There are 1 owner-reported powertrain & transmission complaints for the 2021 Mercedes-Benz S-Classin NHTSA's database. These are unverified consumer reports and may not reflect confirmed defects.
Issue: STARTER BATTERY Repetitive online and dashboard screen message notices stating, "BATTERY CHARGE Status Critical," at all hours of day and night requesting immediate 30-60-min. of driving or car will not start. Have had to wake up from nightime sleep to drive car in middle of night so it would start the next morning to drive to work. Also, multiple electrical problems related to this issue ensue. Unreliable vehicle start up; too great a demand on electrical system. Vehicle taken in to dealer for service five times in six months since new purchase. Dealership Service Department found battery has malfunction. System restricted. Code stated, ". . . battery voltage may drop significantly under or at 45% due to listed operations on document. Most operations are for using vehicle ignition on (on ignition) and screen operation. Battery can be (can) drop due to using these functions." (See attached documentation.) BATTERY MAINTAINER (CHARGER) should be basic part of vehicle included in purchase price given battery drain on excessive electrical component demand not additional cost for Battery Maintainer (Charger) part and installation.
Complaints are unverified consumer reports submitted to NHTSA. A high complaint count may reflect vehicle popularity, not defect severity. Data sourced from NHTSA public records.
Data synced from NHTSA on Apr 25, 2026