Beware Car Battery “Vampires”

Imagine sitting in the driver’s seat of your brand-new dream car and discovering it won’t start. Your battery is dead — not because you left the lights on, but because you don’t drive the car enough.

Turns out, the less you drive certain hi-tech late-model cars, the more you can unknowingly be draining the battery.

Michael Woi is a self-proclaimed BMW enthusiast who purchased his sixth BMW, a 128-i, just three years ago. He barely drives it, "just to work and some weekend trips."

And getting to work is a snap: Woi travels just five miles from his house in Torrance to his job.

But heading home from work last March, Woi got an unpleasant surprise when he tried to start his car.

"I went back to start the car and the lights, the interior instrument lights started blinking like crazy, and I was like 'uh oh!'" Woi recalled.

The car was towed to South Bay BMW, where he learned his battery was dead, and that the cost to fix the problem would be more than $600.

Woi couldn’t understand how his battery could have died, with his odometer registering barely 14,000 miles.

He said the mechanic told him "Oh, you don’t put enough miles on the car."

BMW master technician Ruben Villagrasa of Avus Auto-Sport in Glendale confirmed to the I-Team that a battery can, in fact, be drained by low-mileage driving.

"A lot of people don’t drive their cars a sufficient enough time for the alternator to charge the battery," said Villagrasa.

Villagrasa says the low-mileage battery drainage isn’t exclusive to BMW; many late model hi-tech cars, both foreign and domestic, have the same problem.

And driving too little isn’t the only "vampire" that can prey on your battery.

Certain hi-tech features in some newer makes and models can also create greater demands for battery power, even after you’ve switched off your ignition.

"Some of the [electrical] loads keep going, for instance, on BMWs, some of them up to 16 minutes [after the car has been turned off]," said Villagrasa.

To extend the life of your battery, Villagrasa suggests taking trips of 25 miles or more at least once a week, which will give your battery an opportunity to charge, especially if your normal commutes are short.

The I-Team contacted BMW of North America to inquire about Woi’s $600 dollar battery bill. One week later, the car company reached out to Woi and refunded the cost of his new battery "as a gesture of goodwill."

While thrilled to get his money back, Woi is still confused how a hi-tech car can’t stop draining the battery when it’s not being driven.

"You’d think the car would be better in handling those types of things," said Woi.

In an email to the I-Team, BMW of North America spokesman Hector Arellano-Belloc explained the battery issue from a technological standpoint:

"The battery may become discharged with certain driving profiles, such as when the vehicle is driven over short distances/short periods of time on a frequent basis, or when the telephone or entertainment system is used often while the vehicle engine is switched off. Under these parameters, the vehicle’s charging system may not be able to fully compensate for the discharging of the battery. Our BMW Diagnosis system is able to determine the average journey overview as well as the number of days that the vehicle was parked and not driven which may also contribute to the battery being discharged."

Again, the battery drain issue isn’t specific to BMW, it happens with different makes and models for different reasons.

Villagrasa says automakers are looking for possible solutions.

One option: equipping cars with two batteries, one for starting the engine, and the second for powering other electrical loads.