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Brown: Here's a look at the options when it comes to marine batteries

Brown: Here's a look at the options when it comes to marine batteries

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Some in the boating industry call the new wave of batteries for fishing boats an evolution, but those close to it call it a revolution, and this revolution means better and a more clean power source for boats and, ultimately, anglers.

I get asked all the time about which battery is best and why, but it really comes down to budget and how much you use them. Nothing is worse than being on the water and having a battery give up the ghost and ruin a trip. Below is a poor man’s view of each.

Here is a marine battery 101 primer.

In the beginning

Lead acid were once all that were available. Lithium ion and lithium phosphate battery technology means longer days, clean power for the next generation of electronics and longer days on the water without worry of batteries going dead. Those are all benefits, but the one negative now is they are more expensive that the other technologies. But that, too, is coming down. If you use your boat a lot, a more expensive battery is a good choice. If used sparingly a lower priced option is a good call, but remember it all comes down to taking care of them.

Lead acid, AGM and lithium comparisons

The first generation of lithium batteries were very pricey and a bit volatile, too, which scared some buyers. The volatility was due to overheating and overcharging sometimes with chargers that were not designed for lithium, but once that was rectified, anglers and boaters saw they were the answer to the power conundrum. Warranties were better and some have as much as an 11- to 13-year warranty, so anglers could cost justify their purchase. Prices are coming down, but with that comes a supply issue and it is being felt across the lithium battery community. Domestic suppliers and manufacturers have had less of an issue, but demand is still exceedingly high.

A few years ago the options were lead acid and AGM (absorbed glass mat). Lead acid batteries are less expensive but are messy due to having to be maintained and water added. AGM can be stacked and even laid on their sides and take zero maintenance except for charging. Efficiency of lead acid is less and has a discharge rate of around 50%. AGM is more efficient with a discharge rater of 70-75%, but lithium has a super-efficient discharge rate of 95-97%. What does that mean to buyers? It means the power consumption is less and the charge rates are better with lithium.

The normal life of a standard lead acid battery is 3-4 years while AGM is 6-7 years properly maintained and fully charged after each use. Lithium batteries can last 10 years under the same circumstances.

If weight is an issue in your boat, AGM and lead acid are heavy — most are 60 pounds or more depending on size, while lithium is very light and weigh approximately 1/3 to 1/2 as much. A 54 Ah I have weighs 16 pounds while my starting all-purpose AGM weighs 63 pounds. That is significant.

Still confused? Even more to think about.

When buying lead acid batteries consumers should look for the best reserve capacity. The price is relative to that. Some talk about cold cranking amps but that has little to do with boaters for trolling motors but is more for starting batteries and cold conditions. Marine Cranking Amps, MCAs, is another measure and both are tested at 32 degrees Fahrenheit. MCA ratings are usually higher, but Amp Hours is the best measure of a batteries staying power. MCA is generally thought as a marketing strategy versus a way to measure a battery. Both do, however, determine if they have enough power to start your outboard, but do little else in the marine world.

Another measure is Amp Hour. This is particularly important to boaters, but RV owners are also finding the higher Amp Hour batteries mean better power for longer periods of time. The higher the number of Amp Hours the better the power, as a general rule. A 100Ah has more power than, say, a 54 Ah battery.

What is best?

Taking budget out of the equation there is little doubt that lithium is the best option for boaters and anglers, but a compromise might be AGM. Remember it comes down to how they are used first and budget second. Less expensive is not a good rule of thumb to determine battery selection, and if you are an every-weekend boater or angler, lithium is a great choice for everything except starting batteries today. There are a few companies that now have a lithium starting battery that seem to do doing a great job, but running a AGM or lead acid just to start the engine may save you a few bucks. AGM also is a better choice for the heavy user who doesn’t want to spend an arm and leg to get on the water.

One other thing, I never buy starting batteries but find the all-purpose battery as a better option. It does the same job but allows them to be used for trolling motors and electronics, too, and not just to start the engine. They have better sustainability.

Batteries have to withstand vibration and banging around on the water so marine batteries are always the best choice.

Do your research when buying batteries.

Battery talk gets deep and is boring to many, but it is a large purchase for the outdoor boating enthusiast, plus I get asked a lot about them. Simply put, I am excited about the future in batteries and it’s only going to get better, but buying from a reputable supplier is the best option from a warranty and knowledge perspective. They know their products and will give buyers the best options.

Terry Brown is President of, an industry leading, daily website and social media fishing centered community that provides information on products, industry newsmakers and fishing techniques. You can read more by going to


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