Upgrade alternator and/or battery?
 

I have a Kenwood DDX-419 stereo with all 4 door Alpine SPS-610 speakers, and I want to get some subs.
The Alpine SWS-12D4 subs really caught my eye, I want 2 of them (they are 500w RMS each) and I bought the Kenwood KAC-9105d amp to go with them (900w RMS at 2ohms).

My question was will I need to upgrade my alternor and/or the battery? As far I know I have the stock alternator and a NAPA 75 battery. I will not be installing them myself, I don't know how ha. I'm taking it to my local shop who offers lifetime warranty.

I have a '99 Blazer LT 4dr btw

Thanks for the help/tips!

for a stereo alot of ppl run factory battery and alternator and only upgrade if ur doing alot of audio competitions or if ur running alot of offroad lights and power equipment. just do the big 3 upgrade to ur vehicle and it should help with the electrical system to ur vehicle. if u choose to upgrade the battery i recommend the optima yellow top battery for audio equipment

I see, I'll check how it handles once it's installed. How much does it usually cost to do the big 3 upgrade?

it will prob cost u a minimum of 13 bucks to do the big 3. get 0 gauge or 4 gauge wire and the bronze end terminals that attach to the end of the wires.

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Two upgrades will help you. Like previously mentioned, the big 3 upgrade with no smaller than 4 awg, preferably 0 awg. The other upgrade being either an alternator from a full-sized truck or a high output alternator. The alternator out of a full-sized truck you can get used for around $50 to $80. If you decide to get the full-sized truck alternator, you will need to get a longer belt. Usually an inch longer belt works. For more information, check out this link. The big 3 upgrade with the ad244 (145a version) alt from a full-sized truck helped me with voltage problems. I'm pushing around 700 rms, 2 12" subs.

0g is useless unless you are running some serious serious power. 4awg will be more than enough.
I am running 4awg from alt to battery, grounds, and all the way back to the amp, and I am pushing about 800w to 1 12"... not a single problem. even when AC or heat is on high, headlights are on too.

also, the factory alt will be find as well. most of the time I never drop below 14v

Ah I see, does a longer belt affect anything like performance or anything like that?

Awesome, close to my watts, I guess I'll have to see how it acts once it's installed.

Might as well do it if it's that cheap, thanks guys for the help.

No. You need a longer belt because using the larger alternator moves the pully out a little and you need the longer belt to fit.