Q: Charging system battery keeps getting drained

asked by on

Battery an both battery cables are new,alternator was replaced recently, connections have been cleaned. Had it tested at shop alternator, battery load ck. Every thing passed. But I can drive the car around for 1/2 hour or so shut it off and the battery won't start the car. always carry jumper cables every were I go.:/ Any ideas I was thinking ignition switch maybe shortin out? Starter ,? Besides charging system check well running, also had the alternator bench tested off the car an passed also, .I am stumped. Any help appreciated.

My car has 150000 miles.
My car has a manual transmission.

Hello, You may have a failing voltage regulator that could be allowing the alternator to supply too much or too little amperage to the battery resulting in the battery never maintaining a consistent charge as it is designed to. 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. You may also smell a bit of smoke due to things potentially getting too hot. 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 1,000 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!
  1. Home
  2. Questions
  3. Charging system battery keeps getting drained

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: Gas leaking from underneath hose

If you have a fuel leak I would not recommend driving the vehicle until it is repaired as fuel leaks are a safety hazard. I would also recommend having your engine inspected by a professional to determine where the leak source...

Q: There is a knock under the body.

Hi there. Try putting the transmission in drive and reverse back and forth. If the clunk is heard in both directions and the clunk changes in sound pitch, then there is a universal joint that has the bearings burned up...

Q: Hard to turn.

The power steering most likely has an issue either in the pump assembly or in the steering rack itself. The fluid level in the system needs to be full with the proper fluid. This is done with the engine at...

Related articles

How Do Power Car Windows Increase Passenger Safety?
Power windows are responsible for approximately 2,000 emergency room visits every year. When a power window closes, it exerts enough force to bruise or break bones, crush fingers, or restrict an airway. Though...
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...
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.