You need to read the fine print on those SOC charts. That's the no load voltage of a battery at rest at 60-70 degrees. When you have it hooked up to the car, it's not at no load. I had a dead battery once that was at about 11.3 volts, wouldn't start the car. At 11.5 it will start but you see the voltage briefly dropping down into 9 digit territory so maybe that's what he meant by 10.5. Anyway, after fully charging the battery, it was only at 12.3 volts so I guess the battery is only good to about 70% and I guess some people replace them when they're below 80%. I think once I hooked up the battery, voltage on the display dropped by a half a volt so keep that in mind when you think your battery is shot but not really if you don't factor in the load and the temperature.

 

This is a bit too far disconnected from reality or misleading like SA pitch.
Don't believe anything, just read the document posted earlier by Konigstiger. You will learn the reality of how the voltage management works on w212.

It works with different stages 14.9, 13.5, 12.6v managed by software pioneered by Bosch. Benz picked up this feature, just like Ford, Toyota, Kia.
✌️

 

it's a only 2 year old battery!

How often can you replace a battery this huge before wondering what's going on?

 

Read the attached Benz document to learn how the smart alternator and battery are managed by the ECU and the SAM's brothers.

 

so, NOCO was put on in AGM mode about 90 minutes ago and just now I went out there, top green light is pulsing slow (indicates its in the final charge stage), and my Fluke read 12.98V (which is a far cry from the 13.6 or so I'd expect at this stage, never mind the 14.x V for the 'absorption phase'

 

right, thats the at-rest voltage.... but the charger was running, so the voltage should be significantly higher than the rest voltage.... typically the end of the bulk phase of charging is when the voltage gets up to around 13.8V and the current drops towards zero, then the absorption phase boots the voltage to 14.8V or so (for an AGM) for a few hours to put that last 20% into the battery.


typical AGM charge cycle.....

 

Your NOCO charger is busy stepping through the various stages of its logic. Some are constant voltage, some are constant current until final stage of float pulses.

The outcome will be a fully charged battery. Until then don't worry about the time elapsed or voltage because ultimately that depends on the charge current.

It's not trivial to derive battery condition from resting voltage as it is not an exact science. There is a good chance your 2019 battery has more life given the care you're giving it.

Personally I hook up my CTEK in the trunk to charge the front AGM and measure AUX. The fat red cable comes from front BATT.
✌️

 

this class of smart chargers (CTEK, NOCO..) are the best to maintain lead-acid batteries out of cars.

When reading the above graph you've noticed the high 15.6v used in the AGM mode to try rebalancing cells of deeply discharged batteries.

Electronic capacitors in this car (amplifier module and others) are rated at only 16V!!!

If you don't want to disconnect your battery from the car, I recommend you stick with regular non-AGM mode to preserve aging all the priceless electronic modules.... makes sense??
🙂

fancy Amp module 16v caps!!

 

ok, so I for laughs went out there and got into the System Data menu while the charger was still charging...

short version:

1. with the fob in the car and without stepping on the brake, push the Start button once, this is equiv to key position 1
2. press the 'back' button on the left side of the steering group to get to the trip/odometer display
3. within 5 seconds, press and hold the 'phone call' button on the right side of the steering wheel, then press the OK button on the left and hold it for 5 seconds. voila new menu!
4. select System Data, OK
5. up/down for lotsa stuff.

and geezus, 9.6 amps drain just sitting there with a dome light on, but I did hear a fan or pump or something running.

 

I don't believe the NOCO does that rebalance unless you manually select 'repair' mode. it claims in AGM the max voltage is 14.8 during the absorption phase


EEEEK if those are directly across the car's '12v' system and not on the other side of a voltage regulator. when I designed electronics for automotive use, we generally engineered it to work safely on a 9-18V or 9-24V input.

 

so glad you got in... more power to you👍

Repeat the secret menu procedure before driving to keep an eye on the grumblings. You will see what goes on with your car after it completes its charge cycle ... go for an 1hr highway cruise at 55 mph with an eye on batt vitals, share test findings 🤔
​

15.6v equalization charge in AGM mode: ouch!

 

yeah, i plan on it next time I take the car out solo (my wife would freak if I was nerding out like this while driving with her in the car, hah hah).

btw, I'm charging the battery using the jumpstart terminals, that should be fine, right?

 

that was a random AGM multistage graph I grabbed from google, not one from my specific charger, which like I said only does equalization if you do a specific 'battery repair' procedure where they warn you to disconnect the battery.

and yeah, totally plan on getting into that vehicle data voltage/current display next time I go out for a solo drive. if I did it when my wife was in the car, she'd be freeking about me driving while nerding

 

I'd measured the voltage with my meter a couple hours ago, when I just now did the Vehicle Data thing, I didn't bother with the meter. I figured 'booting up the car' in mode 1 was sucking as much power as my charger could deliver, so any voltage readings were meaningless.

