ok, so charging completed and now the battery is powering the V5. The charger is still connected so if capacity reaches 80% it will start charging again. Disconnect the charger to see how the battery discharges all the way to shutdown.
Once charging stops, the voltage drops quickly in the first 30 seconds, you can see that in the graph in this post.
All cells seem well balanced (ie. they all read the same voltage), so I don’t really see anything wrong. It should last 10 to 15 minutes or so when driving around a competition robot.