I was looking for some simple and cost effective solar lipo charger for my DIY projects...I've seen the GreatScott video about solar lipo charger and i've realized one of it using the same schematic reported in the original video and easyeda project page: here
For my own needs, I've added a MCP1700T 3.3V regulator at the same point of connection of BAT+, as you can see in the attached image, the rest of circuit is the same as reported on EasyEda.
The (when i attach the external Solar Panel) circuit charges without any issue the Lipo battery, the MPTT works fine (with 21V panel) and the 5V boost converter and the 3.3V step down regulator (MCP) works flawlessly!
...but there is a strange issue that I want to solve about...basically, when I attach only the battery (without the external Solar Panel), the 3.3V and 5V step up converter does not work unless I connect manually the GND of the circuit and the BAT- pin.
Every time i need to "start-up the board" i have to do this kind of magic trick...is this an issue? Why is the circuit acting like that?
I need to wire the Gnd of the circuit to the BAT- pin?
If I do this, the battery protection will still be operative?
I'm a little bit confused...it's my first approach to solar and lipo charging world, so, please.. Be patient!