M-Class (W166) Produced 2012-2015

Trickle Charging 2015 ML350 4Matic

Thread Tools
 
Search this Thread
 
Rate Thread
 
Old Feb 23, 2019 | 10:18 PM
  #1  
RLandis's Avatar
Thread Starter
Newbie
 
Joined: Oct 2012
Posts: 12
Likes: 0
Trickle Charging 2015 ML350 4Matic

I bought a CTEK MXS 5.0 to charge (maintain) a '14 SL550, which I've since sold. I never used the CTEK. The MB dealer advised me that there were 2 batteries in the SL, and they were in series, and could be maintained through the 12V power port in the trunk of the SL. So, 2 questions:
1-are there 2 batteries in the '15 ML350 4Matic.
2-can they be maintained by the CTEK through the 12V power port in the rear of the ML.

Sorry for the rookie questions.

Richard
Reply
Old Feb 24, 2019 | 01:45 AM
  #2  
fabbrisd1's Avatar
MBWorld Fanatic!
10 Year Member
 
Joined: Nov 2012
Posts: 6,130
Likes: 1,117
A gaggle of MB's
Well... 1st off your MB dealer was puffing up a bit - yes - your SL550 has a main battery and a auxiliary battery - but "no" they were not in series. Yes - your ML350 has two batteries too - a "main" and a auxiliary.

On your 2014 ML350 - if you are planning up over 2-3 week of inactivity - if your ML350 has Keyless Start (button) - remove the Start Button (it pulls straight out) which lets your ML "sleep" (by deactivating the Keyless Go/Lock-Unlock feature) - with the Start button "out" you use your fob to lock/unlock your ML until you replace the Start button.

Unlike your SL - frankly I don't know if your rear cargo 12V port stays "live" after you shut down your ML - I "think" it will go to sleep. If you wanted to connect your CTEC - if your model has the interchangeable "clip" connects - I would use those connected to the jump points on passenger side engine compartment. Please note for connecting/disconnecting any type of charger - the Start Button should be out on connect/disconnect - and no key in the ignition.

"Most" don't trickle charge anymore - they remove Start Button - and in the unlikely event you need a jump - under warranty or with ongoing dealer service - Roadside assistance offers free 24/7 jump service.
Reply
Old Feb 24, 2019 | 04:24 AM
  #3  
RLandis's Avatar
Thread Starter
Newbie
 
Joined: Oct 2012
Posts: 12
Likes: 0
Originally Posted by fabbrisd1
Well... 1st off your MB dealer was puffing up a bit - yes - your SL550 has a main battery and a auxiliary battery - but "no" they were not in series. Yes - your ML350 has two batteries too - a "main" and a auxiliary.

On your 2014 ML350 - if you are planning up over 2-3 week of inactivity - if your ML350 has Keyless Start (button) - remove the Start Button (it pulls straight out) which lets your ML "sleep" (by deactivating the Keyless Go/Lock-Unlock feature) - with the Start button "out" you use your fob to lock/unlock your ML until you replace the Start button.

Unlike your SL - frankly I don't know if your rear cargo 12V port stays "live" after you shut down your ML - I "think" it will go to sleep. If you wanted to connect your CTEC - if your model has the interchangeable "clip" connects - I would use those connected to the jump points on passenger side engine compartment. Please note for connecting/disconnecting any type of charger - the Start Button should be out on connect/disconnect - and no key in the ignition.

"Most" don't trickle charge anymore - they remove Start Button - and in the unlikely event you need a jump - under warranty or with ongoing dealer service - Roadside assistance offers free 24/7 jump service.
Thank you for your response. Now you have me wondering why BOTH the Tech Support of CTEK, and the Service Dept of MB of Nashville BOTH advised me that plugging the cigarette lighter adapter on the CTEK (which was a separate purchase) into the 12v power port in the trunk of the 550SL would keep both batteries topped up. I only picked CTEK as they manufacture the MB charger (or at least they design it, and are credited thusly on the actual MB unit).

I guess my my safest bet is to have a friend start the ML weekly, and run it for 5 or 10 minutes while I’m away.

