What is the smallest 3.7 VDC LIPO Battery for an ESP32C3 with continuous BLE?

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#1

Hi Everyone,

Happy Friday! I have a question that I need to ask, as I am wasting money on small LiPo batteries. I can power an ESP32C3 with OLED screen and a BME280 for hours from an 18650 feeding through a TP4056 charging module. I recently tried a smaller LiPo battery, attempting to reduce my project’s footprint. I started with a 150mah battery and then, a 500mah battery and neither of them energized the ESP32c3 (both of them feeding through the TP4056). Can someone tell me the smallest LiPo I can use with continuous BLE functions, or should I just keep on keeping on with the 18650’s? I should add that there is no longer an OLED display, just a BME280 and an ESP32C3. Thank you so much for any help!

#2
#3

Hi BenderBud,

Can you explain how the XIAO, TP4056 and battery are connected (with a schematic and a picture showing the connections)

Do you know the current consumption of XIAO?
How much operating time is required?

#4

Hi, I don’t quite have the mental magnitude to crank out a schematic right now. If you are familiar with the TP4056, I hardwire the LIPO onto the battery terminals of the TP4056 and I switch the positive output from the TP4056 to the ESP32C3, feeding pins 13 (gnd) and 14 (vcc) of the ESP32C3. That way, the device can be off when the battery is charged. I have had great success doing this with 18650’s but not with the smaller poly-pack batteries. I also directly wired a 500mAh poly battery directly to the power pins of the ESP and I saw no indicator light.

I am seeking the minimal battery amperage (at 3.3 [3.7] vdc. My unknowledgeable self feels that the 18650 provides enough current (amperage) headroom to last for awhile until it drops below 3.3 vdc while the smaller LIPOs simply sputter and die . . . As I understand it.

Oh, yeah . . . I guess the 18650 is the way to go, as I am requiring long runtime hours and “continuous” BLE transmissions.

#5

Is this the TP4056 module you are using?

If this module is used to charge batteries smaller than 1000 mAh, the charging current would be too high and could damage the battery.
What voltages do the 150mAh and 500mAh batteries connected to this module so far have now?

TP4056 module photo
TP4056 module photo548×625 88 KB

#6

The 500 mAh is down to 2.6 vdc. Surprisingly, the 150 mAh battery is at 3.7 vdc but I am certain that it goes into a capacitance lockdown when the EPC32C3 begins to draw power and the voltage drops below the power threshold.

I will just continue with my clunky 18650’s. I am learning to build around them a little better these days.

#7

BenderBud,
Please give me information for my study.

  1. Is the module you are using the same module as the picture I showed?
  2. If so, what kind of charger (how many watts) is connected to the modue?

Please use this as a reference for your project.
I measured the current consumption with the sketch in the link below and it was average 80mA and peak 150mA. 150mAh or 500mAh battery might be too small.

1 Like
#8

Hi,

Yes, that is the good old toilet paper 4056 charging module. As far as what kind of charger, I am not certain of the wattage but I use it for charging my cell phone, as well. I looked but, of course, it has no nomenclature.

#9

Hi,
Could you please specify which pins of XIAO ESP32C3 are connected to the power supply? If you want to use XIAO ESP32C3 with an external power supply (battery or something else), it should be connected to the BAT+ BAT- pins on the back side.