MKR NB 1500 charge light flashing powered by VIN

Hi Everyone,

When I power the 1500 via a 5.1v power source using the VIN pin, after 30-60mins the charge light starts flashing. When this happens, the board becomes unresponsive and stops functioning.

The voltage does not ever dip under 5.1v, I’m curious as to how I stop this?

I’ve tried searching the forums and looking through the product pages, the only thing I can come up with is that it doesn’t detect a battery and goes into an errored state. Is there any way to stop this error state from happening?

I would hate to have to NVIC_SystemReset() every 15mins.

From the product page:

Charge LED: This LED is driven by the charger chip that monitors the current drawn by the Li-Po battery while charging. Usually it will lit up when the board gets 5V from VIN or USB and the chip starts charging the Li-Po battery connected to the JST connector. Occassionally, this LED will blink at a frequency of about 2Hz. This is caused by any of the following conditions maintained for a long time (over 20 min):

  • No battery is connected to JST connector.
  • Overdischarged / damaged battery is connected. It can’t be recharged.
  • A fully charged battery is put through another unnecessary charging cycle.

So this tells me that the battery is not connected for over 20mins.

Is there any way via software or hardware to stop this from happening besides connecting a battery?

EDIT: After further testing, the board still is functional even while the charge light is flashing. This is good news, I was under the impression that when it entered this state the board would lockup. I’d still like to know if anyone has a way to disable the charge LED?

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