 

yes that's what they are for. Benz just want to avoid people bypassing the Hyundai sensor that keeps tab on I/O currents for internal calculations.

wife don't mind geeking while in control !?!🤗

 

Hum... I don't know about all that... what is clear is that the "Secret-Menu" shows exactly the battery vitals without any interference. Use it, trust it !!

Plugging a voltage monitor in the cig lighter outlet show some voltage drop based on heavy consumers load (A/C, Defrost, Seats, headlts..).

Voltage is lost through the prefuse box Front-Sam and undersized wiring - It's part of the overall low-ball philosophy.

 

I never said I was English major ...😎... about topic: the secret-menu simply displays battery vitals from the HYUNDAY sensor sitted directly on top of the posts.

There is zero wiring error in the Volt, Amp, (Temp) measurements... the display is trust worthy as it shows precise data.

sensor feeds the display data

No need to complicate the basics with fuzy feelings. The complexity lays in the number of factors involved with voltage management (read pdf doc!!) ✌️

 

You guys are in deep with this stuff.

For me, does the car start? Yes? Any weird electronic glitches or consumers not working? No? OK we're good.

The car has a way of showing (without the secret menus) when the battery is going. 4-5 years or so is perfectly acceptable.

 

Well, honestly I've always been irked they sacrificed battery life for a half a mile per gallon, or whatever it is, I think they tried to improve this as model years went on, I have a '12 which I believe was the first year of "Blue Efficiency" I always assumed my '13 was much different but after BMW's posting of both charging cycles, seems they only tweaked it a tiny bit from '12 to '13. I also got much longer battery life in older Benz's.

 

Yep, this one has evolved into a topic with a life all it's own... Facts, theories, debates, pics after pics, more debates, etc. My head is spinning with TMI. Carry on, I guess...

 

FYI, voltage drop in wiring is purely a function of Ohm's Law, volts = amps * ohms. If a piece of wire is 0.1 ohm, and you pull 10 amps through it, you will drop one volt. If there is 0 current, the resistance hardly matters, you will see the source voltage.

 

Normal for facelift W212, 12 amps is during 1st 10 or so seconds after door opened up.

 

If you want to see W212 Facelift charging algo in action, use my data log and do the excel graph. Find attached.
Take note : I disabled ECO mode all the time.

Summary is this :

AA. My W212, will never charge to 100% its battery, I would say 80% and you are already lucky.

BB. It all depends on your "luck" and duration of engine running and how car is driven. The luck portion is rather tricky, because the algo can not predict when you will stop the engine.
So when algo is doing its discharging and then there then you arrive at home and stop engine and keep car for many days = that is your bad luck and you can read 12.4x volts the next day
at battery terminal. If you are lucky, when you reach home the algo so happened to be at charge recovery mode during engine kill.. good for you and next day you can see 12.6x volts at battery terminal.

I have analyze many logging sessions of my drive pertaining to "NET charging", I come to a simple conclusion.
Top up my battery at least once a week, if not twice.... with my 5 amps Ctek charger.
Top up my battery after every car washing, coz opening doors too long even with cabin lights off still wake up the car other electronics and suck battery power.

To know more, you need to log voltage with something like a Torque Apps + OBD2 and get 2 data points per second easy.
There you can see in real time when you do the graph, while driving 12.6 to 12.7 volt is like no charging happening to your battery.
12.5V and below car is discharging your battery.
12.7 up, your car is getting positive charging.

Just to be clear, the instrument cluster amperage reading is what goes IN/OUT to/from the battery as NET and is not representing the alternator GROSS output.

Happy analyzing ..........

 

Are you having starting problems and this is why you charge your battery every week? Or are you doing it just because you measure the voltage and you want it to be higher?

If you never had starting issues and you are doing all this then you are doing it just as your hobby and it is really not needed.

I have not tested my S550 but if I leave doors open on my E550 the car kills power for all internal lights etc. in around 7 minutes.

This all is very interesting talk as a car should not need any battery maintenance charging if the car is used just a couple times a week. I have my E550 sitting now as my daily driver is the S550. I start/drive the sitter every three weeks or so. Between the drives it is not started. Have not had one problem starting it up yet and this has been going on for a year now.

 

If Blue Efficiency means the car has this smart charging system they started it probably in 2009 already. My E550 is a 2010 model made in May 2009 and it has the smart charging.

This body style E-class was made for European market already in 2009 and I believe it was in use already then. It may not have been marketed as “Blue Efficiency” before 2012 but I think it has been in cars before that, at least it is in my car.