Hey guys, i think i posted this in the wrong sub before so here goes

I've recently installed a small battery kit with aluminium tray and I need to relocate my earth cable.

Here is a pic of how it is currently, blue being the earthing bolted to the oem earth location:

http://imgur.com/JBMJTpH
http://imgur.com/GdyeRA3

my question is, can I earth the negative to the battery tray? or where the battery tray mounts to the bay?

thank you, and sorry again for the dumb question

 

You could mount to the battery tray but I wouldn't. The reason is the bolted connections that could corrode and develop high resistance.