yea, i've never noticed my lights getting dimmed, so i never bothered w/ a cap either

but i have seem other cases where a cap helped w/ the lights dimming

some amp don't required much power, but I notice lots of dimming with gain half way up
hopefully the alt can take it

what amp are you running? also did you pass a large enough gauge cable, if your cables are too small they heat up and stop conducting as well draining power.....

Also make sure you volt meter your amp.. I don't have the gain even 1/4 the way on my 1000/1 and i make 1000 watts at 28 volume on the head unit leaving me room to clip up to 31. If you don't volt meter your amp and just turn the gain *** you'll end up clipping really bad, as well as sucking massive power because your amp becomes very inefficient.

running a mtx 7801 with 0/1 gauge cables

in other words I could just go buy any other battery from auto zone and it wouldn't make a big difference
for example duralast, autocraft titanium

I think before even upgrading bettery etc. go to the jl audio site and check out their tutorial on volt metering your amp.

Then proceed to set your gains with a volt meter and after that is set check if it dims.

Unless you are running two 2 ohm subs in series to have a 1ohm load you have less power then it do and should not be dimming as much as you are unless its set incorrectly.

If you wanna spend money on a battery I would buy a Kenetic deep cycle battery or another comparable battery but they are very expensive.

thanks!