2011 E class coupe battery terminal size?

[Mark97]

Hope someone can help? Car is over in France and I need to wire up a battery charging solar panel for when its parked at the airport. Ideally want to affix a permanent plug direct from the battery terminals so its easy for the wife to simply plug in the other side of the harness in order to charge it.

Hopefully someone can advise me the diameter of the terminal bolts so I can crimp the right sized electrical terminals onto my solar panel charging leads?

TIA

 

[keith of kent]

As it happens I've just had the battery out of my 2015 E class. 10mm spanner size so M6 bolts and nuts