Why Should You Disconnect Your Car Battery?

Why disconnect a battery in a stored vehicle?
SponsorOPTIMA Batteries
LocationBonneville Salt Flats
DateMay 17, 2021
Are you going out of town for a long period of time or storing a vehicle for the winter? If you are, you'll need to make plans to ensure your battery is ready to start your vehicle when you need it. If you don't take some pro-active steps, you may return to a vehicle with a dead battery, especially if it's in a newer car or truck. The reason is that nearly every vehicle on the road today has what are commonly-referred to as "parasitic draws" or electrical demands that consume energy, even when your vehicle is not running. If given enough time, these can and will completely discharge your car battery.

In an ideal situation, you would keep your battery fully-charged and ready to go with a quality battery maintenance device, like the OPTIMA Digital 400 battery charger & maintainer. However, if you're parking your vehicle in an airport parking lot or another remote location without access to electricity, you may not be able to keep your battery voltage properly-maintained with a battery charger.

In these more remote areas, your best course of action for vehicle storage is to make sure your battery is fully-charged (at least 12.6 volts) when you park it and completely disconnected from your vehicle. You'll probably lose your radio and seat position presets, but that's a small price to pay, compared to the cost of replacing a battery. Equally important in this scenario is fully-charging the battery in your stored vehicle as soon as you can after bringing it back out of storage. 

All batteries will self-discharge over time and while your vehicle's charging system can deliver current to a discharged battery, it is designed to maintain batteries near a full state of charge, not recover deeply-discharged batteries. Asking your alternator or charging system to recover any deeply-discharged battery can shorten the lifespan of your charging system and lead to a cycle of dead batteries and jump-starts, until either the battery fails (expensive) or the alternator fails (even more expensive).

Just because your battery starts your car doesn't mean the battery is fully-charged either. Car batteries can have just enough energy left to start a car and still be deeply-discharged, so unless you measure battery voltage directly at the terminals and see that it measures at least 12.6 volts, it's a good idea to fully-recharge the battery in your stored vehicle as soon as possible (driving around won't get the job done and will often make the situation worse).