Hello
I'm using this charge/discharge boost lithium module to power 5v to my ESP32C3 project. On the module, there is a little power switch. One click power on, two click power off. The problem is at off state after the double click, the output voltage is 2.2v instead of 0. I did tried 3 modules and all have the same result.
Anything I can do to completly cut power and prevent draining the battery
Martin
Is there still a battery out there? If yes, try disconnecting the battery and see if Off is in fact Off. My best guess is that you are reading a voltage from the battery. Should that be the case I doubt you will be running the battery down.
Ron
The easiest way to guarantee zero power is with a switch. Without a schematic it is hard to tell what that module does. There are many zero power circuits published on the web.
Is that with the output loaded?
That is with your project connected.
OR
Are you measuring the output with no load?
If unloaded, please measure it loaded with your project.
Thanks.. Tom.... 
What voltage do you read if you connect a 1000 Ohm "dummy load" resistor across the output?
"Solid state" switches are not open circuits when "OFF", but high resistance (usually tens of thousand to millions of Ohms). There will still be tiny "leakage" currents through them that will register on a very high impedance digital voltmeter.
What voltage do you read if you connect a 1000 Ohm "dummy load" resistor across the output?
198 mv
Understand that. I was intriged because power led on my ESP32C3 is dimmed , not completly off. It seems a normal behavior for these modules after reading some review.
ChatGPT says that the 0.15A leakage will drainn my 1200ma battery in a little bit less than a year. Sure I would preffer a lower drain voltage, but I could live with that for the moment..
I will look to add a low voltage detector to manage a P mosfet . Don't know yet how to do it, but I won't prioritized it
Martin
Yes whit the ESP32C3 installed
That may be a solution. I will look at it toomorow
Why do you need 5V?
A esp32C3 super mini can run directly from the battery, so no need to waste more power by boosting to 5V and then regulating back down to 3.3V.
Then use a real SPST switch to disconnect the battery.
Hello Jim
The module that I bought to charge/discharge lithium battery will boost 3.7v to output 5v. Fully charged battery is 4.2V, too much for ESP32. So i'm using the internal voltage regulator of the ESP32C3 dev board to get the 3.3v. Also, I plan to use two I2C OLED display and a buzzer. These will be powered from the 5v instead of the 3.3v regulator. A single 18650 li-ion battery will power the unit.
The project is to capture and display temperatures from a BLE cooking wireless temperature probe. Actually, I need to use my phone to get these temperatures data.
Sure this is a solution, but not a challenge for me. I studied and work in electronic t'il 1989. Now, I want to learn more modern technic to keep me awake.
Martin
P.S excuse my English, i'm more fluent in French.
So is this just typical behavior for this module? Do you you know what the 8-pin chip is?
No, the chip identification as been erased.
For the IC that is true but not true of all development boards.
Sure this is a solution, but not a challenge for me.
As an engineer I always look for the simplest and cheapest solution. If you want to add some more circuits, sure go right ahead.
So, 198mV / 1000Ω = about 200 µA leakage through the MOSFET.
