Okay, I have not had any 48V battery issues (knock on wood) at 3 3/34 Years 30k miles, but frequently get the starter battery warning, which I take to mean the 12V, even though the 48V is the real starter battery - " The starter battery charge status of the vehicle SL90882 is critical. To ensure that the vehicle is able to start, please drive the vehicle for 30 to 60 minutes or connect a battery charger. When using the battery charger, please observe the notes in Owner's Manual in your vehicle." This is on a vehicle that is driven a minimum of 4-5 times a week 20 miles at a time.

I assume others are dealing with this as well? I've never had a car that ran the battery down like this and don't understand why.

I got that warning on my 2020 GLE 450 (12 volt) but it was in the first year of ownership. It happened a few days before a scheduled appointment and it turned out to be a bad battery. The test was to charge the battery by the Dealer, sit overnight, test the charge in the AM. Mine wouldn’t adequately hold a charge and was replaced under warranty. A symptom was that the auto leveling function would start to work 5-10 minutes after leaving home. I noticed when sitting at a traffic light that the car would start to level.
As you said, the 48 volt ISG masks the symptoms of a weak 12 volt battery. The 12V can be almost dead but still have enough juice to light up the dash…so since it doesn’t start the car it’s not easy to notice a weak battery.

I have a 350, so may be comparing apples to oranges here. My car sits in the garage most of the week, sometimes not being driven for two weeks at at time. I've never had a low battery warning and never had any problems starting the car when I get in.

I noted the concern to the dealer over a year ago, and they just charged the battery. Will check again when I take it in in March, but then being almost 4 years old there would probably be no prorate to replace it.

We had only put 10k miles on the car in the last 3 years (GLE350) so I am familiar with the messages. I see them as software-based reminders based on some battery voltage threshold with no actual implications. The car always started/worked as expected even after weeks of messages...

I doubt it’s normal, in almost 4 years (2 GLE’s) that’s the only time I got that message. Even letting my GLE 53 sit for over a week it didn’t get a low batter message. My bad battery had some kind of internal short. It would be good to get it sorted out while under warranty…bet a new one is $300+.

I haven't seen the critically low warning but seen plenty of low battery warning as ours sits in the garage for 2-3 weeks at a time without being driven. When I see the message, I drive it for a while and it's gone.

I started seeing that warning on my 350 some time ago. The dealer said they load tested the battery and all was OK. Well several months later it started again and it would prevent the remote start sequence. The dealer then said it was a bad battery and replaced under warranty. Since I make a lot of short trips to the golf course, any time the partial charge comes up in the app, I connect my CTEK charger and I am good to go.

I had the 48v problem - towed to dealer and battery replaced / software updated. Same problem again but this time it is the 12v. Been at the dealership for almost 2 weeks now… This car is garbage! Interested if anyone has successfully dome a buyback?
have A 2021 gls which is the same system…

how could it be at the dealer for 2 weeks. What are the telling you? Can’t just be a bad battery.

If you brought it up a year ago and are a knowledgeable repeat customer like you are, I'd think you will get a warranty replacement. I have had MB since 2008 with a short detour to a Range Rover. It happened to have a bad battery and it didn't take much to get them to test and replace it after initial resistance.

hello. We have a GLE450 2022 and so far have driven it to around 6,000km…. We have changed the 12V battery once under warranty - as it kept going low after not being driven for 4-6 days .. (notice sent to the Mercedes app). The dealer said the battery charge went too low and might be damaged ….

after the battery change - we thought its all sorted.

went to away for 8 days. On the 4th day of being away…. The low battery warning on the phone app came on again…. (!!).

we are beginning to think it’s not entirely the battery’s issue. It’s maybe something to do with some other items. Like leakage etc.

would be grateful too, to hear what other owners have done to solve the matter once and for all

my brother - who drives a small car (POLO VW) would go away for 3 months plus…. He got back home and the PoLo started on the first go with no hiccups). Hehehehe. Put the GLE to shame.

On mine I think they found a phantom current draw with the car off. I checked and can’t find a record of what that was. I believe they replaced some component and it went away. They should be able to check overnight and see if there is such a draw.

