Battery and alternator voltage check - secret dashboard menu Mercedes c class w204

[@QuangNguyen-ng5zh]

Thanks, how do you exit that screen? Push the ok and phone buttons again?

[@mattgreba]

@@QuangNguyen-ng5zh You have two options, just switch your car off or press return and scroll left, right up and down to your preferred menu

[@timjackson4341]

I just had the red battery light on my e350 2010 w212 and it ended up being alternator and the wire that connects to the back voltage regulator has to be installed and allied perfect it is a pain but did it myself took 2 hours and car reset itself after starting it up.

[@hiddenturbo2322]

Did you replace the alternator?

[@adi4694]

Hi thanks for the video, what does IB indicate, voltage is around 13.8 but IB is around 2.7 to 3

[@mattgreba]

@adi4694 IB stands for Battery Current. When engine off you have negative figure as your systems draw from the batteries. When alternator kicks in with engine on you have positive figures as you top up the battery. Your charging looks a bit low, you might look into your alternator if you always have charging below 14V.

[@JoseMercado-od6jk]

Yeah I have this same issue UB always goes 14.8 but IB bounces from 2.8 3.5

[@simon.revill]

⁠​⁠@@mattgrebaThanks for the helpful video. On a cold start, my voltage is a steady 14.8, but the IB reading dropped to around 2. Does this indicate low charging from the alternator?

[@mattgreba]

@@simon.revill no, if you're getting 14.8V your alternator is fine 👌🏻

[@simon.revill]

@ thanks for the reply!

[@BlackIronMayne]

The IB reading on my 2013 c250 is negative when running. Does that mean bad alternator ?

[@sulphursulphurer5170]

Is it always like that or only at times?

[@BlackIronMayne]

@@sulphursulphurer5170 the entire time. Before i start it’s around negative 6-7 .. after start it goes down to negative 30-40

[@mattgreba]

As long as your ub is around 14v your alternator is charging. Mercedes has a couple of stages for charging. When you have new batteries and they ale fully charged the car goes to standby charge around 12.7 and then IB goes to minus figure as it's supporting fuel efficiency. However - 30-40 is drawing a bit too much of power. Check your ground points and clean them up. Potentially scan for any errors with obd.

[@lp3172]

Hi, 2013 C250 What part does the auxillery battery play? Thx

[@mattgreba]

Think of it as a backup system. When you disconnect the main battery it holds the memory but not just that. When you use stop/start and the car is off, power comes from the auxiliary. There's so many systems both batteries support. I tried to do some research on exactly what each battery is linked with, but I couldn't find precise answer.

[@lp3172]

@@mattgreba Thank you

[@РасулКидакоев]

Здравствуйте. Как войти в меню на мерседес бенц w 204 , 2010 года? Чтобы проверить индикатор заряда аккумулятора?

[@Dnasty1]

I just installed. New alternator and it stays pretty much at 12.6 idle then sometimes goes up to 13 when accelerating. I have a 2010 e class so not sure if this is normal. The last one was bad and it showed 13.6 and occasionally dropped to 12 ish.

[@SosMusicStudio]

Hey @Dnasty1, in the charging stage it should be between 14.3 and 14.9V. Sometimes when you have new batteries it goes to standby mode when it sits on 12.6V and when you break it goes up. It's almost like with EVs when you break you recuperate the batteries.

[@justice4romania96]

​@@SosMusicStudioCorect. it has smart charging mode. Ot keeps battery charged at 80% to prolong it's life

[@sasajaku870]

Hallo What is IB And what has to be IB My ist 4.3

[@robins9938]

Can someone help me with my problem (om651 250 CDI year 2013): after starting the engine, I have a voltage of 12.3 volts (no charge). As soon as I accelerate, I immediately have 14.0 volts and this voltage then remains unchanged! until I turn the engine off. When I then start again, I have 12.2-12.3 volts again until I accelerate once. What could the problem be? The OBD2 error log says U012087 „The communication with the starter or generator is malfunctioning“. The message is missing. No error message appears on the display. I am at a loss 😄

[@mattgreba]

I have the same with my car with difference that after 5 seconds the charging kicks in automatically. If I press the accelerator before 5 seconds, charging starts sooner. I don't have any codes.

[@robins9938]

@@mattgreba Now that could still be normal in your case: the BMS is an intelligent system and then starts with the charging voltage after a few seconds. But for me it is the case that I can run the engine for 1-2 minutes after start and no load takes place. The tension then drops further and further (at 11.8V I have always identified the engine). As soon as I take a brief gas, I have 14.0V that do not change (usually the voltage should go up to 14.7V with an AGM battery!)

[@robins9938]

@@mattgreba Now that could still be normal in your case: the BMS is an intelligent system and then starts with the charging voltage after a few seconds. But for me it is the case that I can run the engine for 1-2 minutes after start and no load takes place. The Voltage then drops further and further (at 11.8V I have always turned off the engine). As soon as I take a brief gas, I have 14.0V that do not change (usually the voltage should go up to 14.7V with an AGM battery!) can anyone help?

[@spam7245]

Can someone tell me my car today it came up with the battery logo and then later it stopped is it the alternator or new batteries

[@mattgreba]

Try to top up the battery and check the menu if the alternator is charging. If yes, your battery is dead. If the light came up while driving it's very likely the alternator is not providing enough charge. Good luck

[@RubenPrado-i5c]

Mine gave me a red battery with a see operators manual icon. My battery drained while driving and I lost power to pretty much everything. Then it just died

[@550Pete]

@@RubenPrado-i5cfind issue ?

[@kostas.antoniadis]

hello sir 14.9v is normal the values ​​and not be constant at 13.5v constant?

[@mattgreba]

Your alternator should deliver between 14.3 - 14.9V. 13.5V is a bit too low.

[@kostas.antoniadis]

​@@mattgrebaThanks for your answer