Hello, you purchased the FMB640 device, connected the internal battery, in the configurator the sensor shows that the charge is 87%, but if you turn off the power, the device works no more than 10-30 minutes. We tried to charge the battery, after 8 hours it was removed from the charge, the configurator shows 86-87-90%, disconnected from the power supply, the device works for 5-10 minutes and turns off. Please tell me what is the problem?
Thank you.
P.S. if power is connected, the configurator shows that charging is in progress.