How to charge trolling motor battery – Proper Guide

Welcome, anglers and paddlers! In this blog post, we will teach you how to charge a trolling motor battery. As we all know, a trolling motor is essential for any angler looking to make the most of their fishing trips. However, if your battery isn’t charged up, your trolling motor won’t do you much good.

In this blog post, we’ll show you how to easily charge your trolling motor battery so that you can hit the water prepared and ready to fish. Thanks for reading.

What is trolling motor

A trolling motor is very much similar to what you would find on an outboard motor. It’s a self-contained unit with an engine and propellers. The big difference is that a trolling motor is not gas-powered. Instead, it relies on a battery for power. 

You can easily charge these batteries with a portable battery charger or, more popularly, an onboard battery charger. However, solar chargers are another option for those looking to be more eco-friendly.

As the name implies, a trolling motor is ideal for smaller boats and fishing. And what angler worth their salt doesn’t love a good troll? But seriously, these motors aren’t powerful by any means. In most cases, you can expect them to propel your boat at a leisurely 1-3 miles per hour. But that’s also the point.

You don’t want a fast boat zipping through the water when you’re trolling for fish. You want something that will allow you to take your time and enjoy the experience.

So next time you’re in the market for a new trolling motor, keep all of this in mind, and you’re sure to find the perfect one for your needs.

What is a deep cycle battery, and how do I choose one?

In simple words, a deep cycle battery is an ideal tool that you can use for trolling motors. We know most users will say that car batteries are also suitable for this purpose, but deep cycle batteries are always the better and first choice of many anglers. 

Remember, car batteries provide a quick power thrust to start the engine. In your vehicle, the battery is designed to provide the starting power with that car’s engine demand. But when it’s working, the electrical mechanism remains in the hands of the alternator. We can say that a car battery cannot retain that power for long.

On the other hand, a trolling motor will work with a car battery, but it might not run at its best. However, deep cycle motors and batteries are designed specifically for this purpose. Hence you can use it comfortably, discharge the battery deeply, and recharge it whenever needed.

Similarly, deep cycle battery charging is much quicker and more efficient. The battery plates are much thicker and more durable than a car’s battery. 

According to industry experts, the chemical reaction that produces energy includes dense materials. Thus you will find deep cycle batteries more robust and longer-lasting.

Whether you’re boating for pleasure or fishing for business, you need a marine battery that can withstand the rigors of a saltwater environment. That’s why deep cycle marine batteries are the best choice for your vessel. These batteries are designed specifically for marine use, so they can better resist corrosion and stand up to the harsh conditions of saltwater. 

And because they are sealed properly, deep cycle marine batteries are also less likely to leak and cause problems if they get wet. So when you’re looking for a battery for your boat, make sure you choose a deep cycle marine battery for the best performance and longest life.

When it’s about deep cycle batteries, you have a few choices. Below we will look at the various types of deep cycle trolling motor batteries.

AGM VS Gel VS wet cell batteries

FLA or wet cell batteries

These batteries have many advantages that make them worth considering. For one thing, they’re more cost-effective. They’re also rugged and can provide reliable performance if you take care of them properly. Just be careful not to over flood your battery – that can be a costly mistake.

Keep them in the proper orientation (upright), and you’ll be fine. The battery plates inside are submerged in an electrolyte of dilute sulfuric acid, and most batteries have removable caps that allow the replacement of lost water.

AGM batteries

The AGM battery is the latest and greatest in lead-acid batteries. Rather than using a separator made of paper or other materials, AGM batteries use a separator made of fiberglass. This fiberglass separator holds the electrolyte in place with capillary action, creating a “physical bond” between the lead plates and the electrolyte. This design offers several advantages over traditional lead-acid batteries.

First, it prevents the escape of gasses, making AGM batteries safer to use and more environmentally friendly.

Second, it makes AGM batteries more resistant to vibration, making them ideal for use in applications where vibration is an issue.

Finally, the physical bond between the lead plates and electrolyte helps prevent self-discharge, making AGM batteries more reliable and longer-lasting than traditional lead-acid batteries.

Gel Batteries

Gel batteries are like the Boy Scouts of the battery world: they’re always prepared. At the same time, other battery types might slowly deteriorate when heat or cold exposure; gel batteries can withstand just about anything.

That’s because instead of liquid acid, gel batteries use a silica-based gel to create their electrolyte. This makes them more resistant to vibration, shocks, and extreme temperatures. Gel batteries also don’t require maintenance, meaning you can just set them and forget them.

However, one area where gel batteries aren’t as prepared as their liquid counterparts: is high amperage situations. When exposed to too much current, the gel inside can become scarred, which leads to corrosion and premature failure.

Best Types of battery chargers For Trolling Motor Batteries:

Generally speaking, there are three types of chargers that you can use for trolling motor batteries. The chargers are solar chargers, onboard chargers and portable chargers. Below is a brief explanation of each type for your perusal.

On-board chargers

are permanently installed on your boat. Furthermore, you need to plug these chargers into a power outlet to deliver power. These are the most common chargers out there and work well.

