SL55 R230 is not recharging either battery (and has been stored in a dry environment!)
Posted: Tue Sep 22, 2026 1:47 pm
My service light is confirming its reputation for being quite capricious, and I am confronted with a vehicle displaying the ominous red indicator on the dashboard signalling a battery issue.
A brief multimeter assessment indicates that neither battery is receiving a significant charge, as both register below 13 volts in the 12-volt range.
Alternative context:
Last year, I encountered the common problem of the alarm leading to a trickle drain, which was rectified, and the auxiliary battery was substituted with a new, authentic MB unit. Following an extended duration of operation and successful charging, this vehicle has not been utilised frequently.
Following the initial red light indication last week, I replaced the front battery (unnecessarily) to ensure both batteries are under 12 months old (once more - authentic MB).
The vehicle is kept in a garage, thus rarely exposed to rain.
I am not aware of any instances of jump starting. All other components of the vehicle appear to be functioning properly.
After reviewing numerous discussions, many suggest the BCM as a potential issue, yet I have not encountered anyone exhibiting the precise symptoms during my investigation (as most seem to have one of the two batteries charging, while mine is receiving no power at all).
The vehicle is positioned on a trickle charger in the garage, with the charger connected to the auxiliary power.
I was curious if others experienced symptoms akin to mine and, if so, what they determined as the cause.
All contributions are sincerely appreciated.
A brief multimeter assessment indicates that neither battery is receiving a significant charge, as both register below 13 volts in the 12-volt range.
Alternative context:
Last year, I encountered the common problem of the alarm leading to a trickle drain, which was rectified, and the auxiliary battery was substituted with a new, authentic MB unit. Following an extended duration of operation and successful charging, this vehicle has not been utilised frequently.
Following the initial red light indication last week, I replaced the front battery (unnecessarily) to ensure both batteries are under 12 months old (once more - authentic MB).
The vehicle is kept in a garage, thus rarely exposed to rain.
I am not aware of any instances of jump starting. All other components of the vehicle appear to be functioning properly.
After reviewing numerous discussions, many suggest the BCM as a potential issue, yet I have not encountered anyone exhibiting the precise symptoms during my investigation (as most seem to have one of the two batteries charging, while mine is receiving no power at all).
The vehicle is positioned on a trickle charger in the garage, with the charger connected to the auxiliary power.
I was curious if others experienced symptoms akin to mine and, if so, what they determined as the cause.
All contributions are sincerely appreciated.