Searched around on the forums, can't find anything on this issue (I've seen it mentioned elsewhere, but wanted to check with other C63 owners). My C63S sedan has been great. No complaints. Except this issue with the app and the starter battery. I go a lot of short, local trips with my car. To and from the train station. To and from local shops. To and from my kids' friends houses. It's all local, less then 10 minutes driving. As a result, EVERY SINGLE TIME I get out of the car, I get a warning notification from the app on my phone AND an email with the subject "Mercedes me connect: Battery Monitor – Charge Status Critical." The full email reads as follows:

Of course, the battery doesn't ACTUALLY seem to be an issue, as it starts every time with no issues. Has anyone else experienced this? Is there a fix that doesn't require going to the dealer? I don't want to install a CTEK or similar unless absolutely necessary, and as stated, there doesn't seem to be anything actually wrong with the vehicle.

Thanks in advance for any info.

 

Nope, haven't seen any issues with the starter battery. Shows charged in the app. It showed partially charged when I had the car in for the Xpel installation and it had to stay over the weekend. Do as it says and go for a long drive to see if it goes away. Short drives are actually the worst thing you can do with modern cars. It causes the engine etc. not to reach operating temperature leading to carbon build up etc. and low rpms and lots of idling don't fully charge the battery. You have to give it enough time or rpms to really generate a good charge for the battery. In addition, these cars don't fully shutdown when you park them, because they are in constant communication with the cloud so you can perform the remote control functions from the app like locking/unlocking, so the battery charge gets lower and lower if you don't give it time to properly charge. There's a standby mode you can activate in the Infotainment system, that shuts off the communication and fully powers down the car, but you will no longer be able to check status etc. from the app. In most likelihood your battery is indeed low. The warning comes relatively early to avoid getting you stranded, but I would take it seriously. If after a 30-60 minute drive you still get the critical battery status, then something is wrong, but if it shows fully charged after that, then you have your answer and you need to drive more and for longer distances.

 

Thanks for the response. The reality is that I just don't have the time to drive the car 30-60 minutes on the regular. I work a lot during the week and get home late and crash. On the weekends, I'm often with my family on short trips. Even when I take it on one longer drive per week, it seems to throw this warning eventually. I've had lots of modern cars with lots of technology, and never seen this before. If this is just reality with these cars, I guess I have to look into adding a CTEK, but it's pretty sad that a $90k car requires that. Glad I leased it...

 

It seems to be the new reality with the connected car features staying active even if you park the car, so there is a higher idle draw on the battery than there used to be in the past and more and more systems in the car are electrically powered, so there is higher consumption when the car is running. There are even two batteries in this car because of that. The starter battery and an auxiliary battery. The demands are just going up, hence the new 48V systems coming out with the mild hybrid setups. My previous car essentially went into a deep sleep mode about 10 minutes after shutting it off. I don't drive a lot during the week, either. I work from home, and I try to walk/bike to local places around here. I do often go for fun drives in the canyons over the weekend, though, and some regular road trips, so so far I haven't had any issues. I probably will activate the standby mode, though, for when I go on vacation for a couple of weeks, so I don't come back to a low battery potentially. That's definitely not something I had to worry about with past cars. I did however purchase a trickle charger earlier this year, because I went to Europe for 2 months and I hooked it up to my previous car to make sure the battery stayed in good condition for this long. If you really can't drive it regularly then I would get a trickle charger and hook it up to it. You would probably be a good candidate for an EV to be frank. The C63 doesn't sound like a good fit. These cars need to be properly driven. A redline a day keeps the mechanic away as we sometimes say and it does apply to high performance cars to keep them healthy.

 

Mine either says fully charged or partly charged. I have never seen critical.

 

In the last 1-2 months, my driving has come down due to personal reasons. I get to take my 2019 C63S only on the weekends, and sometimes on weekdays. Each drive between these long gaps varies from 5 miles to a few hundred miles (day trips). When I leave the car parked in my garage, I don't get the Partly charged until at least 15 days or I actually go play around with the car infotainment for a long amount of time (say 30 mins - few hours) without actually starting the car.

