Wiring 2 batteries

[fairpilot]

I purchased a Perko 8501 battery switch for wiring 2 batteries. Instructions on a couple websites conflict on wiring it up. here is what i understand

Postitive from battery #1 to pole #1 on switch
Positive from battery #2 to pole #2 on switch
Cable from starter to Com on switch

Where i have the question is do i connect a negative cable between to two negatives on both batteries then continue to ground on engine OR do I run a seperate negative from each battery and attach it to the ground on engine. I know this is prob simple but just want to be sure
Thank you for any info

 

[MOA_Chaser]

If you think about it, it's completely irrelevant which one you do. BUT... I grounded one battery, then used a jumper to ground the second.

 

[davel501]

The stock setup includes a jumper between the batteries to make sure they maintain the same voltage. I would stick with that design.

 

[fairpilot]

Ok so neg to neg and keep going to ground on engine, this is what i though would work fine. thanks