Sharing..................

One thing I hate when measuring super low DEEP SLEEP MODE current consumption of my E400 is , DMM ( multimeter ) is the only way to go to truly
be accurate seeing low 25 milliamps or less. No positioning worry at all. The repeatability is 100%, unlike current clamp.

Albeit I have super senstive Owon current clamp with 2 amp setting which can read very low current, it is not super stable when current consumption is dynamic and
the car body is steel, which steel is magnetic and effects the current clamp DC mode hall sensor if we are talking of 50 milliamps or less. Move it a bit or wire core not in the
center bull's eye of the current clamp, super low 10 milliamps reading can jump around.


On a wooden table Owon current clamp can read easy 10 milliamps with 1-2 milliamps accuracy, but in a car like my E400 the dynamic load before a car
will go to sleep and DEEP SLEEP consume only under 6 milliamps ......can throw off the Owon current clamp zero setting up to 50 milliamps error, including magnetic field error of
the steel in battery compartment region.

Example of stability of current clamp when it is static and on wooden table and no magnetic field to effect its reading.

I have retired my 6+ years old UNI-T UT210-E red one on the right side. Its 20 amps value has drfited a bit and it has no bluetooth wireless apps.

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Looks good on wooden table
My 13+ or so years old trustworthy Fluke 289 has developed blacken screen, from screen polarizer coating gone bad.
I love the Fluke 289, but it is not the fastest meter.

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I have posted on how you guys can do baseline DEEP SLEEP MODE power consumption of you car, so when one day parasitic drain occurs you know something is wrong, a module
failed to sleep or even worse like wounded cable. Here : https://mbworld.org/forums/e-class-w...-your-car.html


The limitation of DMM ammeter function is the 10 amps maximum rating. Surge power with open door and all interior lights I set to OFF, is still a bit over 10 amps.

Here is my car when already in DEEP SLEEP and I open and close its door again. It is actually a bit over 10 amps peak but the logging is 1 second 1 data point only.




12 minutes to get it back to DEEP SLEEP at 5 milliamps.

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Of which the 5 milliamps is not always 5 milliamps, there is always self-checking happening and can be up to 11 milliamps.




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I made this DIY Load Sharing Relay because there is a need for it when the car in question has battery at the trunk and the car has electric tailgate (SUV or Hatchback).
My case study was a Range Rover 405 of 2017. 3.0 V6 supercharged petrol engine and if GLE 400 would be similar.



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Close up...........



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I think mine is 433 Mhz, like garage door opener.
Below is the local price. In the USA it is this cheap too.



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The video.............




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I needed the wireless functions of these meters, other wise I have to be in the car hot sweating like a pig, waiting for it to sleep.
Also it may not be totally a sleep when you locked the door using the key FOB and the car is detecting the key FOB on you ( close by ) while
you sit in the car, sweating like a pig

My current go to DMM and current clamps with wireless bluetooth.


See above, the baby cheapo Owon 2100B can ready low milliamps, but it is not accurate when the consumption is dynamic. DMM in ammeter function like Hioki DT461 or cheapo UT60BT from UNI-T is still the best choice.





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What I learnt from the Land Rover. Which could apply to MB cars with similar system.

01. Range Rover ( RR) motorized tailgate, like GLE400, uses big electric powered strut.
In RR car case, manually manipulating the latch does not work to tell computer tailgate is locked....WHEN AND IF the eletric powered strut is fully open, it has position decoder
inside it . So car won't fully sleep. I am sure MB cars with big electric powered strut tailgate will have the same operational/safety logic.

RR has two doors for tailgate.


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RR battery location is Whisky Tango Foxtrot....aka WTF so troublesome to get to. Must remove pneumatic air pump that 3/4 circle fat device.





02. Door soft closer mechanism.
This RR has it, it is electric powered. I do not know MB door soft closer is electric or pneumatic.
Whatever it is, it may have safety logic when and if I fool the latch manually and door closer is not triggered, computers will not deem door is properly closed.
Then.....How do I see my DMM when I can't enter the car ? ( doors locked, glass tinting drug dealer dark )
Then....How do I remove the 2nd jumper wire to negative which prevents my DMM fuse to blow when I engaged ALL DOOR LOCK to get car to sleep at 10+ amps ?


GLE400 battery is under driver seat, so same needs to fool the rear door. This is another WTF location to install battery.





