Why would my battery not be charging, already changed the alternator and battery and still it is giving a low amp possible wiring? Old alternator tested and it is fine and installed a new one and still not charging it is giving 4.8 amps at peak, 2k rpms.

No. Charging voltage should be above 13 to 15. BUT, this vehicle has GM's power management feature. It only charges when it needs it. Read this post to see how it works. Ask the shop if they conducted the proper tests for this system.

http://ricksfreeautorepairadvice.com/gm-charging-system-problems/

Did you check power an grounds at the alternator ? The heavy gage wire on the back of the alternator should have B+ voltage , if not fusible link is blown . The connector ,pin's 1 & 3 should have B+ voltage also . There are videos on youtube on checking charging systems . Do you know how to do automotive electrical testing ? How to use a DVOM - digital volt ohm meter ?
How to Test an Alternator Diagnose Charging Issues

If the battery if not holding a charge, it might be time for a new battery (is it over 5 years old?).

check alternator output with engine running.you should have 13.5 - 14.5 volts if not alternator not charging.check alternator wiring to battery feed to alternator.check alternator voltage regulator wiring check alternator fuse make drive belt not slipping.and you have the correct cold cranking amp battery.bad old worn out battery cables will cause charging problems.because old battery cables put high resistance on the charging circuit.if battery cables old as vechicle replace them.

check for 12v at alternator terminal when engine is runing it should reed 14v/check for loose fan belt/or broken wire at alt plug

CODE 12 STAND BY MEMORY POWER LOST.WHAT IT SAYING ECM LOSING MEMORY BECAUSE LACK OF POWER.POSSIBLE CAUSE TO YOUR PROBLEM COULD BE OLD WORN OUT BATTERY CABLES CAUSING POOR GROUND AND HIGH RESISTANCE IN CHARGING CIRCUIT.YOU COULD HAVE WRONG AMP ALTERNATOR AND BATTERY WRONG COLD CRANKING AMPS.MAKE SURE ALTERNATOR BELT TIGHT AND CHECK ALTERNATOR BATTERY FEED WIRE AND ALTERNATOR FIELD WIRES FOR DAMAGE OR LOOSE CONNECTIONS.CHECK ALTERNATOR FUSE. WITH ENGINE RUNNING ALTERNATOR OUT PUT SHOULD BE 13.5 TO 14.5 VOLTS IF NOT ALTERNATOR NOT CHARGING.

MAKE SURE YOUR BATTERY CABLES ARE CLEAN AND TIGHT.MAKE SURE YOU ARE GETTING GOOD GROUND AT NEGATIVE BATTERY CABLE.IF BATTERY CABLES VERY OLD REPLACE THEM.IF ALL IS GOOD ALTERNATOR HAS LOOSE B+ WIRE AND FIELD WIRES CONNECTIONS MAKE SURE NONE OF WIRES DAMAGED AND ALTERNATOR DRIVE BELT NOT LOOSE SLIPPING.IF ALL GOOD YOUR ALTERNATOR HAS THE WRONG AMP AMPS TOO LOW HAVE WRONG ALTERNATOR. OR YOU HAVE FAULTY ALTERNATOR.

have the BCM checked out for that can cause this problem to the display

Go to WalMart, Sears, Pep Boys, O' reilley's, etc. & buy a battery charger. They're about $25 - $35 for a low-end model. Or you can just get a jump start from someone else (via jumper cables between their battery & yours) & drive the car for a while - your alternator should charge the battery back up.
How old is the battery? If it's at least a couple years old, it may be dying. Or you may have a bad alternator or an electrical short that's draining it. If you charge it up & it drains again withing a few days, you need to investigate a possible bad battery, alternator, or other electrical defect.