SR20DET Battery Charging Issue

[mycrapsbroke]

So im decently new to the 240 world, but im a fast learner and have pretty good foundation for car technical skills.

The Problem: My battery is relocated to the backseat for now (trunk doesnt lock). Ive tested my brand new "performance" battery and also tested the alternator. Both checked out ok. The car will start with a charged battery, but the voltage doesnt go above 12.4 volts, the longer i drive the more the battery drains. I have run a hot wire from the back of the alternator straight to the battery and it still doesnt charge. Im positive my grounds are not the problem.

[2_Liter_Turbo]

Is the 12.4 volts during engine idle or engine off? If during engine running, it sounds like the alternator isn't providing the juice you need. I'd try swapping it out. Everything else you are saying points to the alternator being bad.

[mycrapsbroke]

Yeah that's at idle after I charge the battery.

[blkvrtswp]

There is a wire to the alternator in the plastic plug that controls the field coils to charge or not charge the battery. Otherwise the alternator would simply constantly charge the battery, leading to overcharging / battery damage. Check that wire. If it is not connected you will get no charge. You should see 14+ volts at the battery terminals when the engine is running.

[mycrapsbroke]

i checked and its plugged. Also, my battery light is not on in the dash, so i feel like that means the ecu is somehow unaware that there is a battery there or something along those lines.