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Topic starter
2026-02-10 1:29 am
I recently purchased a Firebeetle ESP-32 to use in a battery operated project. According to everything I have readc in deep sleep mode its only to consume less than 100 microamps. My problem is when I plug in the LiPo battery it does not turn on the microprocessor. It charges the battery but never turns on. I have tried to go around the USB connector by using the 3.3v terminal. I have a buck boost connected to the battery and the output from the buck boost is set at 3.3 v. This will turn on the microprocessor but it consumes to much current deep sleep- about 5mA. Has anyone been sucessful in using the Firebeetle from DFRobotics with a battery?
Thanks for your attention.
2026-02-10 6:25 pm
Hi @chas5140,
I haven't got a Firebeetle, but out of curiosity, I looked for data on the web. I found a link to a schematic at:
And the link points to:
which includes:
My interpretation of the circuit follows. Please understand, as I don't have an actual board to check my first impressions, I may include a mistake or two, so please check my logic, etc., and apologies for any confusion on my part.
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The battery connects to J1, and hence net VB.
VB connects to Q3 drain.
Assuming USBVCC is not being driven high (ie is NOT 3 to 5V positive of the 0V/Gnd potential), but rather has a voltage of near 0V/Gnd, then Q3 should conduct, and hence supply battery voltage to Pin 1, Vin, of U5, a 3.3V voltage regulator.
Then assuming the battery voltage is at least 3.61V, the output from U5 should be 3.3V. That voltage should be present on the 3V3 pin of the FireBeetle 32 module, and also supplied to power the ESP32 chip, enabling it to function.
I can only guess at what may actually be happening. I would start by measuring voltages on Q3. This is physically, a small device, so you may initially wish to try monitoring at equivalent points, such as pin 1 of U5.
Hopefully, the picture of what is happening will get clearer! If the 'solution' does not become obvious, then please add a reply, stating your observations. And if you can find a 'solution', then please report that, in case someone else is suffering the same problem!
Good luck and best wishes, Dave
Topic starter
2026-02-10 10:48 pm
I looked at the schematic and started to trace connections. It turns out that the J1 connector is in backwards. What is supposed to be (+) is connected to the negative of the battery. I rewired the connector on the battery to change the polarity. Now I can see 3.3 v on the 3.3 pin when the battery is plugged in. It seems odd that they would get this backwards but in any case I appreciate the help and quick response. I will reconnect the Firebeetle to my project later and see how much current it draws in deep sleep. Thanks for taking the time to find the schematic and give me an idea what I was doing wrong.
2026-02-11 3:20 pm
Hi @chas5140,
Thanks for the reply. I think many of these suppliers are operating on a shoestring, so that problems, like connectors wired or fitted backwards, are more a way of life than an exception. At least you will begin to get acquainted with the board, and better understand its quirks!
Hope the rest of the project goes a little smoother. Best wishes, Dave