Emerald saber stops working

[DarthRondoudou]

Hello there!
Just to see if people can help me troubleshoot my Spectre emerald saber.
I got it last tuesday. Charged it. Ignited it. Perfect. sentinel yellow, white FOC. As specified in the order. But when I use it for a bit, it just stops working. light switch off. No more sound. No nothing.
When I charge it again (port on the saber), it works again for a little while, then stops.
Since it happens while clashing, could it be a loose connection?
I'll take a look at the batteries and try switching them with other batteries to see if they are at fault.
In the mean time, does it ring a bell?