ev0ti0n

When I step in to about 70% throttle, the battery discharge light goes on around 3.5k RPM's. It's kinda weird but I'm assuming it's a loose belt. Anyone know anything about this?

Tammy

Assuming you have not added any large electrical loads that may be failing, i.e. stereo amps, non-stock power inverters ... anything causing excessive electrical load ....

How many miles on the alternator? Is it original or rebuilt.. (Denso tag on alternator, manufactured or remanufactured.) How many years on the battery, it's build date is usually stamped on the top...(letter for month and two digit for year)
You need a meter and provide us with the battery voltage without engine on, at idle and at the failing RPM. A digital multimeter is best, with hundredth or less of a volt reading. It will vary; your looking for an average reading.
It is normal to decrease alternator voltage output as you charge the battery, then stablize. 14.2 volts is good average. 13.0 is on the edge of error.

If the belt is squeeling, note the meter reading when this happens. otherwise, belt should have flexed about 1/4 to 1/2 inch when pressed betwen pulleys.

I would suspect you battery or the alternator is about to go, specifically it's internal voltage regulator. Go to reputable auto electrical shop in your area and have the alternator electrically loaded. The voltage readings should tell the tale.. Hopefully, your battery is bad, but they will check it at the same time. Then your not throwing parts at the problem.