Last edited by RLandis; Feb 24, 2019 at 04:28 AM. Reason: Spelling
Reply
Old Feb 24, 2019 | 04:47 AM
  #4  
peter2772000's Avatar
MBWorld Fanatic!
5 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2017
Posts: 1,234
Likes: 155
From: Montreal/Cape Coral FL
2012 X6 35i Sport, 2013 ML 350 BT, 2019 4Runner TRD Pro, 2020 CRV-AWD
Originally Posted by RLandis


Thank you for your response. Now you have me wondering why BOTH the Tech Support of CTEK, and the Service Dept of MB of Nashville BOTH advised me that plugging the cigarette lighter adapter on the CTEK (which was a separate purchase) into the 12v power port in the trunk of the 550SL would keep both batteries topped up. I only picked CTEK as they manufacture the MB charger (or at least they design it, and are credited thusly on the actual MB unit).

I guess my my safest bet is to have a friend start the ML weekly, and run it for 5 or 10 minutes while I’m away.
I would do as Fab stated and simply connect the charger to the jump-start points under the hood. And starting the car and letting it idle for 5-10 minutes isn't going to do much for your battery. Between the power draw of the starter and the constant draw of the fuel pump, electronics & blower motor, all while the alternator's not even close to optimum charging rpm, I think you're making a bad scenario worse.

Just make sure your charger is designed for AGM batteries, plug it in and be done with it.
Reply
Old Feb 24, 2019 | 05:04 AM
  #5  
peter2772000's Avatar
MBWorld Fanatic!
5 Year Member
Liked
Loved
Community Favorite
 
Joined: May 2017
Posts: 1,234
Likes: 155
From: Montreal/Cape Coral FL
2012 X6 35i Sport, 2013 ML 350 BT, 2019 4Runner TRD Pro, 2020 CRV-AWD
Comments in red below;

Originally Posted by fabbrisd1
Well... 1st off your MB dealer was puffing up a bit - yes - your SL550 has a main battery and a auxiliary battery - but "no" they were not in series. Yes - your ML350 has two batteries too - a "main" and a auxiliary.
I'd love to see them in series LOL. Obviously confused with "in parallel".

On your 2014 ML350 - if you are planning up over 2-3 week of inactivity - if your ML350 has Keyless Start (button) - remove the Start Button (it pulls straight out) which lets your ML "sleep" (by deactivating the Keyless Go/Lock-Unlock feature) - with the Start button "out" you use your fob to lock/unlock your ML until you replace the Start button.
You sure about this? First time I've ever heard about this. We often leave the car unattended at the airport when we fly down to Florida for weeks at a time. I'm already worried about finding the battery dead because we're still running the original batteries (replacing them both this spring). If what you're stating is fact, you've prolly just saved me major grief...

Unlike your SL - frankly I don't know if your rear cargo 12V port stays "live" after you shut down your ML - I "think" it will go to sleep. If you wanted to connect your CTEC - if your model has the interchangeable "clip" connects - I would use those connected to the jump points on passenger side engine compartment. Please note for connecting/disconnecting any type of charger - the Start Button should be out on connect/disconnect - and no key in the ignition.
Again, you're freaking me out. When we leave the truck at home and taxi it to the airport, I leave the truck plugged into our AGM-rated BatteryMinder.
http://www.batteryminders.com/2012ag...acid-batteries

I've never removed the start button and the charging state always shows the battery as being fully charged. What was that doing to the electrical system?


"Most" don't trickle charge anymore - they remove Start Button - and in the unlikely event you need a jump - under warranty or with ongoing dealer service - Roadside assistance offers free 24/7 jump service.
As well, we leave our 2012 X6 plugged into the same type of charger down south. There's no start button on that, you have to stick the fob into a slot (royal PITA). Anything I should know about that?
Reply
Old Feb 24, 2019 | 05:08 PM
  #6  
Diabolis's Avatar
MBWorld Fanatic!
 
Joined: Jan 2013
Posts: 3,745
Likes: 811
From: The Great White North
W204 C63 Coupe, W166 ML350 BlueTEC, 928GT, Taycan GTS Sport Turismo, C5 Z06 & IS300 race cars
fabbrisd1 - pulling out the start button does absolutely nothing of the sort. The car constantly keeps various internal systems powered and always listens for signals from the key fob... in other words, all the RF receivers are always enabled.

