2009 Mercedes SL-Class Owner's Manual - Page 329

Practical hints Battery fore do not have cell caps and the battery cover is non-removable. Do not attempt to open the battery as otherwise the battery will be damaged. Even though VRLA batteries do not require topping-up of the electrolyte level and cannot be opened to check the electrolyte level, the battery condition must be checked periodically by performing a battery conductance test. Refer to Maintenance Booklet for battery condition testing intervals. The factory-equipped VRLA battery is leakproofed. Only use a battery as replacement that has the same security features and is of identical size, voltage, and capacity as the factory-equipped battery. The battery, the battery ventilation hose and the lateral plug must always be securely installed when the vehicle is in operation. Charging the battery G Warning! Never charge a battery while still installed in the vehicle unless the accessory battery charge unit approved by Mercedes-Benz is being used. Gases may escape during charging and cause explosions that may result in paint damage, corrosion or personal injury. An accessory battery charge unit specially adapted for Mercedes-Benz vehicles and tested and approved by Mercedes-Benz is available, permitting the charging of the battery in its installed position. Contact an authorized Mercedes-Benz Center for information and availability. Charge battery in accordance with the separate instructions for the accessory battery charger. Have batteries charged at an authorized Mercedes-Benz Center. If you charge the batteries yourself, follow the operating instructions for your charging device. Only use a battery charge unit with a maximum charging voltage of 14.8 V. Z ! Never loosen or detach battery terminal clamps while the engine is running or the SmartKey is in the starter switch or KEYLESS-GO button is in position 1. Otherwise the alternator and other electronic components could be severely damaged. Have the battery checked regularly at an authorized Mercedes-Benz Center. Refer to Maintenance Booklet for maintenance intervals or contact an authorized Mercedes-Benz Center for further information. i Only replace a discharged battery with a battery recommended by Mercedes-Benz. i After battery power was interrupted, do the following: RSynchronize RSynchronize ! As with any other battery, have the battery disconnect at a qualified workshop or an authorized Mercedes-Benz Center if you do not intend to operate your vehicle for an extended period of time to prevent battery discharge. You may also connect an accessory battery charge unit expressly approved by Mercedes-Benz for your vehicle model to maintain the battery charge. Contact an authorized Mercedes- Benz Center for further information. the ESP® (Y page 257). the power windows (Y page 108). 327