Car Tech

Ghost Battery Drain, and How to (Hopefully) Prevent It

A reader email arrived the other day. One Mr. Abioye Kayode was, in no uncertain terms, at his wits end with the battery in his few-year old crossover.

Kayode said that the vehicle was only a few years old, and that a recent battery check had revealed no problems with the battery itself, or the charging system to which it was attached. The rest of Mr. Kayode’s story is familiar: he’d often park the vehicle and return after some length of time to find that the battery was dead, or close to it.

This often led to lengthy cranking times before the engine turned over, or required Kayode to use a portable booster pack, which he started leaving in the vehicle, to start the engine.

Something was depleting the battery in Kayode’s car, even when the vehicle parked and turned off.

This is strange, but actually, somewhat common.

The lifespan and durability of a vehicle’s battery is subject to a wide range of variables, including maintenance, climate, driving habits, and more.

Some problems with battery life may be the result of a failure to maintain said battery properly, and not a bad battery itself. Further, some owners suspect that some automakers install weak or cheap batteries at the factory, as a cost-saving measure.

Many more factors may also be at play. Below, we’ve compiled some information and tips to bear in mind if you happen to be experiencing unexplained battery drain.

Clean the Battery Terminals

Because of things related to science and chemistry, battery terminals can accumulate a buildup of crusty, salty-looking deposits over time. These deposits form on the battery terminals themselves, as well as on the electrical cables that attach to those terminals.

These deposits should be cleaned as often as they present themselves, perhaps every few months, whether by the vehicle’s owner, or a technician. If not dealt with, these battery terminal deposits can actually discharge the battery, as they’re slightly conductive, and can cause energy to “leak” over time. Translation? If your otherwise-healthy battery keeps dying for no reason, checking and cleaning the battery terminals might be the fix.

Store Your Smart Key Far Away

Here’s another surprising cause of battery drain, and one that your correspondent has experienced on several occasions himself. If you drive a car or truck with a “Smart Key” or similar system (where a special keyfob stays in your pocket or purse, allowing keyless entry and push-button ignition), be certain to keep those keyfobs as far away from your vehicle as possible after you park it.

Your vehicle may only allow you to unlock the doors via touch if the fob and vehicle are within very close proximity, though the range at which the fob and vehicle can wirelessly detect one another can be much greater. Put another way, your smart key may only function at close range, though your vehicle can still wirelessly detect it at a greater distance.

When the vehicle detects the key, a wireless communication channel is opened, which draws power from the battery. In some cases, that wireless link may be activated for an extended length of time – for instance, if keyfobs are left hanging on a rack next to the car in the garage, or kept on an entryway table just a few feet from the parked car outside.

Sometimes, in situations like these, the vehicle and keyfob might spend hours or days wirelessly seeking each other out, which can rapidly deplete the battery in your vehicle, and the smart key. Solution? Try storing the keyfobs as far away from the vehicle as feasible.

Disconnect Your MP3 Player

Some drivers have their music library archived within an MP3 player, which they leave connected via USB to their vehicle stereo system at all times.

Partly due to the intricacies of USB connectivity, and the various compatibilities between devices and vehicle infotainment systems and the software that controls them, an MP3 player may fail to properly power down when the vehicle’s ignition is switched off.

Further, some devices don’t get along with others, and may get stuck in an “indexing loop”, in which the MP3 player, stereo head-unit, or both get locked into the energy-sucking process of trying to scan, identify, and organize all music files on your MP3 player – even when the vehicle is switched off.

Sometimes, leaving an MP3 player connected while your ride is turned off can drain the battery for hours or days on end. This isn’t an extremely common problem, but has been well-documented in some vehicles. If ghost battery drain is ruining your life, try unplugging auxiliary media players when you’re not using them.

Check for Software Updates

Computers run almost everything in our lives, including many parts of our cars and trucks. Computer programming is even responsible for turning certain functions off after a given amount of time when we park our vehicles and walk away.

As computer programming sometimes does, the software responsible for controlling the boot-up and shut-down of various vehicle systems can get corrupted or damaged. If that’s the case, wonky software may allow certain fans, pumps, alarm system provisions, and infotainment system functions to stay switched on for hours, or even indefinitely, after the ignition is turned off.

In some cases, corrupted software can cause certain systems to turn off at the proper time, but to turn back on several hours later. I’ve seen numerous cases in which corrupt software failed to switch off the power-sucking rear-seat entertainment system in some minivans, allowing that Dora the Explorer DVD to keep playing for hours.

Solution? If ghost battery drain is baffling you, contact your dealer service department to see if a software update may be the solution. A software update, often installed in minutes by your dealer, can improve or repair corrupted software, ensuring that all systems shut down at the proper time, and stay turned off until you return to your vehicle.

If you’re wondering, Abioye Kayode’s problems were remedied by a software update like this. Turns out, when he’d lock his car, Kayode’s factory anti-theft system was, on occasion, getting stuck indefinitely in a high-draw “boot-up” mode, which is only supposed to last a few seconds.