MKR1000 is abnormal after using external 5V Li battery as power supply

Dear All,

Since my angular sensor should be powered by 5V voltage, I use a 5V DC Li battery as the power supply of MKR1000 board (connectiong the VIN and GND pins of the board with the positive and negative poles of the battery). After some time of usage, it was found that:

1 first MKR1000 board was damaged; it can not be recognized by the computer again.
2 second MKR1000 board was abnormal. For instance, the voltage of VCC and 5V pins are less than 3 V and 4.7 V respectively. Also, the readings of the angular sensor was not stable even there is no rotation; however, the readings of the same angular sensor was stable when another Arduino board is used.

Actually, I have used MKR 1000 boards for several years and they run smoothly if they are powered by USB cable or pins from PH2.0. May I know whether you have encountered the similar condition? I failed to find the causes of the facults. Thanks a lot for any help.

How did you connect the sensor to your MKR1000? If your sensor needs 5V it likely has 5V signals. If you connect these directly to the MKR1000 you will damage it. The MKR1000 I/O are 3.3V only.

Can you show a schematic of your system? Hand drawn photo taken with smart phone is OK.