The RR has glass tinting so dark, I could not even see my DMM screen.

So the solution to all these crazy located battery cars, would be wireless DMM and Wireless Load Sharing Relay.
Thus I made the DIY Load Sharing Relay.

If you buy UNI-T UT60-BT bluetooth capable which is so cheap at US$40 now, it also have duty cycle %. Good enough for auto works.
The Wireless Load Sharing Relay highest cost for me is the Lit-Ion 18650 cell x 3 units, Samsung.
But 18650 is what I am using for all of my torch, so I gain back up.


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The case study of this RR battery drain could be useful for MB cars too.

01. Range Rover cars need new battery to be programmed or registered size and type wise, like BMW. This way the charging profile will match the new or old battery over time.
I do not know if newer MB cars need new battery to be programmed or registered ? W212 NO NEED

02. My Indie was sick and he needed me to track down why this RR L405 3.0 V6 petrol supercharged is eating up battery in 2 days, can't start.
Charge the batttery and it will start.

Naturally I needed to measure baseline DEEP SLEEP MODE power consumption of the car at this point in time, to see it is indeed above 30 milliamps which is usually highest allowed
for modern cars power consumption in deep sleep mode. But how do I NOT BLOW my DMM 11 amp fuse (Hioki uses 11A fuse, Fluke uses 10A fuse ) ?
This RR has alarm system. When doors are locked via FOB and one or more latch be it door is NOT LATCHING, or tailgate or engine hood, it will emit a unique sound and the side mirrors wont flip in and
the doors won't lock.

My facelift W212 and I hope it is the same with pre-facelift... its Front SAM computer recognize WORKSHOP MODE.
WORKSHOP mode is a mode where we can keep out hood open and the 2 latch/sensors/switch does not need to be tricked to lock.
So car will locked via key FOB and will go into DEEP SLEEP MODE even with hood maximum open height ( gas strut, no electric power ).
I do not have MB original alarm system on my E400, nor aftermarket one.

The RR does not have such WORKSHOP MODE for its 2 hood latch/switch/sensor.
Its spring lock is insanely strong, bast-ard, W212 is so easy to press the latch lock using even chopstick if you want ....
RR needed only 1 side, I choose left side hood latch to fool.... need to be pushed so hard till the lock engaged, and the car computer deemed the car is now ready to be
locked and alarm system activated. Again it does not answer the first question , how do I prevent my DMM ammeter section from getting hit with
more than 15 amps ???? when I press key FOB door LOCK ?

The answer at that point in time is power injection............. using battery maintainer at 13.2 to 13.36 volts, which is 0.5 to 0.66 volt higher than battery voltage.
This technique you can use also for any MB where their main battery is NOT in engine bay or at the trunk and you can't fool the tailgate big actuator motor via only the tailgate latch.

The power injection will always be available as jumper studs in engine bay for all MB cars, BMW and R-rover, for sure.



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Blue masking tape is spark prevention. Those are steel brake line I covered. I am very an-al when it comes to high power DC safety handling.


I needed to inject at least 16 amps if I do not want the DMM to be carrying any current, meaning battery is not contributing power to the car electronic.
The photo below is when I was still using OWON baby currrent clamp, instead of Hioki DMM in in-line ammeter mode. I was scanning the car to see any DTC. Thus I use my Autel MS906BT.



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The car registered a few LOW VOLTAGE stored codes.
Anyway, I charged the battery for 5+ hours and it was full.
I tried scanning the car again and without battery maintenainer assist and within minutes the battery voltage collapsed...hhhmm, bad battery it must be.

So I used RESERVE MINUTES test using electronic battery load tester to test this RR battery after charging it overnite.
25 amps constant load down to 10.5 volts is how Reserve Minutes test is done.




My original MB battery has Reserve Minutes information




Below on top of the left side Varta battery is my electronic load



So I took out the RR battery and.........
AA - It is not AGM as it should be
BB- It is a Fake VARTA... off the shelf retail Varta Silver Dynamic non AGM or AGM, is silver plastic casing. Varta Blue Dynamic is blue battery casing.
There is no such thing as BLACK battery casing Varta Silver Dynamic AGM unless branded and sold specific to Mercedes or Range Rover .