I have got Critical alert when I left my car with the detailers for applying PPF and tinting. They didn't want the car to automatically lock, and were also opening/closing the windows without turning on the engine. After the third day, I started getting the Critical alert and I called them up and asked them to let the engine run for 30 mins or so. They did that the next two days, but on the final day they didn't bother. It sat with the Critical alert warning the entire day and I picked up the car in the evening. After picking up the car, I drove 15 mins and that was sufficient to charge the battery completely.

These cars do have a lot of electronics (the Hermes LTE module), but at the same time these are electronics which consume few consume very few watts of power and enter low power mode when they don't have to do anything. The car also pushes state from the car to the Cloud so that your Mobile app doesn't have to reach the car periodically to get the current status. Once the car is moving, then it starts to more frequently update the location and other state.

In other words, (assuming the battery is in great condition) you should be able to leave the car parked easily for even up to 30 days before you start seeing the Critical Battery alerts. I would recommend you ask your dealer to inspect the car and diagnose the root cause of this issue. Bad battery could be one reason. Cell phone reception being very weak which causes the LTE module to drain more energy for reception or constantly hunting for reception could be one more reason.

How is the cell phone reception for AT&T network in the area(s) where you park your car most of the time? I believe in the US, the Hermes module uses AT&T for LTE connectivity.

If you intend to leave your car parked for longer periods of time (weeks), then you could explore the Standby option.

 

Actually, it uses Verizon. Has a larger coverage area than AT&T. My Audi used AT&T and I have AT&T on my phones. AT&T reception quickly drops out in the more rural areas. On my canyon stints I rarely have phone reception, but thanks to Verizon I now have a connection in the car most of the way and get live traffic etc. Definitely a good move by MB to go with Verizon.

 

Interesting. The Wi-Fi hotspot stuff is offered through AT&T however. So I presumed the MB Connect stuff also uses AT&T. It feels weird to use two different operators for this and I could not get any authoritative information on Mercedes website for Mercedes Me Connect one way or another specific to the free services (except for the Wi-Fi hotspot stuff). Are you sure you're not referring to mbrace since that seem to be configured through Verizon (see below)?

Here is the link to sign up for Wi-Fi hotspot using AT&T for models using Mercedes Me Connect.

Mercedes Me Connect info:



On a little searching it looks like the earlier mbrace was/is being provided by Verizon:

 

Interesting. I honestly haven't looked at the Wi-Fi hotspot at all. It's not something I'm using in the car, but you are right, it is through AT&T. Not necessarily unusual these days to use two carriers for different services. Many newer smartphones have dual SIM/eSIM support now, too, so you can have two independent plans with separate carriers. AT&T has better shared and family data plans and better international roaming, which is why I'm using them for my phones, which also means I could now add the hotspot for only $10/month, but doesn't really provide any benefits over just using my phone's hotspot if I need to.

I know for sure that mBrace is using Verizon Connect. It's even listed on the Verizon Connect website, but I haven't found confirmation that Mercedes Me Connect in the 2019s is still using Verizon. I would think so and given the places I don't have phone reception with AT&T, but the car gets live traffic etc. it can't be AT&T. It makes sense to use Verizon for the connected car services, so they work in more places than they would with AT&T. Verizon has better speed and coverage, but as mentioned AT&T has the better plans. So it kinda makes sense to use them for their respective strength.

https://www.verizonconnect.com/solut...i-diagnostics/

It's quite possible that the system even uses both Verizon and AT&T and switches between them depending on signal strength to maximize coverage, but for the Wi-Fi hotspot that would require one to have two data plans, so it makes sense to only use AT&T for the hotspot.

 

Yes they use Verizon for mbrace (i..e pre-FL cars in case of C63). Yep, most likely they have multiple SIMs because the Wi-Fi hotspot is metered independent of the Mercedes Me Connect stuff. Still feels like more complexity on their side because of the need to coordinate with multiple partners. Yeah, the signal coverage aspect might be a better way to figure this out. Let me also try going to a place where there is no AT&T coverage (on my phone) and see what happens.

