Why It's A Bad Idea To Store A Spare Car Battery In Your Trunk

If you're dealing with a car battery that's on its last legs, or if you just like to be prepared for emergencies, you might think that keeping a spare battery in your trunk is a good idea. But before you do, it's worth considering how this decision fits with long-term car care, safety, and practicality.

A lead-acid battery, even if it's a major car battery brand, can actually lose its charge in the trunk if there's a lack of airflow and the battery gets too hot or even too cold. If this happens, you've defeated the purpose of having a spare battery in the first place. No airflow also means no protection against the hydrogen gasses a car battery emits and this can cause a dangerous environment. At the very least, those gasses can impact the electronics located in your trunk, costing you money in the long run.

If you need peace of mind with your current car battery but don't think you need a replacement just yet, you can invest in a cheap car battery jump starter with good reviews. You won't need booster cables and in most cases, you can get your car jumped and back on the road in no time.

Storing a spare lead-acid car battery can be a good idea, as a brand-new battery can actually stay charged for up to two years with proper maintenance. But since you'll lose some power the longer it's stored, be sure the battery is fully charged first. Then keep the battery in a cool, dry place with good ventilation and if you're worried about moisture in the space, you can add petroleum jelly to the terminals to prevent corrosion.

The garage is an ideal place for the spare battery, as long as it's on a shelf out of harm's way and kept at a temperature of around 50 to 60 degrees Fahrenheit. Keep in mind that the longer you store it, the more you'll need to check it, to ensure it has a full charge. But even charging the battery with a 12V car charger won't make it last longer than the typical lifespan of three to five years.

If you need to store a used battery instead of a new one, you can do so, as long as you keep it charged as well. But it won't keep a charge that long, and you're limited to about a year of storage to ensure the battery is effective when you need it.