Why Does My Battery Die When Not Driven?

We have had customers come in complaining of a dead battery. Upon questioning we find that sometimes the customer does admit that it has been 2 to even 4 weeks or more since they last drove. Even worse are the cars that only drive once a month or less. On the downside this is normal behavior for modern cars with all the electronics and convenience features they have. On the upside there are things that you can do to help with this issue.

Why a Battery Dies While the Car Is Parked

Even when your car is off, systems like the security alarm, infotainment memory, and emission monitors stay active. These things and how they operate varies by car make model and options package. Most cars have some amount of energy use off which is also called parasitic draws. Most vehicles start out when they are first turned off with a relatively high draw. But as the systems power down and finish doing all the tests and other things they do it tapers down to a low sustainable level. New batteries can handle this for a while up to a couple weeks. However, as a battery ages this ability drops off. That means it may only last a few days.

Add-ons like dash cams, aftermarket stereos, or phone chargers can increase battery drain. Especially if they stay powered when the car is off. Some modules and accessories use cell networks or other networks. This allows for remote security or convenience features. All of these increase the draw and can shorten the time you have. In some cases, a malfunctioning module or light that won’t turn off can drain a battery overnight.

This drawing the battery down to a very low level of charge also increases the wear on the battery. This shortens the life of the battery as most auto batteries are designed only to be discharged a small amount. Then charged immediately after starting. They are not like storage batteries that are used in marine and RVs. These are designed to discharge to a relatively low level before recharging.

Tips to Prevent a Dead Battery

If you drive infrequently, here are some ways to keep your battery healthy:

• Drive 15–20 minutes at least once a week to recharge the battery.
• Use a battery maintainer (also called a trickle charger) if the car sits for longer periods.
• Unplug electronics like chargers or dash cams when parked.
• Have your battery tested regularly, especially if it’s over 3 years old.
• If your battery dies often, a professional parasitic draw test may be needed.

Most car manuals cover what to do if the car is stored for longer than 2 weeks. This will include many of the above items. There is another more involved step you can do if say you are going on an extended trip. If you can do so you can also disconnect the battery at the terminals. This extends the storage life. But be aware this will also reset all your settings and learned drivability adapts. This means the car will not function exactly as it did before. You may also have to reprogram all your favorite seat and infotainment memory settings.

Need Help? Accomplished Auto Has You Covered

At Accomplished Auto, we include free battery testing with our free courtesy check. If your battery is weak, we can recommend a replacement. We will also match the replacement to OEM fit and capacity. If you’re dealing with deeper issues. We can also perform advanced diagnostics of the entire electrical system. There may be fees depending on the complexity of the system and problems. Pinpointing a parasitic draw for example can be a time consuming process at times.

All of our work is backed by a 3-year/36,000-mile nationwide warranty through our NAPA Autocare partnership.

👉 If you’re wondering why your battery keeps dying or want peace of mind before winter hits, reach out today.