Q: Parasitic battery drain

asked by on November 03, 2016

While my car is off there is a drain on the battery, I measured the drain and found it averages out at about .50 amps. I'm trying to figure out if that is high, and what the normal draw on a battery is. I have replaced the battery, alternator and serpentine belt within the last three months trying to fix this with no avail. Every time I take it to a shop to have it looked into they say it's the battery even though it's brand new. Thank you for your time. -Jhad

My car has 71000 miles.
My car has an automatic transmission.

Hi there. The Toyota standard for battery draw is 50 milliamps or 0.05amps, so you definitely have a parasitic draw. Check the obvious culprits first: the glove box light, the interior lights, a smart key still in the car, a trunk light that was left on, and so on. Then, you can start removing fuses one at a time to see if the draw disappears. After you’ve found the right fuse, start unplugging components powered by that fuse until the draw goes away. Once the source of the draw is discovered, it can be repaired or replaced as needed. I strongly suggest having a qualified technician, such as one from YourMechanic, perform an inspection of your parasitic draw so you can avoid replacing unnecessary parts.

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