, Marine Cranking Amps: 840, Cold Cranking Amps: 675.” These are all numbers to be aware of so we’ll break things down one by one.
Trolling Motor Battery Specs
First, the R.C. minutes – this stands for reserve capacity. This is the number of minutes it takes to run the battery from a completely full charge to totally empty with a 25 amp draw. In easy to understand terms, this means that if you’re using some electrical product that requires 25 amps to run, and your trolling motor battery is rated at 180 R.C. Minutes, then you can run it for 180 minutes (ie. 3 hours). For comparison, a 40lb trust trolling motor on full speed usually runs around 42 amps continuous draw. So, looking at our hypothetical battery above with 180 R.C. miutes, you would be run such a trolling motor for about 2 hours. 25 -> 42amps = 68% increase in amps. 68% decrease in time from 180 minutes -> 122 minutes = about 2 hours. Now remember, this means you could only troll for 2 hours continuously, but if you’re starting and stopping and not relying on your trolling motor the whole time, then the charge may be able to last you the whole day. Some folks have reported that using a 30lb thrust trolling motor on about half speed uses around 25 amps. A trolling motor of this size could definitely move a 12 or 14ft jon boat pretty well, but may not be enough for a bigger motor/boat.
Next, let’s look at the cranking amps: Marine Cranking Amps and Cold Cranking Amps. In simple terms, these numbers refer to the amount of amps that the battery can put out in a 30 second burst. So if you have a gas-powered motor that requires 800 amps to start, then our hypothetical battery with 840 marine cranking amps should be able to get the job done. So take a look at the specs on your motor and make sure you match your marine battery appropriately. The Cold Cranking Amps is a number that is less important – unless you are fishing in colder areas, in which case it can be very important. It basically refers to the same thing as marine cranking amps, but is usually about a third lower. This is because it is calculated at 0 degrees F instead on 32 degrees F. Definitely a consideration if fishing up north for early spring panfish, etc.
How to prolong the life of your trolling motor battery
Many people say that a trolling motor battery will last about 2 years – but if properly stored, you can get 3 or even 4 years out of even a cheaper battery used more than 20 times per year. What’s the secret? Listen up…What you want to do is as soon as you finish fishing for the day, you need to charge your trolling motor battery right away! This is a habit you should get into before putting your gear away for the day. Just make it a part of your routine and it will become second nature. If you don’t, then sulphates will build up in the battery and cause corrosion. This means your battery will hold less of a charge and ultimately won’t last as long.
There is a lot of great info out there if you know where to look. Minnkota Motors has some excellent material to help you out as well that you can find here.
And if you are a kayak fisherman, be sure to check out the Youtube video below!