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Topic: Mkr GSM 1400 green power LED always on when using LiPo via JST battery Plug (Read 1 time) previous topic - next topic

stefsc

I encountered an issue with my MKR GSM 1400 when powering it with a 3.7V LiPo over the JST battery plug.
When I connect the battery to the Arduino via JST connector, the green "LED ON" next to the USB connector lights up.

There is nothing else connected to the arduino (no USB, no cables to the Pins etc.) except from the 3.7V battery.
I also have an Arduino MKR NB 1500, where I connected the battery to via the JST battery plug. On the NB 1500 the green LED ON stays off when it's powered over battery.

On the Arduino Homepage (https://store.arduino.cc/arduino-mkr-gsm-1400-1415) under the FAQ it says:
"LED ON: This LED is connected to the 5V input from either USB or VIN. It is not connected to the battery power, thus minimizing the impact on battery usage. It is therefore normal to have the board properly running on battery power without the LED ON being lit."

As far as i understand / know the LED ON is hardwired to the VIN Pin and the +5V of the USB connector and there is no way to switch on or off this LED by software.
So could this mean that there is an hardware issue with my Arduino GSM 1400 Board?

Thanks in advance for your help!

stefsc

This behaviour seems probably not normal. I contacted the support and this is the response I got:

Quote
Thank you for contacting Arduino Technical Support.
[...] I have tested the issue with the MKR GSM and MKR NB boards and I experienced the same result as you. I have informed the hardware team about this and I am awaiting for their response.
As soon as I obtain an answer I will get back to you.

ksmith3036

I just can confirm this behaviour: I have been using the MKR GSM 1400 for a while, so being used to the green LED also when running on battery, although a bit weaker than when running off 5V. 
I was actually beleiving that it should be emitting light, so when trying the MKR NB 1500 on battery, I thought it was malfunctioning, since the LED stays dark!
The MKR GSM 1400 seems to have a lot of power issues, it will not supply enough power to work on 2G networks, while working good with 3G.

guiguita

In my board the green LED stays on consuming approx 2.5mA when running on battery only. I got to know the value by unsoldering the LED.

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