Hercules charger problems

Got a used tool and it came with a charger(used) and a brand new 12ah battery. The battery has 2 bars so I threw it on the charger, was solid red then when installed blinks green. Well it’s been 3 hours and still 2 bars and still blinks green and a sold red light. You guys think the charger is bad or maybe a battery problem, what will harbor freight help me with. I don’t expect anything as I never perched new but I’m hoping just a $45 charger and I’ll be set.