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Hello all! I will be leaving a 2017 s550 4matic sedan in a garage for a few months and thought it would be best to get a battery maintainer. I ended up getting a MXS 5.0 for the c63 and was wondering if that would also be good to use for the s550. Also, I noticed that there is a 12v socket in the trunk of the s550, is that where you would connect a battery maintainer/trickle charger? Do I need to worry about the auxiliary battery? Please let me know what maintainer would be best and how to go about connecting it!
I use the terminals under the hood to connect my trickle charger. I have to set it to AGM mode, then lock the doors so the charge is faster than the drain, but it works for my 4 month storage needs.
Agreed. Use the terminal under the hood and the ground point presumably on the strut tower in AGM mode and you should be all set. I also use the CTEK MXS 5 on both of my Benzes.
I left my for 4 months , but as well the car was driven from the garage for on weekly basis. In the meantime battery was charged once. If you have some one to start at least the engine, that will be valuable for the motor and gearbox. Just move the car few centimetres to save a lot of problems. Spring , shaft , camshaft bearings solenoids valves and soft seals all of that need to move.
I use the terminals under the hood to connect my trickle charger. I have to set it to AGM mode, then lock the doors so the charge is faster than the drain, but it works for my 4 month storage needs.
Originally Posted by teksurv
Agreed. Use the terminal under the hood and the ground point presumably on the strut tower in AGM mode and you should be all set. I also use the CTEK MXS 5 on both of my Benzes.
Okay, thank you for the info! I was a little curious if we should use the 12v in the trunk, but if the hood connections worked, no need to change anything!
I left my for 4 months , but as well the car was driven from the garage for on weekly basis. In the meantime battery was charged once. If you have some one to start at least the engine, that will be valuable for the motor and gearbox. Just move the car few centimetres to save a lot of problems. Spring , shaft , camshaft bearings solenoids valves and soft seals all of that need to move.
I would love to have someone drive the car, but it would need to be a good drive. I think the charger will be fine because it won't be left like this often
You don't want to start a stored car for a few minutes. Doing so creates condensation which will stay in the engine and exhaust creating a water and oil mixture in the engine and corrosion in the exhaust. Once a stored car is started, it should be highway driven for a half hour or so to burn off the condensation and lubricate various bearings and seals such as those in the axle.
As far as using a tender to keep the main battery charged, that's fine. However, that will not maintain the auxilliary battery. That needs it's own charger which would require removing some trunk panels to gain access. However, it's been reported on the Forum that MB will void the warranty if a maintainer/charger is used on the aux battery saying it can damage the electronics.
Last edited by Jud Chapin; 01-12-2021 at 09:01 PM.
You should be fine leaving the car just hooked up to the maintainer for up to 6 months or so. Of course your tires will get flat spotted but that shudder from that generally goes away after a few hours of driving the car. If I'm going to leave my car over around 2 months I generally put in "Stabil" fuel additive in the tank to keep down gum and varnish forming in the gas in the tank. I generally leave the tank fairly full to to prevent as much condensation as possible too.
I guess when the doors are locked certain functions kinda go into a sleep mode is my understanding. Furthermore there is a Standy mode in the menu which puts the functions even further to sleep. I've never used this function but probably should be as I do leave cars long term often. When I've left these cars long term I've actually left the doors unlocked and drivers window down as I worry if the car was locked about the alarm going off due to a glitch or something. Plus leaving the window down in a hot garage is a good thing to keep mold from growing in the car. I also have worried in the past if I leave the windows up and lock the car what if there were a glitch in the Mercedes Me app and the car self started in the enclosed garage when I was not there. With at least the drivers window down a a few inches and the car unlocked no way is the car going remote start itself as with those conditions it is not allowed to happen. I dunno maybe I worry to much, but doing things this way has not been a problem. Generally after a few months the rear of the car is sagged due to the airmatic suspension deflating but once the car is started seems to come back up. The car always seems to fire up right away although generally the first week of short trips is kinda rough as the tires do get flat spotted sitting in the same position for so long but will generally get back their original or close to it shape. I can't see going to the trouble of putting the car up on jack stands for this alone as it does generally resolve itself. Also leaving the battery maintainer hooked up with the hood raised and leaving that way has never been a problem, maybe a older car with worn out hood pistons it might be issue though as the hood could possibly slowly close itself. Never had that happen though myself.
Last edited by 2012 merc amg; 01-13-2021 at 01:33 PM.
I like leaving the car unlocked and windows down a few inches when storing the car. The reason being is that with the doors unlocked there is no way the car is gonna remote start in the garage inadvertently or otherwise. Also not using standby mode and shutdown the communication module I can still check up on the cars location and status with the mobil app. I always put the windows down a few inches to try to prevent mold from forming in the car.
Last edited by 2012 merc amg; 04-04-2021 at 11:14 PM.
My 2015 S550 4Matic Sedan would never go into trickle mode with the doors unlocked. The 1.5A charger could keep up with whatever the draw was such that the batteries maintained a charge, but it would never go into trickle mode. I read where the drain is less with the doors locked so the last two seasons I had the car "stored" (Jan-Mar), I locked the doors and the charger went into trickle mode within a day or two. I do not know what draw is removed with the doors locked, but something is different, for sure.
