XSeries-forum

E70 2009 35d I have noticed that the clock keeps losing time and have been told it’s the battery would my car have an AMG battery or normal battery it has a Bosch S5 (444770198) at present just under 4 years old ?? Which was fitted by non Bmw garage .
I have just driven 180 miles left car 6hours and clock has reset to - - - - no out put so I had to input time .
Thanks

That looks like a Bosch S5 conventional ‘wet’ chemistry battery. If the number on the top is S5 013 then it is such. The AGM version is 4047025244367 with a code S5 A13. You need an 019 format (the battery dimensions and terminal type).

You can fit either a wet or AGM type but the car must be coded with the correct battery type and current rating or you will have charging issues. You cannot just swap the battery out for a new one. AGM batteries use a different charging voltage and rate than ‘wet’ batteries, and the E70 has the ‘Intelligent Battery System’ which monitors and changes the charging state as the battery performance changes with age and use. It has to be ‘told’ of a new battery, it’s type (AGM or wet) and current rating (Ah).

Incidentally, all Bosch S5 batteries have a 5-year warranty so as long as you have the receipt it should be replaced free under warranty.

Thank you for ur help will ring garage today who fitted the battery