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This week's Feature Blog

Boat Rigging, are Lithium Batteries in your Future?

By: Mark Romanack

Heavy gauge aluminum boats that feature console forward designs often suffer from weight distribution issues. The author mounted lithium batteries in his Phantom X2 20 OB and dramatically improved the bow lift and performance of the boat.

​Winter time is the perfect time to talk about all things boat rigging. Not only are the majority of fishing boats sold in any given year sold between January and April, this time period is the ideal time to give any ole fishing boat a face lift.


​I’ve said it before and will continue to say that batteries are the life blood of any fishing boat. Cutting corners when it comes to battery size and technology is the same as cheating while playing solitaire in cards. No one ever bought a boat, rigged it and then later said man I wish I would have used lower amp hour batteries.

​The truth is over time a fishing boat is likely to be rigged with a lot of accessories it didn’t have when purchased. Bigger sonar screens, VHF radios, digital throttle controls, auto-pilot electric motors, electric pole anchoring systems and the list goes on and on. All of these accessories and more take juice to operate. If the batteries in a boat are marginal in terms of their size or amp hour rating, it’s a given that dead battery issues are going to be a constant plague.

​The avid angler currently has three choices when it comes to selecting batteries for a fishing boat including traditional lead acid batteries, AGM batteries and lithium-ion style batteries. Lead acid, AGM and lithium batteries can be used as deep cycle batteries for the electric motor and also as a house battery to operate accessories like sonar/GPS. A lithium-ion battery can not be used as a cranking battery to start outboards. Most outboard manufacturers will not honor their warranty if a lithium battery is used as a starting battery.

​ Let’s take a detailed look at all three options and provide more details.


​ Traditional lead acid batteries have been around for decades and they will continue to be a major part of the boating market for many years to come. The advantage of lead acid technology is it’s tied, tested, tough and affordable. If you buy a boat from just about any dealer in the nation, that boat is likely going to be rigged with lead acid batteries, unless the customer requests something different.

​ The down side to lead acid batteries is they are very heavy and when placed in the wrong location can lead to weight distribution problems. Poor weight distribution in a fishing boat means the boat is not likely to come on plane easily or stay on plane when running at slower RPM levels and speeds.

​ Also, lead acid batteries have a rather short life span. A typical angler might get three or even four years from the lead acid batteries in a boat, but an avid angler who fishes every week is probably only going to see half of that life span before the batteries need replacing. In short, the more you use them, the faster lead acid batteries lose their ability to take a full charge.

​There are two types of lead acid batteries including models for deep cycle use and models for starting purposes.


​ The acronym AGM stands for absorbent glass mat and refers to the fine glass fiber separator between the positive and negative plates. These plates help absorb all the battery acid, which in turn means they are zero maintenance and can be mounted on their side to fit in tight places. An AGM battery is essentially an advanced version of a lead acid battery.

​ The advantages of AGM batteries are they are zero maintenance and they can be fit into places it would be difficult or impossible to mount a traditional lead acid battery. The down side of AGM technology is these batteries are just as heavy as lead acid batteries and they cost more they don’t really last any longer.

​ While many manufacturers of AGM batteries claim their products are superior to lead acid batteries, my experience with AGM batteries says otherwise. An AGM battery is simply a more expensive version of a lead acid battery. The only way this option makes sense is if the boat rigging requires placing a battery in a tight space that would make maintaining the battery difficult or impossible.

​ Two types of AGM batteries are on the market including deep cycle and also starting batteries.

Modern fishing boats are long on accessories. Everything it seems that is mounted to a fishing boat these days requires electrical power to operate. All these accessories put a huge amp draw issue on the batteries. The author’s advice is to buy the biggest and the best deep cycle batteries you can afford. Anything less is going to leave you wishing for bigger batteries sooner or later.


​The new kid on the block are lithium-ion batteries. Lithium-ion batteries are in wide use in things like computers, smart phones, tablets and other personal electronic devices. The advantages of lithium batteries is they are smaller and lighter, they hold a charge longer and can be recharged many more times than lead acid or AGM batteries.

​ The down side of lithium batteries is they are expensive and they typically require special charging systems designed to handle lithium-ion technology.

​ For many anglers the fact that lithium batteries are much lighter is the big drawing card. Boats that suffer from weight distribution issues are good candidates for a lithium battery. On average a 100 amp hour lithium battery is about half the weight of a 100 amp hour lead acid battery. So rigging three or four of these batteries into a fishing boat amounts to cutting as much as 150 pounds out of the boat!

​ Secondly, the lifespan of a lithium battery is many times greater than AGM or lead acid batteries. If you are that guy who hates to tinker with stuff like replacing batteries, a lithium battery can sustain thousands of charging cycles before it eventually must be replaced. A lead acid or AGM battery can’t even come close to these numbers.

​ Lithium batteries are expensive and that alone prevents many anglers from considering them. A typical 31 group lead acid battery retails for about $150.00. Meanwhile a comparable lithium-ion battery will cost $800.00-$1,000.00 so there is considerable difference in price. Also it’s important to note that lithium-ion batteries require special charging systems. In some cases these chargers must be purchased as after market items and in some cases the charger required for a lithium battery comes as part of the purchase price of the battery.

​Lithium batteries are strictly for deep cycle use. They are not designed to be used as a starting battery.


​ More and more lithium batteries are taking over the deep cycle market. While the average angler may have trouble justifying the price of lithium batteries, anglers who fish often will enjoy a significant benefit compared to lead acid or AGM battery options.

​The final piece of advice aims at the amp hour of a battery. The higher the amp hour rating, the more expensive a battery becomes. Selecting batteries with modest amp hour ratings is being penny wise and dollar foolish. That advice holds true for lead acid, AGM or lithium-ion batteries.


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