Unless the battery is weak / dying, you can leave the car parked outside for a month and it will start every time. All other things being equal, humid ambient air will discharge it quicker than dry ambient air, but even in the worst possible conditions (100% RH) it is still easily able to fire it right up after you've left it sitting unattended for a month. If it doesn't, either the battery is no longer able to hold a charge or there is some kind of electrical problem with the vehicle resulting in abnormally high current draw.
Reply
Old Aug 6, 2019 | 02:26 PM
  #7  
threeMBs's Avatar
MBWorld Fanatic!
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Jul 2009
Posts: 3,530
Likes: 387
Only MBs - the best or nothing
Originally Posted by fabbrisd1
... Please note for connecting/disconnecting any type of charger - the Start Button should be out on connect/disconnect - and no key in the ignition...
Why? I've used CTEK 3300 on four different MBs all with start/stop button "in" (i.e. 2019 W213 E start/stop button can not be removed) without any issues for years now. Do you mind sharing why start/stop button needs to be removed when connecting/disconnecting a trickle charger like CTEK, please?
Reply

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 


You have already rated this thread Rating: Thread Rating: 0 votes,  average.


All times are GMT -4. The time now is 06:20 PM.

story-0
New Electric Mercedes-AMG GT 4-Door Coupe Unveiled: 10 Things You Need to Know

Slideshow: Mercedes-AMG's new electric GT 4-Door Coupe trades combustion for software, synthetic noise, and more than 1,100 horsepower.

By Verdad Gallardo | 2026-05-20 20:08:15


VIEW MORE
story-1
6 Mercedes Models That Did NOT Age Well (But Are Somehow Still Cool)

Slideshow: Not every Mercedes design becomes timeless, some feel stuck in the era they came from.

By Verdad Gallardo | 2026-05-12 18:09:07


VIEW MORE
story-2
Manual Mercedes? 6 Times Sindelfingen Let Drivers Have All The Fun

Slideshow: Yes, Mercedes built manual cars, and some of them are far more interesting than you'd expect.

By Verdad Gallardo | 2026-05-02 12:36:58


VIEW MORE
story-3
Mercedes SLR McLaren 722 S Is Extremely Rare Example Modified by McLaren

Slideshow: A one-of-one U.S.-spec Mercedes-Benz SLR McLaren Roadster became even rarer after a factory-backed transformation at McLaren's headquarters.

By Verdad Gallardo | 2026-04-29 11:19:28


VIEW MORE
story-4
8 Classic Boxy Mercedes Designs That Have Aged Like Fine Wine

Slideshow: Before curves took over, Mercedes mastered the art of the straight line, and some of those shapes still look right today.

By Verdad Gallardo | 2026-04-25 12:05:49


VIEW MORE
story-5
Flawlessly Restored Mercedes 190E Evo II Heads to Auction

Slideshow: The 190E Evolution II shows how a homologation necessity became a six-figure collector icon.

By Verdad Gallardo | 2026-04-22 17:53:47


VIEW MORE
story-6
Electric Mercedes C-Class Unveiled: 11 Things You Need to Know

Slideshow: Mercedes is turning one of its core nameplates electric, and the details show just how serious this shift is.

By Verdad Gallardo | 2026-04-21 13:58:06


VIEW MORE
story-7
Mercedes EQS Gets A Major Update: Everything You Need to Know

Slideshow: Faster charging, longer range, and a controversial steer-by-wire system define the latest evolution of Mercedes-Benz EQS.

By Verdad Gallardo | 2026-04-15 10:35:34


VIEW MORE
story-8
5 Underrated Mercedes-Benz Models That Don't Get the Love They Deserve

Slideshow: These overlooked Mercedes-Benz models never got the spotlight, but they quietly delivered more than most remember.

By Verdad Gallardo | 2026-04-13 19:35:45


VIEW MORE
story-9
Mercedes 300D Has Pushed Well Past 1 Million Miles and It Ain't Stopping

Slideshow: A well-used 1991 Mercedes-Benz 300D with more than one million miles is now looking for a new owner, and it still appears ready for more.

By Verdad Gallardo | 2026-04-10 10:05:15


VIEW MORE