Right joy con not connecting when out of switch.

I’ve seen this issue before. More than likely the battery was not hooked up properly or the wire running from the battery to the motherboard was damaged. The connector for the battery to the motherboard is rather difficult to disconnected and you could have pulled too hard in the wrong direction causing the wire to be damaged.

1. Inspect that the battery is properly connected by pushing on the connector slightly with a plastic tool. If it does not seem to move and click into place better move onto the next step.
2. Disconnect the battery completely and look at the spot where the wire connects to the connector and see if it has become disconnected. If it has you will probably need a whole new battery.
3. There are two exposed connectors on the top of the black connector. If you used a metal tool to push the connector in and you happened to complete the circuit between the two you could have fried the battery. Look for any signs of scorch marks. Again if this has occurred you’ll need a new battery.

It is very important to always use a non-conductive tool when working with a battery to save the possibility of ruining it. Use a plastic Spudger tool for all batteries.

Here is a link to a new battery for the Joy-Con Nintendo Switch Joy-Con Controller Battery

have you tried chargeing with 3party carger instead on Nintendo switch

This is somebody’s same problem with OLED. And what’s this? Jot Con? Change it!