Mbw2468%

I have a MB Branded Ctek (new) and it will not proceed to 'trickle" state step, the fourth light on this charger, after 30-40 hours. The charger states that is works with both Lithium and Lead Acid batteries which is the case for my car. I hooked it up to the dedicated charging points in the engine compartment. Anybody else experiencing this or have a solution and I'm curious if the MH pre-2023 have also experienced this. While Ctek makes the MB brand they do not offer customer support on private brands. Ctek also makes them for other Mild Hybrids such as BMW and Audi I believe. I also have my dealer looking into this. Thanks for any thoughts.

Diesel Benz

I frequently use my Ctek (most often the 5 A charger, sometimes the 25 A charger if I update maps) on my 223 and the 5 A charger does reach the "final" state (mine has more than 4 leds).

You must be charging the 12 V battery, no way to charge the 48 V battery. It should not make any difference if the car is a mild hybrid or not (or a PHEV like mine).

Just to be sure, you had your car in sleep state, no consumers active?

Mbw2468%

From what I understand the MHEV has DC to DC convertors with battery management. So the 48V system also charges the 12V battery "if needed" (when the IC motor is running) or from the dedicated charging points going first to the 12V battery "if needed" and then to the 48V battery "if needed" by either a "jump start" or a battery charger. It's my understanding that there is no 12V alternator for charging the 12V battery, charges comes from the 48V system (ISG). The car is not designed to charge the 48V battery directly from a battery charger.

It seems like a stretch to me too, to use a 12V 5 amp trickle charger and convert it to 48V and then charge the 48V battery "sufficiently" and then trickle charge it. What I read about Lithium batteries is they do not need to be kept fully charged. Perhaps say, a 50% charge is sufficient. But a charger is sold for this purpose including BMW & Audi.

This car does not have a sleep state but do I lock-it which is suppose to use a minimal amount of battery power.

Diesel Benz

I believe you are right about the 48 V system interaction with the 12 V battery. But the 12 V battery is not charged when the car is parked. On the other hand, only the 12 V battery feeds consumers when the car is parked. For longish parking periods it may be useful to charge the 12 V battery at times.

There is no way to charge the 48 V battery from the 12 V battery (when the car is parked, no need when it is driven). Now I'm confused about what did you actually try to charge and how, if not the 12 V battery?

I did not mean to refer to the real deep sleep state that these new cars have but the normal sleep when the car is parked, ignition off and doors closed. That would be the normal low power state where a 4 to 5 amp Ctek should be able to fully charge the 12 V battery.

Some Mercedes cars have a 12 V lithium battery. I believe your Ctek must be a suitable model for those cars. Mine is not intended for 12 V lithium batteries.

Mbw2468%

I'm attaching the charger to the dedicated positive and negative connectors used for charging or jump starting the car. These connection points pass to the 12V battery but also pass through a Battery Management System. In effect the charger is connected to the 12V battery but passes through the BMS and it is much more convenient then attaching to the battery. Of course the easy solution is running the car periodically but I'm leaving the car unattended for 3 or 4 months. My objective is to simply maintain the battery lives when not using for an extended period of time.

Yes, the charger is compatible with my batteries. Maybe it needs 50-60 hours or more before it steps down to a trickle charge but I hate to overcharge the batteries and Ctek tells me 24 hours should be sufficient. But a lot going on for a little 6 amp charger maintaining two battery and voltage systems.

JohnS500

I have a 2022 S500 purchased in Sept and received a few starter battery "critical" messages in Dec. The car started and I drove the car to charge the battery. Since then, I leave the car locked in the garage and while not getting low battery messages, I noticed the voltage at the under-hood terminals in the range of 11.9v to 12.1v when the car is not running. Less than the 12.6v I expected. As previously mentioned, it seems like it takes forever to charge to battery. Am I missing something? What voltage do other read at the under-hood terminals?
Thanks

Mbw2468%

I don't know what my voltage is at the charging terminals but there is a battery management module (not verified by MB) between the charging terminals and the battery. Perhaps that is sucking juice when checking at the charging terminals and perhaps would be higher if checked at the battery terminals.

