The battery terminal charging voltage must be less than 14.7 volts to prevent excessive gassing. Charging voltages over 14.7 volts can prematurely dry the battery by boiling out electrolyte, and increase risk of a battery hydrogen gas explosion.
Table of Contents
What should the BMW alternator voltage be?
That is, a fully-charged battery at rest should read 12.6 volts, but when the alternator is charging the battery, it should read about 13.5 to 14 volts.
How do I check my BMW battery voltage?

What is an acceptable car battery voltage?
12.6V volts or above – Your battery is healthy and fully charged.
At what voltage is a car battery at 50%?
The voltage doesn’t have to differ much from 12.6v for it to indicate a discharged battery. At 12.2v the battery is in effect 50% discharged. When you start your car, the battery provides the necessary power to the starter motor to turn over the engine.
What should a BMW battery read?
Check the voltmeter reading. It should be around 12.45 volts, but not more than 12.7 volts. If the reading comes in below this range, it might be time to replace your car battery.
How do I know if my BMW alternator is bad?
- Dead Battery.
- Slow Or Malfunctioning Accessories.
- Dashboard Warning Lights.
- Performance Issues.
- Trouble Starting Or Frequent Stalling.
- Growling Or Whining Noises.
- Smell Of Burning Rubber Or Wires.
- Electrical Issues.
How do I know if my BMW needs a new battery?
- Dimming headlights.
- More frequent need for engine revving or jump starts.
- Takes longer to start the engine when you turn the key/push the button.
- Unusual power fluctuations.
What happens when BMW battery is low?
An engine that refuses to crank or start. The lights won’t come on. Intermittent starting, i.e., one day your vehicle will start up fine, and the next it refuses to start, indicating an unreliable battery charge. Your BMW struggles to crank in cold weather.
What voltage is an E90 battery?
Energizer E90 N Alkaline 1.5 Volt Battery (12-Pack)
Is 12.2 volts OK for car battery?
At 12.4 volts the battery is considered 75% charged and can still ignite your engine. When the battery voltage lowers to 12.2 volts without the engine running, it is considered a bad battery that may start your engine but is no longer capable of holding a charge.
Is 11.9 volts enough to start a car?
You need to replace the battery or use Jump Starter to start the car in an emergency. Therefore, the minimum voltage to start the car should be 11.8V, but if you are lucky, you may be able to start at 10.8V, but we don’t recommend on this.
Is 14.5 volts good for a car battery?
With the motor running, the multimeter rating should stay in the 14 to 14.5 volt range. Dropping below 14 means either the battery is weak and unreliable for sustained vehicle operation or the alternator is failing.
What car battery voltage is too low?
Generally, your car battery voltage is too low if it is reading at 12.4 volts or under. Your 12-volt battery should read at around 12.65 or higher on your voltmeter if it’s healthy and fully charged. If your battery drops to 12.5 volts, consider recharging it back to a full charge.
Is 11.6 low for a car battery?
If your battery drops to a voltage of 11.9V or less, you’re going to notice a serious drop-off in performance. Once it goes down to 11.6V, the battery is almost completely discharged.
What should a 12 volt battery read when fully charged?
A 12V sealed lead acid battery will have an open circuit voltage of around 12.9 volts when fully charged. A 12V flooded lead acid battery will have an open circuit voltage of around 12.6 volts when fully charged.
How do I check my car battery health?
To check a car battery, turn off the ignition and pop your vehicle’s hood. Hook up a voltmeter to the car’s battery by connecting the red lead to the positive terminal and the black lead to the negative terminal. If the battery is in good condition, the voltage will read between 12.4 and 12.7 volts.
Why does my BMW car battery keep dying?
One of the electronics on your car drains too much power or does not go into sleep mode. Faulty alternator. Old battery.
How can you tell if its the battery or alternator?
Jumpstart your car. If you can turn the engine on, but it dies shortly thereafter, your car alternator likely isn’t able to charge the battery. On the other hand, if you jumpstart the car and later on it fails to start on its own, it’s likely a dead battery.
Is it my alternator or battery?
If the engine starts but dies immediately, your alternator probably isn’t keeping your battery charged. If a jump starts and keeps your car running, but the car can’t start again off of its own power, a dead battery is probably your answer.
How do I know if my alternator is draining my battery?

Does a BMW need a special battery?
Conventional car batteries can be used for BMWs with average power requirements. Therefore, you don’t need a specific BMW car battery if your car doesn’t have sophisticated car accessories or a start-stop system.
Do I need to reprogram my BMW after changing the battery?
Apart from the registration procedure, you also have to code your BMW computer. It’ll be necessary each time you replace your battery, no matter its specifications – whether your battery is similar or extremely different from your old one.
How do I reset my BMW after changing the battery?
- First of all, turn the ignition key of the BMW car to the accessory position once the lights and radio are on. You have to do this before starting the vehicle.
- Again, press the “Trip” button and hold until Reset appears.
- Then, press the same button for the third time.
How many years does a BMW battery last?
How long will my BMW battery last? There are a lot of factors that go into your battery’s lifespan but, typically, a battery will last anywhere between two and five years depending on a number of factors.