PS3 Controller bluetooth pairing after one controller has lost power

[willy-goergen]

Hello,

lately I've successfully set up my Raspberry Pi 3B with a pre made image of Retropie (>4.0). Everything I want is working well. But I'm having some problems with the controller I'm using.

I use two Dual Shock 3 devices and connect them via bluetooth to the Raspberry Pi. Additionaly I have plugged in an usb-transceiver for a Microsoft All-In-One Media keyboard. To make sure that the controllers are assigned to the right player I'm using this little script:
https://github.com/meleu/RetroPie-joystick-selection

The controllers are selected by number. When a controller automatically powers off it is correctly reassigned again when I power it on.

Problems begin when one of the controllers drop the connection via bluetooth due to low battery power. Mostly when I'm playing alone. Firstly I'm getting no indication that the battery power is low. The controller powers off all of a sudden.
When I now try to connect my second contoller to continue the game it gets assigned the wrong number.

e.g. Before power off due to battery life my controller was js1, the fresh loaded one gets js2 although js1 is no longer connected. When I reconnect the former js1 controller it becomes js3. To resolve this issue I have to restart Retropie completely.

It's only a usability problem, but it is a little bit confusing and annoying. Do you have any ideas how to dig into this or maybe a possible solution? Personally I have thought about manipulating the bluetooth timeout settings for the sixaxis driver. But I'm not sure if this is the right way.

Thanks.

Best regards

willy