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I am an advocate of keeping the batteries of the 48-volt system charged and not letting them become depleted. I believe this is the best way to avoid some of the reported problems (those not caused by a batch of defective Li batteries that has been the source of most issues.) In the 4 years I have had my CLS53 and the 1 year of my GLE53 I have had zero problems -- not a hint of any issues with the electronics. I use a battery maintainer regularly if the car is sitting for more than a few days and I use a full charger occasionally. Until now, I have not had a way to determine the actual state of charge of the batteries. Now, with the Schumacher 6-volt + Maintainer WiFi Charger from AutoZone and the SchuPower app on my Android phone (also available for Apple), I can see the percent charge and view a history of the battery voltage and charge current. (By fully charging the 12-volt battery, the 48-volt battery is charged automatically by the vehicle electronics.)
Here's the link to the Schumacher charger from Autozone (I was unable to find this charger on Amazon, but there are probably equivalent chargers that use the SchuPower app via Wifi.)
Here's a photo of the display from the SchuPower app. The app is a bit quirky. I seems to automatically update the charge level every 15-20 minutes but to ge more frequent updates, one has to shut off the app and restart it. Also, sometimes the graph display is not available for unknown reasons. But the charge info is very helpful. One time, but not always, I received a test stating my battery is fully charged. Perhaps a few bugs will be fixed but in the meantime, this is very helpful and comforting if you are concerned about the state of your battery.
I assume you are connecting to the MB charging points and not directly to the 48V Lithium battery or the 12V Lead Acid battery. The charging points go directly to the 12V battery, so which battery is being monitored? My 2023 S only monitors the 12V through Mercedes Me as "12V needs Charging". My thinking is only the 12V is being monitored and not sure if indeed the 48V battery is even being trickled. I have noticed that my MB charger (private label by Ctek for either Lithium & LA, not sure if for both) never goes to a float status after many days of charging which has been a concern to me regarding overcharging. I can't get an answer from either MB or Ctek. But we do know that the 12V will charge the 48V and vice versa, through the battery electronic module.
You can view 48 volt battery by bringing up service menu by holding down upper left side buttons on left wheel controller while displaying trip from reset display. Hold for 10 seconds then scroll to far left for service menu it available there
I assume you are connecting to the MB charging points and not directly to the 48V Lithium battery or the 12V Lead Acid battery.
Yes -- the the 12V charging posts in the engine compartment. I have confidence that if the 12V battery is charged, the 48 V Li battery is charged via the vehicle electronics.
You can view 48 volt battery by bringing up service menu by holding down upper left side buttons on left wheel controller while displaying trip from reset display. Hold for 10 seconds then scroll to far left for service menu it available there
On my 2022, GLE53 I was able to access the work shop menu by pressing the home button on the cruise control side of the steering wheel and scrolling to the left. I do not know if this workshop menu is available at all times. I found the link below to be helpful if the menu is hidden.
To access this workshop menu, go to ignition position one, go to trip in the middle of the left-hand screen, scroll to show mileage, press, the back button and the trackpad simultaneously for five seconds, then release and press the home button, and scroll to the left, and you should see the additional workshop menu. From there, you can scroll to include vehicle data where the battery voltage conditions are shown.
I am running a test to confirm that charging the 12 V battery via the posts in the engine compartment also charges the 48 V battery. Currently the workshop menu shows the 48 V battery at 74% charge. My Schumacher charger shows the the 12 V battery at 68%. When the 12 V battery is close to 100%. I will check the status of the 48 V battery and report.
This has nothing to do with a battery tender but Don Schumacher owns Schumacher Electric which I believe was originally started by his father. Don is a big-time drag racer whose son Tony is a multi-time Top Fuel Champion. I think he had as many as eight teams at one time but divested himself of some of them last year. His daughter manages the teams now out of the Indianapolis area under DSR OR Don Schumacher Racing.
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