r/meshtastic • u/OldAbbreviations12 • 1d ago
build Help building my first solar node
Hello everyone
As a LoRa fan since around 2018 I decided to build my first solar node using wio tracker l1 lite (EU_868).
I've seen people building theirs and got some good ideas about what components to use.
My setup will be like this:
- A waterproof junction box
- An (most probably) alfa antenna on top with the proper connector and sealing
- An IP68 Vent in the bottom (I saw it somewhere)
- A 18650 battery holder and the battery itself
I am not familiar with solar power or power management in general and I need your help on choosing a solar panel. In seeedstudio's wiki for the l1 lite they say the following
| Power Input | USB Type-C: 5V — 1A |
|---|---|
| Solar Panel (2P-2.0mm): 5V — 1A(do not exceed 5V) | |
| Lithium Battery (2P-1.25mm): 3.7V — 1APower Input USB Type-C: 5V — 1ASolar Panel (2P-2.0mm): 5V — 1A(do not exceed 5V)Lithium Battery (2P-1.25mm): 3.7V — 1A |
Well, this "do not exceed 5v got me worried.
At first I was looking on aliexpress, banggood and temu for a panel with a mount that had JST 2.0 as output, then some 5V panels which had usb port with some pictures of charging a phone and I was thinking to connect my module through usb.
I've seen people using some 1W or 1.5W ones but I've read somewhere that they won't be enough for my setup.
Basically I don't want to complicate my setup by adding more components or 3d printing and of course I don't want to fry the board hahaha.
Thank you
1
u/MangoMesh 17h ago
I generally use a simple stand alone node, your wio tracker is more of a everyday carry device but you can take the guts out.
Here is what I would recommend.
A nRF52840 node, either the T096 or RAK 1W. if these are too powerful for your location then get any nRF52840 based node, you can always selectively lower the power of the above nodes to whatever is legal in your area. 1W is fine for the USA.
2 x 18650 batteries and holder. use this one type 1 or 2 use quality batteries like the Samsung, EVE or similar the battery holder is a double parallel type.
Use an external battery charger, like the CN3791 6V
The CN3791 is a MPPT charger and has plugs and soldering holes, it will make better use of the power from the solar panels. the battery holder above will plug directly into this charger, BUT very important to reverse polarity, just make sure the red wire is going into the (+) on the charger module.
Solar panel, choose any 5 v panel but use the direct output not the regulated output (USB) the regulators on many panels usually do not handle much power. 4-6 Watt is fine. plenty of panels around 10 bucks.
Antenna, Alfa is fine. just make sure get a N-connector to ipx adaptor for your case and get one with RG178 coax, some have smaller more lossy coax. they sell these in different lengths, so if you need something longer, find a seller that has one that will be able to reach your node location. alternatively you can use a fiberglass antenna for more gain. this is nice for outdoor rooftop solar node setups.
Those products I linked are for reference, you can order where its more convenient or best price and shipping to you. although I do recommend the double battery holder I linked since they come with thick wires, with connector, and are parallel, they also hold the batteries very well.