I'm trying to connect a ~5.5V (2 x 3V coin cells in series, but their voltage drops a little) to the VBat (or V+) of my Adafruit Huzzah ESP8266 module (not the black Feather one, the smaller blue one: https://learn.adafruit.com/adafruit-huzzah-esp8266-breakout/pinouts) Whenever I do that the voltage output from the 3.3V pin drops to ~0-1 V and thus the ESP stops working.

However when I use the FTDI cable (3.3 V) and connect it to my laptop, there is no problem, I get almost 3 V.

I also added a 1000mF capacitor to smooth out voltage signals and actually that also helps to increase the volt a little (without it I get almost a 0 V on the 3.3V output)

Any ideas?

1 Answer 1


After tinkering more, I figured out that the Huzzah module is happy to take in up 4.5V via a 3 AAA battery cell so I guess it's ok up to 5V since my previous battery input was over 5V.

That's a little weird considering that in Adafruit's page, it says

..to make it easier to power, we put a high-current-capable 3.3V voltage regulator on the board. It can take 3.4-6V in but you should stick to 4-6V since the ESP8288 has high current usage when WiFi is on.

Hope this may help someone else.

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