[Martyn76]

So,

This morning had a red battery symbol ping up on my dash it didn't come on straight away but after a few minutes of driving, stayed on for about 15 mins, dropped the kids off at school got back in and started the car up again and it didn't re-appear.



Didn't notice anything wrong, AC still working, etc.

Not had the time today (typical Monday so far) to check what it means, can anyone shed any light on this?

Thanks in advance

[rasa bmw]

can only think of a dodgy alternator..maybe bad earth or its on its way out..

[AWSAWS]

As above. Need to do some checks for:

Bad battery - might have a bad cell(s)

Bad alternator - might not be providing enough current to recharge the battery. Bearings can go.

Bad wiring - May have a lose or broken connection.

1st step. See if you can get a voltage reading from your battery. Should be a little under 12v (Ignition off)

2nd step. See if you can get a voltage reading of battery with car running. Should be around 14v with alternator running I believe.

[Martyn76]

For for the replies, I've got a BT ODB dongle at home will get it connected and see what I get back voltage wise.

What is the spec for a battery, I see there are 2 different types on euro car parts...

[juld0zer]

Originally Posted by AWSAWS

As above. Need to do some checks for:

Bad battery - might have a bad cell(s)

Bad alternator - might not be providing enough current to recharge the battery. Bearings can go.

Bad wiring - May have a lose or broken connection.

1st step. See if you can get a voltage reading from your battery. Should be a little under 12v (Ignition off)

2nd step. See if you can get a voltage reading of battery with car running. Should be around 14v with alternator running I believe.

Voltage with engine off should be above 12V.

Voltage with engine running will vary. If the vehicle has an AGM battery, the voltage will agaim be different. Non-regenerative braking models will be anywhere between 13.8v - 14.7V. Regenerative braking models might not show any alternator output with the engine running. For those, you will need to load up the electrical system by putting the headlights on, blower on max, rear demister on, seat heaters on etc.

[AndyVR]

If it does need a new battery, try https://www.tayna.co.uk/

I had no luck with ECP/GSF for my 2010 320i AGM battery, they were all the wrong spec or crazy expensive. Tayna had an exact match, at a decent price for a Bosch AGM.