I too got a "critical'' battery message and driving it for a time charged the battery sufficiently for it to go away. I had previously sat in the car without the motor running for maybe an hour playing the radio and tweaking/ learning the various functions of my recently purchased car. Two things I have learned, is with all the electronics running this car, the 12V battery does not hold a charge very long without the motor running. And driving the car charges the 12V battery much easier and faster than anything else, that is through the 48V ISG. And I'm questioning if I can get a trickle charger that will protect my batteries for extended periods of time.

JohnS500

I will be leaving my car unattended for about 5 weeks and, at this point, plan to connect a Battery Tender during that period.

Diesel Benz

This is a good idea. If I remember right, the workshop documents suggest charging the 12 V battery every 4 weeks. Since you cannot do that while away for 6 weeks, the maintenance charger would keep the battery healthy.

Diesel Benz

The 48 V battery can indeed be charged from the 12 V battery if needed but this does not work when the car is parked. The DC/DC converter is not active when ignition is off.

Mbw2468%

Yes, the only way to go if the charger functions properly.

Again, my problem is after 40+ hours of charging by my new MB 5 Amp Charger for both Lead Acid & Lithium batteries (made by Ctek) and on my new 2023 S580, it never stepped the charging rate down to "trickle/ maintenance" and continued at the higher charging rates of Bulk/ Absorption. Ctek tells me it should have stepped down at least by 24 hours of charging and suggesting it may be over charging the batteries, which is more of a concern than under charging batteries.

Since I tried two different chargers that didn't step down after considerable time, I think it has more to do with the 48V/ 12V ISG two battery electrical systems than the charger. Why don't you try it before you leave and see if it steps down or not. I would love any input regarding if your trickle chargers are stepping down the charging rate or not in these MHEV's type cars.

Mbw2468%

"The 48 V battery can indeed be charged from the 12 V battery if needed but this does not work when the car is parked. The DC/DC converter is not active when ignition is off."

So one can not trickle charge the 48V battery from the charging posts when leaving the car for an extended period of time, only the 12V. I can't imagine you could leave the ignition on for months.

JohnS500

I connected my 4 amp Battery Tender yesterday afternoon and in the evening it showed 80% charge. This morning it was fully charged. Voltage was 12.1v.

Diesel Benz

No, of course not. Leaving ignition on would make the car consume many times more amps than the 6 A charger can provide.

The 48 V lithium battery has zero load during long term parking. Only internal leakage makes it lose charge and that is very insignificant. How many months would the car need to withstand? We have many big machines that sleep off-season, 5 to 6 months. Even a standard VRLA battery keeps enough current (these do not have any load from remote door locks or alarm systems etc.).

crabman

What do you folks think about simply disconnecting the 12V batt? I'll be overseas for a few months and I was thinking that would be easier than hooking up and having to rely on someone to check on it.

Mbw2468%

Thanks. Most automatic chargers I have seen indicate what state of charge the charger is giving the battery, and it is indicated on the charger. The highest rate of charge is normally called Bulk and Absorption. Once the battery is "topped off", the charger automatically goes to a very low rate of charge often called Maintenance or Trickle or Float. Maybe your charger does not indicate such. My concern, is my charger shutting down the high charge rate after the battery is topped off, like it should, so not to continue at a high rate and over charge them. At this time I'm not concerned about what my battery voltage is.

I had had an unfortunate event when my almost new house bank batteries (on our boat) were over charged by my inverter/ charger, and it cost me $13k to replace them. In this case the batteries actually started melting besides being ruined. If they were Lithium like the 48V, they may have exploded if they shorted out. Although I question if a small amp trickle charger could actually melt batteries, but it could ruin them. That is why the automatic chargers step the charging rate down, not to save on the electric bill.

