How To Install A Second Battery In A Boat?

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Is it indispensable to distort the manufacturer’s idea and add a second battery to your boat? Well, that’s a commonly asked question among folks who have deep concerns about their investments. Who would not like a little bit more? More power in your systems, more resilience to tides, and longboat rides. To get all these and much more, all you need is to never worry about your boat’s powerhouse. That is why you need to get an extra battery for your boat. The battery will conquer all your second thoughts and give you assurance in your explorations. The second battery installed will work as the backup powerhouse to all your systems if the first battery starts malfunctioning. The operator also can choose which battery will be charged by the engine at any given time.

Step by Step Installation Process

For you to have a successful second battery installation, one should consider the below-inaugurating procedure.

  1. Battery selection

After selecting the best battery you require, you should understand that batteries are sensitive when installing. They are manufactured with a potentially dangerous energy amount that can be quickly executed in the wrong way. These calls for massive attention when you are attending to the battery. Your connection to their respective appliances must be precise, using clean rust free copper wires that are well coated.

The installation should be done around the water-resistant ground. The battery itself should not be exposed; hence should be enclosed to avoid corrosion with water or any other elements. Be sure to put on safety glasses when working on batteries. They will prevent the risk of having battery acid spill on your eyes.

  1. Battery tray

Before placing the batteries inside your boat, you should attach a dual battery tray on the surface of your boat. The tray will aid ease the corrosion between the boat and the batteries put in place. The battery tray should be fixed firmly in the boat to avoid movement when sailing.

  1. Switchboard

The switch will help you have control of the amount of power you need and also when to recharge your battery. As a user, you can set the battery switch to your preferred option:

  • To either adjust the battery to a charging position as the engine is running.
  • With a deep cycle, you can anchor your boat and relax, leaving the engine running, which will facilitate your battery’s charging.
  • At another juncture, you can opt to use both batteries to get an enormous power output. However, it can be risky as it might drain all the power before you notice it.
  • The off position will switch off all the running accessories and start charging the battery.

The user can purchase a fully automated battery switch, although it is a little elegant. That kind of control may malfunction and use an unauthorized option to a disadvantage on your resources.

  1. The ACR

This automatic charging relay will help the alternator in the boat to charge the batteries. It will also regulate the amount of power being used by accessories around the boat so that you don’t overpower anything. The ACR also determines which battery will be used for a specific action. When you are anchored and the motor is not running, the automatic charging relay will use power from the reserve battery hence you will not have to worry about draining off unnecessary power from your battery. The automatic charge relay is connected to the switch and two fuses.

  1. Fuses and bus bar

Fuses are attached to protect the automatic charge relay. The fuse will aid a longer life span of your ACR preventing it from overpowering or the engines or even blowing up.

A negative bus bar is relatively significant to your successful dual battery installation. All the negative wires from the engine to the batteries to any other accessory are attached to the bus bar. A 1amp fuse is attached from the bus bar to the ACR as a safety precaution in case anything runs short from the fuse and will not terminate the ACR or the switch.

All these applicants can be mounted on a board to ease the pressure of adding them to different sections in your boat. It is easier and time-saving and also will not need a lot of wires to attach.

  1. Covering the battery wires

The naked wires can be covered using dielectric grease. This will prevent any shock incidences that may occur. You can also opt for a battery plastic cover but they might be a little spacious and inconvenient but will work with the same purpose.

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Tips on Selecting Second Battery

To have a battery worth investing in, it must be of acceptable quality and durable. Below are some of the battery categories to look up to before purchasing a second battery for your boat.

  • Deep Cycle Batteries

With deep cycle batteries, your objective of having a quality battery is well convened. This battery can sustain consecutive deep recharging and discharge without getting wrecked. Qualities of an excellent durable battery that can suit your needs as backup leverage for your boat. The deep cycle batteries are suitable for boats with an immense DC power thirst. The majority of boat owners endorse that one requires a deep cycle battery, either as the first or second battery in service.

  • Dual-purpose Batteries

The dual-purpose batteries are not the very best batteries you can get in the market. However, they have a tremendous work rate but also have difficulty sustaining deep discharges and would quickly ruin the typical starting battery. The dual-purpose batteries are also known to have a lower storage capacity compared to deep sized cycles. Because of their complex nature, it is recommended that you use the same kind of dual-purpose batteries for the first and second batteries on your boat.

  • Starting Batteries

Well, with starting batteries, everything is a little different. They are not prone to hold high capacities never the less; they can supply plenty of current for a short period. With this feature, the starting batteries require charging almost now and hence do not allow deep discharges. You do not expect to use this kind of battery in a powerful boat engine. It is appropriate to use for small boats that have minimal Direct Current loads


Placing a new battery on your boat is a good idea. However, you want to get all your credentials on the installation right. A little bit of extra power will improve your engine performance and provide efficient lighting on your boat. Despite how big or how small your boat is, it can always be fitted with a second battery that is up to its standards.

With the perfect set of necessary skills and quality battery, the installation creates a mega powerhouse for your boat. You can later add accessories to your boat because there will no longer be limited power.


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