Solar Chargers :

As the name states, these chargers use sunlight to deliver energy and power to your boat’s battery. Some solar chargers need proper installation and wiring. Besides, you need to connect them with solar panels to get power.

Portable Chargers :

To some extent, we can say that portable chargers are more suitable for smaller boats and kayaks and in places where space is limited. Like onboard chargers, portable chargers also need an electrical outlet to deliver energy and power.

Float and trickle chargers:

Float chargers and trickle chargers are other options that you can use for your trolling motor. Float chargers utilize a unique working process called automated multi-stage charging. It includes plenty of power, current and voltage to provide your battery with a sufficient charge. According to consumer reports, float chargers will charge your battery up to 80% ASAP.

Besides, the voltage remains the same during the process; however, you might see fluctuation in the current. On the other hand, a trickle charger works entirely differently. From start to end, trickle chargers are known to charge the battery at the same rate as it charges or discharges electricity. Once your battery reaches up to 100%, this charger can overload it.

Onboard vs portable charger :

As mentioned above in this read, if you are using a small boat and you have to remove the battery from your boat to charge it, a portable charger is an option. Portable chargers are also ideal if you want to charge multiple boats.

The size of portable chargers is compact, and some chargers are hardly larger than a standard computer mouse. At the same time, some modern portable chargers look like small briefcase. The traditional “trickle chargers” come under this category. However, some modern portable chargers feature short circuit/reverse polarity protection and LED displays.

On the other hand, onboard chargers are efficient for trolling motors but are more expensive than portable chargers. The biggest benefit of these chargers comes in convenience and ease of use. Using these chargers is simple, just plug the charger into a 120-volt electric outlet and let them handle the rest; no hassles.

Furthermore, these chargers are always connected and permanently installed inside your boat. Hence they are safe than the others. Lastly, some latest onboard marine chargers are more advanced and offer satisfactory multi-stage switching to maintain a boat’s batteries.

Deep cycle charging and maintenance

Maintenance for your deep cycle batteries is important if you want to get the most out of them – after all, they aren’t cheap. You can do a few things to keep them in tip-top shape and extend their lifespan.

Battery temperature

Like people, deep cycle batteries don’t function as well when it’s too hot or too cold. If you want your battery to give you its best performance, you need to keep it within a comfortable temperature range. That means avoiding extreme temperatures, both hot and cold.

Similarly, when charging your battery, ensure that your charger takes and keeps temperature data into account. Batteries require more voltage per cell, especially in cold months.

Battery charging cycle

As you know, batteries are made up of various cells. So, these cells can get unaligned and cannot hold and maintain equal charge. This can result in various problems and decrease its lifespan.

You need to eliminate this severe threat by adopting equalizing charges. These charges will align the battery cells and keep them in proper order.

To equalize, you need to maintain the battery’s water level. You can also look at your battery manual to know the exact voltage to equalize the battery.

Charging speed and time

Batteries just don’t like hot conditions. But do you know that batteries also don’t like rapid charging. Furthermore, the high internal temperature of your battery can damage and decrease its lifespan and performance.

If you’ve ever had your marine battery die on you unexpectedly, you know the importance of keeping it healthy and happy. And as with most things in life, that starts with a good night’s sleep. That’s right; slow charging overnight is the key to extending the life of your marine battery.

Not only will it thank you for giving it a chance to rest and recharge, but you’ll also avoid those annoying “low battery” warnings at the most inconvenient times.

So next time you’re getting ready to head out on the open water, make sure you give your battery a good night’s sleep – it’ll be happier and healthier.

How to Charge a Deep Cycle Battery Safely: Step by Step

Anyone who has ever dealt with a dead battery knows the feeling of frustration that comes with it. Fortunately, charging a battery is relatively simple, as long as you have the right charger. Here’s a step-by-step guide to getting you up and running::

  • Ensure that terminals are clean and tidy.
  • Next, attach the red cables with the red ones. Then you will have to connect the black (negative) wires to the black ones.
  • Next, connect your charger and switch it on.
  • If you have a smart charger, just “set it and forget it”. Smart chargers will stop charging automatically. Most lead-acid chargers need a timer and remove the charger when your battery is fully charged.
  • Remove the cables when your battery is completely charged, and you are good to go.

Congratulations, you’ve just learned how to charge a deep cycle battery correctly! This knowledge will come in handy the next time you’re out on the water, enjoying the great outdoors.

How to solar charge

The solar charging process looks identical; however, there are some key differences between the charging processes. Here is how to solar charge a trolling motor battery:

  1. First, you need to ensure that your solar panels are placed under a well-lit area and get the maximum solar heat.
  2. Next, you need to disconnect your battery from the trolling motor. After that, you will have to connect your charger. The key here is to connect red with red and black to black. In other words, positive terminals with positive and negative terminals with negative terminals.
  3. Now, it’s time to turn on your solar charger. Remember, the process via solar is slower than the portable or other chargers. So you need to keep an eye on the charging progress and never leave it for too long unattended.

How to charge while on the lake

As any seasoned fisherman will tell you, there’s nothing worse than being out on the open water with a dead trolling motor. Fortunately, charging trolling motor batteries while on the lake is actually quite simple even if you are on the lake. The best way, in our opinion, is to charge your motor via an outboard charger. Most boats have permanently installed outboard chargers to charge the battery.

