Car wont restart at traffic lights

[Steveb123]

I have a ford focus 2017 plate. I recently installed a dash cam and reversing camera. I followed all the video guidance and it all looked fine. My start stop then stop working. 
a few days ago it started working again and I stopped at the traffic lights and it wouldn’t start again. Had to get a jump start. 
went to Halfords who said battery was fine just needed a little charge. Charged over night and the a few days later it’s happened again. stopped at the drive through and now car won’t start again! Any advice please. 

[unofix]

"Car wont restart at traffic lights"

1 hour ago, Steveb123 said:

Any advice please.

Use road junctions without traffic lights ??

[Carl123]

2 hours ago, Steveb123 said:

Any advice please. 

Switch off stop/start

Is the dash cam always on (live) or ignition fed?

[TomsFocus]

Stop start shouldn't cut the engine if the battery is likely to be too low to restart it.  If the SOC drops far enough while engine off in traffic it should restart immediately.  (In a manual, possibly not if auto).  Have you reset the BMS on a lowish battery?

Ultimately it sounds like one of the cams is draining power, but the stop start issue isn't right either.

[mougly]

Key fob battery if you have a push start button ?

Deffective alternator ?

or battery reach end life