I traded the 2015 for a 2020 this past December. Locked the doors for the Jan-Mar timeframe. Charger went into trickle mode within a day. If I understand what the communication modules do, they seem to have worked fine with the doors locked. There was an automatic software update and I could check the car status, lock/unlock the doors, etc. via the mobile App during that time. So, I'm not sure what "2012 Merc AMG" is referring regarding communication modules shutting down with the doors locked unless he/she has a different model.
Agreed. Use the terminal under the hood and the ground point presumably on the strut tower in AGM mode and you should be all set. I also use the CTEK MXS 5 on both of my Benzes.
Are you setting the CTEK MXS 5.0 to AGM on a standard lead-acid battery?
One thing I've learned about battery charging lately as a result of Covid 19 (less driving, shorter trips) is that driving a car for a few miles doesn't bring the the battery back to full charge. After several trips to town and back,15 miles or so, it takes 10 of so hours to get my 1 year old OEM battery fully charged using my CTEK MXS 5.0.
Are you setting the CTEK MXS 5.0 to AGM on a standard lead-acid battery?
I was confused like you with my CTEK AGM mode. After all AGM are lead-acid batteries so why the difference in charging mode then...??
I believe CTEK uses "AGM" as a poor translation for "DEEP CYCLE" battery and use a charge step up over 15 to 16V to try re-balancing the cells of deeply drained units.
Higher voltage causes electrolyte to boil out hydrogen in conventional batteries but in AGM the electrolyte is a GEL ... does not mean they like high voltage on regular basis.
Our cars have electronic module built with 16V Max parts - Hardly anyone disconnects their battery before charging it... so overall I say regular mode is our BEST CHOICE here.
If you are interested to find out why your battery is not well charged, you can simply drive around with your IC display showing "Workshop Menu" - Battery: Voltage/Amps
This will show you if your battery charges well all the time (14.9V > 13.5V > 12.6V) like most cars.
or
if your battery goes into uncontrolled dischargeafter 1hour of highway cruising (14.9V > 13.5V > 12.6V > 12.3v > 11.x) sign of charging problems.
AGM and "deep cycle" batteries aren't the same. There's many articles on this subject that can be found (Google). Here's an example and I quote:
"AGM batteries can discharge deeper than conventional deep cycle batteries without major damage. AGM batteries only discharge at the rate of up to 3% per month. Even after 12 months sitting idle they can recharge and go back into full service without any major damage."
AGM and "deep cycle" batteries aren't the same.
"AGM batteries can discharge deeper than conventional deep cycle batteries without major damage.
What does that say: "AGM can discharge deeper than "deep cycle" batteries but they are not "deep cycle" batteries" ?
Originally Posted by Jud Chapin
... As far as using a tender to keep the main battery charged, that's fine...
it's been reported on the Forum that MB will void the warranty if a maintainer/charger is used on the aux battery saying it can damage the electronics.
As I mentioned above the issue here is selecting "AGM Mode" on CTEK while the battery attached to all the car electronics -
> Simply put:
-- The CTEK NORMAL Mode is BEST for connected car batteries.
-- Do not use the misleading "AGM MODE" that may fry car modules with unnecessary higher voltage (used for disconnected Deep-Cycle applications).
-- Keep your batteries floated as often as practical.
Last edited by CaliBenzDriver; 05-10-2021 at 02:09 PM.
Reason: formatin'
Battery Issues SOLVED -- The CTEK Battery Tender is GREAT!
All my battery woes are SOLVED -- Thank you to everyone here for your wisdom! I purchased the CTEK MXS 5.0, and I can echo what others have said -- It's GREAT!
Prior to purchasing the CTEK, I used to have 3 battery-related issues:
1- Eco Start/Stop would rarely, if ever, engage, presumably due to insufficient battery charge. I would have to drive for 60+ minutes, if I had even a hope of Eco Start/Stop engaging. NOT ANY MORE! Now it's operational nearly every time I come to a complete stop.
2- I used to receive a "START ENGINE" battery warning (see pic below), when I would open the driver's door, after having not driven the car for 2-3+ days. NOT ANY MORE! I haven't seen this message once, since I've been using the CTEK!
3- I couldn't use COMAND with the engine off for more than about 4 minutes, without COMAND threatening to shut down, due to insufficient battery charge. NOT ANY MORE! I can now stay in the car for 30 minutes listening to music with the engine off, before COMAND wants to shut down, which is normal.
I would see this message when I first opened the door, after the car had been not been driven for more than 2-3 days.
I would see this message after driving and then stopping the engine while remaining in the car, like if I was waiting for my wife to run into the store for 10-15 minutes, as I enjoy REST and Spotify. This message would pop up after only sitting for a few minutes. Not any more! Now I can stay in the car for as long as I want, with no warning message (except the normal one, if it's been 30 minutes and COMAND is going to shut down normally).
Thanks again to all of you willing to share your expertise -- I'm loving the CTEK!
Nice to see you are satisfied with CTEK. We have got a CTEK as well. Although , we don't use it as much as we used to do , it has served and fulfilled our expectations every time we use it
01-11-2021, 01:14 PM
CTEK... AGM ... and low charge batteries
To be or not to be...