I wonder, must be the driver or owner office staff who bought this battery. It was bought in March 2024
So he/she went around looking for lowest cost VARTA.....and got a fake one instead...LOL
Car owner in Indonesia do not handle trivial matters for their cars, more so if luxury cars. Its never hands-on, only wallet-ON.... ha ha ha.
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GENUINE



The fake 15 months old Varta battery could also got accelerated "aging" due to AGM charging profile this RR uses and this one is a regular flooded battery.
Its Reserve Minutes capacity is less than 5 minutes hahahahah. If a healthy 95Ah battery, its reserve minutes capacity is typical 160 minutes at 25 amps to 10.5 Volt.

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The unique part I want to share with you guys is this :

01 - There is a Low Voltage Alarm while I scanned this car, even when I injected power into the car via battery maintainer.
02 - I guess Low Voltage DTC made the car not able to go into DEEP SLEEP MODE, so it is a double whammy....low voltage and modules stay up to suck more power
It was approx 200 milliamps as lowest HALF-SLEEP MODE based on Owon currentc clamp.

So I thought, 200 milliamps will not drain battery in 2 days as reported, it will drain battery in 10-14 days.
0.2Amp x 24 hours x 7 days = 33.6 amps only. If 10 days 48 amps. A healthy 95Ah hour battery even at 55% SOC, still have enough CCA to crank-start the engine.

I then use my year 2021 E400 80Ah battery in the RR . AGM battery is indeed beefier. 80Ah mine is , it weighs 22.8kg




Fake Varta, non agm, supposedly 100A, weighs only 21.4kg . Save money on lead.


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With proper healthy battery ( mine ) albeit 4 years old and lower Ah rating, and I cleared all DTC, the RR finally went to DEEP SLEEP MODE at 10 to 12 milliamps with peaks ( system check to 22 milliamps )
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HIOKI DT4261



So the lesson learnt is, modules maybe healthy but did not want to sleep due to pending DTC of decent urgency. So not always module stay awake due to defective module.
I suspect the module in question will be Body Control Module.
My Autel has no topo capability for CAN bus, I also do not have any wiring diagram for the RR L405....I can only guess.

To note : My Autel MS906BT can not register new battery for this RR L405. Failed.
I saw Launch can do it, in youtube. Not crazy high end Launch, dencent mid class equal to my Autel.


So, there is the case study which may help you guys in the future.............

 

If a person had a graphing lab scope, you could test for DC millivolts, then if any anomalies, convert the millivolts to amps. Also very accurate

 

Its not simple to deliver an effective repair to the standard "drained by parking" - This mature issue quietly drives sales of new batterie.

Battery drain is like... "DEATH BY A THOUSAND CUTS!"

-- The No1 step for all of us is to learn to LOCK the car to spleep else it drains more readily.

-- The No2 step without going too deep is going to be reboot chassis to sanitize CGW operations.

There's a lot of variability in this topic of discharge... the hard part is to reach zero drain like a good car.

> Of course cheating with your own car is really welcomed: use a CTEK/NOCO smart charger to keep batteries full regardless of draining conditions.


> Let's ignore usual BATT + ALT issues (old age, low stock charge,...) and only deal with the abnormal stock chassis load.

> There can be a soaked module holding CAN-B awake

> There can be a string of unstable modules slowing CAN-B coms interactions. This the mode MB used to drain over 5 days.

> MEASURING DRAIN CURRENT....
Gaining action items is not easy because the drain current is like fish bites.

There's normal small current and frequent high currents and in-between currents.

What to do once the Amp-clamp shows unusual current? The type of parasitic drain (S-M-L) is an indication of what's driving it up.

In my book my favorite suspects are on CAN-B.
Disabling modules to help catch the bad-guy is fouble edged: it helps as much as it hurts - Beware at not racing to conclusion by disabling modules.
Case in point disabling SAM's off CAN-C....

 

If the illegal power drain is only say 50 milliamps, voltage drop test can't see this low properly. In line ammeter is the only way.
I have picoscope 4 channel, automotive version one.

 

Cali,
Ur car has more modules than mine. I been curious about more modules loaded cars.
Can you one day logged its deep sleep power consumption please, thanks.
1 data point per second is good enough.

 

Anything for MS!! You always discover interesting things following your research path.


I don't know if I can capture quality data that meet your standards.
Actually, I am not equipped to log over a significantly long amount of time to identify patterns I'd be interested in.

We want to witness chassis wake/sleep cycles to poll security status. I can try to grab Min/Max reference points.


What's awesome is this chaos was carefully crafted to channel ownership experience l. The battery drain complements the limited oiling rattles ....

