Batteries with open cells may read fully charged in idle, but they fail under a load test every time. Once a battery reaches this point, there is no going back. The best thing to do is recycle the thing.
Can a battery read good but still be bad?
Sure. It could be showing a voltage higher than 12 volts and still be bad. If it is bad it will die or drop significantly when put under load. Battery testers don’t just measure voltage.
Can a car battery test good but still not hold a charge?
Even if your battery isn’t old, corrosion on or around the battery can still be behind why your car battery won’t hold a charge. Corrosion prevents the battery from reaching a full charge, so you’ll be driving around with a poorly performing battery.
Why won’t my car start when the battery is fully charged?
Similar to the starter engine, a broken or damaged ignition switch can stop your car from starting. If your headlights can turn on, but your car won’t crank, that means that your battery is charged, but either the starter or ignition is the problem.
What are the signs of a bad battery?
5 Unmistakable Signs Your Car Battery is Failing
- Dim headlights. If your car battery is failing, it’s not going to be able to fully power your vehicle’s electrical components – including your headlights. …
- Clicking sound when you turn the key. …
- Slow crank. …
- Needing to press on the gas pedal to start. …
How can you tell if your car battery is going bad?
The most common symptoms that come with a bad battery include:
- Battery light illuminated on the dashboard.
- Engine cranks slowly when starting.
- Vehicle requires frequent jump starts.
- Clicking when you turn the engine.
- Lights are dim.
- Car won’t start.
How can you tell if you need a new battery?
5 Signs That Your Car Battery Needs to Be Replaced
- Car Struggling to Start. If the vehicle isn’t starting or seems slow to fire up, then it’s often the battery that’s the problem. …
- Flickering/Dimming Lights. …
- Dashboard Warning Light. …
- Electrical Malfunctions. …
What should a 12 volt battery read when fully charged?
When Fully Charged, How Many Volts Should A Car Battery Have? Fully charged automotive batteries should measure at 12.6 volts or above. When the engine is running, this measurement should be 13.7 to 14.7 volts.
How long will a bad car battery hold a charge?
If you’re dealing with a fully charged battery that’s relatively new and in perfect condition, it will take 2-3 months for it to lose its power completely. However, you’re probably pushing your luck if you let it sit idle for more than two months.
How do I know if it’s the battery or the alternator?
If your engine won’t turn over or takes far longer than usual, it’s time to grab the jumper cables and attempt a jump-start. If your engine starts and stays running but won’t start again later, it’s likely a battery problem. If your vehicle immediately stalls, it’s probably a bad alternator.