do you have eco start/stop? Then it should be in the trunk, maybe under a carpet panel.... No eco start stop, and it might be a much smaller batt inside the left end of the dashboard, pretty deep.

 

Yeah, I have the eco start stop. I've checked both sides of the dashboard, and nah, it's just not there lol. I did an entire ambient lighting retrofit from the trash and dim 3 colours to 12 colour RGB, so I had the whole dash apart, and no aux battery in there. Could be under that silver panel where the cabin air filter is replaced, but I never opened that area.

 

Ok, I need college credit for this course. LoL

 

In the name of lower carbon dioxide emission I think, that is why that dumb-azz always-undercharged charging algo is invented.
Actually MB did the same for the electro thermostat. When cooling reserve is abundant, they push my engine coolant temperature to 110C in the name of best combustion efficiency.....which freaked me out when I did not know about it.

 

All scuba divers and friends get an A because we all go deep down searching for evidence. There are many Masters in this forum 👍

SIMPLIFIED TEST:
Charge your main battery full overnight then go for a highway drive with NO consumers (no A/C, no Defroster, no Headlights,...) at mostly stable speeds (no 14.9V burst).
-- Watch your IC display after the "quick charge" cycle (14.9... 13.5V) once the ECU decides to get away from 13.x, this is when the interesting part begins.
-- If your voltage is stable about 12.6v: it's most likely ok!
-- If it drifts down in the weeds (12.4... 11.9) and keeps getting lower the more you drive: it's impacted.
-----
End of test:
If you stop the car and restart all bets are off. At that point you'll be dealing a drained battery and the ECU will keep recharching it under "quick cycle".

Here we are interested about the condition after the 80% threshold is met. It's designed to be 12.6V float, not deep discharge.
----
🙂

 

I never understood why so many people treat electricity as some alien monster to be afraid of. The stuff is actually very simple, follows very simple rules. I learned most of the basics in an after school electronics class when I was in the 5th grade. While my career was nominally 'software engineer' (systems programming), I often worked so close to the hardware that I ended up designing and building a number of computer controller components, video cards, electric motor servo controllers, disk controller interface cards, and so forth.

 

Everyone has different areas of expertise, hobbies and goals. When our cars need attention we try to step up to the plate with a fix.

Cars have been loaded with computers for quite a while so many of us have learned that fault codes are no replacement for troubleshooting skills.

This time, there is no DTC, just an array of evidence some folks are having a hard time recognizing.

I have updated my prior post with a "QUICK TEST"... a good reason to go on a test drive 🤗

Q: who will be first to get a fix identified ??
🙂

 

I certainly find things like this interesting and would like to setup my data-logging DMM... but like a lot of things in life, gotta prioritize your time. Since starting or drivability are non-issue at the moment, my interest only so much.

Like LILBENZ says

Even if you find these deeper discharge "events" then what.... I haven't spent much time exploring Xentry in that regard. If possible, you'd want to see what the system is commanding and verify the result.

 

Took a 65 mile drive yesterday. The only time I saw battery drain was when the engine was off. Volts while engine on never went below 14.5. After the initial recharge after starting, the battery saw a current input of about 1.5 amps for the rest of the drive.
Everything works.

 

That's perfect, lucky you!

Seeing a 1Amp super low charge current is a positive sign everything is humming and battery is nearly full. That's the way systems perform best.

Your car does not have the rocky voltage problem, you may be blessed with a good VIN. Yet it's strange you voltage kept so high and never went down to 12.6v at all.

Thank you for letting us know. It gives me hope there is a way to fix what I've identified.

Can you show us a picture of your battery sensor for comps??
👍👍

 

At the same time, it seems suspect it remained at 14.5... why didn’t it go into alt management? Was the battery fairly discharged prior to this 65 mile trip...

Also I think S-Prihadi noted a discrepancy in the amperage reading in the workshop menu. I’ll let him correct me. I’m assuming rapidox findings are off that menu.

 

Yep, we do think alike.

I am not sure the battery sensor being 5 or 10% out of spec would create the overall lack of 12.6V regulation. Perhaps the car stayed on default voltage because ECU could not read the battery sensor at all! (Pdf doc mentions that safety mode)

My money is on...:
-- the Valeo regulator being incompatible
-- broken sensor loop (SAM'S, Hyundai)
-- Benz trickery in needs of a firmware bump
-- bad painted ground strap.

 

It is the reading/update speed of my UNI-T clamp amp meter vs the MB Hyundai shunt/sensor when fluctuation happen. When a reading has 2 seconds stability, UNI-T is within 0.1 amps accuracy for any load/charge into the battery.