Back when I had to chart my course, I picked an action oriented path instead of analyzing more data, which is my background - I do that in my sleep.

 

To note: if you are not testing a fuse, this method below does not work. And Surya's original post does not pertain to checking fuses. I should have been more clear in my previous post.

One of the videos I often watch is South Main Auto. He often has cars with parasitic draw problems. His method to determine the circuit(s)with a draw is to check for current draw across each fuse in the fusebox with a DVM set to MV, and then uses the attached chart to determine the amount of MA current across the fuse. Of course, if you have a very good (expensive) low-amp clamp, you can read it directly, but this method allows the reading without having that expensive amp clamp. Even an inexpensive DVM will accurately test MV. And a graphing lab scope will record the activity over a much longer period, such as overnight, to identify those pesky, hard-to-verify drops.

 

Dealing with "Parasitic drain" is very much like fishing... you need the right gear setup for what you're trying to catch else you get nothing!

The first step is to figure what type of drain you're trying to catch:
A - Slow drain: couple weeks span
B - Quick drain: couple days
C - Super quick: couple hours /overnight

Chances are you're dealing with "Quick drain" type. Battery is flat in a few days.

This is the MB stock for standard struggle: Exhausted under-charged batteries can not handle the unstable chassis networking that becomes increasingly restless and slow.
Both batteries get wasted.

> Two quick tips:

1. Always LOCK the car to sleep,
2. Indulge in REBOOT therapy.

Did I mention SCANNING?
If you're dealing with unstable modules, good luck measuring current to spot the chief offender. Yes, it can be done but in too many hours.
This is not a basic DC drain, it's a busy drain.


Put it this way... the car security network is shared with a dozen modules built to get unstable.
Polling non-stop that all door modules report being locked takes an increasing amount of awaken time.
That uses significant power due to network modules gone wildly slow.

 

At the least every MB owners must do at least once, the DEEP SLEEP MODE current consumption as baseline.
Each car is different, while the general rule below 30mA is true, to learn that it is 5.6mA and minor spikes for my car, is even better.

This is C200 W204 Deep Sleep Mode, specific to my friend's car option level.
Is this normal ? Honestly I don't know because the car is not new , it is a 2010.
It is still 5 ish milliamps for the majority, but the spike is higher than mine.



If one does not log at least at 1Hz and over 10+ minutes, you will never learnt of the spikes.








Does this behaviour kill battery in 3 weeks, NOPE.
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MB cars with F32 prefuse box and Circuit 30 and 30G at both Front and Rear SAM is so easy to separate all of them power consumer big solo ones or group ones.
If any abnormal drain say higher than 200 milliamps while supposedly in DEEP SLEEP mode and K2 relay in F32 has gone to OPEN MODE ( off ),
the problem is not in any circuit 30G, but in Circuit 30......that easy to isolate power consumers as long as you know how to read the total wiring schematic.

 

Thank you Master Surya for your excellent logs.


power draining activities vs. time

This shows "death by thousand cuts": power is used by a combination of sleepless circuits:

1. various activity cycle
2. various current level

> FAST VS SLOW ...
Faster drain occurs from higher loads working more often or from fixed static loads.

Most of the chassis power is CUT-OFF by the F-SAM but a few essential modules are ALWAYS POWERED ON into a low-power sleep-mode:

1. Headlights
2. Big Fan
3. F-SAM+CGW
4. KeylessGo
5. EIS/EZS
6. Doors + Trunk modules
7. (3G-TELCO module)
8. (R-SAM ?)
9. (AAC ?)

-- Headlights are always powered but asleep until signaled for activity.
Once water condensation has a chance to puddle inside the open concept HL, crusties develop bridges on the unprotected circuits...

-- Some modules are never asleep that's the CGW/SAM: they are network backbone without which zero Com can take place.

 

Any device that is direct contact with the battery terminals should have an inline fuse (eg glass 3AG 5Amps, or whatever is needed)
where one is not in the device itself.

If the device develops a short circuit, goes into meltdown etc, you have a massive current direct from the battery which will set the wires alight
and possibly your car as well.

I know this from my two-way radio days when the radios were connected directly to the car battery.
In fact, you fuse the negative side as well in some cases, because if the battery earth (chassis connection) comes adrift or is corroded
current is path of lead resistance, and you will be cranking the car through the power cable to the radio and BANG