[img alt="Just got the message a short while ago. Keeping the car running idle in the garage for 1 hour - hopefully it will get the charge back up to acceptable level.
"]https://cimg8.ibsrv.net/gimg/www.mbworld.org-vbulletin/920x2000/img_7153_52f767f3dd98f86395c05c167239910126032342. png[/img]
Just got the message a short while ago. Keeping the car running idle in the garage for 1 hour - hopefully it will get the charge back up to acceptable level.

A parasitic current draw won't just magically go away. The vehicle should be able to sit idle for weeks without draining the batteries. Have the problem diagnosed.

Yes, good point.. will do just that.

we have brought this matter up with the dealer before when the first battery was changed due to repeated low voltage cases that occurred. The dealer replied that the GLE is a big car and contains loads of electronics … and that’s why if it’s not driven regularly - the low voltage issue will occur. Which explains my quip about my brother using the “small car”…probably meant less electronics…(?). I do not know.

this time - will have to insist that this doesn’t make sense and they should at least try to diagnose it.

thanks again.

but if anyone had the issue resolved and can share the exact problem that caused it - I would point the dealer in the right direction. Would be very grateful…. (I think they prefer to spend their time servicing cars and getting paid… instead of trying to diagnose an issue..)

Yes eventually it would drain, but this should be measured in weeks, not days. I can't imagine being gone on a vacation for two weeks to return to a car that has drained its battery. I'm saying a module has gone on the fritz and isn't allowing the car to sleep properly. A test you can do at home, charge the battery, lock the car and put the key(s) into a faraday pouch so they cannot communicate with the car and monitor. I have seen people report that if the keys are too close to the car and/or it is unlocked it will not properly sleep.

will try faraday caging the FOBS and see. Texted the Service Advisor at the dealership and will hopefully get a helpful reply about sending the car for a few nights to let them observe. Please see below a photo I took and some inputs…! Thanks a lot again for bothering to respond jkaetz….



[img alt="Thanks jkaetz for taking the time to respond. Regarding the faraday caging the FOB- I tried double pressing the lock button on FOB to deactivate the keyless entry. (Meaning have to unlock car using FOB unlock button)…. The voltage still dropped. (Will try to put the FOBS in a faraday cage).

The photo shows the battery voltage this morning …. After we ran the car for 60 minutes last night. Blimey…. According to what I read online … the voltage of the 12V battery should stay around 12.6-12.8v"]https://cimg8.ibsrv.net/gimg/www.mbworld.org-vbulletin/2000x1504/img_7161_23ce8f060dfc65e44326f8cd57b8fedad4c6840d. jpeg[/img]
Thanks jkaetz for taking the time to respond. Regarding the faraday caging the FOB- I tried double pressing the lock button on FOB to deactivate the keyless entry. (Meaning have to unlock car using FOB unlock button)…. The voltage still dropped. (Will try to put the FOBS in a faraday cage). The photo shows the battery voltage this morning …. After we ran the car for 60 minutes last night. Blimey…it dropped to 12.1v. According to what I read online … the voltage of the 12V battery should stay around 12.6-12.8v

A double press of the lock button on the key disables the keyless go feature so no need for a Faraday pouch.

Make sure to do it for both keys.

With everything powered up that's not a bad voltage. The 12.4-12.6 voltage is measured with nothing connected to the battery. As soon as the battery is powering something that voltage will go down. What it shouldn't do is be in the low 11's. The best way to measure the resting (no load) voltage would be to close/lock the car but leave the hood open and measure the voltage at the jump start terminals with a meter. That will give you a better picture of what the resting voltage of the battery is doing. Personally I would close/lock/keys in pouch with hood open. Charge overnight with a good charger, then remove charger and start measuring the voltage over the next few days.

Keep the key far away.
And don't touch anything like the door handle because you will wake the car up and that, in itself, will lower the reading by at least 0.4 volts.

That's why leaving the hood open before measuring voltage is important.

The car wakes up every time you approach the car with the key, or when there's communication from Mercedes.
The car wakes up, drains the battery a bit, and goes to sleep. Wash, rinse, repeat.

(I don't think the double press on the key itself keeps the car from seeing it anymore. I think all what does is keep from draining the key battery.)

Is standby still available?

Good question.