Skip the auto shop - Our mechanics make house calls

Q: Battery draining after new alternator installed

asked by on

The alternator is new, but the left battery has 60% life. I hope it is normal because the volts show 14 volts.

My car has 198000 miles.
My car has an automatic transmission.

Hi, thanks for writing in. It’s very common for mechanics to forget to replace alternator sensors or charging wires to the battery when they replace the alternator. However, one other item that directs the flow of electricity to the battery is the battery temperature sensor. Usually it’s installed underneath the battery and triggers flow to the battery as the battery temperature decreases. They are supposed to last a long time, but dirt, debris and other "stuff" can clog or wear this sensor out prematurely. If you would like help with this replacement, consider having an expert automotive technician from YourMechanic come to your home or office to perform the replacement for you.

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!
  1. Home
  2. Questions
  3. Battery draining after new alternator installed

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: How do I use the turn signals?

Turn signals are very important safety features. The turn signal lights allow surrounding drivers to know that you are going to make a turn, which is an important safety precaution. Failing to use your turn signals is also illegal. Using...

Q: While I'm driving my brake light will start flashing and my "at oil temp" light will come on a

Yes, the warning lights are suggestive of a problem but identification of the specific cause requires diagnosis. There are many possible underlying causes including even something as mundane as a low transmission fluid level, dragging brakes, under inflated tires, and...

Q: transmission overtemp

Hi there. If you are going to have the transmission flushed and filters changed, I would recommend having them also check the transmission cooler to see if there is some failure there. Usually when you have this type of transmission...

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...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...
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.