What is Best Battery For Trolling Motor?

OPTIMA Batteries
Leesburg, Florida

The short answer to the question of "best trolling motor battery?" is "identical," but there's a lot more to it than that. While you may not feel like reading this entire blog, if you're going to spend several hundred or perhaps several thousand dollars on trolling motor batteries, you really should take the time to read this entire blog. It could end up saving you a lot of money and help you avoid a lot of frustration, regardless of the brand you choose

The legendary Harris Chain of Lakes is considered by some to be the best bass fishery in the world. Thousands of tournament anglers make their way onto this 75,000+ acre body of water each year and countless recreational fishermen join them. We don't talk to every angler who enters the OPTIMA Canal on the Harris Chain, but we have talked to hundreds of them about their trolling motor batteries (and their starting batteries), what brands they are using, how long they've owned them, how they maintain them and how satisfied they are with them. Their feedback has been enlightening. 

Most indicate they charge their batteries as soon as they come off the water, as they should. However, many indicate they don't leave their chargers plugged in, once the batteries are fully-charged. That may be ok, but we always encourage anglers to use "smart" (or microprocessor-controlled) chargers and to leave them plugged in, just in case something is left on in the boat, that may discharge the batteries.

Not only is it a major inconvenience to get to a boat launch only to have a battery that won't start your engine, whenever any battery is discharged below 12.4 volts and is left sitting in that state, sulfation begins forming in the battery, which can diminish performance and lifespan. With that PSA out of the way, let's dive deeper into the conversations we've had with anglers about their trolling motor batteries.

The Case for Flooded Lead-Acid Trolling Motor Batteries

Many anglers use flooded lead-acid batteries for their trolling motors, because they came with the boat, were readily-available when they needed batteries or they were the most-affordable option. While we are on the subject of affordability, we should remind everyone that regardless of the type or brand of battery they choose for their trolling motor, whenever two or more batteries are connected in series or parallel, those batteries should be identical in age, size and type.

That means if one battery in a bank of three trolling motor batteries goes bad, you really should replace all three. That doesn't mean the other two "good" batteries need to be recycled, but they should be moved to another application and replaced with batteries identical to the third battery. Older batteries tend to have higher internal resistance and even if they are the same size as a new replacement, they may take longer to charge, which means they may never get fully-charged, while the new battery in the same bank may get constantly overcharged. The same is true for flooded lead-acid batteries, which may have higher internal resistance than AGM lead-acid batteries (like OPTIMA), which could leave flooded lead-acid batteries constantly undercharged and AGM batteries constantly overcharged, if they are in the same string.

That can make a stronger case for using flooded lead-acid batteries, because replacing three of those will typically be much less expensive than replacing three AGM batteries and far less expensive than replacing three lithium-based products. An angler can also probably get away with replacing a single flooded or AGM battery with another flooded battery for a weekend tournament, although we honestly don't know if that's possible with lithium-based products and owners of those batteries should consult their manufacturer, to see if that is even an option.

We've spoken to some anglers who go with the biggest, least-expensive flooded lead-acid batteries they can find and they just make a habit of replacing them every year. That strategy can certainly work for some anglers, depending on how often they fish and how deeply they discharge their batteries, although they may end up paying more money in the long run. The reason is that an AGM battery may last two or three times as long (or longer) than a flooded battery. If the AGM option doesn't cost two or three times more, then annual replacements will add up in a hurry.

Before we get into the case for AGM batteries, we should mention that regardless of the type of battery you choose, selecting the battery option with the most reserve capacity will mean your batteries will not be as deeply-discharged, which is a good thing. The shallower the discharge cycle, the longer life you will get from your battery, so if you can handle the weight of heavier batteries with more amp hours (Ah), they will probably be able to deliver more cycles than lighter trolling motor batteries (don't pay attention to cold cranking amps when shopping for trolling motor batteries, look at the reserve capacity or Ah rating on a battery).

The Case for AGM Trolling Motor Batteries

AGM lead-acid batteries are not "gel" batteries and should never be charged on "gel" or confusing "gel/AGM" settings. In fact, you should probably only charge true gel batteries on those settings...if you can find one. We've never come across one in a trolling motor application and for the record, all OPTIMA batteries are AGM, not gel batteries. Having clarified that, we should now also clarify that not all AGM batteries are the same.

OPTIMA batteries are made from 99.99% pure virgin lead, which resists corrosion, allowing our batteries to perform better and last longer than AGM or flooded batteries that use recycled lead, which have more impurities and corrode faster. Don't be mislead by confusing descriptions like "military-grade alloy." "Military-grade alloy" doesn't mean 99.99% pure virgin lead, in fact, it may mean the third-party manufacturer that brand is buying their batteries from uses "recycled lead." If a battery uses 99.99% pure virgin lead, as OPTIMA does, they will call that out specifically.

