Gone are the days when lead-acid batteries were your only option for your car batteries or any other source of power storage. Lead-acid batteries were the first rechargeable option for the DC world.
Thanks to new technology introduced in the early ’90s by Sony, the domination of lead-acid batteries were overturned. Lithium-ion batteries offer quite a handful of features that lead-acid cannot.
Your trolling motor can only be as good as the battery it uses. Read our guide below to learn how to choose the best lithium trolling motor battery.
What do the specs of your motor require?
Electric trolling motors are the best option for quiet and efficient propulsion. The smaller electric trolling engines usually require 12 volts to operate. Still, there are 24 V and 36 V batteries for larger trolling motors.
24 V batteries will often offer a thrust of up to 100 pounds, while 36 V batteries can provide above 100 pounds of thrust.
During operation, trolling motors are always forced to work at maximum power. They, therefore, must meet specific power reserve requirements. This is to be able not only to operate efficiently but also to power other motors during emergencies. This gives the need for the installation of lithium trolling motor battery.
Though they produce high power to start your trolling motor, lead-acid batteries can be quite bulky. This is where lithium-ion trolling motor batteries come in. A typical 12V 100Ah lithium-ion battery weighs around 27 lbs. You can reduce your boat’s carrying weight by about 200lbs by switching to a lithium-ion trolling motor battery.
How many hours will you be on the lake?
How long your boat will operate on the waters primarily depends on your battery’s maximum amp draw. Using a higher power setting on your boat could also cut down on your fishing time.
A 24V or 36 V system may serve your purpose better than a 12V system. However, you could choose the latter if the cost is your top priority.
If your electric trolling motor requires a max current of 58 Amps at 12 volts and you need to use it for at least two hours, your battery should have a capacity of ~120 Ah.
What speeds will you run your boat at?
As stated earlier, higher performance requires more current. You will have to either spend less time on your fishing spree or choose a high voltage battery. This is in the event where you want to operate your trolling motor at higher power settings,
Lithium-ion batteries are preferable on electric trolling motors because they sustain top performances. They are also less bulky in nature. You will still have to choose between energy and power consumption when selecting your trolling motor.
More thrust will be required if your motor will be running at maximum speeds. The same is true for long distances and high current winds on your fishing voyage.
There are three main types of batteries you can use in your trolling motorboat. You need to look for a battery that is designed for deep cycling since they last longer. That is because they are designed to trickle charge over a long period. These batteries are unlike cranking batteries that are designed to give short bursts of high power.
The improved performance in deep cycle batteries means that you get more performance from a smaller battery. If you are looking for a battery that fits explicitly your trolling motor, the deep cycle batteries are what you want.
There are also dual-purpose batteries designed for trolling motors. Dual-purpose batteries serve in deep cycling, starting with electric trolling motors. They do not offer as high performance for deep cycling. Still, if you want to buy one battery for your entire boat, it is advisable to get a dual purpose battery.
1. Lead Acid Wet-Cell Batteries
The lead-acid batteries come at low prices and can have a lifespan of between one and two years. They can also withstand frequent draining and charging while in use.
These batteries require maintenance to live up to their potential. You will need to top off the water in lead-acid batteries regularly.
The wet-cell batteries contain a mixture of water and battery acid that enables them to store energy in chemical form. The cells, therefore, carry a risk of vibration and spillage. These are two factors that are very common in a rocking boat.
The lead-acid batteries consistently use water when in operation. You need to always top off the used up water to keep the plates inside the cell fully submerged in liquid.
Generally, lead-acid batteries are not convenient on motorboats due to the high risk of spillage that comes with their use.
2. AGM Batteries
Absorbed Glass Mat (AGM) batteries offer the best lifetime and performance because they are sealed. They could serve you for a period between three and four years.
While AGM batteries offer double the lifespan of lead-acid batteries, they come at double the price.
AGM batteries are worth the extra cost since they do not require any maintenance.
AGM batteries are designed with a glass plate and gel inside a wholly sealed cell. The design allows them to be considerably smaller than their wet-cell equivalents.
