I have built several nodes based on the Heltec ESP32 v3.1 boards, with 18650 battery and 5v 3W solar panels. They work fine except for one problem. In the case where the battery depletes and the node shuts down, it does not start by itself when the battery recharges to 3.6 to 3.7V from the solar panel. Pressing RST causes the node to boot up and run fine. This is not a good situation in the places where I plan to deploy these nodes. Anyone have a suggestion??
Wes
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A solar-powered node, with solar recharging battery, whose battery has run flat (‘brownout’) will not normally re-start when the battery is re-charged again by the sun. Many (all?) nodes need a clean 5 V rising edge trigger to switch on and many solar setups do not provide this and the node stays off forever despite your cool build. One example is the RAK wisblock kit (RAK Wireless Wisblock + Lora = SKU: 110082 & SKU: 115000 https://store.rakwireless.com/), which has a solar in and battery socket but stays off at ‘brownout’. The only solution I found was to use a solar battery manager circuit in the build. There might be several commercial ones and many cheap and good DIY designs, but I use Waveshare Solar Power Manager D (https://www.waveshare.com Waveshare SKU 20909 OR Solar power manager (D) SKU 26363) which works with the Wisblock kit and re-starts of its own accord after brownout.