========================

Since the charging algo is dominant software based and temperature based ( if WIS function description is spot on ) , it is difficult to compare cold countries vs hot countries.
I think what is best is to read NET result, which for me is read battery voltage the next day, 30 minutes minimum after I opened the door to let computer/s sleep well.
Usually I keep hood open well ahead of time, and lock the door and keep FOB key 4 meters away....and then read battery voltage.
Since we know state of charge can be read with decent accuracy on a healthy battery based on voltage, that is what I use.
The next maintenance is by my ear. I know cranking speed and sound very well for all my cars starter, so when cranking power has been reduced ( well charged battery), I will replace the battery.
While at it, the duration of the crank will also indicate if ignition/fueling is not perfect, if the battery is not the sole issue.

When I got this car in May 2018 at 9,562 KM only, previous owner got a new MB original battery ( Varta) on 28th March 2016. This car is a July 2014 registered date.
Owner was the wife of I heard is the local franchise holder of US Dunkin Donut, according to my workshop friend who recognized the name on the registration.
These well above everage families usually will sell their cars past the MB 3 years warranty, they just like brand new car feel at all times.

So previous owner which I am sure her driver/s does not do weekly charge like I finally learnt is needed, have original battery MB one survived only for 2 years 9 months.
Since I was kinda fooled by the dum-azz undercharging algo back then in 2018, I often read 12.4V next day after use, I replaced the battery with also a Varta AGM, a Silver Dynamic, but not MB original one...same Varta anyway... on 15th July 2018.
That 2016 battery I still keep till now for jump starting my small 6.5Kw diesel generator when needed. I charged it every month or so.

If I can use this July 2018* Varta ( *production date 2017 ) up to say 5 full years in Jakarta's hot weather and driving profile, I will smile ear to ear . 2.x to 3 years is the norm for non AGM battery life in Jakarta in standard alternator charging profile.
Where I am now on 28th April 2021, this 2018 Varta has served me 2 years 10 months and still VERY healthy, due to the top up charging regime I performed.
This 2018 Varta cranking speed and power is sweet till now. At this point today, I have out performed original/1st owner longevity of the battery.
I will find this post and report back on 27th July 2023, to update if my battery survived full 5 years ... LOL

 

Here is from the April 2019 test I did.
Video is 50 frame per second.
I inserted 1/1,000th second time code.

See how fast the Hyundai shunt/sensor can read and how fast also the discharging can happen.
All 6 events below are within 1 second.







Clamp amp meter can't cope with this kind of speed

 

You should consider a longer time base for recording. What we are observing is fairly slow. The interesting events come after 13.4v charge phase is complete.

The 25000 lines in your dataset made the lack of 12.6V regulation more clear with swings down to 11._V. until an engine restart occurs.

I recall a trip to Singapore in winter and realized what relief A/C bring to tropical regions. ✌️
​​​​​​

 

Here you go, I have uploaded the 12 minutes condensed version of the 43 minutes raw.
Unfortunately I did not place a fully charged battery on the GoPro and the 43 minutes is not yet till engine kill.


Now that I have a keen crowd hungry for answers........ I LOVE IT !!!
This Sunday when I cruise around to do my regular Italian tune up, I shall record via a GoPro camera the Volt + Amp display again from start to engine kill and with OBD2 data too.
The Race Render video editor can take the CSV file times stamp from Torque App for ECU voltage , speed and RPM + outside ambient temperature and integrate it as a moving graph in real time.
So I can merge the dashcam video from Viofo A119 v3 + GoPro + the Torque App graphs for better view and situational awareness.

Something like below , this was when I analyzed the electro thermostat behaviour triggered by the "optimum combustion efficiency" algo pushing 110C coolan temp, which freaked me out.

 

Thank you Surya for posting the video. I will analyse it further at breakfast (See couple posts down).

Already I see 2 things:
- crazy high 68Amp abusive currents...80A!
- unstable voltage swings during charge phase
Who is guilty: (Valeo, Hyundai, Benz) ?

You really believe algo is supposed to get your voltage danse up/down like that....

To me 60Amps charge means you started with a deeply discharged battery 🙃

What sort of Consumer load was ON during video test: A/C or no...?

 

A/C is always ON for us in Jakarta. We will not use a car if the A/C broke down ...no way.
Daylight running light for sure, it was daytime so no low beam. Music /radio NIL. That was my driver driving somewhere.

 

This seems more in-line with what MB has published... 14.5-15, 13.5 and 12.6/7 VDC all ranges the car was in at some point during that drive.

