This is an old topic but would like to add some comments that can be useful to someone having this kind of issues. I have an expansion board 3 with a Wipy, using the SD card and some sensors, and everything is working well being powered throu USB or battery. I had some issues that were fixed by following these steps: When powered by battery, P19 and P20 are affected by RTS and CTS respectively, and it was blocking one sensor I have connected to those pins. Removing those jumpers from Expansion Board resolved this issue. Don't use P8 with any sensor if you are using SD card. Looking at the Wipy3 pinout, I suppose the same is true for P3, P9 and P10. Even thou, P10 is also connected to the user button, then I configured it as an input pin with pull=PULL-UP, and avoid read/write SD operations and user button clicks at the same time. Also, this post helped me with a weird behavior of user button when using the battery: https://forum.pycom.io/topic/7364/exp-board-user-push-button/3?_=1648562954689 I connected the 10K pull-up resistor to P8 as indicated in the expansion board documentation, but honestly, I don't understand why it's needed. Most of these "tricks" are not clearly documented and I found them reading several posts and connecting ideas between them. In my opinion, Pycom boards are very good in general (with a very few details that could be improved), but as said in many places, its documentation should be reviewed to add many things like these that one has to chase reading somewhere else or by try/fail methods.

Hi @turbolego Power consumption will vary with usage, you can find all the details on the datasheet: https://docs.pycom.io/chapter/datasheets/downloads/fipy-specsheet.pdf

@robert-hh - Further to this - I actually haven't got the sensor to hand (awaiting shipment), but once it arrives, I'll measure the current draw at 3V3 to confirm that the datasheet is accurate.

@jcaron Thanks. Just to note this method works also for both a software reset AND powercycle.

@robert-hh Things are much better now it's wired correctly! :-) The batteries and the converter have been at room temperature for the last few hours and my LoPy and sensor are working fine. Thanks again for your help Robert.

@jmarcelino Once again, thanks for the great feedback. I was looking for a simple way to alert when the battery needs to be recharged. Looks like some simple logic could be: if voltages gets to 3.3, alert for recharge... So many LiPo batteries have differing characteristics, even among the same model/make/capacity/manufacturer. I don't think there is real value is tracking a percentage... without extensive battery testing. Simplest thing to do is just report voltage. From the example from HERE do you recommend using the following: numADCreadings = const(100) def ADCloopMeanStdDev(): adc = machine.ADC(0) adcread = adc.channel(attn=1, pin='P16') samplesADC = [0.0]*numADCreadings; meanADC = 0.0 i = 0 while (i < numADCreadings): adcint = adcread() samplesADC[i] = adcint meanADC += adcint i += 1 meanADC /= numADCreadings varianceADC = 0.0 for adcint in samplesADC: varianceADC += (adcint - meanADC)**2 varianceADC /= (numADCreadings - 1) print("%u ADC readings :\n%s" %(numADCreadings, str(samplesADC))) print("Mean of ADC readings (0-1023) = %15.13f" % meanADC) print("Mean of ADC readings (0-1400 mV) = %15.13f" % (meanADC*1400/1024)) print("Variance of ADC readings = %15.13f" % varianceADC) print("10**6*Variance/(Mean**2) of ADC readings = %15.13f" % ((varianceADC*10**6)//(meanADC**2))) print("ADC reading for Voltage (0-1400 mV) = %15.4f" % (meanADC*1400/1024)) From the ACD pin 16 voltage, the voltage is the meanACD*1400/1024 Does not seem right, the output is 4966.3634.

@rolandvs said in Is the time in the RTC preserved after hard reset w/o power down?: If true it makes the use of the RTC sort of worthless in situations where you want to keep time with an attached battery without the possibility to use Wi-Fi to NTP your time like with LoPy or SiPy... It doesn't solve the original issue, but you can update time without network connection using GPS receiver, e.g. on the pytrack extension board.