XIAO ESP32C3 & External charging board

[Knetjester]

Just looking for some advice, please.

I want to isolate the C3 when charging.

Where should I add the switch to isolate the charger from the XIAO ESP32C3?

Image 2 or 3?

[cgwaltney]

usually the center pin of the switch is common… so i am thinking 2
switch one way will be charge and the other way would be run

[Knetjester]

I’ve currently got lots of SPDT switches, so I’m thinking image 3 would work?

[cgwaltney]

why would you do this way… it has a charger built in right?

[Knetjester]

It does, but I’d like to isolate the ESP32 from the battery to charge it.

I’ve come up with this:

[msfujino]

Hi Knetjster,
Do you use 110mAh batteries? If so, the charging current should be less than 110mA to prevent battery degradation.
Is the charging current on the LiPo charger less than 110mA?
Also the ESP32C3 on-board chargerr has a charge current of 370mA, which is not suitable for charging a 110mAh battery.

[cgwaltney]

@Knetjester

It does, but I’d like to isolate the ESP32 from the battery to charge it.

i mean i am asking why you like to to this… what is the reason?

[Knetjester]

Hi msfujino, this is the charger I’m using, the battery is 100mAh, will it be suitable?

I’m new to all this, so…

[Knetjester]

Hi cgwaltney,

I’m new to all this, so I thought a separate charger board that I can isolate will be the safest option.

[msfujino]

The charge current on this board is 1A and is intended for charging larger batteries such as 18650. Charging a 100mAh LiPo with this board may eventually degrade the battery.
I would not use an external charging board and use a 370mAh or larger LiPo connected to the XIAO.

[Knetjester]

@msfujino

370mAh

They’re physically too big to fit in my project, unfortunately.

Would the XIAO built in charger work?

Alternately, one of these?

Adafruit Mini Lipo w/Mini-B USB Jack - USB LiIon/LiPoly charger (v1)

[msfujino]

The built-in charger of the ESP32C3 has a charging current of 370mA.
I was using a 250mAh LiPo connected to it, but it has deteriorated and become a little bulky. Therefore, it is not recommended to connect your 100mAh LiPo to the ESP32C3.
If you want to use a 100mAh LiPo, you need to find an external charger with a charging current of 100mA or less, or use an XIAO (ESP32C6, ESP32S3, nRF52840) with a built-in charger charging current of 100mA.

[Knetjester]

Thanks’ for all your help, I’ve ordered one of these:

[msfujino]

I think you have made the right choice.

FYI, the charging board you have now can probably be set to 100mA charging current by replacing the resistor. You will need to be skilled in soldering surface mount components.

Please refer to the following link as well.

Charging characteristics of XIAO_nRF52840 and XIAO_ESP32C3

XIAO_nRF52840 and XIAO_ESP32C3 have a built-in charging function, but since the circuit diagram was not disclosed, I assumed that they have the same circuit. I was curious and measured the charging characteristics. They are completely different, XIAO_nRF52840’s charging current can be set to 50mA or 100mA by firmware, but XIAO_ESP32C3’s is fixed and very large at 370mA, so I need to be very careful when using small capacity batteries. [XIAO_Charge]

[Rob73]

I would like to run a XIAO on batteries. I wont need to charge them from the project, I can just swap them out when they run down.

When using battery power, is everyone soldering to the battery pads on the bottom of the board or using some sort of adapter board with pogo pins or something?

I was really trying to avoid soldering to the bottom of the board but it looks like that may be the only good way of connecting a battery.

Rob

[msfujino]

For XIAO_ESP32C3, only LiPo batteries can be connected to the battery pad on the bottom of the board. Never connect any battery other than a LiPo battery, as it is dangerous.
What kind of battery do you use?
What voltage and type?