Most cars come with a single battery located under the hood, or in the trunk. But some older Mercedes models like the S, CLS, CL, SL, or the E-Class offer batteries both in the trunk, and under the hood, or sometimes in the passenger’s footwell.
This is due to the increased electricity demands some Mercedes models experience because of a lot of features and accessories. The battery in the front is called the starter battery, and the one in the back is called the consumer battery.
These batteries control different aspects of the vehicle, and Mercedes wanted to make sure that this double battery setup is able to fully power all the luxury and safety features packed in these models.
Starter Battery
A starter battery as the name suggests is used to start up the engine. These batteries are different than others because of the ability to provide lots of energy on the initial startup. This means that these batteries are only occasionally used to provide a larger capacity.
These batteries consist out of a lot of thin lead plates, these plates are specifically designed for such occasional short burst large capacity usage scenarios. These batteries are not suited for longer, more even power demands.
That is the reason why Mercedes decided that a good idea would be to use an additional battery for longer, more even power demands. This way the starter battery will be used for starting the car and some other specific short burst power demands only, which would increase the longevity of the battery.
Most Mercedes models use an AGM-type starter battery which offers high accessory loads, but the models with two batteries usually use specific Lead-Acid starter batteries. Mercedes recommended battery brands are Mercedes-Benz, Exide, AC Delco, Optima, Bosch, Varta.
Consumer battery
As mentioned previously, the purpose of the consumer battery is to power all the additional electronics with an evenly distributed power demand. This means that this battery is the usual AGM battery which is specifically designed to deliver continuous electricity to the A/C, lights, radio, cameras, sensors, radars, etc.
Some models like the SL-Class (R230) or the W221 S-Class are more power-hungry than others. The SL offers a retractable hard-top which consumes a lot of energy while operating. Because of this, and the fact that many owners tend to not drive SL’s too often means that this model might run out of juice a bit too early.
If you don’t drive the SL for a while, the consumer battery might discharge to the point that the car itself will start turning off many of its functions, but thanks to the starter battery you are still going to be able to start the car up.
This is a usual problem for many exotic cars that tend to offer smaller batteries due to weight-saving reasons. And almost every manufacturer recommends that you always keep your car on a trickle charger, and C-Tek is one of the leading trickle charger manufacturers on the market.
How to change a cars battery
Most batteries last for about 3-6 years, and if you notice your headlights dimming, or that some of the car’s accessories are losing power, this means that it is time for you to change the battery. But, in today’s day and age with Covid restrictions, it’s not so easy to just walk into a car-shop and demand a battery swap.
You can change the battery yourself by following these simple steps. First of all, you should park your car on a level surface that is not surrounded by water, sparks, open flames, or traffic. Take the key out of the ignition, put the car in park, open up the hood, and disconnect the old battery.
You should also use protective gloves due to the car battery’s acidic properties. Always disconnect the negative cable first to prevent any electrical shorts. A negative cable is usually black and contains a visible – designation on it. Only then you are able to disconnect the positive (+, red) one, and secure them with cable ties.
Loosen up the connectors and take out the battery. Then take the new battery, grease the terminals and secure it to the bracket. Connect the positive cable first, and make sure the cable does not touch anything inside the car. Then connect the black cable in the same way, put on the cover, close the hood, and start the car.
FAQ Section
Which batteries are in the newest Mercedes models?
Modern-day Mercedes models use Genuine Mercedes lithium-ion batteries. These batteries are specifically designed for Mercedes Benz models, and no other battery manufacturer builds batteries just for Mercedes models.
This means that these batteries are your best choice if you drive a modern-day Mercedes. These batteries meet all the highest standards required for power-hungry Mercedes models. Many other batteries will also do the trick, but these batteries are surely the ones recommended by Mercedes.
How should I dispose of my old car battery?
Car batteries contain toxic lead and acid, which surely means that you can not just throw them out anywhere. These batteries should always be recycled. The majority of battery shops and retails will usually take your older battery for recycling when you buy a new one.
Many retailers will sell you the battery for less money if you turn in your old battery. This is to encourage many owners to opt for battery recycling as these batteries are extremely harmful to the environment, and human health as well.
Are car batteries dangerous?
Car batteries usually emit hydrogen gas during charging. This gas is extremely flammable, so a small spark might cause battery explosions. Furthermore, while jump-starting a car, you should never connect both the cables to the battery.
Connect the positive one, the negative one should be connected to the ground on the vehicle away from the battery for explosion-avoiding purposes. You should also wear protective glasses and gloves whenever you fiddle with the battery, just to make sure nothing goes wrong.
Avoid contact with potential spills from the battery, and only handle them with heavy-duty protective gloves. Furthermore, you can not jump-start a frozen battery, as this can also lead to an explosion.