When To Charge A Trolling Motor Battery? [Optimal Performance Tips]

Industry experts recommend charging your trolling motor battery within a discharge range of 50%.

That’s for lead-acid batteries. Luckily for us, marine battery manufacturers also produce lithium batteries which only need recharging when they get to around 20%-30% depleted. Here’s a quick snapshot of what to know.

At a Glance:
1️⃣ Charge trolling motor batteries at 20-50% discharge and when performance declines.

2️⃣ Prevent damage by avoiding overcharging, complete discharging, and following regular maintenance.

3️⃣ Choose suitable chargers and understand your specific battery type’s needs. Charging methods include; onboard, solar, portable, multi-stage and smart chargers.

Now that you have a rough idea of when to hook up your trolling motor’s battery to a power source let’s dive further into the topic to learn more about it.

⏰ When To Charge A Trolling Motor Battery?

Charge your battery (ies) at between 20-50% discharge (depending on battery type) or when performance declines.

Regularly keeping track of your trolling motor battery usage plays a crucial role in deciding when it’s time to charge. 

Depending on the motor’s age and the quality of the battery, some may last up to six to eight hours of continuous use, while newer models with high-quality batteries can run for much longer. 

Remember that the battery’s discharge level can impact its life span. Frequently dropping below or near these levels can shorten a battery’s life. On the other hand, allowing a battery to dip by only 5-10% frequently can also decrease the battery’s longevity.

Signs of Low Battery Power

Several signs indicate a low battery charge. These include:

  • Reduced motor speed and power.
  • Dimming of connected electronics or lights.
  • Motor cutting out or stalling.

If you see these signs while using your trolling motor, read the tea leaves and charge the battery.

Damage Prevention

To prevent damage refrain from overcharging or discharging it completely. Overcharging can result in overheating and battery swelling, while discharging the battery fully can lead to sulfation, rendering the battery unusable.

Adopt a regular maintenance and charging schedule to avoid both overcharging and deep discharge. Using a quality charger that is compatible with the type of battery in use can also help prevent damage and ensure optimal battery life.

🪫 Charging Methods and Devices

Charging your motor battery is an essential step to ensure the smooth operation of your motor and extend the battery’s lifespan.

There are various methods and devices available for charging these batteries, each with its own advantages and suitability for different situations.

Charger TypeDescriptionAdvantagesConsiderations
Onboard ChargerPermanently mounted on the boat and directly connected to batteries. Designed to charge multiple batteries simultaneously.Convenience, efficiency, charges multiple batteries, safe, quick.Should be compatible with both flooded and sealed-type batteries.
Solar ChargerUses solar panels to convert sunlight into electricity for charging.May take longer to charge compared to onboard chargers. Cleaning, drying, and protective gear are essential when using.May take longer to charge a battery. Suitable for different boat sizes and power requirements.
Portable ChargerLightweight, compact, designed for easy transport. Typically has a single connection point.Portability, versatility, can charge battery away from the boat.May take longer to charge compared to onboard chargers. Cleaning, drying, and protective gear are important when using.
Multi-Stage ChargerUses a microprocessor to control the charge voltage and current. Involves bulk, absorption, and float stages.More efficient and safer, optimizes battery performance and lifespan.Offered by many modern onboard and portable chargers.
Smart ChargerIncorporates advanced charging technology and monitoring features. Can automatically detect battery type and current charge level.Advanced technology, automatic detection, diagnostic information on battery health and performance.Correct settings essential for optimum performance.

🦾 Factors Affecting Battery Life and Performance

There are several important factors to consider when charging a trolling motor battery. These factors play a crucial role in determining the charging performance and ensuring efficient power output for your motor.

Wiring and Cable Connections

One of the primary factors affecting battery charging is the quality and condition of the wiring and cable connections. Poor connections or damaged cables can lead to reduced charging efficiency and weakened power output.

Make sure that the cables are correctly connected, with “+” connected to the positive terminal and “-” connected to the negative terminal. Check for any signs of wear, damage, or corrosion, and replace or clean them as necessary.

Battery Capacity and Amp-Hours

Capacity plays a crucial role in determining the charging performance. Greater reserve capacity or amp-hours (Ah) indicates that your trolling motor battery will provide more power for a longer duration. It affects how long you can keep your batteries charged and how much power they can deliver.

As the battery’s capacity increases, the charging process may take longer. Make sure to check the manufacturer’s recommendations for the charging times to prevent overcharging or undercharging.

Environmental Factors

External factors, such as temperature and humidity, can impact the charging process. Extreme heat or cold may result in reduced battery performance and charging efficiency. 

Only store and operate the battery within the specified temperature range and make necessary adjustments during extreme weather conditions.

Vibration and shock can also impact battery performance. It is vital to securely mount your battery to prevent damage from excessive movement.