But if that is not the case with your boat, you can easily convert the charger for a quick recharge. You will need a regulator/rectifier for this purpose.

When using an outboard motor charger, ensure that all regulators and components are compatible. 

To ensure that boat’s trolling motor battery remain charged while on the lake, you need to follow this process:

  • First, ensure that your vessel has a lightning coil installed.
  • Next, you must ensure that the regulator/rectifier has all the needed wires. Generally speaking, the regulator needs to have four cables that are a red one, a black one, and two other cables. The black and red cables represent the DC wires, whereas the others are AC-in wires.
  • Ensure that red wires are connected to the battery’s terminal and connect the black wires to the negative terminal afterward.
  • Now disconnect the flywheel wires and attach them to the other wires of the regulator.
  • If you want to mount a lightning coil, pick the one that suits your boat’s motor. To install it, disconnect the flywheel and lightning coil into the appropriate place.
  • Lastly, ensure that all bolts are firmly locked, and the screws are lined up.

How to charge from outboard (same as above )

The process of charging from the outboard is simple as well. Plus, the charging process for portable and onboard chargers is the same. Here is the process:

  1. Start the process by disconnecting your boat’s motor. Now, check your battery for spills, leaks and other damages. Similarly, also ensure that battery terminal are free of debris.
  2. Then, you will have to connect your charger to your boat’s battery. Again, ensure to connect red wires with the red and black wires to black wires.
  3. Now, you can attach your charger to your boat’s power source. Once it is appropriately connected, switch it on.
  4. Remember, don’t leave it alone and check the progress. The latest chargers will show you the status, but some will not. Cautious about overcharging and overheating.

How long it takes to fully charge a deep cycle battery?

The duration and charging time of your deep cycle relies on three crucial factors:

  • The amp and output of your battery charger.
  • The charge is left in your trolling battery.
  • The battery’s capacity.

Didn’t get it; let me elaborate:

For instance, if your charger delivers and charges your battery at 5 amps, and you have a 50 Ah deep cycle battery which is 50% charged, it will take around 4 to 5 hours for a complete charge.

Tips to extend battery life

Here are a few simple things that you can do to get the most out of your trolling motor battery.

  • Never try to mix or change the battery’s chemistry types.
  • Don’t use or mix new batteries with older batteries.
  • Never allow your battery to deplete completely. A general rule in this regard is to leave a 40% charge in the battery when you recharge. Similarly, don’t allow the charge to go down below 20%.
  • If possible, try to charge your batteries after every use.
  • Regularly check your battery’s terminal for rust and corrosion.

When storing your trolling motor battery, store it in a cool and dry area to maintain its trickle charge. However, if you don’t want to use a maintenance charger during the offseason, charge the batteries frequently to avoid any problems.


Can I use a car battery for trolling motor?

Some people think they can save a few bucks by using a car battery to power their trolling motor. But trust me, it’s not worth it. Not only will you risk damaging your trolling motor, but you could also end up stranded out on the water. That’s because car batteries are not designed to be discharged at the same rate as trolling motors.
Over time, this can lead to the formation of sulfate crystals, which can reduce the battery’s capacity and eventually kill it. So save yourself some trouble and stick with a marine battery. Your trolling motor will thank you for it.

Can a trickle charger fully charge a deep cycle battery?

Any boat owner knows a reliable marine battery is essential for a successful day out on the water. However, marine batteries can be expensive, and it’s frustrating when they don’t last as long as they should. One way to extend the life of your marine battery is to use a trickle charger.
Trickle chargers work by slowly and steadily charging the battery, which helps to prevent the build-up of excess heat.
Excess heat is one of the main causes of damage to marine batteries, so by using a trickle charger, you can help prolong your battery’s life. In addition, trickle chargers are easy to use and relatively inexpensive, so they are worth considering if you want to get the most out of your marine battery.

Should you charge a deep cycle battery at 2 amp or 10 amp?

The charger’s amp rating mostly relies on your deep cycle battery’s amp-hour ratings. For example, if you have a 12-volt deep cycle battery, you can charge it with a 2 amp charger. Similarly, if you have a 100 amp-hour deep cycle battery, you can charge it with a charger having ratings of 10 amp or higher.

Do deep-cycle batteries discharge when not in use?

There’s nothing worse than being stranded with a dead battery – except maybe being stranded next to a boat with a dead battery. That’s why ensuring your deep cycle battery is fully charged is always important. 
Deep cycle batteries are made to last and don’t lose much charge when they’re not in use. So whether you’re planning to hit the open waters or just sit in your garage, your deep cycle battery will be ready to go when you are.

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Michael has been an avid boater and a battery expert for over 10 years now. He is passionate about sharing the knowledge he has acquired so that everyone can benefit from it. His posts are dedicated to helping all kinds of boat owners, from recreational fishermen to hardcore sailors, get the most out of their batteries and motors. Through his articles, reviews, and tips on battery care, Michael has been providing valuable insights to boaters all over the world.

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