I have an HP pavilion dv6 1299ea artist edition and the battery is getting low really fast (<10mins) which is annoying for a laptop. Charger is an aftermarket not the original which might affect it. I've found the battery and it is a 4400 mAh. I've as well found a 6600 mAh battery. Which one should i buy and what will the difference be? With the new battery should i buy a new original charger as well? (My battery has been changed an other time as well 2 years ago...)