I have had several problems to work through on my MKR NB 1500 project. The latest was that I finally had good code to do my bidding, but the board would reset constantly when trying for a cell connection with certain types of power. Everything worked great when I was powering the system through the USB port on my laptop, but when I tried to transition over to supplying power via the Vin pin, things turned bad.
I was using a Voltaic battery, which is a nice battery that buck boosts to a 5v output and up to 2 amps with 10000 mA hour rating. I was unable to make a cell connection with this power source until I added a 2000 uF capacitor to the Vin on the MKR board. Now all is well and I am impressed with the system. The overall power consumption seems lower than a GSM modem and I am using Hologram service plan which works great for me and very affordable!
Thank you very much for sharing your project with the Arduino community.
It is great you figured out a way to make it work with an external battery. However it could be useful for you to consider these points for better performance of the board:
Using a portable power bank sometimes fix issues with external power sources and can be more convenient.
By default the 1500 is configured to connect via CAT-M1 as preferred protocol and NB-IoT as failover.
There is a sketch that allows you to select your preferred protocol for communication. You can choose among CAT-M1, NB-IoT or a combination of both. Selecting JUST ONE technology will speed up the modem's network registration A LOT! To do so, follow this guide:
Make sure you have the 'MKRNB' library installed. If not, go to Arduino IDE top menu:
Sketch > Include Library > Manage Libraries: Search for MKRNB and install.
Then go to File > Examples > MKRNB > Tools > ChooseRadioAccessTechnology.
Upload this sketch and open the serial monitor
0 - CAT M1 only
1 - NB IoT only
2 - CAT M1 preferred, NB IoT as failover (default)
3 - NB IoT preferred, CAT M1 as failover
After many problems with power of my MKR NB 1500 can I confirm that add a 1000uF capacitor on the vin input solved my problem and the board is now working great uploading data to Thingspeak.
I have experienced problems too by Powering the board through the jst connector, with a capacitor on the battery input works fine.
The capacitor seems to be a solution for people that have problems with the MKR.
Without capacitor begins the builtin led to fade in and out and the board stops to work.
Without capacitor only works good connecting the board directly to an usb port from my pc.
Maybe have another users the same problem and can solve it with this simple solution...
I'm using a Pololu 5V Step-Up/Step-Down module S18V20F5 on VIN and it works fairly well. I've been measuring the current between the battery and S18V20F5 module and last night decided measuring between the module and VIN would be better choice. When I insert the meter in the 5V the MKR1500 doesn't work and I suspect that it's reseting when it attempts to use the modem. I'll try the capacitor and see if that helps. I'm using about 12" jumpers between the meter leads and the connections so must be getting too much resistance in series causing the 5V to be too low. Just started to pursue this and ran into this post which is in the neighborhood.