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.

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!
  • Home
  • Questions
  • Changed out the alternator and battery. Car will not start without a jump.

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: A/C system failure

Hello. The clutch engaged with the heat on may cause your problem. Doing this may cause your HVAC control module to become out of sequence. It also could be low on refrigerant but I suggest to recalibrate the HVAC control module first. I'd...

Q: Possible causes of P0303 code 2009 Dodge Journey

Hi there - misfires can be caused by worn spark plugs, failing coils, or injectors dumping too much (or no) fuel into a cylinder, causing a misfire. Yes, this could be a failing coil. Swap the cylinder #3 coil with...

Q: How to use Napa 85-200 12V. 1 Amp. This battery charger is slow.

Hi there. When you get a Napa 85-200 12 volt 1 amp battery charger, first you will need to check the battery for the water level. This is done by removing the caps to the battery. (Warning: Do not remove...

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...
Rules of the Road For Iowa Drivers
Driving on the roads requires knowledge of the rules, many of which are based on common sense and courtesy. However, even though you know the rules in...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...