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I noticed my 1.5 yr old AGM battery was not fully charging, I have a CTEK remote battery monitor with app, it charged with my regular battery charger , CCA went up 110a ! Do mb alternator Regulators fail, fail often ? For 100$ changing the Alternator Regulator sounds logical. The battery load tests as 100%
This happens over months, the charge just gets weak sometimes when I look at a long term graph of charge data. The CTEK app saves it. The alternator puts our 14.5 often, so it’s not bad , a simple and obvious cause is a bad regulator, it’s also the cheapest solution for me to try,
This happens over months, the charge just gets weak sometimes when I look at a long term graph of charge data. The CTEK app saves it.
The alternator puts our 14.5 often, so it’s not bad , a simple and obvious cause is a bad regulator, it’s also the cheapest solution for me to try,
Why replace the regulator if you know the alternator is not bad?
Have you looked at live "volts/Amps" on display cluster while driving ? Do you get high currents greater than 10Amps
How do I access volts amps to display ? The Glk doesn’t show that or give any options that I’ve seen. On the CTEK app it often goes to 14.1 v but never stays up , often going back to 12.75 or so. Since I’ve seen it jump i figure the regulator is bad. I’ve heard they go bad , it’s cheaper than a 500-1000$ alternator! Only 100$ for the regulator.
How do I access volts amps to display ? The Glk doesn’t show that or give any options that I’ve seen.
On the CTEK app it often goes to 14.1 v but never stays up , often going back to 12.75 or so. Since I’ve seen it jump i figure the regulator is bad. I’ve heard they go bad , it’s cheaper than a 500-1000$ alternator! Only 100$ for the regulator.
Love what the smart Ctek charger do with the multi-steps charge and float.
Realize that the car does much the same courtesy of the Bosch design picked up by MB.
The ECU controls the alternator output to deliver a variable voltage 14.9, 14.4, 13.7, 12.6V very much like a CTEK. These steps are guided by a battery sensor. The battery is expected to be well charged up, the car delivers "best efforts" to close in near 100% ASAP. Then switches to a 12.6V float.
You can see battery vitals while driving through the display of "Workshop Menu" option.
> Amperage as it shows charge/discharge level. Amps between 10 and 1 are a good sign. Anything above 30A 50, 70, 90A is serious concern.
> Voltage: Normal values transition slowly between 14.9V down 12.6v. Battery voltage should never swing below 12.3, 12.0, 11.8V during long drives when 12.6V is expected, not drainage.
See where you stand using the menu. High Amps into battery is a sign of a discharged battery.
I wish the voltage and amperage could be displayed on my gauge cluster permanently as an option. The CTEK battery monitor and app show voltage updated about every 5 seconds, The battery is good. It manually charged to 100%, thanks for the info
I wish the voltage and amperage could be displayed on my gauge cluster permanently as an option.
The CTEK battery monitor and app show voltage updated about every 5 seconds,
The battery is good. It manually charged to 100%, thanks for the info
You can see battery vitals while driving through the gauge cluster display of "Workshop" Menu options. Pull up the display before starting the engine.
You can't conclude the car charging system is working well unless you've seen it perform a 12.6V float. This step is a difficult act that involves the Rear-SAM to help ECU control alternator... a long shot!
Is “workshop menu “ on the gauge cluster found by scrolling the steering wheel buttons ? I was driving and could not find it. I will try with motor off.
I did notice driving maybe 1/2 Mile several time voltage on my CTEK showed 12.75, I think that’s low for driving
Or is it found in the engineering menu through the radio buttons?
Can a bad Auxiliary battery throw main battery charging off? Mine is bad, but I like how StopStart now won’t operate .
> Q: A....
Is “workshop menu “ on the gauge cluster found by scrolling the steering wheel buttons ? I was driving and could not find it. I will try with motor off.
> Q: B.......
I did notice driving maybe 1/2 Mile several time voltage on my CTEK showed 12.75, I think that’s low for driving
> Q: C......
Or is it found in the engineering menu through the radio buttons?
> Q: D.....
Can a bad Auxiliary battery throw main battery charging off?
