Why does my phone say invalid battery and not charging

Zccsalter, could be caused by a bad battery. Consider changing it. Try to remove the battery and keep it out for while then reinsert and see if that helps. You could also try a hard reset (carefully because you may lose your files). It may be because the battery is discharged beyond its threshold and does not take a charge. Once that happens, your phone does not get the right information (proper voltage is part of the signature information) from the (smart battery)it declares it as "invalid" and will not charge it. For that you could try to charge the battery on an aftermarket charger outside the phone for a few hours.