XJ?2010

Went out wheelin yesterday and fried my alternator. Sense I drove home under the power of my battery alone it naturally went dead. So After installing the new alt. and getting a jump start I let the jeep idle to recharge my battery after about an hour my voltage gauge is still reading low. (just over 13V) it use to be at 14.7 before I installed the new alt. I took off the wire on the alternator and tested its output with no resistance and it was right around 24V (normal) so I know thats not the issue. I went and cleaned off my battery connecters/ terminals. and also cleaned off the larger grounds going from the block to the Battery. Not sure if this is normal or not this is the first time sense I got an optima red top sense it went dead idk if that plays any role.

Just looking for any insight to this.

Thanks.