yellow battery light - when engine is off

[Barroni]

Morning all

I noticed at the weekend when the engine was off but the kids were listening to the radio that the bong alert sounded and a yellow battery warning light was displayed.
Ive never seen it when the car is driving or the engine is started. I tested again later in the day and within a couple of minutes of switching the engine off and radio active i saw the yellow battery light.

Does this indicate that its just the battery or perhaps something more sinister like the alternator? I just called local pro-tyre and they immediately suspected its the alternator.

Cheers

[X5Sport]

Low battery. These cars use significant amounts of power with the engine off. 20 mins max and then it may well shut off your systems in order to ensure that you can start the car. It also takes 20 miles of running just to put the charge power taken from starting the engine back in to the battery. The iDrive should also report a message about either low battery or excess discharge on the screen.

I doubt there is anything wrong with the alternator. It’s the kids in the car killing the battery

My X6 draws more than 60A off the battery in ‘radio ready’ state due to all of the other systems being awake.

[Barroni]

Evening

Thanks for the info, i knew the batteries worked hard but didnt realise how hard. Thinking back its been having quite a few short runs so I might just let it run for 30 mins tomorrow with everything off before i look to replace anything. Thanks for the advice

[X5Sport]

That could start clogging your DPF!

If you are only doing short runs then it will be worth investing in a Battery Conditioner. A few in here have such, I use a CTEK unit (MXS10 but the MXS5.0 will also do) to keep the battery topped up. BMW rebadge CTEK and add mucho dollars to the OEM price!

Simply connect under the bonnet at the jump/charge points. 8-12 hours later your battery is fully charged.

I use mine to keep our stored E46 battery fully topped up over Winter (they can be left connected and running). Better than a dead battery! By using one I kept the original E71 battery going for over 8 years - 6 is the average life.

Worth also checking the voltage 4 hours after last use (from under the bonnet again) with the car asleep (open the bonnet a tad then lock the car and leave it for 4 hours) to see what the voltage reads. It should be above 12.6 for a fully charged battery. If it’s below 12V then your battery is dying.

If you weren’t aware, a new battery has to be coded to the car because of the Intelligent Battery System. It’s not a simple swap out anymore

[Barroni]

Hi X5Sport

Thanks for the great tips. I priced up the MXS5 for £68 on Amazon so I think ill go for that