You’re sitting on top of a piece of submerged structure, got one hanging on the end of your line and your trolling motor quits running. What follows is an experience all anglers come to learn about very fast, panic. Now mechanical issues with the trolling motor are rare. It’s typically quite reliable.
More often than not, it’s simply a case of the trolling motor drawing more current then the battery can provide at a given speed. This becomes even more common if you’re fighting current or wind by increasing speed settings. It’s not a guess; it’s physics.
How to Choose the Right Battery for Your Trolling Motor
How many batteries do I need? This chart shows a direct link between amp-hours and motor thrust. Each time you go out, you don’t have to do the math in your head. You could plug a thirty pound thrust motor into a fifty amp hour battery and get about eight hours of run time at low speed. But if you step it up to five, that number plummets pretty fast. Most folks mess up here by thinking capacity doesn’t change based off load. The truth is high speed draws way more amps and will empty even a big battery in only two or three hour.
Wind changes your plan quicker than you can turn the control knob. Because of this, expecting power loss is critical. The size of the battery is not the only consideration when choosing a battery. The type of battery chemistry are equally important.
The least expensive battery available is a flooded lead acid battery. These batteries need periodic maintenance to top up water lost when they release gases. Very few people do this. Absorbed glass mat or AGM batteries have become the standard for most anglers because they are sealed and spill-proof. These types of batteries withstand deeper cycle discharges different than flooded batteries. They don’t need any maintenance either. There are some similarities with gel cell batteries in that regard too.
Gel cells is spill proof and sealed just like AGMs but will be damaged if overcharged. To charge your gel cells properly you’ll want a gel cell charger profile that doesn’t cook them. For someone who wants to keep things simple and casual, this can make gel cell batteries more troublesome.
The top-of-the-line category is lithium iron phosphate batteries that sell based on longevity and weight. For instance, you’ll get a much lighter battery compared to flooded or AGM batteries. The lighter batteries keeps the center of gravity lower on the boat. This is especially nice on small craft like light jon boats or kayaks. They are also easier to store and handle.
Cycle life is much higher. These batteries lasts two or three times as long as traditional lead acid batteries before they begin to degrade. While initial cost is higher with these batteries, knowing you’re saving weight helps make up for it. You aren’t just buying energy storage; you are also buying performance and conveniance.
The size of the boat. Motor Power Requirements The voltage system scales proportionally with the size of the boat and the needs of its engines. For example, small boats up to sixteen feet that require up to forty pounds of thrust can be managed on one battery rated at 12 volts. Typically midsize bass boats is wired with two batteries in series to create a 24 volt system which offers the extra punch needed for an eighty-pound motor but does not pull too much juice from one bank of batteries. Three batteries wired in series creates a 36 volt system often seen in large tournament rigs with heavy thrust demands. It allows them to get away with lower gauge wires for less resistance and keep heat generation reasonable on longer runs.
Do not use a starting battery for this application. Starting batteries is meant for short bursts of high current, not to provide sustained power. You’ll tear up the plates in that battery real quick and be stranded quicker than you’d think.
Always purchase a higher amp-hour capacity then what your minimum calculations indicate. I recommend getting at least twenty percent above minimum. Theoretical run times never account for real world conditions such as heavy gear loads and cold water. Maintain good connections by keeping your terminals clean. Keeping batteries stored in a healthy state means storing them fully charged when out of season. To extend their life, recharge prior to letting it go below fifty percent depth of discharge.
You should of checked this earlier. Staying safe while on the water means staying on the water.