 

I have this problem. My car is a 2016 and it's being warning me of a battery low for the last year. Never cause any issues with the car starting. I figure I need a new battery - my car was in storage for a good 6 months, not being used.
The benefit of the low battery (if you can get past the warnings) is that eco mode never enables when the car warms up. The engine start/stop at traffic lights doesn't happen, but you still do get coasting mode (the sail boat) which would normally get disabled if you turn off eco mode.
My car is due for a service in a couple of months and will get the battery replaced then.

 

Drove the car for about 45 mins last night and didn't drive it this morning. Let's see how long it takes to come back with short drives to and from the train station and what not. Thanks for all the responses.

 

Glad to hear I'm not the only one!

I'm in the UK and my C63S had the same problem, I had the battery replaced and the dealer tweaked various sensors, which didn't really improve matters. I traded the car in for a new E63S Estate and now have exactly the same issue. Both emails and messages to my mobile phone. It used to really annoy me, but now I just ignore them.

My driving patters are very similar, but what surprised me was that I did a 60 mile round trip on Saturday and the same on Sunday and am still got a message yesterday. I'll raise it again with the dealer shortly. In all fairness the car has never let me down, but it might one day....

Funny how they don't say don't buy this car if your usage is low (6,000 miles a year)

 

My car (brand new 2020 C63S sedan) is currently at the detailer getting PPF and tint, and I'm getting start battery critical alerts as well. I have a trickle charger they are going to use to prevent this but I'm curious if anyone has had the limp mode issue (https://mbworld.org/forums/c63-c63s-...ss-anyone.html) as a result of this? I'm hoping Mercedes fixed that issue in the FL but I'm not sure TBH.

 

A 20-30 min trip should normally fully charge the battery again. If it doesn't then I would say there is an issue. Otherwise this really shouldn't be too much of a problem. I've had my car in for service twice now for three weeks each dealing with my side skirt replacement and I started to get battery critical warnings towards the end of three weeks. During that time the car wasn't driven very much, but also had doors open etc. while working on the car. After a couple of trips it was fully charged again. Over last Christmas/New Year I was out of the country for two weeks and I put the car in standby mode for the duration. When I came back, the battery was still fully charged. If you really don't drive the car for a while then consider putting it in standby mode. That's what it's for. In that mode it turns off everything including the online services, so nothing is draining the battery while the car is parked.

 

Many thanks. I'd never heard of standby mode (RTFM...) and will do that if needed.

 

+1 for standby mode. Left my car for 2-3 months for summer travels out of the country (came back in between for a week) and had no issues and no app warnings

I think the app is overboard with the warnings too. Had countless non-stop warnings when my car was in the shop getting some work done for three weeks. But hopping in the car it was perfectly fine and after a drive home the warnings stopped completely. Not a big deal in my experience

 

Yeah, I turn off the security notifications when the car is in the shop, otherwise I constantly keep getting alerts that the car is unlocked every time they start and stop the engine. I ended up setting up a geofence around the dealership so I could see when it left and came back. They do not work all that reliable, though. I probably only got about 2 out of 3 alerts, but it was helpful knowing when the car was going to the body shop for the side skirts and when it came back. Combined with always being able to see the current location of the car it's a nice piece of mind and made the wait a bit more bearable.

 

Yep, the notification delays (sometimes 4+ hours), missing notifications (a few of them) are some of the things I wish MB improved on this. I know for sure I'm not paying for a subscription to this service after the free period ends.

 

Most times after I wash my car soon after when checking app. it will show Battery Partial Charge.
Believe it from hose water pressure setting off the door handle sensors Lock and Unlock and outside mirrors folding in and out.
No big deal, just take the car for nice ride.

 

Keep your key inside the car or away from it. It's not the pressure, but if you keep the key in your pocket and holding the hose, the water stream conducts enough electricity to act as an extension of your hand and if it hits the door handle it thinks you are touching it.

 

Good point. Will do next time I wash.

 

I left my car in a storage unit for six months while out of the country. It was winter and it was COLD. Car fired up immediately at the end of its extended stay and never had any battery issues.

 

Did you get a resolution to the battery problem? I am having the same trouble on a year-old E300 coupe.

 

Yes I did, they fitted a new battery under warranty. I had the same problem with the same outcome on my C63S, so I feel it is a sticking plaster solution, rather than a permanent one.

Only time will tell.....