It only needs to drop down to around 10.5 volts to be considered fully discharged. If it drops down below that, the battery will become damaged due to excessive sulfation. Sulfation refers to the formation of lead sulfate crystals on the surface of the battery's lead plates.
Yes, you have an immediate problem because your car battery doesn't have enough charge to start your car. The deeper problem is how long it takes you to fully recharge it. Leaving a car battery drained for just a few hours will leave permanent damage.
Usually, dead car batteries may be revived – at least temporarily – to get you back on the road. However, the accumulation of damage may lead to an untimely demise of your car battery, and this typically needs to be replaced. But as the saying goes, prevention is always better than cure.
A car battery exists to provide starting power and to buffer electrical demands when the alternator isn't spinning fast enough to keep up. As such, a dying battery puts a big load on the alternator. This will overload the alternator and damage it.
Discharging below 10.5V can permanently damage the battery. Additionally, if the battery is left dead, the lead sulfate eventually forms into hardened crystals that can't be broken up by alternator current or a regular car battery charger. At this point, you may have to get a new battery.
“How long does a car battery last without driving?” is a common question. As noted above, you're probably safe for four weeks to two months; however, it can depend.
If it is slowly losing power with electronic problems, trouble staring the car and other signs of battery failure, then it may need to be replaced because a recharge might not last that long. If it is just completely dead through no fault of your own, then it definitely should be replaced.
At times, a dead car battery might not indicate a problem with the battery, per se, but rather your car's charging system. If the battery warning icon comes on while you're driving, this is likely a sign that there's a malfunction within your charging system.
Your car battery can drain over time from stereo components (subwoofers), phone chargers, and anything you leave plugged into vehicle outlets that continue to draw power from the battery after the car is turned off. Other power drains include interior and below-vehicle LED lights. Loose or corroded connections.
Signs you have a bad battery
According to Matthew Hart, owner of AxleWise.com, signs your battery is going bad include: The car is difficult to start. Once started, the car doesn't hold a charge for very long. Dim or flickering taillights and headlights.
If your battery is over 4 years old we'd advise replacing it with a new one. You may find you're able to temporarily recharge a battery this old, however it's likely to lose its charge again very soon. Older batteries do deteriorate over time and naturally lose their ability to hold a charge.
These include overcharging, undercharging and excessive vibration. Overcharging can kill a battery very quickly by boiling electrolyte out of the cells, and by overheating and warping the cell plates. Undercharging can shorten a battery's life by allowing the plates to be come permanently sulfated.
When the battery is low, it cannot deliver that power but often can still supply enough power for lights or accessories, that don't require as much amperage. Keep in mind, jump-starting the car in these situations should only be done in an emergency.
If your engine takes more time to start, that can be a sign that the battery is failing. Perhaps you hear some weird noises every time you turn the key, or the lights begin to flicker. These are signs of a dying battery. You should have a professional check the starting system or have the battery replaced.
Answer: You would rather be safe than sorry when it comes to your car battery, as it is best to avoid getting stuck without a functional vehicle due to a dead battery. Therefore, most mechanics will recommend that you get your battery replaced when it reaches 50% of its full capacity charge.
There are some reasons a car battery may not hold a charge. The most common cause is that the battery is old and needs to be replaced. Another possibility is that the battery has been damaged by heat or cold. If you think your car battery is not holding a charge, it is vital to take action.
A parasitic drain refers to when your car's battery continues to drain even after the car's parked, and the amount of drainage is much higher than normal. Usually, it's a faulty accessory in the car causing the drain – for example, a sensor or interior light doesn't switch off automatically.
Some of the most common causes of a parasitic drain include the trunk, glove compartment, and other lights that are on due to some type of malfunction. These and other interior lights are designed to shut off automatically, and if they fail to do so, they are fully capable of draining a battery dead overnight.
But if you're only taking short trips, your battery may not be getting the recharge it needs for the next time you start your vehicle. This is certainly an annoyance if you happen to be away from home. But even worse, it can significantly shorten the life of your battery.
Extreme temperatures, frequent short trips, and general everyday use could shorten the life of your battery to two to three years. If your car battery dies quickly, even after a jumpstart, it might be time for a new one.
How Long Does It Take To Charge A Car Battery? If you have jump-started your car, it is recommended to let your vehicle run for at least 30 minutes because it would typically require at least half an hour to charge a dead battery entirely or at least sufficiently.
If your car does start, let it run for a few minutes to help charge the battery further. Unhook the clamps in the reverse order of how you put them on. Be sure to drive your car for about 30 minutes before stopping again so the battery can continue to charge. Otherwise, you might need another jump start.
If your car starts but stalls when you're underway, your battery is probably not being recharged due to a faulty alternator. A squealing sound coming from the engine that gets louder when drains like the heater or sound system are on may be your alternator bearings.