When your car isn’t being driven for extended periods, its battery often becomes the first casualty. Whether you’re storing a classic car for the winter or simply using a secondary vehicle less frequently, understanding how to maintain your car’s battery is crucial.
Letting it run flat can lead to reduced lifespan or even permanent damage. Luckily, with a few simple steps, you can keep your car battery in optimal condition.
Why Car Batteries Deteriorate During Storage
Car batteries lose charge naturally over time, even when the vehicle isn’t in use. This is known as self-discharge. Modern vehicles have electronic systems like alarms and clocks that continue to draw power.
In the UK, cold winters exacerbate the problem, as batteries struggle to hold charge in lower temperatures. Statistics show that a car battery can lose up to 50% of its charge in freezing conditions if left unattended for months.
If a battery is left in a discharged state for too long, sulphation can occur. This process involves the build-up of lead sulphate crystals on the battery plates, significantly reducing its ability to hold a charge.
With these risks in mind, taking preventative measures can save you from the inconvenience and cost of replacing a dead battery.
Steps to Maintain Your Car Battery During Storage
1. Clean the Battery Terminals
Before storing your car, inspect the battery terminals. Dirt, grease, or corrosion can interfere with electrical connections and accelerate self-discharge. Use a mixture of baking soda and water with a wire brush to clean any build-up.
Ensuring the terminals are dry and free of residue before storage is equally important to avoid additional corrosion.
You might also consider applying a thin layer of petroleum jelly to the terminals after cleaning. This creates a protective barrier against moisture and corrosion during storage.
2. Disconnect the Battery
If you’re planning to store your car for several months, disconnecting the battery is a smart move. This stops the gradual power drain from the vehicle’s electrical systems.
When disconnecting, always remove the negative terminal first to prevent accidental short circuits. Store the disconnected battery in a cool, dry place, ideally above freezing but not in direct sunlight.
Remember, if your car has electronic settings or a security system that may reset upon battery disconnection, you might need to reset these when the battery is reconnected. Keep this in mind when planning your storage.
3. Use a Battery Maintainer
A battery maintainer, also known as a trickle charger, is a lifesaver for long-term car storage. These devices provide a steady, low charge to the battery, keeping it at an optimal level without overcharging.
Look for models compatible with mains power and equipped with overcharge protection for added safety. This is particularly helpful if you’re storing the vehicle in a garage.
Unlike traditional chargers, maintainers are designed to be left connected for extended periods. They adjust their charging levels automatically, ensuring the battery remains in peak condition without the risk of damage.
4. Start the Car Occasionally
If possible, start the car every two weeks and let the engine run for about 15 minutes. This helps recharge the battery while also circulating engine fluids to prevent stagnation. Be sure to do this in a well-ventilated area or outdoors to avoid carbon monoxide build-up.
During these start-ups, you can also move the vehicle slightly to prevent flat spots developing on the tyres. However, ensure the battery has enough charge before attempting this to avoid unnecessary strain.
5. Check the Battery’s Voltage
Invest in a multimeter to periodically check the battery’s voltage. A healthy car battery should read between 12.4 and 12.7 volts when fully charged. If it dips below this range, recharge it promptly to avoid sulphation – a condition where lead sulphate crystals form and reduce the battery’s capacity.
Regular voltage checks also allow you to detect any issues early, giving you time to address them before they escalate.
Tips for Winter Storage
Keep the Battery Warm
Extreme cold can sap the life out of your car battery. If you’re storing your vehicle in an unheated garage or outside, consider insulating the battery. Specially designed thermal wraps are available and can prevent temperatures from dropping too low.
In cases where insulation isn’t possible, storing the battery indoors might be a better option. This way, it stays protected from the harsh winter conditions.
Check Electrolyte Levels
For non-maintenance-free batteries, checking the electrolyte levels is essential. Top up with distilled water if levels are low, ensuring the plates are fully submerged. Never use tap water as it contains minerals that can damage the battery.
If you’re unsure whether your battery is maintenance-free, consult your vehicle’s manual or check the label on the battery itself.
Avoid Long Periods Without Charging
Even with careful storage, it’s essential to recharge the battery periodically. Letting it sit for months without any charge can lead to irreversible damage. Aim to recharge the battery at least once every three months if you’re not using a maintainer.
What to Avoid
Overcharging
While keeping the battery charged is essential, overcharging can be equally damaging. It causes excessive heat and evaporation of the electrolyte, shortening the battery’s lifespan. Always use a charger with automatic shut-off features to prevent this.
Letting the Battery Discharge Completely
A completely flat battery is harder to recharge and may suffer permanent damage. Avoid leaving your battery unattended for months without monitoring its charge level.
Using Incompatible Chargers
Ensure the charger you use is suitable for your battery type. Incorrect chargers can cause damage and even pose safety risks. For example, some chargers are not compatible with AGM or gel batteries, which are becoming more common in modern cars.
Reinstalling the Battery
When it’s time to put your car back on the road, reconnect the battery terminals securely. Attach the positive terminal first, followed by the negative. Make sure all connections are tight and free from corrosion. If you’ve used a trickle charger, test the battery voltage one last time to ensure it’s ready for use.
After reinstalling the battery, check that all electronic systems are functioning correctly. Reset any settings that may have been lost during storage.
Additional Considerations
Professional Inspection
If your car has been in storage for an extended period, it might be worth having a professional inspect the battery. They can assess its health and recommend replacement if necessary.
Environmentally Friendly Disposal
Should your battery need replacing, ensure it’s disposed of responsibly. Most recycling centres and garages accept old batteries for recycling, helping reduce environmental impact.
Maintaining your car’s battery while in storage doesn’t have to be complicated. With regular checks, proper storage techniques, and the use of tools like trickle chargers, you can extend its life and avoid unnecessary costs.
🚗 You might like this guide: How Car Storage Can Save Money on Maintenance.
