Where are the positive and negative terminals of the Mercedes-Benz E300 battery located?

[StCamila]

The red cover on the Mercedes-Benz E300 battery is the positive terminal, and the negative terminal, which is a black electrode head, can be seen by opening the engine block. The car battery, also known as a storage battery, is a type of battery that works by converting chemical energy into electrical energy. Batteries are categorized into conventional lead-acid batteries, dry-charged batteries, and maintenance-free batteries. Typically, when people refer to a car battery, they mean a lead-acid battery. Taking the Mercedes-Benz E-Class 2021 E300L Luxury model as an example, its body dimensions are 5078mm in length, 1860mm in width, and 1484mm in height, with a wheelbase of 3079mm. The body structure is a 4-door, 5-seater sedan, and both the front and rear suspension types are multi-link independent suspensions.

[DiAugust]

The positive and negative terminals of the Mercedes-Benz E300's battery are mainly located in the trunk. Lift the trunk floor panel, and near the rear seats or rear bumper, you'll find a black square box. Open its cover to reveal the battery itself. The positive terminal is covered with a conspicuous red protective cap, possibly marked with a '+' sign nearby, while the negative terminal is usually exposed metal or covered with a black plastic casing. This design is quite clever, as the trunk's temperature is much more stable than the engine compartment, which helps extend the battery's lifespan. Before performing any operations, remember to turn off the engine and remove the key, using an insulated wrench to disconnect the negative terminal first, followed by the positive terminal. Near the fuse box on the right side of the engine compartment, there's also a red auxiliary positive terminal, but that's for temporary jump-starting purposes—it's best not to tamper with it when modifying wiring harnesses.

[LouisRose]

My old E300 had battery issues before, and it took me a while to locate the terminals. Actually, Mercedes hides them quite cleverly—you need to lift the bottom layer in the trunk to find a plastic box with clips, which is the battery compartment. Under the lid, the red cover marks the positive terminal, while the metal post with a black rubber sleeve is the negative. Once during winter when the battery died and I called for roadside assistance, the mechanic warned me not to be misled by the auxiliary positive terminal: that copper post in the front right corner under the hood is only for emergency jump-starting, while the real power source remains the big unit in the trunk. When replacing the battery, keep the car key at least three meters away to avoid triggering the anti-theft alarm.

[DiOwen]

The battery layout of the Mercedes-Benz E300 is quite deliberate. The main battery is located under the trunk floor, with its positive and negative terminals easily accessible on the surface. The terminal with the red cover is the positive pole, while the one marked with a minus sign is the negative pole. Interestingly, there is an auxiliary positive terminal in the engine compartment, designed to avoid the hassle of opening the trunk when jump-starting. Recently, while helping a friend deal with a dead battery, I noticed that the positive terminal post on the new 48V mild hybrid model has become smaller, requiring more careful use of insulated tools. This trunk layout contributes to better front-rear weight distribution, but extra caution is needed to prevent metal tools from simultaneously touching both the positive and negative terminals during handling.