Bittle Battery problems

Hello

I have a bittle with NyBoard V1_0,

Connecting a fully charged battery to the NyBoard it starts beeping that the battery is dead.

I tried downloading OpenCat again but it didn't help I also checked if the voltage is right (it was about 7V) I don't really know what to do else that could help.

I really hope someone has a idea what to do.

Thanks in advance.