8.49v is above the damage limit for a 7.4v LiPo, Much higher above the damage limit for a Li-Ion. May be measurement error. Remember that when removed from charger, the LiPo or Li-Ion voltage would be higher still.
My separate computer controlled charger will tell me how much energy was put back into the battery after draining it, and give an idea of battery health.
My battery is only stock 1300mah Li-Ion, with four other 1000mah LiPo's which work, but mess up the DH9104 balance.
Understanding RC LiPo Batteries