Fig. 9.1. A battery arrangement under a back seat on the right side in T-model (station wagon) similar to an arrangement in the sedan: 1 – rechargeable battery; 2 – the negative plug, "weight" (–); 3 – ventilating tube; 4 – fastening of the battery; 5 – block of safety locks

On all cars of the E-class the rechargeable battery is located under a back seat on the right side. For access to the battery it is necessary to remove a pillow of a back seat (sedan) or to sklozhit the right back seat (T-model), the battery is closed by an additional cover. In a motor compartment the control contact for check of the battery is located. It is designated by a + symbol (fig. 9.1).

Fig. 9.2. Device of the rechargeable battery: 1 – lattice of a positive electrode; 2 – positive electrode; 3 – separator; 4 – lattice of a negative electrode; 5 – negative electrode; 6 – block of negative electrodes; 7 – section of the rechargeable battery; 8 – block of positive electrodes

Six consistently switched on accumulators form the rechargeable battery (12 V) (fig. 9.2). One accumulator consists of the block of positive and negative plates which together create tension of 12 Century. Plates consist of lead lattices which are filled with active electrolyte. Positive plates are made of lead dioxide, negative — of pure lead. Between them the separator is established. It divides plates, preventing short circuit, but electrolyte can pass through its minute pores. Electrolyte is a conducting liquid which approximately consists of 37% the concentrated chamois of acid and 63% of the distilled water.

TECHNICAL DICTIONARY Rechargeable battery Marking. Is on the battery case, specifies its characteristic. For example, marking of "12 V 74Ah 350 A" designates the following: 12 V — rated voltage; 74 A · h — nominal capacity; 350 A — control current of a discharge. The rated voltage of the rechargeable battery makes 12 Century. The actual tension depends on degree of state of charge of the battery, it can be higher or lower than nominal. Nominal capacity is current which completely charged rechargeable battery can give during 20 h, at a temperature of +27 °C, without power failure on plugs not lower than 10,5 Century. Control current of a discharge in a cold state reflects an indicator of the given capacity on current of the rechargeable battery in a cold state. Current of a discharge of 12 V which the battery can give at a temperature of -18 °C without tension did not fall lower than 9 in during 30 with and 6 V during 150 pages. Self-discharge — the chemical process proceeding in the battery and the leader to its discharge when consumers are not attached to it. The charged new automobile battery daily loses about 0,5% of the charge. High temperature, damages or pollution of covers of the battery accelerate process of a self-discharge.