Drop in voltage

[Phoenixfire1989]

So, the voltage issue has been ok for the most part since i got my new alternator..but for some reason, when i turn my AC or heat on, my voltage is dropping close to 8..when i turn it off, it jumps back up to 13. Is there a resister or something that might be bad that is causing this issue? It's not the gauge, cause my lights are dimming..RPM and oil pressure is dropping.. There's too much of a load on the engine for an unknown reason..

[deadtrend1]

Is it low with the a/c on just at idle? If you bring the rpms up does it go to normal?

[Phoenixfire1989]

Is it low with the a/c on just at idle? If you bring the rpms up does it go to normal?

Just at idle. If i'm actively driving it down the road it's ok. When i stop at traffic lights and such it's dropping. i tried to adjust the carb to up the RPMs to compensate, but it didn't do anything