 

Well, I have more than a passing interest in this topic, I've had my '12 for nine years now and am on my third battery, granted I don't drive it much, it's two miles to work for me and I don't go in every day. I just turned 30k. We drive the '13 daily and for chores, but when we go on trips or out for fun, we drive the '12. I do charge it winters, I do realize that charging it might get me more life with the battery, but charging it only to find that the car will bring it to an 80% charge seems like a lot to get an extra year out of the battery. What I would like to do is keep this car another ten years if possible, as I have done with past Benz's, so if there was a way to change the charging algorithm to make the battery last longer, I would like that, but that "dongle would have to cost less than a new battery to pass the cost-benefit analysis. I am also hoping to keep my '13 until the W214 debuts, but who knows, I am only on my second battery in that one with 77k miles and eight years, replaced under extended warranty.
I am taking a moderate range trip this weekend, I will monitor my charge discharge rate to see what I get. I'm sure Senecan is right, many come here to get help with repairs, but I also believe there are many enthusiasts who follow along without comment and enjoy this level of expertise and knowledge, I do!

 

how about that: 81Amp punch !!!

not making all this stuff up... There is a world of abuse between a 1Amp charge and 80Amp punch.

This sort of power rollercoaster is a big deal for ALL the on-board electronics working... imagine your VVT Solenoids trying to adjust timing angles with yoyo power supply. It must drive that logic nuts!

99% of the running power in working cars comes from the low impedance alternator, hardly ever from the more resistive battery. It's purposely built that way because the alternator is wired in parralel with the battery and the Load current comes out from the least resitive path: alternator!

VIDEO EVIDENCE:
1-- Benz algorithm appears to step properly through its multistage charge.

2-- Hyundai reading loop through CAN messaging appears to be fairly consistent with the stages. It has 2nd greatest potential to disrupt the ECU logic

3-- Valeo output is like a rodeo unable to get steady power. Dataset showed untold amounts of spikes for some reasons. It does a poor job at coping with any load to supply smooth power.

Alternator cost around $350... ditch Valeo >Bosch?
(leaking/broken 6 diodes rectifier $70??)
OEM regulator around $80, China "Transpo" $15

Not all these cars are impacted, some work well as designed and quite a collection are off the chart with abnormal battery casualties.

Sky-high charge currents and deep discharge are a good explanation for abnormally short battery life.

My point all along has been that simply replacing AGM does not make the car run right nor fix the cause: Valeo?

 

I'll try to help you save unnecessary battery expenses to enjoy a good ownership....

1_-_ For the longest time it's been a good practice to keep unused batteries floated on a CTEK/NOCO so they don't build up an internal layer of plate sulfate. Once sulfatation has happen the battery capacity is reduced and it does not charge too well due to internal resistance. AGM are a better in that regard than old fashioned batteries.

2_-_ The other can of warm is DRAIN WHILE PARKED. Some cars with modules gone wild don't go into low power sleep mode and keep draining the main battery more or less fast. Some cars keep waking up too often, the champion for that is the COM module that keeps phoning home to rat your location. Our cars dont have it real bad in that department unlike W213 going dead overnight. Xentry has tools to track "bus awake" else suspect 4G module...

3_-_ The trickiest issue on some cars: "uncontrolled discharge while driving" - *Some* cars came out of factory with a defect that promotes deep battery drain and sky-high current spikes after the "Quick Charge" cycle. This is the topic I have been exposing in all my above posts.

-- The workaround is to drive with the headlights ON to keep alternator output at or above 13.5V minimum.
-- The Fix I believe is a replacement of "Smart/LIN" Valeo regulator.
-- The Test is to look at the obvious: low charge current is good sign vs. high current swings are sign of bad regulation and discharged battery.

-- The Misconception is the car trying to keep the battery at 80%... nop!
ECU control exits its multistage 14.9..13.5v "quick charge" cycle around 80% then goes into 12.6V float mode
ECU still keeps charging with opportunistic deceleration bursts of 14.9v then quits bursting around 100% .
ECU has 2 safety features: "DriverDoor: ajar" and "Headlights ON" both command a non-stop high charge over 100%
ECU appears to command ALT:OFF during accelerations... dangerous on highways with a drained battery!!!
ECU does NOT purposely deep discharge the AGM for long periods of 11._V by commanding ALT: OFF

The bottom line is don't replace your $200 battery before looking at the IC display for tell tale signs, problem is not obvious.

 

​​​​-- For those of us who need quick & easy:
Your ECO display flag being Yellow more often than Green is the ECU saying it's unsatisfied with your AGM status (amongst other conditions... (...))

Nobody with the mischarge issue gets a quick GREEN flag in 5mn - The best way I can describe my ECO is flaky: comes on GRN and goes YLW all by itself.

My apologies if all of this writing is backwards from tedious to trivial, it's based on understanding the design inside out for troubleshooting.

 

I love this thread

 

not sure i've ever seen the "ECO' flag yellow on my speedometer status display.
but since seeing that -25 amp drain when the stereo and headlights were off when Eco stopped the motor, I'm turning it off most of the time now.