If you’re new to trolling motors, you might be unsure how to keep them in good working order. When it comes to trolling motor battery charging, you want to be sure you do it correctly.
On the water, the last thing you want is to run out of battery juice. Knowing how to charge your trolling motor battery can vary based on the type of battery you have.
In our guide, you can learn more about the battery types you can get and how you need to go about charging a deep cycle marine battery.
By the end, you’ll know all you need to ensure you use the correct deep cycle battery charger and have enough power from the battery charging process to ensure your onboard electric motor has the power and longevity for your kayak fishing trip. (Learn How To Debone Trout)
How Do You Charge Two Trolling Motor Batteries?
If you only have one charger, disconnect the jumper wire that connects the two batteries and charge each one independently.
The best option is to purchase and install a dual (2 bank) marine boat charge in your boat. It will allow you to leave everything connected while simultaneously charging both batteries.
However, before you dive in, there is much more to understand, and first off, the battery type can make a difference. (Find the Best Portable Fish Finder For Kayak)
AGM (Absorbed Glass Mat) batteries are sealed, spill-proof, and maintenance-free, making them popular among anglers.
AGM batteries provide many advantages over wet cell batteries, both on and off the water.
AGM batteries are more resistant to vibration and impact than flooded batteries and can withstand deeper discharges than flooded batteries. Lithium batteries are similar, yet they are far more expensive at this size.
Gel batteries are sealed, spill-proof, and maintenance-free; however, they are not AGM batteries.
Aside from design and engineering differences, gel batteries are less heat resistant than AGM batteries and have less power capacity than AGM batteries of the same size.
Gel batteries are typically charged slower than AGM batteries to avoid overheating, limiting their use in trolling motor applications.
Wet Cell Batteries
You find them very different from the above in a flooded lead-acid battery as you can only orient this battery upright. If not, the liquids inside a wet cell battery could spill.
The battery contains an electrolyte that covers and interacts with the battery plates inside. The electrolyte is accessible through the top caps, where you would add distilled water to maintain the levels. Otherwise, the battery may fail sooner than expected. But they are significantly cheaper than other batteries.
Besides this, you need to understand your electrical system and how you go about charging trolling motor batteries.
Deep Cycle Battery Charging
It is critical to understand how temperature affects battery performance and charging, especially while using and storing boats—first, chilly temperatures – below freezing.
Freezing boat batteries have less capacity than batteries at warmer temperatures. Therefore, for example, a car battery might start your car quickly in the summer but struggle in the winter.
Likewise, a boat battery capacity improves with temperature, but boat battery lifetime decreases, especially at high temperatures.
The voltage required to charge a drained battery varies with temperature. A cold battery requires more charging voltages per cell than a warm battery. Regardless of the season or ambient temperature, automatic temperature compensation in a battery charger is critical.
Battery Charging Cycles
Regardless of its design, a deep cycle battery is used to a significant drain depth, then recharged to total capacity many times over its lifespan.
A typical deep cycle battery cycle starts at 100% capacity, discharges between 20% and 50% capacity, and finally recharges to 100%.
The average depth of discharge affects battery life, and a battery that is routinely discharged to 50% will last longer than a battery that is frequently discharged to greater depths.
However, repetitive, shallow discharge (5-10%) of a deep cycle battery reduces longevity.
Float Charger vs. Trickle Charger
Float chargers and trickle chargers are the most common types of battery chargers.
Float chargers use a process known as automated multi-stage charging. It all starts with a lot of current and voltage. This is to give your battery a substantial charge as soon as possible while it’s at its lowest point. This should charge your battery to around 80%.
After the bulk charge phase, the absorption charge begins. This will charge the battery to 90% or 95% of its capacity. The voltage remains constant during this phase, but the current decreases.
The float phase is the last 5% to 10% of the process. The current and voltage both decrease until the battery is fully charged. This charges the battery safely and effectively so that it lasts as long as possible.
