Battery Powering the RAK2245, PiZero and ChirpstackOS base

Hi,

I am working on Powering a Pi Zero with the RAK2245 running ChirpstackOS base. Everything works fine when the Pi is powered through the USB cable which provides 5v. Incidentally, I have measured the draw at 5V. For information, a Pi Zero W will pull about 120mA. With the RAK2245 header, it looks more like 400mA, which is quite an increase.

The RAK2245 datasheet does claim that it works at 3.3v or 5v so in theory what I am proposing could be feasible (https://docs.rakwireless.com/Product-Categories/WisLink/RAK2245-Pi-HAT/Datasheet/).

In terms of how I am powering them, is by connecting wires directly to the Pi. If you look at the image below. I have highlighted how I am attaching the battery to Pin 1 (3.3v) and 39 (GND)

As a result of attaching power to these pins, those two pins are no longer going into the RAK2245 header. This should be fine… I think. The pinout here:

suggests that while those pins are being used, the RAK2245 header should still get 3.3v power through pin 17 and ground through a number of other ground pins.

Regardless, the concentrator header does not work through the 3.3v methods I am using. I does however work when power is coming through 5v. When I mean that it is not working, I mean that the error messages are consistent with something that appears to be miswired or disconnected. An example has been described here: Concentratord on Rpi3 with RAK2245 HAT

Is there anything really obvious that I am missing?

Thanks so much for your time

I’m running the same config (but not off-grid).

Regardless of whether you get this to work the challenge you have is that the power consumption of a device should be the same regardless of the voltage at which it is supplied. So lowering the voltage would increase the current draw with no net benefit to battery drain.

@roy_muzz,

A bit out of the topic but it is just a suggestion since you are opting for battery powering the Pi + RAK2245 concentrator.

Suggest use this UPS HAT since it uses Pogo Pins to power up the Pi 5V from underneath. Meaning to say that you can stack it in this manner UPS HAT below then - Pi in the middle and then - RAK2245 on top. UPS HAT+PI+RAK2245. See the link below:-

It uses 18510 rechargeable batteries which are similar to the ones used in some old Laptops. It also has I2C interface to monitor battery parameters. It has form factor for PI3 but you can also adapt it on Pi Zero.

Hope this is of some help to your application.