@robert-hh Thanks for your reply, you have true. I searched components during the starting. And I comment this lines codes : #wlan = WLAN() #wlan.deinit() #bt = Bluetooth() #bt.deinit() #serveur_ftp = Server() #serveur_ftp.deinit() I don't test with each line only, but now it's working. I have fix coordinate when the Fipy powered by Lipo.

@pevrard from what I understand it’s not viable as the voltage may be above or below the thresholds for USB (unless your panel comes with some sort of regulator of course, but then you will have lots of compounded losses). You will probably need to add another circuit if you want to squeeze as much power as you can from the solar panel. You may want to look into this: https://www.adafruit.com/product/390 Never tried it myself.

@jardar It's not really possible to give one efficiency figure for the built-in charger because of the many modes and dynamic operation. For full details I refer you to the datasheet of the charger chip used, the BQ24040 http://www.ti.com/lit/ds/symlink/bq24040.pdf

@mj Any single cell lipo with a JST-PH connector. Be careful of the polarity of the connector, there doesn't seem to be a standard so you may need to swap the connector wires around before plugging it in.

@seb Thanks a lot for quick response!

@crumble thanks for your tips and enthusiasm. I'll keep you posted as I progress on the project, but time is scarse so don't hold your breath :-) You're not the first to bring to my attention the "good diffusor" issue.

Hi @jcaron The charger on Pysense/Pytrack is not configurable - always set to 450mA

Hi @Xykon , Thanks for reply, that works for the PySense update! The Battery I am using is a 3.7v 2000mAh. Thanks Michael

@ledbelly2142 Not yet, I did read somewhere here that the battery voltage is connected to ADC pin 16 so it should be possible. Hoping for an example that can report it as a Battery percentage. I'd like to have the following Topic structure on my LoPy's MQTT topic: lopy/ip lopy/probes/1 ... lopy/probes/4 lopy/battery lopy/rgb lopy/oled/1 ... lopy/oled/4 lopy/ble Cant think of any more yet. Still not sure how i'll go with my plan of 4x SPI Type K temp probes and 4x 128x32 OLEDs as they are SPI as well and require more than just a CS per screen. Reporting on the Battery topic would be things like percentage when it hits internal warning levels.. but with the view to using deep sleep it would probably report on wake up. Also a notification when its charging if at all possible would be nice. I changed the IP topic and paylod to this btw client.publish(topic="lopy/ip", msg=wifiaddress) And on the far end I use Node-red to append to the front: "LoPy Booted with IP: " + msg.payload; *node red function code - not micropython And send the string to Pushover for a push notification on my phone. I've also mapped the on board button to do a machine.reset() so I can carry it around, hit reset then get a notification on my phone if it connects to WiFi (good for range testing).

@cfaessler Did you eventually tried the 18650? Can you share some experience? Thanks!

@scg94 Even if a solar cell is mostly a current source, I would limit the voltage to about 5V, to be compliant with the regulators and the interface you are using. About the charge current look at the documentation here : https://docs.pycom.io/pycom_esp32/_downloads/exp_v03_pinout_v13.pdf It's 450 mA (with jumper) or 100 mA (without jumper).

Hi @tholden, no problem! :) We had a similar issue when we ordered in a number of JST connectors from ebay as well!