Mine is bad, but I like how StopStart now won’t operate .
> Q -A:
the "workshop" menu can only be opened with IGN: ON and engine: OFF.
You can use it while driving only if it was opened prior to starting.
Have a look on Youtube for instructions how to get in. It's not entirely simple the first couple times!
> Q: -B:
Is driving on 12.75V low? Nop that's totally fine all the way down to 12.6V float so long all power coming from the ALT as it should and not from the AGM when charging is messed up.
Alternator must always supplies 100% of power with nothing out of battery.
> Q: -C:
The central display media screen is not involved at all here.
> Q: -D:
AUX does not help/impact the main AGM charging system. AUX works separately without a proper battery sensor found on main batt.
The Rear SAM calculates a value of AUX "internal resistance" to decide when it's bad. Often time it charges just fine and stays at 12.75V well above minimum....good!
In any case AUX is protected by fuses. Dump it if it's below 12.5V at rest after a CTEK charge cycle.
You're doing well by keeping batteries toped off. It shoul not get drained by driving! Car PREFUSE circuit can wears out from extreme charging currents.
Yes thank you it helped. I only drove around the block with headlights on. My voltage was 13.7 but amps only 9-12a momentarily jumping to 25-35 when taking foot off gas, from 600-2000 rpm the amps stayed basically the same. Definitely it’s not right.
I hope it’s only the regulator. I don’t know how you can tell the difference from regulator or alternator. It does jump up temporarily. Tomorrow I’ll drive it for an hour. Maybe I’ll get someone to test it .
Yes thank you it helped. I only drove around the block with headlights on. My voltage was 13.7 but amps only 9-12a momentarily jumping to 25-35 when taking foot off gas, from 600-2000 rpm the amps stayed basically the same. Definitely it’s not right.
I hope it’s only the regulator. I don’t know how you can tell the difference from regulator or alternator. It does jump up temporarily. Tomorrow I’ll drive it for an hour. Maybe I’ll get someone to test it .
Don't jump to conclusion too fast!
90% chance your ALT/Regulator are okay.
Voltage from 14.9V down to 12.6V are fine - Remember the ECU remote controls the alternator output to charge battery with couple different voltages just like CYEK does.
Using the headlights is a good trick to force a 13.7V when the charging system fails. To test normal charging do not use consumer loads (No HL, no A/C) to prevent holding voltage from going to 12.6v <<<< that is your test drive goal Once you get to that 12.6 float voltage, keep driving a bit more and note any wild swings into low voltage and high Amps marks.
This picture looks about okay.
It shows AGM undergoing charge with 11.5A... that number is supposed to come down towards charge complete... look for Amps getting near zero.
Keep in mind that a NEGATIVE (-) AMP value will mean discharge - You should not see any discharge but it's entirely possible you may.
faulty charging system 😳
Last edited by CaliBenzDriver; 09-22-2022 at 08:38 PM.
Ok I’m not even sure what issue I have now and what to do. I did order a Regulator from fcp on the belief it regulated the voltage. You say the ICU does. I think the regulator is only a connector to the rotor. I’m going to include photos of what led me to my situation. And thank you for your help, I’m still learning. The charger showed 83% capacity when I started all this testing, 83 % is to low, this was the Glk full charge The CTEK warned me first, I’m sure it’s not accurate but this is a warning 12.64 was Glk full charge This was Glk full charge , the battery is 850 CCA 20 months old , interstate AGM , 738 is of concern
More photos of diagnosis The ctek fully charged it The CTEK even got the 850. CCA battery to 850, that’s amazing on a nearly two year old battery ! CTEK got it to 100%
This is what the CTEK long term looks like , Voltage is consistent , state of charge is all over the place, I never use stop start or sit and idle except for stop lights. Voltage is basically steady except for Glk charge peaks This showed constant discharge charge by the Glk
More voltage , it looks normal , I guess!
