Q: Battery voltage is low.

asked by on

put new alternator in, now battery gauge went from like 16 to 9, also serpetine belt is NOT put on tightly charging system?

My car has 218000 miles.
My car has an automatic transmission.

Hello. If the battery voltage reads low on the gauge then that is a sign that the charging system is not functioning correctly. If the alternator is brand new then there is little chance that it is the source of the issue. More likely then that, is the loose belt. The alternator functions using the serpentine belt to turn the pulley and generate power. If the belt is loose then the pulley may not be turning properly, which could potentially be causing your low voltage reading. It may be possible that the belt is worn, that the tensioner is bad, or that the belt was routed incorrectly when it was installed. I would take a careful look at the drive belt system, and verify that it is routed correctly. If everything looks okay, I would recommend having a professional technician, such as one from YourMechanic, come to your location to (determine if it is the tensioner that needs to be replaced](https://www.yourmechanic.com/services/drive-belt-tensioner-replacement) or if there is another issue present.

Was this answer helpful?
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
  1. Home
  2. Questions
  3. Battery voltage is low.

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: Why is my truck is leaking transmission fluid?

Hi there. Check the location of the transmission fluid leak on the case to determine what needs replaced. There are 5 locations for the transmission to leak that are common. Locations of a leak The input shaft seal The...

Q: Fast Vibration that increases with speed, and can be felt best through the steering wheel

Usually, vibration in the steering wheel is due to dynamic imbalance of the wheel/tire assembly and/or a rim is bent. Wireless chassis ears can be helpful in the diagnostic as they can pinpoint if one side, versus the other, is...

Q: We changed the alternator and battery and it ran for 24 hours and now it's doing the same thing and will run for 2 mins and die

Hello, and thank you for writing in. The vehicle may be having issues with the wiring, or it may be an issue with the replacement starter. Start by checking the condition of the starter cables, the battery's ground connection, and...

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...
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...
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...