Mbw2468%

I have done that for years on other cars but what I've read on this car it is a no, no. Why I'm not exactly sure but sort of makes sense to me with all the electric stuff going on and a lot never shut-off. But disconnecting the 48V Lithium really unhinges me. Of course the message from Diesel Mercedes states the 48V is not being charged without the ignition on. I wonder if that is the case on 2023's, thinking if it changed to allow charging the 48V, maybe that's why it's taking so much time on Bulk/ Absorption, 2 battery systems of different volts.

crabman

I've got the dealership calling me back about it; they weren't sure themselves so they bucked it up the hill. We'll see if they come up with something interesting.

crabman

The dealership thinks the car will be fine on a maintenance charger or should be ok if it's started once in a while to top off. They did not recommend disconnecting because of a lack of data; they don't want to say yes or no because they simply don't know. I'm thinking of starting it when the app tells me it's low and seeing what happens.

JohnS500

Does anyone know the location of the 12v and 48v batteries in the 223? Just curious. I think the battery in my 17 GLE350 is under the passenger seat.

kafklatsch

Possible easy solution

Buy an appropriately power rated 7 day timer... plug the charger to it
Set it to timer(charge) for a few hours once a week OR 30 minutes a day
OR
Whatever charging set up you feel comfortable with
With this setup the possibilities are endless

You may have to have a charger that has buttons as opposed to Digital controls ( clueless here)... Which in my case I do have... So when I set the charge to trickle 5, 10, 30, jump, it is a button setting so applying wall power immediately activates whatever setting I have on the charger

I personally have had a manual setting charger for 20 years... trickle setting Has served me perfectly while being on travel for many months at a time..

Mbw2468%

Here is what I just received from MB .... in my manual pages 196 (Climate Control) and 208 (Driving and Parking) don't have anything to do with batteries. My manual is Edition B-2023 (Order no. P223 0556 13, Part no. 223584 01 11).

"Thank you for contacting the Premier Luxury Department. In regards to proper charging of your vehicle for longterm battery preservation information can also be found on page 196 of your owner's manual. If leaving the vehicle idle for extended periods, park the vehicle with the high-voltage battery condition of charge at between 30% and 50%. Do not keep the high-voltage battery continuously connected to power supply equipment. If leaving the vehicle idle for extended periods of time avoid, if possible, high ambient temperatures. Check the high-voltage battery's condition of charge every six weeks (page 208). Charge the high-voltage battery if the condition of charge is below 20%. Do not disconnect the 12 V battery even if the vehicle is left idle for an extended period. Otherwise, the condition of the vehicle's high-voltage battery cannot be monitored."

Mbw2468%

Bottom line for me. I'm not going to trickle charge my battery(s) or disconnect them for the 4 month storage period I will be leaving the car. I'll just buy new batteries if necessary. Trickle charging both a 12V (Lead Acid) and a 48V (Lithium) from a single trickle charger (Ctek or MB) does not seem possible or safe at this time.

Diesel Benz

The advice you got from Mercedes looks very much what I have on my manual for a plug-in hybrid (the same for an EV).

If you are going to be away for 4 months, I'm afraid the 12 V battery will run completely flat. Not sure about the 223 idle current but older models consumed some 80 mA if they had an alarm system (40 mA without alarm). The 223 has all the on-line connectivity "half active", the idle current must be higher than 80 mA. But calculate 4 months times 30 days times 24 hours times 80 mA and you'll get a ridiculously high Ah figure (please check, I had to calculate 3 times and still feel it is surprisingly high).

It would be better to unplug the 12 V battery ground rather than leave the car for 4 months without any charging. The 48 V lithium battery would survive if it had decent SOC at start, no consumption on that battery when the car is parked.

I find it odd that your trickle charger does not reach the final state, perhaps it just assumes a lower idle current on the car than the 223 has. Don't know if it is a good idea then to have the trickle charger connected all the time but the timer proposal sounds much better than leaving the car as it is. The very minimum I would do is activate the deep sleep mode but I'm afraid even that is not good enough. The timer approach needs a proper charger, easy to test. Some chargers even stop charging after any mains loss (I had one for a 12 V car battery providing power for a GPS base, it died frequently for a flat battery). Ctek would be fine, I'm sure many others are.

crabman

I use a local outfit to put my cars in heated storage. It matters because I know them fairly well having done quite a lot of traveling and I solved the problem by slipping the guy extra cash to put it on a charger once a week.