Bad Alternator?

[wykr32]

Hi guys, I've own a R32 GST-t for a week now and for some reasons, it couldn't start after topping up my fuel. It doesn't even tick at all like a bad battery and the battery reads about 11.8 to 12.5 when in the On key position.

So I got to borrow a battery from one of my mates and I accidentally connect the wrong terminals (positive on negative and negative on positive), and then I place it back again and nothing is working except for the headlights.

After that we tried to hill start the car and it started running (woohoo) but none of the electrics are working except for headlights, turbo timer and the cluster clock backlight but clock isn't working. (Battery showing from 11.2 to 10.5)

So after driving for about 15 mins, all the electrics went back online but the after market gauges and water temp in the factory cluster was flickering and the head unit doesn't work.

after driving for another 10 mins or so, the battery voltage keeps dropping from 10.5 to 9.8 and so on.

Is it a bad alternator/battery/diode?

[wykr32]

Also, when I turn the car off and turn it back on, the same problem occurs. None of the electrics are working until I drive for a while and they will come back on. Any ideas?

[R.3.2.G.T.R]

you need to check all your fuses first, ones in the engine bay + one above your right knee under the dash, then report back