Adding dual battery - how to ground?

[nelswhytry]

I am planning on adding another battery so I have a dual battery setup, to handle a stereo upgrade. I think I have most of it figured out, but not sure how or where to ground the new second battery. Currently there is a very thick ground cable that looks to run back to the engine, I am guessing there must be a way I can use that somehow to ground the new battery.
Any suggestions or pictures would be great.
This is on a 2013 LSV.

[The_Robo_Fighter]

This is how I set mine. Picture is from another member and not my original work!25567

[lee]

You will need to ground the new battery the same way, you need to either tie it to the other battery or ground it to the block.

[TrueKaotik]

Connect it to the other battery.

[nelswhytry]

Perfect, that is the information I was looking for. Thanks!