I have been doing some tests on the AB-01 boards, without sensors. I have 5 boards here for the test and was testing the sleep current for each, as I have been getting some strange battery life performance.
On investigation with the same sketch ( I am using a battery voltage reporting LoraWAN Sketch) and the same battery and same USB lead to charge, I have found that not all the boards behave the same.
While they all work in transmitting and receiving on LoRaWAN correctly to my gateways and work with sensors correctly, I have found:
• 3 of the boards behave ok with a battery powered sleep current of 22-24uA which is ok.
• One board has a sleep current of 290uA
• One board has a sleep current of 1.3mA
This leads me to consider what is causing the issue as I suspect it will not just affect me. There is either something wrong in the design or the component tolerances of the devices.
The issues could be in one of the following areas:
• Power circuit of the USB charge and switch circuit leading to the power 3v3 regulator or the regulator used , as not much info on this .
• CubeCell MCU unit
• Auto Boot circuit
• The Vext /ADC switching
• SDA line pull ups missing on board
Heltec do you test sleep current on every unit with a LoRaWAN test script?
Before I take apart the board to investigate has anyone any views. I would say that it is not the issues of putting the MCU unit in to sleep, as this works with 3 of the units and also the units perform normal activity its just the varying sleep current on 2 units . This is a DESIGN / QUALITY ISSUE.