Battery Voltage?

[architect1337]

I'm getting some strange issues with my W203 C270 CDI

When starting the car, sometimes the lights on the front panel flash and car either doesn't start (turn key and no cranking) or starts then stalls. As it's summer, air con is on etc. I also notice that once, while driving, all the lights on the display lit, then went out. No issues with the car.

I checked the battery voltage using OBD2 (no codes showing by the way) and the battery showed 11.2V. When I started the car, it went up to 13.5V.

This all happens occasionally. The battery is factory fitted so must be about nearly 8 years old.

Would a battery on the way out exhibit these symptoms to the electronics? Why would car stall about three seconds after starting if its the battery?

Thanks for any advice. I don't want to spend money if I don't have to (and have just spend out £500 on the automatic gearbox!)

 

[SavMan]

Your battery voltage should be higher than that so could be on its way out but could also be that there is a corroded earth. Check the voltage directly at the battery while running to see if there is a voltage drop from what the ODB is showing, and check the earths for corrosion.

 

[architect1337]

Thanks for the reply. The car has been doing well recently until today. It started first time, I was driving out of my road (about 1 mins down the road), turning at a junction and the engine just cut out completely. Tried to restart and no cranking whatsoever. Waited a minute or so, then restarted and it fired up ok.

It's now getting dangerous. Checked for any codes and nothing. It failing like that points to a fuel pump? Does a battery have anything to do with a fuel pump. Taking it to garage today (if I make it!) to investigate.

 

[architect1337]

Took car to garage (no stalls thankfully) and they plugged in and confirmed no codes. Took a look at battery while I waited (multimeter on cells, started engine etc). Voltages looked OK

Opened each cell and took an acid sample and tested it. Showed a problem with a number of the cells (device showed borderline fair / recharge) so indicated the battery may not be holding it's charge very well.

As battery was over eight years old, decided first port of call was to change battery so did that and now running around to see if problem persists.

 

[grober]

I am still surprised when owners of modern cars appear surprised that a plethora of strange electrical faults/ mysterious fault codes etc appear to be down to an aged battery. Where once upon a time the car battery's role was almost exclusively starting the car its now an integral part of the car's complex electrical system. Forgive me if I say that at 8 years old your battery is way past its sell by date on a modern [ post 2000] car. My rough rule of thumb ----- after 3 years- any hint of multiple electrical faults- problems starting- battery flat etc - RENEW After 5/6 years RENEW anyway. That's assuming fairly normal use/car mileage/ stop starts etc If you want to extend your new battery's life hook it up to an intelligent charger like a CTEK on a regular basis.[ like overnight once a week as a minimum ]

Hope a new battery solves your problem