Winter 2023 has been a mild one on record, however a few cold snaps over the last few months saw temperatures falling below 0°C in most parts of the UK for consecutive days, and as low as -10°C in Inverness, Scotland. Those of you who enjoy the exploring the wintery scenery in your motorhome and campervans, or those with off-grid garden offices or sheds, may have noticed a decreased performance in your batteries.

Why is this? Is there such a thing as winter batteries? And what can you do to take care of your lithium batteries in cold weather?

What happens to batteries in cold weather?

A battery stores and releases energy but cold weather can prevent the battery from performing these functions. The cold temperature increases the internal resistance of a battery which means it cannot release as much energy or retain a charge as well, therefore having a lower battery capacity. This means you will need to charge those batteries more frequently. A standard lead-acid battery will be able to provide 70-80% of its usable capacity in sub-zero temperatures.

Do batteries go bad in the cold?

As the lifespan of a battery is determined by its charging cycles, using your battery in cold weather will mean charging more frequently which can degrade its health and longevity. This therefore decreases the lifespan of your battery.

Lithium battery in cold weather

Lithium-ion batteries perform much better in cold winter conditions but you’re still going to want to take care of them. In comparison to a standard lead-acid battery, lithium batteries can operate with very little loss providing 95-98% of their capacity. However, below freezing temperatures cause the lithium ions to the coat the surface of the anode in a process called lithium plating. This will reduce the battery capacity and increase resistance. If enough plating builds up, it can puncture the separator, as seen in the image below, and cause a short in the cell which can be dangerous.

Most lithium batteries have a built-in Battery Management System (BMS) which is a set of electronics that balance and protects the battery from getting damaged. One protection method is by disabling charging and discharging below certain temperatures. Lithium batteries with a BMS will prevent you from charging the battery below 0°C and discharging below -5°C. If the temperature drops below these figures, then the battery will need to warm back up above these temperatures before allowing charging and discharging.

To learn more about the differences between lead-acid, AGM and lithium batteries click here.

How to keep lithium batteries warm in cold weather?

Storing lithium-ion batteries correctly can help keep the battery away from the colder weather. Moving the battery into a warmer environment would be the best solution, however this isn’t always possible so insulating the battery in a thermal blanket would be more convenient. You could also make sure that the batteries are not near any windows, doors or anywhere there is ventilation from the outside as the colder air can draft across the batteries causing the internal temperature to drop.

If your batteries are resting on the floor try placing them up higher or placing insultation underneath them, as floor temperatures can be colder than room temperature.

If you own a motorhome or caravan, then it can be even easier to keep your lithium leisure batteries warm during the cold weather. Whilst driving to your destination during the cold weather make sure to have your cabin heating on, and if possible direct some of the warm air down to the feet as most leisure batteries are kept under the driver or passenger’s seat.

Is there such a thing as a heated lithium battery?

Some lithium batteries come with thermal management systems or thermal core heating technology which have pre-built heating elements within the battery that heats the cells to allow charging when the outside temperature drops below the minimum temperatures of usual lithium batteries. Whilst this is a benefit for users who cannot protect or relocate their leisure battery, these heated lithium batteries are more expensive due to the additional parts.

Summary

So, whilst lithium batteries outperform lead-acid or AGM batteries in colder conditions they have their limitations, and their intelligent battery management system will prevent them from being charged or discharged below certain temperatures. The location where you house your lithium leisure battery can also affect its internal temperature and you should consider moving or protecting the battery when the temperature starts to drop over the winter months. Heated lithium batteries should only be considered when the battery is being used in an application where it is impossible to protect the battery from close-to-freezing ambient temperatures.