Does anyone know whether the 12v battery under the hood is lead acid or lithium ion (or other)?
The reason I ask is that lead-acid batteries tend to fail every few years. If the hood is not meant to be opened by non-technicians, then what happens if you are in an inconvenient location and need to call road-side assistance?
I have copied the extract below from the owners manual
Vehicle battery General As well as the high-voltage battery, the vehicle has a 12-volt vehicle battery. The vehicle battery supplies the vehicle electronics with energy. The battery is maintenance-free. More information regarding the battery can be obtained from a Service Partner of the manufac‐ turer or another qualified Service Partner or a specialist workshop. Seite 363 Replacing parts MOBILITY 363 Online Edition for Part no. 01405A38CB9 - VI/21 Safety notes DANGER Touching live components can result in an electric shock. There is a risk of injury or even death. Do not touch any components that could be live. WARNING Vehicle batteries that are classified as unsuita‐ ble may damage systems or result in functions no longer being carried out. There is a risk of injury or material damage. Only use vehicle bat‐ teries that have been classified as suitable by the vehicle manufacturer. NOTE Battery chargers that charge the vehicle battery via sockets or cigarette lighters in the vehicle may overload or damage the 12 V electrical system. There is a risk of material damage. In the case of a discharged vehicle battery, con‐ tact a manufacturer Service Partner or other qualified Service Partner or specialist work‐ shop. Registering the battery with the vehicle The manufacturer of the vehicle recommends having a Service Partner of the manufacturer or another qualified Service Partner or a specialist workshop register the vehicle battery with the vehicle after the battery has been replaced. Once the battery has been registered again, all comfort functions will be available without restriction and any Check Control messages relating to the comfort functions will no longer be displayed. Hazard icons The following hazard icons can be found on the vehicle battery: Icon Meaning No smoking, no naked flames, no sparks. Wear protective goggles. Keep away from children. Risk of acid burns: wear gloves, do not tilt the battery. Rinse any splashes of acid with water immediately. If acid comes into contact with eyes or is swal‐ lowed, seek medical attention immediately. No direct sunlight, no frost. Follow the operating instruc‐ tions. Explosive gas mixture. Do not seal any openings on the bat‐ tery. Replacing the battery General The manufacturer of the vehicle recommends only having the vehicle battery replaced by a Service Partner of the manufacturer or another qualified Service Partner or a specialist work‐ shop. If the battery is not replaced correctly, the vehicle may not recognise it properly and perfect functioning cannot be guaranteed. Seite 364 MOBILITY Replacing parts 364 Online Edition for Part no. 01405A38CB9 - VI/21 Notes on removal Observe the following notes on removing the ve‐ hicle battery: ▷ Park the vehicle and switch off consumers. ▷ First disconnect the power at the negative terminal. Then disconnect the power at the positive terminal. Notes on installation Observe the following notes on installing the ve‐ hicle battery: ▷ Remove any foreign bodies from the battery holder. ▷ Only install the battery in the intended posi‐ tion in the vehicle. ▷ Keep the battery and vehicle connection con‐ tacts clean. ▷ First connect the power at the positive termi‐ nal. Then connect the power at the negative terminal. ▷ Use the connections, connectors and covers provided. ▷ Connect a hose to the gas outlet opening if necessary. Initial operation The battery is operational. No special precau‐ tions are required for start-up. Charging the battery A battery charger installed in the vehicle supplies the vehicle battery with current. The battery charger draws the energy required from the high-voltage battery. For further information: Charge vehicle, see page 322. Open circuit Following an open circuit, some equipment will have to be reinitialised or individual settings will need to be updated, for example: ▷ Parking brake, see page 147. ▷ With memory function: save positions again. ▷ Time: update. ▷ Date: update. Storing the battery Observe the following information on storing ve‐ hicle batteries: ▷ Store the battery in a cool and dry place. ▷ Protect the battery from direct sunlight and frost. ▷ Only clean the battery with a damp, anti-static cloth. ▷ Store the battery upright and secure it against falling over. ▷ Install the oldest batteries first. ▷ Do not remove the protective cap from the contacts. ▷ Charge or install the battery by the date on the battery label at the latest. Once fully charged, the battery will work for another 10 months. Disposing of the old battery Dispose of old batteries at a Service Partner of the manufacturer or another qualified Service Partner or a specialist workshop or hand them in to an authorised col‐ lecting point. Batteries filled with acid should be transported upright. Protect batteries against falling over when in transit. Warranty See the vehicle purchase contract for informa‐ tion on the battery warranty