Q: Q: Alternator or Battery?

asked by on

Driving home, my windshield wipers seemed sluggish, everything else seemed normal. As I turned into my driveway, my radio and nav system shut off, I got a battery light on my dash. I rev'ed the engine and the battery light went off, the radio and nav turned back on. Moments after I let off the gas my instrument panel flickered and again with the battery light. I was able to again rev my engine and get things to normal again.. only for a moment once I let off the gas same type scenario. I pulled forward into my parking sspot, no power steering at this point. I shut the car off can could not start it again. Does this describe alternator failed, dead battery or something else?

My car has 85000 miles.
My car has an automatic transmission.

Greetings! This definitely sounds like you may have an alternator beginning to fail. As you know, the alternator is responsible for charging the battery. The rate at which this happens is correlated to the engine RPM’s as the alternator turns with the rest of the various engine pulleys. This is why the battery light tends to go away and the accessories all work properly as you rev the engine up. As you let off the gas pedal and engine RPM’s decrease again, the alternator charging rate also slows down. This may also potentially be connected to the voltage regulator failing as well. This is a unit that regulates the rate at which the alternator charges the battery. When this is not working properly, this may result in the alternator either over charging or under charging the battery and not maintaining the proper system voltage. I would recommend having a professional from YourMechanic come to your location to diagnose and inspect your charging system.

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. Q: Alternator or Battery?

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: Q: Battery drain

It sounds like your alternator may not be charging quite as effectively as it should be. The drop in amperage at idle is not necessarily unheard of but could be the beginning of it starting to fail. The voltage when...

Q: my IS250 lexus cant start, just cranks

Hello. Thanks for writing in. vehicles that only crank can be frustrating. Although the battery may seem fine, it is always a good idea if it is over 2 years old, to have it tested. This can be done quickly...

Q: I have a 2007 lexus is250. I got an oil change 3 weeks ago. A few days ago it showed a low engine oil warning on the dash so I dec

Check the engine oil level using the dipstick. If the level on the dipstick is below the add level, or if no oil appears on the dipstick, add enough oil to bring the level to the full mark on the...

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...
How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
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.