Posts: 7
Joined: Mon Mar 14, 2022 7:14 pm

PI 3B and battery indicator

Mon Jan 16, 2023 1:00 pm

Hi all,
I have Raspberry PI 3b with 7" DSI touch display, battery 9000mAh, and power boost 5V 2.1A.
It works well but now I need add battery indicator, link here: ... bo-li-pol/
Here you can see my wiring:
When I switch on, I can see battery status, but Raspberry is not starting - only red led flashes slightly. If I press button on power boost, then Raspberry starts OK. If I disconnect battery indicator, Raspberry starts OK by main switch without press button on power boost.
Could you help me how to wire it correctly?

Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
Posts: 161
Joined: Wed Aug 09, 2017 2:07 pm

Re: PI 3B and battery indicator

Fri Jan 27, 2023 10:50 am

What does button S1 do? Is it another on/off switch?

I see one potential problem with your wiring. When the switch is off, stray current can flow through the black wires between the battery, voltage indicator, Pi and regulator. Consider replacing the switch with a 2-pole switch, so the battery indicator is isolated from the Pi. Or add a separate push-button to control the indicator.

Alternatively maybe you can use the "Ext Button" connector (if it does what I imagine?) to turn the Pi on and off. With a bit more electronics you could rig up a MOSFET circuit to turn the indicator on only when the Pi is powered up.

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