AGM batteries can also maintain power for longer when they are not in use. Experts refer to this as a slow self-discharge rate.
Why you need to use a Deep Cycle battery
The typical car battery is designed to produce a tremendous amount of current in a short period to start the engine during ignition. After the engine successfully starts, the alternator produces all the power the vehicle will require until it shuts off.
Due to this, the lead-acid battery can serve its entire lifespan without going under 20% of its maximum capacity. The lead-acid car battery can last a few years when used this way.
On the other hand, deep cycle batteries are designed to produce a steady amount of higher voltage current over an extended period. Though a deep cycle battery can provide a surge when needed, it is nothing close to that of a car battery.
The most significant difference of a deep cycle battery is it’s ability to be discharged over and over again. This would destroy a lead-acid battery.
A deep cycle battery has thicker plates than a lead-acid battery, which gives it a Reserve Capacity that is about three times that of a car battery. Reserve capacity is the number of minutes that a battery can sustain 25 amps or higher production while maintaining its voltage above 10.5 V.
Amperage Hour Rating
The amperage (Ah) is how long your battery can last while it uses 25amps. Your best option is to choose the highest amperage that you can afford and works well with your boat.
While on the waters, you would like to make sure that your battery lasts as long as possible. There is a simple formula to calculate amps when shopping for an electric trolling motor battery.
Assuming your battery has an amperage rating of 100Ah, you can run your trolling motor at a rate of 4amps as follows.
At a rate of 4 amps, your battery can last about 25 hours. If your motor produces 40 amp, you can expect its battery to last about two and a half hours.
What are the best size and weight battery for your trailing motor?
There is a difference in weight between lead-acid, AGM batteries, and lithium-ion batteries. Lithium-ion batteries are virtually weightless. The lightest models even float on water.
I had to learn through experience how essential it is to have more carrying capacity on my boat. While my boat is a medium-sized trolling boat, I had no idea how much the trolling battery affected functionality. This is until I replaced the three lead-acid batteries with a lithium-ion battery.
If a typical 12V trolling motor battery weighs 75lbs and three of them are required to start my boat, a total weight of 225lbs. A lithium-ion battery weighs only 28lbs. The battery is also the strongest of all other Group 31 batteries.
By switching your lead acid or AGM batteries for lithium-ion batteries, you could reduce the boat’s weight by up to 197lbs. With a lighter boat, your trolling motor will produce more thrust power to propel it over the water.
Do you need a battery box?
It is essential to have a battery box if you are using lead-acid or AGM batteries with your electric trolling motor.
With lithium-ion batteries, there is no need to use a battery box since they have no risk of acid spills like the lead-acid batteries.
With AGM batteries, it is also essential to have a box to contain them in one place. While it is not a requirement with AGM batteries, I must warn you to take good care when handling the batteries.
Battery Life Extension Tips
No matter which battery you choose to install in your trolling boat, you need to take care of it.
Do not wait to charge: Put your batteries on charge immediately after you get back from using your boat. Leaving them at low levels of charge will shorten their life span.
Store your batteries in a cool, dry place when they are not in use. Storing your batteries properly will sustain its performance.
Regularly top off your battery with water if you are using a lead-acid battery. Wet-cell cells can quickly lower their performance and lifespan if kept at low water and acid levels.
Trickle charge your battery when you are not using it for a long time. A trickle charge is better for your battery’s life than a fast and hard charge.
How to charge trolling motor battery
There are different methods to charge the different types of trolling motor batteries. There are even different chargers for specific battery types. There are some recommended charging methods regarded as the best ways to charge your trolling motor battery.
AGM batteries can be charged either on-board, off-board, or using a solar panel.
Keep in mind that overcharging batteries can shorten their life. It is crucial that you monitor the cycle when charging AGM batteries.
Lead-acid cells are quite dangerous, and you have to take precautions when charging them. The acid can burn your skin if it spills on you. For this reason, it is recommended that you charge your lead acid battery off-board.
You could also charge a trolling motor battery using a portable charger. You must use the correct type of charger for your battery. Your battery must also be charged using the right amp charger. That is because using the wrong amp charger can easily shorten the life of your battery.