Vehicle will not keep voltage

ROMAN_RECKLESS

MEMBER
2007 JEEP COMPASS
2.4L
2WD
MANUAL
115,000 MILES

I just finished replacing my alternator and battery on my vehicle because it was not holding a charge or even starting. Now it is finally starting and I can get it to a healthy 12.6 volts when I jump it but once I start it, the voltage drops to around 5-7 volts within the minute. I also did a deep clean of the battery terminals to rid it of any corrosion. Has anyone else had this problem or know what it could be?

2 Replies

ASEMASTER6371

MECHANIC
52,797 POSTS

Good morning,

The battery needs to be slowly charged to 12.6 volts. The alternator needs that much voltage to work. Once that is done, then start it and measure the voltage at the battery while running.

https://www.2carpros.com/articles/how-to-charge-your-car-battery

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Roy

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Tuesday, July 23rd, 2019 AT 10:49 AM

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

Where did you buy the battery from? Was this a new battery? It sounds like you have a couple of dead cells in it. Also, here is a link for you to go to confirm that your alternator is working properly:

https://www.2carpros.com/articles/how-to-check-a-car-alternator

Please go through this guide and get back to us with what you are able to find out.

Thanks,
Alex
2CarPros

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Tuesday, July 23rd, 2019 AT 10:57 AM