BMWs come loaded with tons of electronic features, which means they have a pretty sophisticated battery and electronic system.
If you’ve had a hard time finding your BMW’s battery, then you aren’t alone. A lot of people struggle to find the battery in their BMW.
The battery for most BMWs can be found on the right-hand side of the trunk underneath the trunk upholstery. Placing the battery in the trunk frees up space in the engine bay and allows for more even weight distribution.
With that in mind, let’s take a deeper look to learn more about why BMW batteries are placed in the trunk, and how you access the battery for charging and jump-starts.
Why Are BMW Batteries in the Trunk?
Since trunk batteries aren’t all that common, you might wonder why it’s there?
Well, trunk-mounted batteries offer a few benefits over other battery configurations. However, the most important reason would have to be weight distribution.
The way a vehicle’s weight distributes over the chassis impacts its handling.
Putting too much weight in the front could cause it to wear unevenly.
So, you might notice that other cars tend to need front tire replacements more often.
With a BMW, you’ve got a perfectly distributed vehicle.
None of their tires should wear out faster than the rest.
As a result, the vehicle’s handling tends to feel better than other vehicles.
Another reason you’ll find batteries in the trunk of your BMW would be space constraints.
Usually, BMWs only have a limited amount of space in the engine bay. And, they’ve got pretty powerful engines, too.
As such, there’s not always enough room in there for a battery.
Placing the battery in the trunk eliminates these space issues.
So, BMW engineers can focus on building the most powerful engine possible for your car.
They’re able to use every bit of space in the engine bay for mechanical components.
Finally, putting your battery in the engine bay would expose it to high temperatures.
Most batteries work better whenever they’re kept cool.
Because BMW uses performance-oriented batteries, mounting them in the trunk makes sense.
What Other Vehicles Have Trunk Batteries?
BMWs aren’t the only vehicles with trunk-mounted batteries.
They’re actually quite common in luxury-class autos.
Most of Subura’s performance vehicles also place their batteries in the trunk.
Toyota Rav4s tend to put them back there as well. Even Jaguars usually put them in the trunk, too.
However, there’s one thing in common between all these vehicles.
They’ve all got larger than average engines.
So, their engineers compromised to save space in the engine bay.
Trunk-mounted batteries might be more difficult to access.
But, it opens up space in the engine’s compartment.
And, it redistributes weight more evenly over the vehicle.
Performance vehicles need equally high-performance batteries. Putting the battery in the trunk keeps them cool, improving their performance.
How Do You Charge the BMW Trunk Battery?
Are you struggling to charge the battery on your BMW? If so, then you’ve probably had a tough time finding it.
Charging a BMW’s battery works the same way it would with a conventional one. You’ve got to connect a battery charger to the positive and negative terminals.
Still, you’ll have to access it first.
To find a BMW’s battery, try opening up its trunk.
Once that’s open, lift up the upholstery matt covering the bottom.
Look underneath it to see if you can spot the battery compartment.
If you’re having a hard time finding that, look at your owner’s manual. It’ll show you how it’ll look.
Now, you should’ve found the battery compartment. Next, you’ve got to use a screwdriver to unscrew everything keeping it in place.
After unscrewing its screws, lift the cover off gently. You should have a clear view of the battery at this point.
There should be two connectors covering the battery’s terminals. One of them is the positive terminal, and the other one is the negative.
Typically, the negative terminal is going to be black. Take the negative terminal off first by removing its protective cover.
After removing the negative terminal, you can move on to the positive one. Most of the time, you’ll need a socket wrench for this part.
There should be a few blots keeping the terminal locked in place.
Using the socket wrench, loosen them enough to remove the terminal from the battery. Be careful, though. You wouldn’t want to lose any of those bolts.
Finally, your battery should be ready to charge. Remove it from the trunk by lifting it straight up.
Then, take it to somewhere with a battery charging station. Usually, it’ll take a few hours to fully charge the battery.
You could also use a battery charging station at home.
If you’ve got one of them, simply hook up your battery to it.
Place the charging station’s red clamp on the battery’s positive terminal.
And, place the black clamp on the negative one.
A lot of home-operated charging stations don’t charge as fast as the ones you’d find in a store. So, it might take all night for your battery to charge.
Either way, once the battery has been charged, you can put it back in place.
Hook everything up as you found it. As long as you’ve done everything properly, your BMW should crank right up.
How Do You Jump Start a BMW With Battery in the Trunk?
Jump starting a battery on a BMW isn’t as tough as it seems. If you’ve jump-started another car, you’ll know most of what you’ve got to do.
Using the same method from above, open the battery compartment. After exposing the battery, don’t remove its terminals this time.
You’ll need someone to pull up behind your BMW for this part, though.
Get them to open their vehicle’s trunk while it’s still running. Then, connect a pair of jumper cables to its battery.
Use the red cable to connect to the battery’s positive terminal.
And, the black one should connect to the negative.
After connecting the cables to the other car’s battery, hook them up to yours.
ike before, the black cable should connect with your battery’s negative terminal.
And, the red cable should connect to your positive terminal.
If you’ve done this correctly, you’ll have a negative to negative connection. And, the other one will be positive to positive.
Let the other car continue running for a little while. Charging a battery enough to jump-start it can take about 20 to 30 minutes.
After letting the battery charge for a bit, try starting your car.
If you’ve let it charge enough, it’ll start up right away. Otherwise, you might hear the engine turn over but it might not start.
If that happens, you’ve got to let it charge for a little longer.
Learning About BMW Batteries
BMWs put their batteries in the trunk instead of the engine bay most of the time.
Accessing them takes a little more effort, but they work pretty much the same.
If you’ve charged other batteries before, you’ll know how to work with them.