Skip the auto shop - Our mechanics make house calls

Q: Parasitic load on battery.

asked by on

The battery drains while my car is running.

A: Cars basically use the battery at start up....

Cars basically use the battery at start up. Once the vehicle is running the alternator takes over and provides the car with the electricity it needs to run. If the alternator stops producing the electricity the car needs, the car simply starts taking it from the battery. The car will continue to run until it drains the battery then it will turn off. A technician will be able to test your charging system and determine if the alternator is the culprit.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: I alway have o jmp my truck after four days, I bought a new battery and after a few month it starte doing the ame hin again, what

If the battery is new and charging system output has been measured and is within Factory Service Manual specifications, the only reason a battery will discharge is if the car sits for a long period of time (batteries self-discharge, but...

Q: replaced oil pan gasket, engine and trans mount Jaguar Stype

Hello, thank you for writing in. It is always disheartening to hear these reports. From here you are going to want to either take it back to the original mechanic with the complaint, and discuss any further charges to take...

Q: Power steering pump leaking.

Hello, this comes up quite often on this vehicle as it ages. The most common location if the leak is the front seal of the pump. If you cannot pinpoint the leak I would add dye to the power steering...

Related articles

P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2103 OBD-II Trouble Code: Throttle Actuator Control Motor Circuit High
P2103 means there is a fault with the throttle actuator control motor circuit, likely due to a defective electrical component or part.