BMW Battery Trickle Charge Instructions
Updated Tuesday Jan 23, 2018
In this tutorial, we will show you how to charge a BMW car battery. Slow charging is recommended if you will leave your BMW parked for a few months or weeks. It is the best way to charge a completely dead BMW battery as well. BMW batteries are used even when the car is turned off. Typically it takes anywhere from 15 to 30 minutes for all BMW system to go to "sleep". Even when the car has entered a "sleep mode" 0.1-0.5A are still drawn from the battery.
- Car won't start
- Battery Warning Light on
- Airbag light on
- Battery dies when parked for extended time
- Instrument Cluster Warning Lights on
What you will need
- Smart Battery Charger
You will need a smart charger to trickle charge a BMW. Smart chargers output very low current once the battery is charged to avoid overcharging the battery which is critical. Here are a few options:
BMW recommends that the battery is charged via the jump start terminals under the hood. If your BMW battery is completely dead, disconnect the battery and slow charge it.
- Open the hood of your BMW.
- Locate positive terminal under the hood and connect the red clamp from your charger.
- Locate the negative terminal under the hood. BMW has a designated copper post. Use that instead of the strut tower.
- Set your charger to 2 Amp which is a slow charge. Set voltage to 12 volts. Select battery type it will be either Regular/Lead Acid/Flooded or AGM battery. If you are not sure look at your battery in the trunk. If the battery has a black case it most likely is an AGM battery. If the battery has a white case it is a regular or flooded battery.
- Plug your charger into a wall outlet or extension cord.
- Allow the battery to get charged or stay fully charged. Do not keep the key in the ignition while the battery is charging. If you are charging a fully discharged battery, it can take up to 24 hours to charge your BMW battery.
Frequently Asked Questions
Can I use a slow charger to jump start a BMW?
Yes, you can but you need to allow the battery to charge for several hours. A slow charger only puts out about 2 to 12 amps which is not a lot much current. If your BMW battery is fully discharged it can take about 10 hours or more for the battery to get charged.
Where are battery charging points on a BMW?
The charging points on a BMW are (also known as the jump starting terminals) located in the engine bay. The positive terminal is covered with a red plastic cover.
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