Belt and possible battery issues?!?

So quick question (hopefully): I have had an Optima Red Top in for over 7 years. Running aftermarket stereo with amp, head unit and sub (nothing crazy) and plug & play HIDs along with Unorthodox UD pulley. Ever since I switched to UDP, i have had problems with squealing belts (normal from what I've read). One mechanic got it right finally fro a couple of years then I had belts, water pump, etc done and voila squealing belts again. Belt squealing is temporary and goes away after a couple of minutes. I have a volt gauge attached and noticed at 14 there is no squeal with lights off. The second I put lights on it drops to 12 and squealing starts. At this point I am sure that belts are getting chewed up again and need to be replaced, but I am curious if a dying battery could also be contributing to issues. If I leave the car in the garage for about 3 days or more it is almost guaranteed to not start and requires a jump. Thanks in advance, just trying to finally solve the issue and stop annoying the neighbors

What's happening is you're getting a bigger draw from the alternator, your belts aren't adjusted probly and slip on the pulley (squeel) rather than move with it. Try to tighten them a little bit

Your battery may be dying too. It's 7 years old, I don't know how long Optimas are supposed to last though.

There are two drive belts. You can feel the tension and adjust them on your own with 1/4 drive metric sockets. One bolt locks the bracket for the accessory in place and the other bolt lets you adjust the tension on the drive belt. There's another bolt too that attaches the accessory bracket to the engine block but doesn't alter tension of the drive belt.

i've had an optima red for 10 years...with similar electrical load to the thread maker...never had a problem with squeeling until the belts needed replaced.

its what tweety said, and i'm guessing the battery is perfectly fine. The squeeling is starting because of heavier load from the alternator...the volts are dropping because the alternator's pulley isn't being turned fast enough.

its either worn out belts, and/or improper tension on the inner belt (adjusted by the alternator's pivot)..its very easy to check yourself, but you do need to get under the car to loosen the long screw under the alternator...the adjustment screw is on the passenger side of the engine, under the cruise control and strut bar sort of. You also need to loosen the clamp nut on the top of the alternator to get it to pivot properly. You use the top screw to apply tension to the inner belt. Take the belt out first and see if its torn, or if the ribs are all chewed up...if it looks ok, and you're sure its not drying out or anything...put it back on and tighten it until you can turn the belt 90 degrees with resistance, but not much farther...don't over do it though, the belt will last a few days if you go nuts with it...

Thanks all for the speedy input, going to try and get on that this week and check the quality of the belts and the tension. See what happens.