2003 Suburban 2nd Battery add

I need to add a 2nd battery to my 2003 1500 suburban. Can anyone give me ideas on how to do it? Or is there a Kit i can buy for it? Also would i need to change the alternator?

I need to add a 2nd battery to my 2003 1500 suburban. Can anyone give me ideas on how to do it? Or is there a Kit i can buy for it? Also would i need to change the alternator?

why is this needed ?

The alternator will not need changing.
when wiring the 2nd battery it is best to solder the wires not just crimped. also use high quality copper wire of the same gauge.

you may want to put a cut out switch in the feed of the 2nd battery but that would depend on why your doing this. make sure that both batteries use the same exact ground point. the wiring must be covered with a loom material to protect from shorting out.

Go look at the diesel set-up of your same vehicle- they run 2 batteries in parallel all day long- just copy that set-up. They only use one alternator- and you have the battery tray already available- just remove the stowage box.