Remote Telemetry Solar Circuit Feasibility


I am looking at the feasibility of doing a solar charger for a battery unit for a remote sensor suite (primarily weather and some Raspberry pi units). I came up with the attached diagram. So far I have a battery disconnect for safety, along with a switch to disconnect from the power output, and another internal switch to disconnect the Arduino. I have been looking at adding a PV Disconnect as well but cant find any for a 17V, 1.47A panel.

This image is missing a Ethernet shield on the MKR GSM 1400 Arduino, which receives the data from the other sensors in the other unit (listed below). I am planning on having a power cable connecting the two boxes, so if I use the “Sensor box” else where I can just power it off of 12V DC from a wall wart.

MKR GSM 1400
MKR Ethernet Shield
Uno Ethernet Shield
Raspberry Pi
12V RG-11 by Hydreon
SHT-30 Temp/Humidity Sensor
Davis Anemometer/ Vane

I was looking at a 25W PV panel, with a 12V 10-15 amp hour battery for reference.

Thank you for any feedback! Just looking to have some feedback on the design/feasibility before investing in some components.

At a glance, the battery will probably not able to power the setup for more than 10-20 hours, in the absence of full sun. If that is not OK, you need to address the following questions.

What is the average current drain of the entire setup?

How long do you want it to run during stormy weather?

Rough estimate of battery lifetime in hours is (battery ampere hours)/(average drain in amperes).

That helps, thank you! I was going through the numbers again this morning, and will likely have to double the battery size to account for typical Midwest weather. I might also look at ways to implement a standby mode in the code.

Sleep mode is what you need, and much of the equipment you have chosen is not capable of doing that (the RPi, for example).

That makes sense (especially regarding the RPI - which only needs to be on at certain times anyway to download data when certain conditions are met). I am adding the full schematic of all the devices to show full project intent (just finished drafting it up).

In the power box (light blue), would it be possible to configure a relay between the main buss and DPST selector switch that allows the MKR to act as a sleep mode device that essentially shuts power off to the computational box (light gray) until time conditions are met? Or vice versa, maybe have the relay up near the RPI, and have the UNO control it?

For a really minimalist solar powered Arduino system, capable of transmitting data to a remote location, you may find the ideas in this excellent tutorial helpful.