🏆 Best Practices for Battery Chargers and Maintenance

Preventing Overcharging and Undercharging; Trickle Charging

Maintaining the proper charge level for your battery is crucial to its performance and lifespan. To prevent overcharging, use a quality trickle charger that automatically detects when the battery is full and switches to maintenance mode. This mode helps keep the battery topped up without overcharging.

Undercharging can also be harmful, as it might lead to insufficient power for your trolling motor. To avoid undercharging, charge your battery after every use or when the voltage drops to around 50%.

A quality charger with an automatic shut-off feature can help prevent both overcharging and undercharging.

Proper Storage and Handling

Your battery needs to be stored correctly if you want to avoid damaging the battery and decreasing its longevity. Always disconnect the battery when not in use and store it in a cool, dry place. Keep it away from direct sunlight, heat sources, and water to prevent damage.

When handling lead-acid batteries during the charging process, wearing rubber gloves is recommended to avoid direct contact with battery terminals or acid. 

This will also help avoid accidental short circuits. Ensure you connect the charger correctly: red positive terminal first, followed by the black negative terminal.

Regular Inspections

Performing regular inspections of your trolling motor battery helps to identify potential problems early and prolong its life. 

Examine the battery’s terminals for signs of corrosion or damage and clean them with a soft brush, if required. Check the battery case for cracks or bulging, which may indicate a severe internal issue requiring professional attention.

For maintenance-free batteries, check the voltage regularly to ensure it remains within the recommended range. For batteries with water levels to monitor, inspect the water in the battery cells and top up using distilled water, if necessary.

🔄 Alternative Ways to Charge Your Batteries

In addition to regular chargers, there are alternative methods for charging trolling motor batteries. This section will explore charging with an outboard motor alternator and using battery combiners.

Charging with an Outboard Motor Alternator

One method to charge a trolling motor battery is by using an outboard motor alternator. Outboard motor alternators produce AC current, which can be converted to DC current to charge the battery. 

Before attempting to charge the battery with an outboard motor, consult the motor’s manual for proper instructions and safety measures.

Keep in mind that this method should not be relied on as the primary source of charging but rather as a supplemental option.

Battery Combiners

Battery combiners are another alternative. These devices can connect multiple batteries in a system, allowing you to charge your trolling motor battery while the main battery is also being charged.

Battery combiners balance the charging process between batteries, ensuring that all connected batteries receive an adequate charge.

When selecting a battery combiner, make sure it is compatible with your battery type and system requirements. And only install according to the manufacturer’s instructions to ensure a safe and effective charging process for your battery.

Another alternate method is to charge your battery by using solar panels. This has proven to actually be more cost-effective in the long term.

🔍 Selecting an Appropriate Battery for Your Needs

To choose the best battery for your needs, consider the power output, cost, and lifetime of the available options.

Match Battery Power Output to Trolling Motor Requirements

Trolling motors have different power requirements based on their thrust levels, so you’ll need to consider the size of the battery when choosing it for your motor.

For motors with up to 55 pounds (lbs) of thrust, a single 12-volt battery is usually sufficient. For motors over 55 lbs of thrust up to 80 lbs, you will require two 12-volt batteries, providing a total of 24 volts.

You also need to consider the motor’s amp draw when choosing a trolling motor battery.

For example, if you have a battery with a 100 amp-hour rating and your trolling motor draws 20 amps, the battery will last approximately 5 hours if consistently running.

Calculated as follows: 100 amp-hour / 20 amps drawn = 5 hours of run time.

Cost and Lifetime Considerations

A battery can cost considerably more than the initial price when you factor in the battery’s expected lifespan.

While lead-acid batteries remain the most affordable option for deep-cycle trolling motor applications, they typically last between 2-3 years, depending on their quality.

It’s important to strike a balance between cost and longevity, as the replacement costs of cheaper batteries can quickly add up. In addition, not all batteries provide the same power output or cycle life.

Always compare different options and read customer reviews before making your final decision. Factors such as the battery’s brand, size, and capabilities all play a role in determining whether it’s the right choice for your trolling motor and fishing adventures.

🔑 Key Takeaways

Let’s recap what we have covered on the topic of optimal charging schedules:

1️⃣ The quality of wiring and cable connections, battery capacity, and environmental factors all influence battery life and performance.

2️⃣ Good practices for battery maintenance include avoiding overcharging and undercharging, using a trickle charger, proper storage, and regular inspections.

3️⃣ Alternatives to traditional charging methods include using an outboard motor alternator and battery combiners.

4️⃣ Choose the right battery by considering power output requirements, costs, and lifespan. Align power output with trolling motor needs and consider long-term costs relating to battery life.

Now that you know the best charging practices, I’d like to point out another important point which is the long-term value of using lithium trolling motor batteries.

I’m the founder and chief editor here at Kite Ship. The electrification of boating is the most exciting thing to happen to the marine industry in a generation! Welcome, and I hope that we can provide the portal you need to dive into the world of electric propulsion and power.