Bernafon CROS miniRITE T R Notice D'utilisation page 18

Low battery indication
When the battery is running low, you hear three alternate beeps. This
gives you approximately two hours before the transmitter runs out of
battery.
The beeps are repeated every 30 minutes. Just before the battery runs
out, you hear four descending tones.
Three alternate beeps Four descending tones
= The battery is running low. = The battery has run out.
18 About Getting started Daily use Warnings More info