Skip the auto shop - Our mechanics make house calls

Q: Battery is not charging properly

asked by on

Battery keeps going dead but we took it to get tested and they said it was good

My car has 130000 miles.
My car has an automatic transmission.

A: This may be a sign of a weak battery, a fai...

This may be a sign of a weak battery, a failing voltage regulator or failing alternator. As you may know, the alternator is responsible for charging the battery while the engine runs by generating amperage and recharging the battery while the engine turns the alternator. The voltage regulator is a unit that regulates the charging of the battery by the alternator.

This may suggest a failing voltage regulator. The voltage regulator is a unit that regulates the charging of the battery by the alternator. When the voltage regulator is not working properly, this may result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery. A common sign of this is usually the acid inside the battery boiling causing the battery to swell. In other cases it may result in the alternator not supplying enough power to the battery, resulting in undercharging the battery or not charging it at all. I would recommend having an expert from YourMechanic come to your location to diagnose your vehicle’s charging system.

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: Charging system failure.

This may indicate you have a bad alternator or voltage regulator causing the lights to dim and the voltage meter to fluctuate. As you may know, the alternator is responsible for charging the battery while the engine runs by generating...

Q: Car won't start

Hello. When a car won't start, start with the basics: If the vehicle has power, then power to the starter motor must be checked, and voltage drops performed. The larger wire at the starter motor should have 12v at all...

Q: my 300 fan

Hi there. It is possible that you may have an obstruction or blockage inside the vents of your AC and heating system. It is also possible that the blower motor or control vents are damaged or wearing out. It's probably...

Related articles

How Long Does a Distributor O Ring Last?
The distributor is part of the ignition system in your vehicle and its purpose is to route high voltage from the ignition coil to the spark plug. The spark plug then...
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...
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.