Skip the auto shop - Our mechanics make house calls
  1. Home
  2. Articles
  3. What Is Key-Off Battery Drain?

What Is Key-Off Battery Drain?

key off battery drain

Many things in your car continue to work even after your vehicle is turned off – radio presets, security alarms, emissions computers and clocks are just a few. They continue to draw power from your car battery, and the cumulative load that these devices produce is called key-off car battery drain, or parasitic drain. Some drain is perfectly normal, but if the load goes above 150 milliamps, that’s about twice what it should be, and you could end up with a dead battery. Loads below 75 milliamps are normal.

What causes excessive parasitic drain?

If you find your battery dead in the morning, chances are it’s because something has been left on. Common offenders include under hood lights, glove compartment lights, or trunk lights that fail to turn off. Other problems, like shorted alternator diodes, can also cause excessive key off car battery drain. And of course if you forget to turn off your headlights, your battery can discharge in a matter of a few hours.

Whether the problem is key off drain, or a faulty battery, the last thing you want is to discover that your car won’t start, especially on a cold winter morning. If it does happen, though, our mobile mechanics can help. We come to you, so you don’t have to worry about having your vehicle towed. We can diagnose your car battery problem, and determine if the problem is key-off battery drain or something else within your vehicle’s charging system.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How to Buy Fuel Treatments
Adding a fuel additive to your gas tank when you fill up is one way to clean vital engine parts of deposits, improve the performance of your engine,...
Insurance Requirements for Car Registration in Kentucky
The Kentucky Transportation Cabinet requires that all drivers in Kentucky carry liability automotive insurance, or “financial responsibility” in order to operate a vehicle legally and maintain vehicle...
How to Transfer a Car Title in Idaho
In order to prove ownership of a car, you must have the title. However, when a car is sold, given away or inherited, the title needs...


Related questions

Q: Battery keeps blowing fuse.

It sounds like there is an electrical short in your starting system. The power needed to start your vehicle is not traveling its intended path. This power may also be traveling to a circuit not meant to handle that much...

Q: Battery or cables or what? 1998 Dodge Dakota

Hello there, many common faults will cause your 1998 Dodge Dakota to crank but not start. Given than your car starts fine when jump started, the fuel system is unlikely to be the cause. Leaving the starting system and the...

Q: Sunroof was open during rain and car won't start

If the ignition switch sustained damage from the water, it could cause the vehicle to start. Unfortunately, with this amount of water in the vehicle, it can short out wiring and cause extensive corrosion in the various systems. The vehicle...