A trickle charger operates differently. From start to finish, trickle chargers charge the battery at the same rate as it discharges electricity. Once the battery reaches 100%, this has the potential to overload it. Overcharge protection is included in modern onboard battery chargers. (Read How Does A Fish Finder Work)
What Is The Best Way To Charge a Trolling Motor Battery?
- Using an intelligent battery charger is good advice for using deep cycle battery chargers.
- Modern chargers, whether portable chargers, an onboard charger, or another variant, can all have similar features that help battery life and charge to the battery’s capacity.
- Here are some features that these chargers deliver, so you have the power for electric trolling motors.
- Automatic multi-stage charging, meaning the charger, changes the output throughout the charging process. Simply put, it can speed up charging while it protects your battery at the same time.
- Automatic temperature compensation prolongs battery life by up to 15%. It measures the temperature and adjusts the charge output accordingly.
- Digital chargers have a Led display and lights, so you know your charging process stage.
- Based on where your batteries are and how you use them, you could need:
- A portable battery charger is something you can take and hook up to a battery wherever you have power. You often use these for charging trolling motor batteries on kayaks.
- An onboard battery charger will often be used when batteries are fixed in the boat, and you charge them as they remain in their fixed position.
- Home chargers will be used for charging a battery at home and maintaining battery charge through the winter. Here, you find smart battery chargers optimize the charging process automatically.
How To Charge Different Trolling Motor Deep Cycle Batteries
The sort of charger you use is usually determined by the type and quantity of batteries you have, as well as the size of your battery bank.
If you use more than one battery, chargers with multiple banks are ideal since they can charge two or more cells simultaneously. Your cranking battery may require a different charge than your other batteries.
For example, if you have four batteries, you need more banks than if you only had one or two batteries.
Some chargers detect a starting battery and will not charge your outboard motor batteries until the cranking battery power has a voltage greater than 13.6 volts.
Unplug Trolling Motor: To begin, disconnect your trolling motor from the battery box and any other devices attached to the battery. You should also check that the battery is clean and dry.
Connect Your Charger: Connect charger’s leads to your battery terminals with the red positive lead to the battery’s positive terminal. Return to the negative terminal using the negative lead. If charging multiple batteries with a multi-bank charger, repeat the process for each battery.
Connect To Power Source: Connect your onboard charger to a power source, which can be a wall outlet or extension cord. Some larger boats can use an outboard motor and alternator to charge their trolling motor battery.
Most onboard chargers feature built-in electronics to determine how much charge your deep cycle batteries need. Onboard chargers can halt charging when the battery is full or offer a trickle charge to keep your deep cycle batteries charged.
Remove Battery: If your battery is in an inconvenient spot for charging, it may be quicker to remove it from its current location and connect it to the charger. Before connecting the charger, make sure all of your equipment is unplugged from the battery.
Connect Your Charger: Connect the charger’s leads to the battery’s matching terminals. If your charger only has one bank and you have many batteries, repeat the steps for each battery.
If you are away from any power source, you can now take advantage of the sun’s power.
Position Solar Panel In Direct Sunlight: Before you begin charging, make sure your charger’s solar panel is in direct sunlight so it can absorb the maximum amount of energy.
Disconnect Battery From Motor: To ensure you don’t damage your trolling motor, disconnect your trolling motor from your battery.
Connect Charger To Your Battery: Using the cables on your charger, connect to your battery terminals. The positive cable goes on the positive terminal, and the negative cable on the negative terminal.
Turn On Power: Even though you use the sun’s power. There will be a power switch on your charger. Enable this to let the current flow from the solar panel to your battery. You’ll find this slow, and you may not reach full charge, yet it’s enough to get you home.
How Long Should You Charge A Trolling Motor Battery?
The time to charge your battery depends on three variables:
- The amp output of your charger.
- The amount of remaining charge in your battery.
- The battery capacity.
If your charger charges at five amps on a 50 Ah battery that’s 50% charged, it’ll take a little over 5 hours.
Smart chargers can be left on as they adjust, so you don’t have to worry about the time it takes. If you charge a marine battery with an older charger, you will need to check the charge level before disconnecting the power.