Winter Boat Battery Maintenance And Storage Guide

As the boating season comes to an end, it's important to consider how to store your boat's batteries during the winter months. Proper storage will ensure your boat is ready to go when spring arrives. This includes performing regular maintenance, such as watering and removing corrosion, and following a winter storage checklist. One of the key steps is to charge your batteries before storing them in a cool, dry place, like a garage, to reduce the risk of freezing. It's also important to disconnect the terminals from any electrical loads, as even small power draws can damage the battery over time.

Charge the battery to full before storing

Before storing your boat and its battery away for the winter, it is important to charge the battery to full. This is because all batteries will lose charge over time, even when not in use. By starting at full charge, you give your battery the best chance of having sufficient power remaining when you come to use it again in the spring.

Marine batteries should always be stored full. Some batteries cannot be recharged once they drop below 20% charge, and even those that can be recharged from a very low level are at risk of damage from freezing. Therefore, it is best to start with a full charge to reduce this risk.

If you are using traditional lead-acid batteries, they will lose charge over time, even in cold temperatures, and this can cause permanent damage and shorten the battery's life. A battery maintainer can be used to prevent this damage and keep the battery in optimal condition.

In contrast, lithium-ion batteries are less impacted by cold weather and will not freeze under most conditions. They also generally do not experience a major loss of energy over time. However, it is still recommended to store them at full charge to ensure they are ready for use in the spring.

It is also important to note that batteries should be charged to full before storing even if they are being left in the boat over winter. This is because, in cold temperatures, batteries are at risk of cracking or draining completely. Therefore, if you do decide to leave your battery in the boat, it is crucial to ensure it is fully charged before storing it away.

Disconnect negative cable and terminals

Disconnecting the negative cable and terminals is a crucial step in preparing your boat's batteries for winter storage. This process helps to protect your batteries from damage during the off-season. Here's a detailed guide on why and how to do it:

Disconnecting the negative cable and terminals is an essential step in winterising your boat batteries. Even when they appear to be turned off, electronics can still draw small amounts of power from your batteries. This slow drain, combined with the natural self-discharge of the battery, can be enough to damage your batteries if left connected during the winter. By disconnecting the negative cable and terminals, you eliminate any electrical loads and prevent your batteries from losing their charge.

Steps to Disconnect the Negative Cable and Terminals:

• Locate the Negative Cable: Start by identifying the negative cable connected to your boat's battery. It should be clearly marked or coloured, typically with a black covering or a "-" symbol.
• Disconnect the Negative Cable: Using the appropriate tools, carefully disconnect the negative cable from the battery terminal. Loosen any clamps or fasteners securing the cable and remove it from the terminal post.
• Wait Before Checking Voltage: Once the negative cable is disconnected, wait a few hours before checking the voltage of your battery. This allows the system to stabilise and provides an accurate reading.
• Check Voltage: After the waiting period, use a voltmeter to check the voltage of your battery. A fully charged battery should read 12.6V. If the voltage is significantly lower, it may indicate an issue with the battery or charging system.
• Disconnect Terminals: Proceed to disconnect the terminals to ensure no electrical loads remain. This step is crucial, as any parasitic loads from electronics can still drain your battery even when the negative cable is disconnected.
• Store Batteries Properly: After disconnecting the negative cable and terminals, remove the batteries from your boat and store them in a cool, dry place where they won't freeze. Garages or storage facilities with controlled temperatures are ideal.

Remember, proper winter storage of your boat batteries is essential to ensure they remain in optimal condition during the off-season. By following these steps and disconnecting the negative cable and terminals, you can help protect your batteries and ensure they're ready for use when the boating season starts again in the spring.

Remove the battery from the boat

Removing the battery from your boat is a crucial step in preparing your boat for winter and ensuring it remains in good working condition. Here are some detailed instructions to guide you through the process:

Firstly, it is important to charge your battery before removal. Batteries should always be stored full as some batteries cannot be recharged once they drop below a certain level, and it is normal for them to lose charge during storage. By starting with a full charge, you reduce the risk of freezing and ensure they will be ready for use in the spring.

Next, disconnect the negative cable from the battery and wait a few hours before proceeding. This is an important safety precaution. After waiting, you should check the specific gravity or voltage of the battery. The specific gravity should be between 1.265 and 1.285, or 12.6V if you are using a voltmeter.

Now it is time to disconnect the terminals. This step is crucial as it removes all electrical loads from your battery. Even small power draws from electronics can slowly drain the battery, damaging it over the winter.

With the terminals disconnected, you can now safely remove the battery from your boat. Be sure to handle the battery with care and avoid dropping or causing any physical damage during removal. Place the battery in a cool, dry location where it won't freeze, such as a garage or storage facility. Wood surfaces are also recommended. Ensure the storage area is well-ventilated, especially if you are storing lead-acid batteries which can off-gas even when disconnected.

Finally, consider using a battery maintainer or trickle charger to keep your battery charged over the winter. This is not necessary for lithium-ion batteries, which generally do not experience a major loss of energy over time, but is recommended for lead-acid batteries. If using a maintainer or charger, be sure to select one that is designed for your specific battery type.

Store in a cool, dry place

When storing your boat batteries for the winter, it's important to keep them in a cool, dry place. This is to ensure they don't freeze and to maintain a proper temperature. A garage is a great option, as it provides shelter from the cold and protection from the elements. It's also easily accessible, which is ideal for regular maintenance and charging.

It's crucial to avoid storing your boat batteries in freezing temperatures. Extreme cold can cause a cracked case or a completely drained battery. It's also important to keep them away from any electrical loads, as even a small power draw can damage the battery over the off-season.

When choosing a storage location, opt for a well-ventilated area. Lead-acid batteries, in particular, can off-gas even when disconnected, so they should not be stored in a living space. Additionally, ensure the storage area is free from any elements that could leak and damage the battery. Even something as innocuous as a plastic bag can cause issues if it gathers condensation.

By storing your boat batteries in a cool, dry place, you can help ensure they remain in good working condition and maintain their charge throughout the winter. This will give you peace of mind and save you time and money when the boating season starts in the spring.

Check the charge each month

Marine batteries should always be stored full. If you're using traditional lead-acid batteries, leaving them without charge, especially in cold temperatures, can cause permanent damage and shorten their lifespan. Therefore, it's important to check the charge each month.

Every battery will lose a certain amount of charge each month, even when it's not being used. Depending on the type of battery, this loss of charge could be significant. To keep your battery from losing too much charge, check the voltage each month.

Some batteries, such as MK Battery's AGM and gel marine batteries, lose less than 2% of their charge per month. However, if your battery is stored in potentially volatile conditions, it's best to double-check the charge to ensure it will be in good working condition when you need it.

You can choose to attach a trickle charger to maintain the voltage over the winter. This will provide a slow, constant charge that counteracts the natural energy loss incurred by cold weather. Trickle chargers with smart technology will prevent overcharging and other unsafe operating conditions.

By checking the charge each month and maintaining it with a trickle charger if needed, you can ensure your boat battery stays optimally charged and ready for the next boating season.

Frequently asked questions