How To Add a Second Battery to a Pontoon Boat

How To Add a Second Battery to a Pontoon Boat

Have you ever imagined running short of power while in the waters? It can be a chaotic situation you never wish to find yourself in, right? Did you know that you can install an extra battery on your pontoon? A second battery is a must-have if you have power-hungry gadgets such as a music system, a fridge, or a trolling motor in your pontoon!

But why a second battery when my beauty already has a standard starter motor on? Depending on how you use your pontoon, you always need to be sure the engine will start at the end of the day and get you back to the shore.

As mentioned above, the starter motor won’t just do the trick with a series of appliances on your pontoon. For this, you need a dual battery setup.

Howbeit, do you know how to add a second battery to a pontoon boat? Please don’t panic; we have your back. This post gives you easy-peasy steps to solving this problem!

How To Add a Second Battery to a Pontoon Boat

What Is a Dual Battery Setup?

A dual battery setup refers to a system where a second battery is installed alongside the original factory fitted battery. Running electronics in your pontoon consumes more power than the standard battery can produce. An extra battery could do the work to avoid power depletion, which could cause trouble.

What Are the Types of Batteries Available for Your Pontoon?

If you are a first-time pontoon owner, it is wise to understand the types of batteries in the market to get the right one for your beauty. There are three types of marine batteries: starting batteries, deep cycle batteries, and dual-purpose batteries.

Starting Batteries

Starting batteries, also known as the cranking batteries, are the batteries used to start your boat’s engine. Upon activating the ignition, the battery sends a strong but short time power that travels to the motor and starts the engine. The battery then goes off shortly after the engine runs. The energy these batteries produce is not enough to be used on the extra appliance on your pontoon, such as trolling motors.

Deep Cycle Batteries

Deep cycle batteries are designed to release power slowly and for a longer time. They can endure discharging and recharging without any damage. The batteries emit higher voltage power that can steer the ship throughout the journey or power all the other devices on your pontoon.

Deep cycle batteries are suitable for any boat with high power requirements. Most boats with trolling motors, inverted and other appliances use the starter battery to start the boat’s engine and the deep cycle battery to power all the other appliances.

Dual-purpose Batteries 

As the name suggests, you can use dual-purpose batteries to perform several functions at a go, for this purpose to start the engine and power any other divides that need energy in the boat. It’s designed to provide enough power to start and turn the boat’s engine off and keep all the other appliances running for as long as you need them. They are strong enough to tolerate deep discharges with no damage. 

How To Add a Second Battery to a Pontoon Boat

How To Choose the Right Battery for Your Pontoon

How do you tell the right battery for your boat? Consider the following factors;

Determine the Energy Needs of Your Pontoon

As we’ve discussed above, there are three different battery types. To make the right choice, you have to determine the electrical requirements of your boat, right from powering the engine to all the gadgets you intend to power. 

Many pontoon users prefer mounting a trolling motor onto their boats, especially if they are fishermen. Others have fridges, music systems and other appliances on their pontoons. The appropriate battery for your boat is the one that can produce the right amount of power for your boat’s needs.

Consider the Battery’s Cold Cranking Amps.

As a Pontoon or an owner of an electric machine, you understand how low temperatures make the engine hard to start. This means the battery produces less power, which is insufficient to start the cold engine for a marine craft; that can always be the case.

Therefore, before purchasing a battery for your boat, consider its CCA. The higher the battery’s CCA, the more powerful it is. You will always need to pick the battery that you’re sure won’t trouble you if you intend to use it to power your engine.

Keep in Mind the Reserve Capacity of the Battery

A power cell’s reserve capacity is the time it can supply the power needed for your boat’s electrical components. In other words, the reserve capacity shows the time a fully charged battery can serve the craft’s power needs before it drops below 10.5 volts when discharging 25amp. If your boat’s electrical need is high, the reserved capacity of the battery you purchase should also be high.

