Where can I purchase a Li-Po batterie for the MKRZero?
Ebay, Adafruit, Almost anywhere that sells them for drones, RC shops, Amazon and probably lots of other places.
Just make sure they are 1000mAh or higher as called for in the specifications.
More help HERE
Just ensure it has the correct JST connector. Before you plug it in also verify the VCC and GND wires dont need swapping over
I bought a couple of 3.7V 1s 1100mAh LiPo batteries for the MKRZero on Amazon for about £12: https://www.amazon.co.uk/gp/product/B015ZFKUXQ
I needed to snip off the lugs on the side of the plug though, to get them to fit.
Make sure the Positive/Red wire is on the left (closest to the USB socket) and the Negative/Black is on the right (closest to the AREF & PINOUTS).
Use "analogRead(ADC_BATTERY)" to read the voltage of the battery (scale is 0 to 1023, equating to 0V to 4.3V supposedly). However, I found this to be inaccurate - at 3.9V it read 1000, which is a scale of 0V to 4.0V, not 0V to 4.3V! Anyway 4.3V is too high for a LiPo battery, which shouldn't be charged higher than 4.2V.
HobbyKing sell 1S batteries with the JST PH plug wired correctly for the MKRZero and MKR1000
Don't have hobby king in Canada and get stung BADLY on shipping and customs Plus they are a little more expensive than a lot of other places overall.
Good to know though the connectors are already correct for anyone else.