Mercedes-AMG - CLAMercedes CLA45 Battery Replacement in Dubai
Most CLA45 battery calls are not about the main battery at all. The car carries a second, much smaller AGM of 13Ah rated at 200 amps, and that little unit is what throws the auxiliary battery message, disables start-stop and, on the C118, starts the strange electrical behaviour. Battery Zone UAE tests both units at your location in Dubai, replaces the one that has failed and registers it to the car.
Mercedes CLA45 at a Glance
- Main battery
- AGM, engine bay
- Auxiliary battery
- 12V 13Ah AGM
- Engine, C117
- M133 2.0 turbo
- Engine, C118
- M139 2.0 turbo
- Coding
- Required
- Service
- At your location
Under the cover on the passenger side.
Rated 200A, C56 case, 150 x 90 x 145mm.
360hp, 381hp from 2016.
387hp, 421hp as the CLA45 S.
Main battery registered to the car on fitting.
24 hours a day, anywhere in Dubai.
Mercedes CLA45 by Generation
The name stayed the same, the electrical system did not. Find the years your car was built in and the differences that matter.
The M133, the most powerful four-cylinder of its day, in a car based on the W176 A-Class. Main AGM in the engine bay, 13Ah auxiliary AGM alongside the electrical systems.
The M139 in CLA45 and CLA45 S form, on the W177 platform. MBUX adds standing load, the auxiliary unit remains, and on the S the AMG Dynamics systems make the electronics the first thing to misbehave when either battery tires.
The Two Batteries in a CLA45
One turns a 2.0 litre AMG engine over. The other keeps the car alive for the second and a half that it is not running.
| Specification | Main battery | Auxiliary battery |
|---|---|---|
| Type | AGM | AGM |
| Capacity | Around 70 - 80Ah | 13Ah |
| Rating | Cranking current for the M133 or M139 | 200A |
| Case | Full-size, engine-bay tray | C56, 150 x 90 x 145mm |
| Job | Starting, charging system, everything when parked | Holding the electronics up during start-stop restarts |
| What fails when it goes | The car does not start | Warning message, start-stop off, odd electrical behaviour |
Figures from supplier fitment data for the C117 CLA45. Battery Zone UAE confirms both parts for your VIN before coming out.
Why the Small Battery Goes First
The auxiliary battery in a CLA45 has a hard life. Every time start-stop shuts the engine off at a junction, it carries the load of the infotainment, the instruments and the control units alone, then takes a hit when the starter pulls the main battery down during the restart. In Dubai traffic that can be fifty cycles on a short drive.
It is also small, and small batteries have less thermal mass. In summer the engine bay of an M133 or M139 runs hot, and a 13Ah AGM reaches the temperature at which it starts to lose capacity far sooner than a 70Ah unit next to it. Two summers is a common life for the auxiliary unit on this car.
When it fails the car reports a battery malfunction, which sends most owners looking for the main battery. Replacing that does nothing, and Battery Zone UAE sees CLA45s that have had a new main battery fitted elsewhere with the message still on the dash. The test takes a few minutes and settles which unit is at fault.
What Battery Zone UAE Brings to a CLA45
Both parts on the van, because on this car either can be the answer.
Signs It Is the Auxiliary, Not the Main
The pattern is distinctive once you know it: the car starts fine, and everything else is wrong.
An auxiliary battery malfunction message with an engine that still cranks strongly
Start-stop disabled while the main battery tests healthy
MBUX or COMAND rebooting when the engine restarts at a junction
The instrument cluster blinking or resetting during a start-stop restart
Dash warnings that appear on restart and vanish within a minute
A main battery fitted elsewhere recently with the message still showing
The Battery Zone UAE Visit on a CLA45
Both Parts Loaded
Year and VIN confirm the generation. The main AGM and the 13Ah auxiliary both go on the van.
Both Units Tested
Main battery under cranking load, auxiliary battery on its own, alternator output with the AMG systems live.
The Right One Replaced
If it is the auxiliary, that is what is fitted and what you pay for. If it is the main, it is fitted and registered to the car.
Confirmed Clean
Message cleared, start-stop working, systems checked, invoice and warranty issued, old unit taken for recycling.
Mercedes CLA45 Battery Questions
In the engine bay on most C117 cars, near the main battery, and behind trim in the passenger footwell on many C118 cars. It is a small AGM in a C56 case, 150 x 90 x 145mm. Battery Zone UAE technicians know both positions.
A 12V 13Ah AGM rated at 200A, in the C56 case size. It is a published fitment for the C117 CLA45 and Battery Zone UAE carries it, so an auxiliary fault is fixed on the first visit.
Because the fault is almost certainly the auxiliary battery, which does not take part in starting the engine. It supports the electronics during start-stop restarts, and when it weakens the car reports it as a battery malfunction. Replacing the main battery will not clear it.
Yes. The C117 uses the M133 and the C118 the M139, both shared with the equivalent A45. That means the hot-restart behaviour of those engines, where a tired battery starts the car cold and fails after a summer drive, applies to the CLA45 as well.
Yes. The battery management system sets the charging rate from what it knows about the battery, and it has to be told a new one is fitted. Battery Zone UAE does this at your location as part of the job. The auxiliary battery does not need registration.
Typically within about 30 minutes, anywhere in Dubai, 24 hours a day. Both batteries are carried, so the visit ends with the car fixed rather than a part on order.
Not Your Model?
We fit batteries across the whole Mercedes-Benz range, and the marque page lists every model we cover.
We Cover All Of Dubai
Mobile units are positioned across the city for the fastest possible response. We're closest to Business Bay and Downtown Dubai, with rapid coverage extending to Al Karama, Al Jaddaf, and offices, residential areas, and highways citywide.
CLA45 Showing a Battery Warning? Test Before You Buy
Battery Zone UAE comes to you anywhere in Dubai with both the main AGM and the 13Ah auxiliary on board, tests both, and replaces only the one that has failed. Call or WhatsApp, any hour.
- Both batteries tested
- Coded to the car
- Old unit recycled