DIY / Electronics / Maintenance / Functioning

When, Why & How to Replace Mercedes Auxiliary Battery

August 24, 2020

As the push button for ever increasing fuel economy has pushed engines to be more efficient and use innovative technology we may not otherwise run across, in that location are some configurations of Mercedes that run a dual battery fix-upwardly with one bombardment primarily, to my knowledge, to power start the engine and power most things, and another for start stop organisation reserve and to regulate voltage.  To run into how to modify the main bombardment check out this postal service.

Modernistic Mercedes use so much computing in the delivery of torque to the wheels, and in almost every sensor, computer, etc.  I figured taking a lesson from Range Rover Buying that these cars may be sensitive to voltage and I could non be more than right. Right out of the gate previously my brakes felt more powerful and confident with the big H8 battery.  With this smaller Aux battery in my auto, a 200 CCA Duralast Platinum replacing a 7 year old OEM battery, I wondered what the bear upon would be.

If y'all are on a factory battery in years 5-7 you lot may want to preemptively change your battery without even testing information technology.  Information technology drives that much ameliorate.

In a empty stretch of road I gently striking the gas to a known level.  And wow, she took off.  There was such a large divergence I inverse the plans for the remainder of my day.  Literally, not just taking the long style home, but hey let'south drive that cute back road to the UPS Store to send the cable equipment dorsum.  Then let's return the core even though this new one isn't even an exact fit.

Wow, completely different.  So different the transmission really had to remap itself in eco pro or whatsoever, e mode stands for. A CLA 250 was driving very difficult stop calorie-free to stop light and in eco with virtually no effort I outpaced it but she was a bit jerky equally the transmission learned.  Perchance the transmission control unit (TCU) itself was operating differently with the additional torque.  Either way she put downward power very nicely.

This drive was so nice. It really made ,e reflect on the fact that with ESP mode on there is a giant barrier of computer between the go pedal and the drivetrain.  I would not recommend running an ECU tune with ESP off.

When to Supplant Your Auxiliary Bombardment

  • It says to
    • There can be a nuance alert "Supervene upon Aux Battery". Information technology is ok to drive for a flake but non likewise long.
  • Your auto is a certain age
    • I beloved the 2014-2016 Mercedes but if yous are running original OEM AUX bombardment you may want to switch information technology.
  • Information technology doesn't exam to rated power
  • Start/Stop Stops Stopping the Engine
    • If your eco is always yellow, and your motorcar isn't staying off as long or equally often every bit it used to, it is a skilful sign your AUX bombardment is worn
  • Park Help Stops Assisting
    • When you pull adjacent to an open spot to parallel park, your auto may have previously asked if you want to engage Park assist or something similar
      • If this stops working every bit often you may want to consider replacing your AUX battery

Why Replace Your Aux Battery

  • You're about to tune your car and the batteries are more than than five years one-time
    • For me my automobile runs ameliorate tuned with the batteries updated
      • I would guess it has to exercise with voltage droop nether load while trying to bargain with crumbling batteries every bit part of the load
  • You want your park aid to assist, and your eco mode to finish your car
  • Overall yous like your cars in top operating condition
    • Irresolute a worn AUX bombardment does brand a palpable difference in my case, and for many reported on MBforums.

Tubing setup aftermarket AUX battery replacement

Here you can run across my use of a cut downwards jura milk frothing adapter and the milk container adapter to connect to the factory tubing.  Using this Upgrade Provides an additional ten% capacity over factory, also using the function compatible AMG battery volition yield similar gains.

How to Replace Your Aux Battery

  • These batteries are often located in the torso of your auto or nether the dashboard
    • For ones in the nuance I cannot propose further but to point you to MBworld and suggest you ask at that place, which is not a bad choice when posed with a Mercedes question
  • For the ones located in the boot
    • Adequately easy, a 10mm wrench unhook the terminals
      • I loosely taped positive out of an abundance of caution
      • A 10mm bolt that secures a swinging holder in the example of the C218 likely W212 and similar
      • Unhook the vent
      • Install new bombardment
        • If you are using an aftermarket battery you will likely demand to hold the aftermarket bolt loosely with your paw
        • If you lot are using aftermarket consider the venting solution if it doesn't fit stock
          • I ended upward using two tips from a JURA Espresso Machine Milk hook up
            • I cutting the black frothing tip down and used the tubing to connect while using the articulate tip to connect to the factory tubing

Upgrade Mercedes Battery

  • AUX 14, and various 14 size batteries will work
    • Some car audio batteries may fit, these are hybrid batteries designed with large capacitors to capture and evangelize power faster
    • Y'all will probable need to modify the vent system or holding arrangement in some cases.
  • AUX xiv Platinum
    • Will probable need to utilize vent adapter as above, and hold the bolts in
  • AMG Batteries are often bigger than non-AMG simply will direct fit
    • CLS 63 battery near surely fits perfectly into the CLS550 and provides ~12% increase in CCA from 170 to 200.

Ease of DIY: 1 for MB Battery 4 for not-MB bombardment

You will need a 10mm wrench or socket.  No extenders are needed.   If you are going to a dissimilar battery other than MB, may need to fabricate a vent adapter every bit above out of a cut down Jura milk adapter.