RE: JR Charger dead & JR FM XP6102 vs OEM 2.4ghz
I have been in this hobby a long time. I still use the simple Wall Charger, occasionally, with NiMh batteries, but a long time ago, I started purchasing Cycling type chargers that use Pulsed charging and anticipate the Peak voltage of the batteries so as not to Overcharge. There are various ones on the market that work with specific batteries, such as LiPos, or for all types of batteries.
Buy a decent charger and you will end up with batteries that have longer life and better performance.