Late post but relevant.
Yes, a long socket 13mm will release the securing strap. In addition to being super careful not to let the nut, when loosened, fall away into the engine bottom pan, also make sure that whilst grabbing the loosened nut with one hand you do not (as I did
) drop the socket itself into the engine pan.
There's more grief on the way... the flat black box sitting on top of the positive terminal looks as if it should open if the two clips on the front end are released, perhaps by prying with a screwdriver. WRONG! Having snapped both these blighters trying to open the box, I find that I should have just slipped the two flat spring-loaded sections on the back of the box. Doh!
Opening this box I see an array of big terminals and cables, and also see the two brass screws referred to by our deceased friend (above). I've not unscrewed them yet because I am filled with dread of the unknown: as soon as the battery + terminal is loosened and the whole shebang lifted off, the Alfa will be without power obviously. Now, what is going to happen when the new battery is fitted and the power restored? All hell is going to break loose I reckon, with alarms going off, lights flashing etc. The Alfa owner's manual recommends leaving a newly installed battery for 'several minutes' before inserting ignition key to let the climate control settle itself. Surely I don't have to listen to this racket for 'several minutes'
before inserting the key to shut it up? Or is there another way to over-ride the alarm? I ask because I have never yet triggered the alarm.
Finally, can someone please advise whether there are any other problems which might crop up when the battery is re-connected? I did read on another post about having to enter a keycode for the radio, for example - but this surely must refer to an after-market device, as far as I am aware, the factory fitted radio doesn't need a code - or if it does, I don't have it, and so I am reluctant to go any further without reassurance that the radio will still work when I reconnect the battery.
Thanks for reading this over-long post, and I hope you can help.