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Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 11:51
by codegrau
Hi there, this is my first post so please be nice to me ;)

- I own a NodeMCU v3 and flashed a _VCC build to it.
- I have a 18650 battery shield v3 with USB-A, 5V out and 3V out.

I want to use NodeMCU v3 with this "shield" and I really don't know how to wire this correctly (I guess 5V Shield to Vin NodeMCU would be correct?). So do I need additional wiring to measure VCC and get informed when battery is running low? Would be cool to hear from you.

EDIT2: Don't use 5V to VIN but 3V(Shield) to 3V(NodeMCU) for voltage measuring.

Edit: I connected 5V to VIN and get 2.99V on System Input VCC - is this correct?



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18650_batterie_Schild_V3_Für_Raspberry_Pi_WEMOS_Für_Arduino_Micro_USB_Typ_EINE_USB_Ausgang_Diy_Kit_in_18650_batterie_Schild_V3_Für_Raspberry_Pi_WEMOS_Für_Arduino_Micro_USB_Typ-EINE_USB_Ausgang_Diy_Kit_aus_Integrierte_Schaltungen_auf_AliExpr.jpg (33.63 KiB) Viewed 4492 times

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 11:59
by grovkillen
Sounds about right. The VCC reported via the Analog is what the ESP is "seeing" and the ESP is working on 3.3V.

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 13:21
by codegrau
grovkillen wrote: 14 Jan 2019, 11:59 Sounds about right. The VCC reported via the Analog is what the ESP is "seeing" and the ESP is working on 3.3V.
Thanks for your fast reply grovkillen, but I didn't connect anything on A0 - so I don't know how this measurement comes from.

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 13:43
by grovkillen
Its internally, I suspect you using the VCC bin file?

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 13:59
by codegrau
Yes, I'm using a recent _ESP8266_4096_VCC.bin - so this value should decline rapidly when battery starts to empty, right? So no information how much percentage or mAh left.

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 15:47
by grovkillen
No you need to test yourself what levels are good and then you can use formulas to show percentage.

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 15:52
by codegrau
Ok, thank you very much!
Last question: For deep sleep mode I set up sleep time in config and connect D0/GPIO16 to RST and NodeMCU comes up periodically to send values?

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 18:39
by grovkillen
Yes, but you might want to use rules to get the values sent more efficient.

Re: Wiring & measure VCC with NodeMCU v3

Posted: 14 Jan 2019, 22:07
by codegrau
EDIT2: Don't use 5V to VIN but 3V(Shield) to 3V(NodeMCU) for voltage measuring.