HELP HELP HELP w219 battery alternator fault

[revajones]

Hi guys

I'm in urgent help of some people who may of had this issue or may even know a solution

I have a mercedes cls63 amg with an alternater/ charging fault

I have changed the alternator to a brand new one also changed the battery but I'm still having no joy

When I first start the car it is showing 13.2v then drops slowly until the red dash warning light comes up and the voltage falls to 11.6v this is when the car will no longer charges the cattery so it starts to die in me after a few short journeys.

The back of the alternater is reading the exact same as the battery above

I'm also lead to believe it is a smart alternater. Is there anything I may missing

The car has been with a mercedes specialist near me for the last two days who diagnosed the alternator as the issue but now this is changed there is no difference

Really hoping someone on here can help me out as this car is costing me a fortune.

Any help greatly receive

Thanks

 

[4life211]

Hi guys

I'm in urgent help of some people who may of had this issue or may even know a solution

I have a mercedes cls63 amg with an alternater/ charging fault

I have changed the alternator to a brand new one also changed the battery but I'm still having no joy

When I first start the car it is showing 13.2v then drops slowly until the red dash warning light comes up and the voltage falls to 11.6v this is when the car will no longer charges the cattery so it starts to die in me after a few short journeys.

The back of the alternater is reading the exact same as the battery above

I'm also lead to believe it is a smart alternater. Is there anything I may missing

The car has been with a mercedes specialist near me for the last two days who diagnosed the alternator as the issue but now this is changed there is no difference

Really hoping someone on here can help me out as this car is costing me a fortune.

Any help greatly receive

Thanks

I have the same problem with my w211 .mine keeps voltage 13.5 v.replaced main battery +voltage regulator nothing happens. My battery drop to 9v after a day.

 

[optimusprime]

You need to contact Television on here . Electronic whiz kid.

 

[Suky Sangha]

I had the same issue on my Cls and replaced the battery module.

 

[Suky Sangha]

Also is the alternator a oem part?

 

[revajones]

Hi guys thanks for the input

I have changed the alternator twice now for two broad new ones as the garage said one may be faulty but still no joy

Is there a way to by pass the battery control module so I can check it

For some reason my alternator is putting out 11.6v after running for like tow minutes

I can even disconnect the battery and the car still runs is that normal ?,

I also can't find the battery control relay to test that either ?

Thanks again for all your help

 

[brucemillar]

The car running without the battery is NOT good practice. You can fry the electrics.

I would be thinking that you have a short somewhere that is possibly killing your alternator(s) Have you had the old alternator checked to see if it is dead/damaged?

Have you had any work done on the car recently that may have disturbed some wiring?

It does sound like you have massive drain that would suggest that you have a short to earth somewhere. Is everything working on the car. Heated seats? Seat controls & motors?

 

[revajones]

Hi mate

Yea I literally disconnected for a couple of seconds I was under the impression it should have cut out but it didn't

Is there anyway I can check for a drain as such ?

I no nothing had been done to the car for a while this is the first major issue

And yes everything works once you start the car but after a little while it all stop as the battery hasn't got enough piwiler in it .

The voltage drops the same at the rear of the alternator as it does at the battery

I haven't had a chance yet to get the old alternator checked altho I fitted a brand new regulator to it to check that just before I removed it for this brand new alternator

Thanks

 

[theogeor]

Hi guys

I'm in urgent help of some people who may of had this issue or may even know a solution

I have a mercedes cls63 amg with an alternater/ charging fault

I have changed the alternator to a brand new one also changed the battery but I'm still having no joy

When I first start the car it is showing 13.2v then drops slowly until the red dash warning light comes up and the voltage falls to 11.6v this is when the car will no longer charges the cattery so it starts to die in me after a few short journeys.

The back of the alternater is reading the exact same as the battery above

I'm also lead to believe it is a smart alternater. Is there anything I may missing

The car has been with a mercedes specialist near me for the last two days who diagnosed the alternator as the issue but now this is changed there is no difference

Really hoping someone on here can help me out as this car is costing me a fortune.

