When should I replace the RS186/RS191 batteries?

When should I replace the Rs186/RS191 batteries?

RS186/RS191 battery discharge is roughly linear up until 20%, at which point the batteries will start to discharge faster. It is recomended to replace the batteries ASAP after reaching 20% depending on the sensors duty cycle.

If your application provides battery notifications/flags then when the capacity reaches 20% would be a good time to push that notification.