With many cars, it’s quite an easy job to replace the battery. However, on some others, it’s quite literally a pain – bruised knuckles are practically guaranteed, and frustration is the order of the day. Unfortunately, the F48-generation BMW X1 falls in the latter category. So, if your X1’s battery calls it a day, you’d be better off having a professional do the job. Allow us to explain why this is the case.
Power Up!
Before we begin, it has to be said that the first-generation BMW X1 had a very easily-accessible battery: open the boot, unclip the inner side cover behind the right rear wheel, and in the recess next to the boot floor thus exposed, the battery would be staring you in the face. But all that changed when the F48-generation (2016-2022) X1 came around.
With its switch from a rear-wheel drive-based design to a front-wheel drive-based platform, the X1’s battery moved from the rear of the car to the front. It now resides just behind the engine, and just ahead of the windscreen. That doesn’t sound too difficult to reach, and in most cars, it isn’t, but the X1 has an intricate arrangement of covers and structural braces installed over the battery, and a rather complex electrical system situated very close by.
This means that there’s quite a lot of stripping involved just to get to the battery, followed by some careful manoeuvring to loosen and extract it. Because some of the stripping involves a structural element of the car’s body, and due to the close proximity of critical electrical components, it’s advisable rather to get a professional to handle this job. Nonetheless, we took the plunge and jumped into an X1’s engine bay, to show you just how much work this seemingly simple operation entails.
Let’s get started!
1. The first step is to remove the ventilation tray cover, under which the battery is mounted. First, remove the rubber sealing strip (marked with red arrows) by grabbing a hold of either end and “peeling it away” from the ridge upon which it is mounted.
2. Remove the three locating pins (marked with green arrows). This is an easy operation, for which you’ll need a medium-width flat screwdriver and small pliers. Use the flat end of the screwdriver to pry the centre pin loose as shown in the image, then pull the pin out with the pliers. The rest of the locating pin can now be removed without notable effort, with the same procedure applied to all three pins.
3. Remove the ventilation tray cover. First, lift up its front edge, and then gently pull it towards the front of the car (using both hands) to dislodge it from its rear location groove. Be very careful with this operation, as this is a large plastic piece that may crack if bent too far. This is what the engine bay should look like afterward:
4. Now we get to the final battery cover. To remove this two-piece plastic section, unfasten the two bolts holding it down (circled in green) with an 8mm socket wrench – a spanner will work as well, but there isn’t a lot of room for the spanner to move. Once these bolts are removed, lift the final two pieces of the battery cover (marked by the purple arrows) straight up and set it aside. Try to keep these two parts together, because if they separate, you may struggle by the time you want to re-fit the cover.
5. The battery is now almost fully visible. You will notice a number of plastic boxes and wiring looms directly next to the battery (marked with yellow arrows): take care not to disturb these, as indiscriminate handling may loosen electrical junctions or damage control units. They are not your main worry at this point, though, because there’s yet more stripping to be done before the battery can come out.
6. Marked with an orange arrow in the picture above is a structural brace, bolted to the firewall at one end, and to the strut tower at the other. This one also has to come out before the battery will have enough space to be lifted out of its tray. Using a 13mm socket wrench, remove the two bolts holding it in position, and put it aside.
7. Here’s the easy bit: remove the battery terminals. Convention dictates that the negative (-) terminal gets disconnected first, followed by the positive terminal (+). This is done by loosening (but not removing) the 10mm nuts (marked with red arrows) which hold the terminals in place. Lift the terminals from the battery, tuck the negative terminal out of the way behind the battery, and suspend the positive terminal by hand. Just for safety’s sake, don’t let the positive terminal touch the body or engine, as there might still be control systems holding a charge elsewhere, and such contact might cause damage.
8. You’ve finally reached the point where you could access the battery’s mounting bracket (market by the green arrow). This is located behind the battery, and features a BMW-specific clamp which is fastened by another 13mm bolt (marked with the purple arrow). The battery bracket also locates a section of the wiring harness, so be careful not to pinch any wires in this area, and don’t put any strain on the wires, either.
9. The battery can now be lifted out of its location tray, by first sliding it about half a centimeter towards the windscreen, and then carefully lifting it upwards. Always take care to avoid putting strain on any of the wires surrounding the battery!
10. Fit the new battery, and re-assemble in the reverse order of disassembly. Don’t worry, you won’t be able to fit the battery “the wrong way round”, because the terminals won’t reach, and the battery posts are of different sizes.
11. Finally, once everything is complete again and you’ve checked that the car starts, close the bonnet, and congratulate yourself on a job well done. Oh wait, not just yet…
That’s not the end of it, though.
Yes, you’ve replaced the actual battery, but you’ll also need to re-code the car’s engine control unit – essentially, you need to tell the car that it has a new battery. Failing to do so increases the likelihood of electrical system malfunctions, and may be lethal to the new battery, alternator, and main electrical system. This is easily done by means of a diagnostic scanner, but if you don’t have access to a suitable OBD2 device, you’ll need to phone a mobile technician (with the appropriate scanner) to come to you to re-code the control unit.
Why is this a necessary step? Starting around 2002, BMW refined their cars’ electrical systems a great deal. The battery’s charge rate is now controlled by a control module, which adapts to an aging battery by increasing the alternator’s output over time. Just fitting a new battery to a car whose alternator charges as though it’s connected to an old battery, will lead to over-charging of the new battery and could damage other electronic components in the process.
If you’re not completely at ease working on cars and don’t have access to an appropriate diagnostic scanner, this operation likely won’t be within your abilities. But, if you enjoy a bit of a challenge and have the right tools at hand, you’ll be satisfied at overcoming this fairly intricate activity.
Thank you to the very friendly folks at Centurion Select, who provided the car, and assisted in capturing these images.
* This article was created as an advisory piece. AutoTrader SA does not accept any responsibility for possible damages incurred by individuals or workshops following these instructions. If in doubt, please consult a professional auto technician.
Keyword: How to replace the car battery on a BMW X1