Cap Or Alternator???

Cap Or Alternator???

right now in my 98 rolla, i have a 800 watt kenwood amp pumping a rockfor fosgate 12 inch hx2 sub in a sealed box. this hits hard for now but....i lights at night dim big time. i bought this 1 farad pyramid cap, hooked it up and my lights don't dim like they used to, but they still dim? what could it be?
could it be the pyramid cap or what?

i have 8 ga power running from the battery and 12 ga speaker wire from the amp to the sub. any suggestions?

8 gauge for 800watts? You'll want to run 4 gauge power wire. Also, try regrounding your engine. I have a DIY for that at http://vamp.darkravers.net/DIYRegro...Full#SizeSwitch

you should gett a better capacitor also. ive seen big differences from cheap one to top of the line ones.