After several different on-again off-again interactions with various mesh networks, I finally seem to have found a community around Meshcore and the WCMesh folks driving their way up north! This drove me to put up my own meager repeater, house bound due to a lack of free time and community contacts for a better location— for now.
Digging through my bin of ADHD shame labeled LoRa Mesh, I was able to find a couple of Heltec T114 boards from the last time I went deep into trying to get get some Meshtastic momentum in my area and completely spinning out… not before hitting up AliExpress. Needless to say, I was able to cobble together a repeater entirely from parts on hand: throw it in a weatherproof project box, drill some holes, mount a 5.5dB fiberglass antenna from said prior deep dive, add a trio of 18650s from another yet-to-be-completed battery pack project, and finally finished off with some new-in-box solar panels from my mesh box.
With the false confidence of “I did a deep dive a year ago, I know what I’m doing!” I set out with soldering iron and heat shrink and connected everything together. I chose the T114 as it had on-board ‘solar’ support, and I had solar panels on hand. The panels I have come with a regulated USB out, as well as a straight panel voltage output (for chaining). With aforementioned bravado, I hastily disassembled the solar panel box and connected directly up, thinking cleverly to myself: ‘Yes, yes, solar goes to solar, makes sense!’
Well, with everything connected, I slapped some who-knows-what-charge 18650 batteries in it off my desk, saw the orange light by the solar indicator light up, called it good and closed up the box. Several days later I tossed the whole thing up in a tree, complete with zip ties, made contact with myself, and sat happily in my little mesh island. The next morning, I checked the repeater anxiously, curious if the batteries had made it through the night. Surprise—reported over 90%! For a couple of days it stayed over 90%, much to my surprise, but then I recalled that the T114 had been somewhat of a low-power consumption device. Maybe this was expected and we just hadn’t hit the charging circuit’s hysteresis or something.
Several days go by, I get distracted by life, check in, notice the battery in the 80s. Weird. Add it to Home Assistant because more data more better—let’s graph this stuff rather than just spot check when I remember, have a free minute, and am close enough to a device… aka 1-2 times a day max.
Just so we’re looking at the same thing, here’s the graph. All data points are aggregated to the mean of the hour, so some early spikes from ‘successful fixes’ are minimized on the graph, vs what I was seeing in the field from the repeater’s metrics.
Graph of repeater battery voltage over 8 days
The spike on the 29th is me thinking ‘Clearly I did not fully screw down the solar connection (I cleverly used screw-lock quick disconnects in case I needed to change panels), easy fix!’, getting out an extension ladder and applying my IT skills by disconnecting and reconnecting the solar panel. Immediately I saw a higher voltage on the repeater, and saw it start to charge. Unfortunately, I did this late enough in the day that the panel quickly fell into shade and I ran out of time monitoring.
The spike on the 30th is much the same, except I took the whole thing down and made sure that the internal connections were secure and properly routed. Around this time I started to have suspicions around my design as I saw the device not start to charge on the bench despite being in full sun, usually when gradually exposed when slowly turning it over, but clearly charging when disconnected or quickly put back in full sun.
The night of the 31st is when I realized… oh, maybe raw panel voltage is not what this thing wants, maybe I should actually read up on this stuff again… Some short RTFMing later, I find that Solar really wants a decently stable solar supply, kinda like the perfectly good 5V regulated circuit in the USB-A connector I had jettisoned in a pique of hubris. Fortunately, past me had purchased a 2 pack of solar panels, so I just put the right connector on the second one and swapped them out. Immediately the batteries charged up to full, then the charger went to sleep, as expected.
Amazing what reading the docs can do.
Several days up in the tree now, mostly sunny, but one big rain/wind event but hasn’t gotten below 85%.
As Always, hit me up on mastodon if you want to chat more on the topic, have yet to find a better way to interact with this blog until I move it to something federated.