[Mboon]

I have a 2010 LCI E90 M Sport. Within 1 minute of me turning the engine off but leaving the ignition on so the radio is playing it warns me the battery is very low. It would do this after a 2 hour drive or a 2 minute drive.

The car had the maps updated etc recently and the guy who did this said the battery was in good shape when he did some checks.

Is this a common issue with these cars?

It is well specced but even so would expect the battery to last longer than this.

I have never had any issues starting the car and is never lazy at starting

Thanks

[Sensible_]

How old is the battery?

Have the battery properly tested. You may have a drain. Any aftermarket equipment installed?

Monitor the voltage using the secret menu.

[oli3]

How old is the battery? If more than 5 years I would look at replacing it.

[old grey steve]

Seen AGM battery whether 80aH or 90aH go for around 3-4 years then when seen and diagnosed show signs of fatigue charge rate can be viewed via diagnostic (depends on the quality of diagnostic) so can (start-ability) where in percentage terms you can get a birds eye view on the battery condition in terms of general starting plus when you call upon the battery when starting or if your car has stop start technology when this is in use (drop testing these can prove to be inaccurate) but yes their durability for me as I see these things day in day out seems to be 3-4 years.

Gen BMW battery's only carry a 2 year warranty remember strange that, but yes overall on these cars batteries long term don't have a good shelf life

[Josh_G]

i have this exact issue as described in the first post.. on a 335i that has done it since the day i purchased it from BMW. it always starts first time every time. i have flashed MHD with the warning and had no adverse effects and started the car strait away

on the negative terminal is a device which monitors the voltage of the battery 9 times out of 10 that is the culprit i haven’t bothered to replace mine yet as for me it’s more an annoyance than anything else. I forget what the part is called though but maybe worth replacing that first as it’s a lot cheaper than a brand new AGM battery