Check the Manufacture Date

You want to go for a battery that will serve you for long. By looking at the date of manufacture, you’ll get a hint of how long the battery will serve you. Buying a power cell that will serve you for a single year is money wastage.

There are many more other aspects to consider along with the above. If you are not conversant with batteries, consider consulting a boat expert for further guidance on getting the right battery for your pontoon boat.

Now let’s dig into the process of installing a second battery on your pontoon below;

How To Add a Second Battery to a Pontoon Boat

Step-by-Step Guide on How To Add a Second Battery to a Pontoon

 What you need

  • The second battery
  • Screwdriver
  • Drill and drill bits
  • Cable clamps
  • Terminal caps 
  • Battery selector switch

Step 1: Select a Suitable Battery Switch

Before connecting the additional battery, ensure that the switch you selected is designed for two batteries. Ensure the switch can handle the high amps when starting the boat’s engine. A 250 amps continuous rating switch can serve the purpose; it can withstand the amperage on both outboards and inboards. A lockable switch can also be good for your boat’s security against theft.

Step 2: Mount the Second Battery on the Boat

As discussed earlier, you now know how to choose the right battery for your boat, so we believe you already have one. Now, following ABYC regulations, mount the battery on its banks on your boat. 

However, choose an appropriate location if your boat has no place assigned for the batteries. Remember, too high temperatures will damage the batteries. Therefore, choose a place that has good ventilation. If you’re using a wet cell battery, secure it using a box, and for a glass mat battery, secure it using a tie-dow or a bracket. Also, cover the positive terminals using a non-conducive boot.

Step 3: Identify an Appropriate Location for the Switch on the Boat

A battery switch can occupy between four to six inches of the surface. Therefore, wherever the space you choose to locate it should be wide enough. However, the ABYC standards require locating the switch close to the batteries.  

Step 4: Connect the Positive Terminals

Once you’ve identified a suitable location for your battery switch, you can now connect the positive terminals of the two batteries to the positive terminal on the switch. Afterwards, connect the positive wire from the engine to the output port on the switch.

Step 5: Connect the Negative Terminal

Lastly, to complete the circuit, connect a cable from the negative terminal of battery one across to the same terminal on battery two. Also, connect the negative cable from the engine with the negative accessory wire to either of the negative battery slots and voila! Your battery is ready to get into work.

Best Batteries For A Pontoon Boat

Safety Tips When Working on Batteries

When working on batteries, you should consider how much power they contain. Consider the following tips to avoid accidents;

  • When working on batteries, make sure to stick to the approved guidelines from the American Boats and Yacht Council.
  • Batteries can explode; keep flames or cigarettes away while handling them
  • Always disconnect the positive cables while operating on them
  • Ensure to use low resistance cables as your connectors
  • Put on protective gear when handling batteries. Batteries contain acid, which should not come in contact with you. Ensure you include gloves and eye gear for acid prevention and a hard hat for the lifting of the batteries when needed

How To Increase Your Pontoon’s Battery Lifespan

You’ll agree that purchasing a quality battery for your beauty is financially draining. It would be best if you found ways to make it serve you longer. Consider the following maintenance practices;

  • Make sure your battery is always fully charged. When idle, your boat’s battery voltage should remain 12.5v and above—leaving your battery partially charged or with no charge at all causes long-lasting damage.
  • Ensure all your battery connections are intact. Keep the top part of your battery clean and free from grime, allowing electric currents to pass through, losing their charge.
  • Install a cover on top of your battery’s positive terminals to prevent explosion if an object falls on it.
  • Secure the battery with a perfect battery tray and screw them tightly to the boat to ensure they don’t sway around while the boat is moving. 
How To Add a Second Battery to a Pontoon Boat


If you were wondering how to add a second battery to your pontoon, you have it! Did you realize how easy it was? You don’t have to go left and right in confusion. But, if you are not confident to handle the batteries, always get in touch with a boat expert to avoid accidents or damage.




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