Any help greatly receive

Thanks

Check the wiring between the alternator and battery . While I have no specific experience with the specific car is a common problem in other cars.
The voltage of the alternator should be closer to 14v.
So do the following
1. Fully charge the battery and measure voltage. Should be 12.8-13 but not less than 12.6
2. Check the voltage directly on the alternator with engine running . It should read 14-14.2v
3. Check the voltage with engine running. That should still read 14.xv

If 2 is 14 X and 3 is less then you need to check your wiring loom beteen alternator and battery. Anything less than 13.8 will not charge the battery thus the issues you see

TG

 

[revajones]

Thanks for the reply mate

The battery is showing 12.6 the alternator is showing 13 initially then decreases with the battery to 11.6
I will try a new battery today to see if that isuits it altho I would have thought the alternator would still put out at least 13.5 volts

It is measuring the same from the back of the alternator as it is at the battery

Any other ideas mate its confusing me

The car was previously running at 13.5v when I first had this fault 2 weeks ago. it has seemed to deteriate now to only being at 11.6v do you think there may be a relay that was on its was out has now failed?

 

[Ted]

Not familiar with these, but is there a battery sense wire between the battery and the alternator? If this is broken in any way the alternator will not charge.

 

[theogeor]

Thanks for the reply mate

The battery is showing 12.6 the alternator is showing 13 initially then decreases with the battery to 11.6
I will try a new battery today to see if that isuits it altho I would have thought the alternator would still put out at least 13.5 volts

It is measuring the same from the back of the alternator as it is at the battery

Any other ideas mate its confusing me

The car was previously running at 13.5v when I first had this fault 2 weeks ago. it has seemed to deteriate now to only being at 11.6v do you think there may be a relay that was on its was out has now failed?

Voltage is too low for alternator. . You might have a fryed/cooked wire loom that is having losses. Check both the earth and positive. If possible disconnect loom at alternator and check voltage. If voltage then goes up then wiring is your best shot. Also thinking of it it looks more likely as it heats up voltage drops further. ..

TG

 

[revajones]

Yes there is a battery sense wire I have checked that and it's running 11.8v so I assume that is fine

With regards to disconnecting the main wire off the alternator and then measuring the voltage at the alternator. willthe car continue to run when I do this I'm just a afraid it may cause damage

Thanks

 

[Ted]

Don't disconnect the main wire. The alternator is designed to connect to a load (the battery). You run the likelihood of damaging the alternator.
Do you have a circuit diagram you could post up?

 

[revajones]

I don't haveither a circuit diagram sorry

I slight development today on idle the car is now running g at 13v the I blip it it drops to 12.6.

I also when to halfords to try a larger battery and after one attempt at starting the car with that battery the machine was then saying the brand new battery needs charging ,

Could it be my started draining the battery by any chance

 

[revajones]

Another question should the alternater have an earth cable

When I check it with a mulimiter it says it's not grounding

 

[Ted]

The alternator shouldn't need an earth cable as it should earth via its mountings to the engine which should then be earthed to the chassis and battery.
Easy way to test ( I MUCH prefer a testlight) what is the voltage between battery positive and alternator body - should be the same as the voltage across the battery.
What is tour meter reading that makes you think that it isn't connected to earth?

 

[topdown]

Is there a battery sensor on the earth cable at the battery? If so disconnect the small plug and check the output again with the engine running. it should cycle 13.5 / 14.5. This is default alternator output.

Cars with a battery sensor have 'managed' battery charging. Battery sensor monitors the system voltage and tells the Engine Control Module to manage alternator output.

www.aftermarketonline.net/ewcommon/tools/download.ashx?docId=23715

The above shows how this system works.

You need to have it on a star machine.

Mine was the alternator and the battery sensor.

 

[revajones]

When I chekc the alternators continuity to and earth point there is nothing that's what leads me to believe it need to be earthed

. Yea i have disconnected the sensor but it doesn't change the voltage in the slightest which is completely strange to me.

Today has given a little development it's idling at 13v but I can't get it to raise at all I have tried removing fuses to see if one of them is draining the car to see if the voltage increases but nothing , is this likely to be the battery control module ?

 

[revajones]

I may also add as I rev the car at all the voltage drops