Skip the auto shop - Our mechanics make house calls

Q: Changed out the alternator and battery. Car will not start without a jump.

asked by on

Changed alternator, and battery and will not start without a Jump What will cause the battery not to charged back up. the car was driven 3,2 miles and was cut off for 20 minutes then then would not start back up

My car has 146000 miles.
My car has an automatic transmission.

A: This may be a sign of a failing voltage reg...

This may be a sign of a failing voltage regulator. This is a unit that regulates the charging of the battery by the alternator. Often times this will result in the alternator allowing too much power to be delivered to the battery resulting in damaging wires and prematurely sometimes destroying the battery.

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.

In either case, I would recommend having an expert from YourMechanic come to your location to diagnose and properly diagnose and test 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: It was revving up switching gears like it was stuck in neutral then it corrected itself, I made it home now it will not go into ge

Hi there. It sounds like you have a serious transmission failure going on. What you've described is the first sign of a transmission problem on this vehicle. To diagnose this, I'd typically start by removing the transmission pan and inspecting...

Q: I a hit a curve and now I got a rubbing vibration on my front tire.

Hi there: If you have damaged your wheel and it wasn't replaced after hitting the curb, then the bent wheel or the tire / wheel combination is most likely the source of the vibration. When a curb, pothole or other...

Q: Car wont start

This suggests you may have an alternator that has failed and potentially fried some of the wiring causing the burning smell and the smoke you describe followed by the loss of all power. Generally, when an alternator fails it will...

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...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
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.