Q: Battery or Charging system problem

asked by on

My car died in my driveway yesterday, I went out and checked my fuses and the connections on my battery. The voltage read 8.4. Today I jumpstarted my car and it started right up, the voltage went up to 15.1. Within 15 minutes the car was dead again with 8.2 volts last time I checked. A few minutes ago I went out and checked what kind of battery I have. When I unlocked my car what little power I still have came on. When I opened my hood I could hear the battery making what sounded like a boiling sound. Could my problem be just a bad battery or something with my charging system like the alternator overcharging?

My car has 40701 miles.
My car has an automatic transmission.

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?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Battery or Charging system problem

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: Runs fine with the map sensor vacuum line plugged off

Hello, the map sensor is an input of engine load. When the map sensor is disconnected it will set a fault code which is emission base and check engine will come on,this cause the system to go into a default...

Q: AC off - 2011 Chevrolet Cruze

Hello. Your Chevy Cruze uses a "heated" engine thermostat (under computer control) which has caused some problems. There is a Technical Service Bulletin (301268) to address the "engine is cold" issue - software reprogramming). There are also multiple temperature sensors,...

Q: right side back up light inop .

Hello, thank you for writing in. The reverse lights have a switch located on the transmission itself. They also have a fuse before that. Chances are both of these are good and your issue lies with the wiring itself, or...

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...
How Much Does a Mechanic Make in Vermont?
Automotive technician jobs in Vermont have an average mechanic salary of $37k, with some mechanics earning a salary of $53k.
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.