Battery Performance

[migabc]

On the W211 COMAND APS you can see the voltage that is being supplied to the headunit using the following procedure:

1. Go into the ENGINEERING MODE Menu (Press “Mute” + “Endcall” + “Service” all together and hold for 5 secs)
2. Press the "Devices" button (4th soft key on the left)
3. Select "Headunit". There you will see the following info:

FOT temp.: 51.3 ºC (varies)
Voltage: 12.4V (varies)
Urloader: 2.00
Bootloader: 2.1.0
HW Revision: D2.0
Image Variant: ECE211

 

[Satch]

Cannot remember where I read this slightly alarming statistic but it was suggested that thanks to a combination circumstances only 30% of new car batteries will now make it to 4 years old. Many car makers thus allow new batteries to be silently fitted during servicing within the warranty period so as not to upset customers.

They have in effect become a service item with a life in some cases below that of the air filter.

 

[BTB 500]

Of course supply voltage to the headunit will not be the same as battery voltage. The voltage drop along a couple of metres of low-current (small cross-section) wiring loom will be significant if you're evaluating battery condition - the difference between fully charged and fully discharged is only 0.8 volts.

This is almost certainly why the information is 'hidden' - it's of limited interest/relevance.

 

[mchips]

FWIW, my w202 wouldn't start yesterday and it had 12.38 volts when measured across the terminals. You could hear the starter begin to engage but not enough to turn anything. Luckily, there was still plenty of power to power interior lights, and most importantly, the pumps and receivers for the locking system. While a bit annoying, I consider myself lucky It happened at home, I wasn't running on my way to a crucial meeting, and I didn't have deal with being locked out of my trunk where the battery is located. I will have to check my papers, but the battery lasted either 6 or 8 years, so I can't complain. Also, I thought the engine sounded weak during the last two startups before it died and I forgot to proactively check things out when I got home. Therefore, the car had "warned" me that it needed help

 

[grober]

OLD BATTERY 5 YEARS OLD = NEW BATTERY REQUIRED NOW! Why even pause to think about it on a modern automobile so dependent on electronic systems.

 

[MangoMan]

Yeah, I paid £16.94 for a new battery for my ce before I sold it, well worth it! Lucas 2 yr guarantee...