USING an Imax B6 AC V2

Good afternoon I recently purchased an imax b6ac skyrc to learn how to balance my hv battery pack I do know that I need more chargers to finish in less than a month but I do not know if I am running my charger correctly following one of the post in pc, I use 7000mah cut off and 6V discharge at a 2A charge discharge seems fine but when charging comes it goes above 8.5 V and never seems to reach a 7000mah capacity on the module im using to experiment. Could it be that I have a completely bad module with no resistance?