Error -110 setting battery level threshold on HSM6


I’m testing the battery threshold functions so have two python scripts where I find the current voltage and then set the threshold above/below that so I can ‘pretend’ a battery going flat. Example of setting the threshold to above the current battery voltage:

import zymkey
import time
battLevel = zymkey.client.get_batt_volt()
print(f'Current battery level: {battLevel}v')
threshold = battLevel - 0.2
print(f'Set threshold to: {threshold}')

However, this fails producing the following output:
Current battery level: 3.064746141433716v Traceback (most recent call last): File "./", line 12, in <module> zymkey.client.set_battery_voltage_threshold(threshold) File "/usr/local/lib/python3.8/dist-packages/zymkey/", line 1807, in set_battery_voltage_threshold raise AssertionError("bad return code %d" % ret) AssertionError: bad return code -110


Trying to set to 2.5V or higher is not allowed and will throw an exception. Try something that ends up below 2.5V.