Battery Guidance for the nRF52840 Sense

Products & Technology Arduino & Seeeduino
#1

Hello.

Are there any good pages for best practices for setting up a project with battery management? I’m using a Sense with a 4.2 LiH AA. I’m looking for advice, recommended circuits, best practices, etc. Power management (sleep mode), etc is welcomed too.

Thanks in advance.

#2

Hi there and welcome,
Can you be more specific, which Sense the ESP32s3 Sense or the Xiao nRF52840 Sense ?
Both are awesome so you can’t go wrong. If I were starting at the battery which imo makes a lot of sense no pun intended :smile:
Check out the battery life calc. [

Battery Life Calculator

](Battery Life Calculator | DigiKey Electronics)

18350 3.7V-4.2V 1200mAh High Performance Rechargeable Li-ion Lithium Battery

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1a7bb8d2-09b5-48ed-8b23-c2d83d2387c7_1600x160011600×1600 169 KB

for example 1200 mah at ESP32s3 Lite sleep most of the time 2ma. power use gives you approx ballpark of 25 days cut that in half for head room is what I would do.
shooting from the hip.
HTH
GL :slight_smile: PJ
Specifications

Processor ESP32-S3R8 Xtensa LX7 dual-core, 32-bit processor 240 MHz
Low Power Consumption Model Light-sleep: ~ 2mA Deep Sleep: ~ 14 μA
WiFi Enabled Power Consumption ~ 100 mA
BLE Enabled Power Consumption ~ 85 mA
Working Temperature -40°C ~ 65°C
#3

That’s great info. Thank you @PJ_Glasso !

I’m using the Xiao nRF52840 Sense.

Does one just connect the battery to the battery leads & charge through the 5v pin or USB connection? All the battery charging management just magically happens?

#4

Hi there,
Yea, if it were only that easy…LOL
The Xiao has built in charge control chip, so if you use the usb for external connection to power it. The Xiao charges and manages the battery for you.(provided you use the BATT pads on the bottom of the PCB for connection. It doesn’t do that if you use the 5V pin connection.
HTH
GL :slight_smile: PJ

#5

On a similar vein, are rechargeable coin cells like the LIR2032 compatible with the nRF52840 sense power management chip? I need a very small battery footprint, so coin cells would be brilliant.

Any help appreciated!

#6

Hi there,
After looking over the Spec sheet for the BQ25100 it can deliver 50ma or 100ma charge current
the LIR2032 has confusing specs, 40ma. ideal charge current , max 200ma supply current.
they are frequent recharge batteries. I would try it and I would but a temperature probe , nothing fancy even a IR-temp gun and see what the case does if anything, same rules for the battery management apply as far as drop out , OVP , temp. If you had access the app note shows how to RC it for lower charge current like 40ma. (Pg22)

I wouldn’t be afraid to try it, but it’s gonna drain fast if you spend allot of time awake, so DeeP sleep model code for that battery.
my .02
HTH
GL :slight_smile: PJ