Doing a BSI reset is a GOOD THING so changing the battery using the rules above is better than trying to keep it alive with dodgy accessories if you really want to NOT reset the BSI then just hot swap the battery while engine is running !Hi all,
Could you not instead use an EOBD memory saver ?
This plugs into the 16-pin EOBD diagnostics port and allows removal of the vehicles battery without losing any codes or settings and leaves your ECU energised.
Then you don't have to worry if you have followed all the correct procedures.
You do however need the use of a slave battery and the device itself costs just over £20.