Powering the WROVER-Kit

[electricjoker]

Hi does anyone know if you can power the WROVER-Kit by soldering a LiPo to the 3.3v and GND pins? Or the 5v and GND pins? I do not wish to use the micro-usb or barrel jack port.

Thanks!

[ESP_Sprite]

A LiIon can output anywhere from, say, 4.2V when it's recently fully charged, to 2.5-3.0V when it's fully empty. If you connect it to the 3.3V pin and the LiIon is 4.2V, you will be feeding the Wroom module more than it can handle. You could connect it safely to the 5V and the NCP1117-33 on the board will make sure the Wroom module gets a safe voltage... but the dropout of that LDO can be as much as 1.2V, which means that even with a fully charged LiIon cell, the ESP32 only gets fed 3.0V. It'll probably still work OK with that, but the lower limit for the ESP32 is 2.7V IIRC, which means when your LiIon is discharged to 3.9V (which means it's still 80% or so full) the Wroom can already brown out.

All in all, if you really want to do this, I'd suggest using a boost converter to boost the LiIon voltage up to 5V, then feed it into the 5V input.

[electricjoker]

Thanks so much for all the detail!

Just to be clear, we are talking about soldering the battery to the 5v pin correct? I do not want to use the 5v barrel jack input.

[ESP_Sprite]

According to the schematics, that should work. Be aware that the power on/off switch does not work in that case. Also, suggest not applying power over the 5V pin and connecting over USB at the same time; you may backfeed the USB port when you do that and it may not like that.

[Drummond]

The MAX drop on the "LDO" is 1.2V which would make a 4.2V fully charged LiPo 2.9V. Try using a MCP1826-33 with appropriate capacitors, resistors and if you want to prevent low voltage and draining the battery too far, put a KA75330 on the output and shdn pin (MSC1826-33).

Do not plug in to the USB port while the battery is connected as there are probably diodes which will get fried or other damage. If you want to charge the battery while attached use a separate module like TP-4056 or better. All are very inexpensive via mouser. I think the MCP1826-33 is probably the most expensive at around a euro. You should be able to use a standard connector on the pins rather than soldering but check the schematic to be sure there are not diodes on them.

The MCP1826 needs a small cap on input and output (see datasheet) as well as a resistor from output to shdn, wiht the KA75330 when the battery drops below about 3.2V it pulls shdn low and turns off the power, when power comes back up to releases shdn and power comes back on. I am using this on 2 solar powered ESP8266 and MCP1825 ( MCP1825 is 500ma - MCP1826 is 1A which is more appropriate for the Wrover -kit). There certainly are other options, but I have not tested them.