So why is my voltage and Cca lower than what my CTEK charger will get it? Is it the computer? Regulator? Alternator ? Or is this normal . It has actually always been like this, I think, I bought it used 37000 miles. I believe the Glk should charge it better. It has now declined after the CTEK charged it to 100% to 90% in a day
I just drove it 40 minutes in city , getting to 50 mph , even at 50 it went negative , it’s all over the place , + - . What do I replace or what do I do? Thanks
battery drained by car multiple DEEP discharge down to 20% 😳
long draining then charge up.... HOT battery!!
Your careful battery testing has captured unequivocally the cause of short lived battery!
Your car is acting as a battery killer due to disfunction of its charging system.
Thanks to your CTEK Log for showing us the length of time the system battery is drained to near empty before going back to near full .... that transition is when you can witness 90A currents for extended period.
> Tip of the iceberg:
As you do more test driving you're going to see more occurrence of this chaos. Such as lower voltage in the 11.xV and bigger Amps swings in the 50, 80A "charging current".... ouch!
> Killer caught:
(90A x 14.9v) = 1,340 Watts "charge" 😳
This 1.3kW "punch charge" cooks the battery under the most extreme heat conditions. This happens during extended periods until the lack of charge is reduced a bit.
> Spoting troubles :
THIS DEFECT IS A MAJOR BUG shared across chassis.
BTW falks... "NO code" !
You have to look carefully under some circumstances to catch this problem.
When you witness high charge current this means low charge status. Then you begin a search for clues.
Drive carefully...
+++
Many ppl don't think twice and keep swapping batteries every 2.5 years. That's the wrong way to connect any dots.
When the car voltage is marginal all sorts of goofy situations take place.
Transient voltages yield...
Dash messages: "yadi-yada unavailable".
Front Radars start picking up ghosts.
Keyless-Go gets tempermental.
F-SAM fast drain while parked.
HIGHWAY LIMP-MODES
banging shifts from poor timings
Reduced engine performances
....
> Car Nirvana :
A possible but ultra rare occurrence.... Float voltage fully charged! ✔️
When the ECU works well without CAN peripheral modules soft-crashed by glitches, the engine is smooth and responsive right off idle AND the battery gets fully charged properly.
It is not simply the battery that suffers, everything works marginally in a degraded mode.
Last edited by CaliBenzDriver; 09-23-2022 at 03:10 PM.
Does the regulator on the alternator regulate charge ? If not what does it do and why is it called a Regulator!
Brushes do wear and stick on the Regulator.
Could a new Alternator - Regulator or just Regulator fix it?
Could it be a bad connection?
Autozone tested the system today it checked out good.
Battery can still go to 100% with CTEK charger . What do I do ?
Thank you for your help .
Does the regulator on the alternator regulate charge ? If not what does it do and why is it called a Regulator!
Brushes do wear and stick on the Regulator.
Could a new Alternator - Regulator or just Regulator fix it?
Could it be a bad connection?
Autozone tested the system today it checked out good.
Battery can still go to 100% with CTEK charger .
What do I do ?
Thank you for your help .
> Helpful Steps :
There is no easy fix but there is a 5mn easy workaround.
Disconnect the control connector from alternator. ALT will then regulate voltage perfectly and provide uninterrupted power. Test to validate results are as expected: stable car voltage.
Until you adopt the workaround you can:
CTEK float often
Drive with HL:ON = 13.7v guaranteed !
> How... Why ??
The regulator is NOT the problem causing deep battery drain.
The engine computer is the module responsible for this chaos. It stops controling the alternator under particular circumstances.
It's not entirely the ECU's fault. The remote battery sensor is a smoking gun. It drives the ECU crazy with corrupted data records. It's a poorly designed system where no data-in causes no data-out. Bosch developers forgot to give a default value to "voltage".... a 5¢ fix for an idiot's mistake.
If you are curious you may search the forum for keyword: "YOYO"...
This may be the last battery your car ever needs.
Last edited by CaliBenzDriver; 09-23-2022 at 03:45 PM.
You say disconnect the Control Connector, what does it look like? What does it do? What happens when I disconnect it? What are the drawbacks?
Are there any negatives to having a bad Auxiliary battery , as mine has been giving me notices for years !
I enjoy stop start not functioning! but it will function and bother me most days after awhile. The battery is not dead just weak.
09-20-2022, 09:11 AM