OPTIMA BLUETOP batteries also have a unique SPIRALCELL design topped with robust, cast straps. That makes OPTIMA batteries extremely resistant (up to 15x) to damage from vibration, than a traditional flooded lead-acid battery. We actually put our batteries in paint shakers and ran them until the paint shakers stopped working (the batteries still worked). That can be very important in marine applications, if you find yourself in rough conditions or even on land, where boat trailer suspension systems can be less than forgiving on bumpy terrain.

AGM batteries tend to be more expensive than their flooded counterparts, but they can also last much longer. We conservatively indicate our batteries can last up to three times as long as their flooded counterparts. While most people don't consider the value of their own time in the cost of replacing a battery, even at $15/hour, you're probably adding $30 to $50 to the cost of your batteries every time you have to replace them, depending on the circumstances surrounding the replacement.

AGM batteries also minimize the chance of harmful acid leaking and damaging your boat. However, they may be heavier than the same-sized flooded battery, which is a consideration for some anglers. While we can't speak for all AGM manufacturers and brands, we can tell you that the drop-off in performance on OPTIMA BLUETOP batteries will not be as severe or as sudden as what you'll typically see in a flooded trolling motor battery.

The Case for Lithium Trolling Motor Batteries

The final trolling motor battery type we'll mention today are lithium-based trolling motor batteries. As we do not currently manufacture or offer this type of batteries, we have more questions than answers. We can say one of the biggest advantages of lithium trolling motor batteries over lead-acid-based batteries is weight. Lithium batteries are significantly lighter. However, they are also significantly more expensive. How much lighter and how much more expensive obviously depends on the trolling motor batteries you are looking at, but your research should give you plenty of information on those two subjects. The only anglers we spoke to in the OPTIMA Canal who were using lithium batteries were tournament anglers and nearly all of them either received their lithium batteries free of charge or at a significant discount.

If you are considering lithium batteries, we would encourage you to speak to lithium battery manufacturers directly with any questions you might have, although that may prove to be a challenge. Many (but not all) lithium batteries are made by third-party manufacturers in Asia. If you contact a lithium trolling motor battery brand, ask them if they manufacture their own batteries, in their own production facility. Why is that important? As the manufacturer of our own batteries, we've found the only way you can ensure batteries are being manufactured to your exacting specifications, is if you aren't just the brand selling them, but you are the also a manufacturer who builds batteries (you can take a virtual tour of the OPTIMA production facility here).

In our conversations with anglers in the OPTIMA Canal, we encountered several, who had issues with various batteries in the past, including some who indicated they had previous issues with their lithium batteries. One even indicated the brand that previously-told them any charger would work fine on their batteries, now indicated after his second battery failure, that he'd need to purchase a specific charger to properly-charge their lithium batteries. With that in mind, it's a good idea to ask a lithium battery manufacturer if a special charger is needed for their batteries and if you do run into trouble with one or more if them, if you can run lead-acid trolling motor batteries in the same bank or if you need to stop fishing until you can get a replacement. What happens if you really want to drop pounds and run a single 36-volt battery, but it goes bad during a tournament? Are you going to have to run to the closest battery retailer and buy three lead-acid batteries anyway?

You should also ask lithium battery manufacturers about their warranty terms & conditions (you can find our full warranty terms & conditions here). There isn't an extensive network of retailers selling lithium products, like you would find with lead-acid batteries, so what is involved in the warranty process? Do you need to ship batteries somewhere? Is the warranty pro-rated? How long is the warranty?

We've come across some very aggressive claims about lithium battery lifespan and some very long warranty terms. A ten-year trolling motor battery warranty sounds great, but does it still sound great if the brand offering that warranty didn't exist three years ago, they don't manufacture their own batteries, they require you to ship them somewhere for warranty service, they charge pro-ration fees and they may have exclusions that void your warranty? Those are all questions that should definitely be answered before making a significant investment in any trolling motor battery, regardless of the expense involved. If you have questions about OPTIMA batteries that you can't find answers for on our website, please email us at info@optimabatteries.com

While some of you may have been expecting a definitive answer of what the best trolling motor battery might be or might've expected us to recommend an OPTIMA, we don't believe it's possible to single out a specific brand or manufacturer as being the best trolling motor battery for the reasons we mentioned above. Not everyone has the same budget and not everyone has the same needs from a trolling motor battery. If OPTIMA is the best fit for you, we'd love to have your business. If we're outside of your price range or you need to have the absolutely lightest boat possible and money is no object, we understand that too and hope you'll keep us in mind if your first choice doesn't work out.