Appropriate for low power usage?

[kxygk]

Hi @wuxx, I was wondering if you could potentially give me a bit of advice. You seem responsive on Github :)) and much more experienced than me.

A friend ( @SWPhantom ) and I are working on making a low power logger for a scientific project： https://github.com/SWPhantom/Rainus

The device has very simple logic:

• wakes up when a pin is driven high/low （this is connected to a rain gauge)
• Get a time/date from RTC
• Writes the time/date to an SD card
• Goes back to sleep

We have a version made with an ESP32-C3 board ( TTGO T-OI PLUS ), but we are have reliability issue. Those boards often have some power bleed that drains the batteries. We also require external RTC and SD boards which makes the device a bit expensive

Your board seems to have everything we need, and the CH32V203 has a big range of voltage tolerance on input

Would the nanoCH32V203 be appropriate for a low power usage? Do you think we could solder a battery to 3.3V and Ground without issues? We'd like it to run for several months making just a few logs a days

我的中文不太好哈哈但你可以用中文回答。 謝謝！

[wuxx]

Hello, the VDD voltage in the manual is required to be between 2.4V and 3.6V, but the voltage of lithium batteries is generally between 3.7V and 4.2V, which may be a problem.

[kxygk]

thank you so much for catching that :))

I didn't notice that only the lower end is 3.3V - 5V tolerant. Looking at alternatives - a ch32v003 would require an external RTC. And there aren't a lot of ch32v103 boards (I think it's a newer chip?)

Do you have any recommendations ?