Q: Battery dying and both alternator and battery passed for good when inspected

asked by on March 26, 2017

My car has been dying overnight over the past 2 weeks. 3-4 days after being jumped off it dies. I went and got my battery and alternator checked and they both tested in good condition, mechanic asked if I had a car charger hooked up and then instructed me to take it out so I did but the day after the visit it died again. I'm really just trying to understand what is goin on with my car.

My car has 193000 miles.
My car has an automatic transmission.

If the battery passes a load test and charging system output has been measured and is within specifications, the only reason a battery will discharge is if the car sits for a long period of time (batteries will self-discharge even if not used) or if there are parasitic (excess) loads on any of the car’s electrical circuits. If there is excess current flow that is slowly draining the battery, a Mechanic would use an ammeter to test all of the various circuits until the faulty circuit is found. Then that circuit is traced to find the fault and repair it. If you want these steps performed by a certified Mechanic, dispatched by YourMechanic right to your location, please request an electrical diagnostic and the responding certified mechanic will get this resolved for you. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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


Experienced Mechanic?

Earn up to $70/hr

What others are asking

Paint is peeling off all over, will it rust?
First, I would recommend going to your local Ford dealership for a rust inspection. Other Escape owners have experienced similar issues, and if yours is similar enough, it may be covered by Ford. Ford covering the damages is the best...
How do I turn on automatic headlights in a 2012 Dodge Ram?
If your vehicle is equipped with automatic headlights, they will be on the headlight switch, which is to the left of the steering wheel. If you turn the switch to the “Auto” setting, then the lights will automatically come on...
Car outlets not working.
If none of your car's power outlets are working, the first thing I would check would be the fuses. A blown fuse is the most common reason as to why interior electronics fail, so a simple replacement of an inexpensive...
Window not working
Thank you for your inquiry. If the window will not go up or down easily, or seems to shift during operation, the window regulator may have a mechanical failure. This includes a broken mechanical connection to the glass or even...
Replaced oxygen sensors, but code P0135 still visible - 1996 Lexus LX450
P0135 is a "heater circuit" malfunction in the O2 sensor. This is usually a fused circuit. Check your Owners Manual to verify that it is fused, then check that fuse to make sure it isn't blown ("something" caused the old...
Diagnostics show the EGR and idle air control valve - what does this mean?
The idle air control valve is a unit that monitors the air intake into the engine as it is mixed with fuel prior to entering the motor. When this is not working properly, this will cause an imbalance in the...
Rpm's started to rise to around 1400 when idling and a dash message lit up saying reduce engine power.
Hi there. Check the idle air control valve (IAC) on your vehicle. This valve is what controls the idle and is most likely stuck or has failed. When turning off the vehicle and then turning it back on, the valve...
Toyota Surf 1kz-te 3L 1994 - hard starting in the morning (ambient Temp. usually 30C) - have to wait for plug relay to shut off...
Hi there. Let me offer option #4 - cold start injector. The cold start injector (https://www.yourmechanic.com/services/cold-start-injector-replacement) is also known as the cold start valve. The part is located on the cold air intake, which is found on the intake manifold....
My check engine light is on , mechanic said it is catalyst converter however the car run perfectly fine , no misfire or more
The impact on engine operation (and fuel efficiency) of a "failed" catalytic converter depends on exactly what the failure mode was. In one scenario, if the catalyst within the converter is simply "poisoned" and thus there is no longer any...

Related articles

A Buyer’s Guide to the 2012 Chevrolet Captiva Sport
The The 2012 Chevrolet Captiva Sport is a brand new vehicle and is an eco-conscious crossover SUV for the environmentally friend consumer. It comes standard with many features, but also has many available options so it can suit any buyer’s...
A Buyer’s Guide to the 2012 Chevrolet Tahoe
The The Chevy Tahoe has always been one of the most popular SUVs on the market, and this trend continued in 2012. As always, the vehicle proved to be reliable and powerful, with plenty of space and features that people...
Symptoms of a Bad or Failing Battery Cable
If you experience problems starting and powering the car or find corrosion on the battery terminals, you may need to replace a battery cable.