How do I set up a backup battery system?

[SiNFuL]

Hi guys, I have major power issues that result in a bouncy idle. When i just sit there and everythings off and the e-brake is on(no power brakes), it's 750-800rpm. When I push the brake in I lose 50rpm...with the CD player on(powered by a 600w amp) I lose about 100, and w/ parking lots I lose about 100, and with my PIAAs on as well I lose about 300rpms. I asked Don about this and he suggested the EGR valve being clogged, and it's fine. So he also said I need to set up a backup battery power system. How would I go about doing this? Thanks!-Galen

[TrueSlide]

Did you get your battery and alternator tested?

[midwestdrifter]

i have had bad expeirences with the testing stuff. i have that same problem on my girlfriends car. on hers it is the belt tension....stupid mx3s with no belt tensioners. check your belts, replace if needed, and tighten.