Charging time and running time

I would like some help on this, I have my Dyson V8 for 1 year and a half now bought it locally and suppose still under warranty but when I took it from where I had bought it they told me that the battery needs to be replaced and battery it’s not covered by the warranty.

The problem that it has is that it’s charging for only one hour and a half maximum and running on max speed for only one minute even when the battery is suppose to be fully drained charging the same for only one hour and a half when suppose it takes over five hours to be fully charged.

Hope someone can help me regarding this issue.

thanks in advance