On the LiFePO4 solar charge solution above, what default charge current limit should I get? Is that even the right question to ask, or is more information required? My day job is selling cookies on the internet, so you can assume you’re talking to someone with the ee intelligence of a labrador retriever.
Looking to put in a solar/battery node in the hills of San Diego, so no temp extremes to deal with and plenty of sun.
Awesome post! learned a lot. Here’s my little simple solution to solar charging the Battery and running the board:
Simple stupid setup, the panel was able to completely charge the battery in just about 3 hours of sun. Water proof and has a USB port (5.5v) on the side so no fancy wiring needed.
You have to set it to match the max of your cell, generally 1C charge it’s ok for this type of battery.
Just asking, but do you really need a battery? What if you oversized the solar panels (which perform ok in cold climates) and let it power off in the night? I believe hiking is not taking place at night in Alaska for safety reasons?
I guess it depends on what activity your doing. In Dec - Jan the sun is up by 0930 and down by 1630. Obviously give or take a few mins. I go to work in the dark and come home in the dark. If I only got out in the sunlight, I wouldnt be outside much. In the winter time, even though the sun isnt out, its suprising how well you can still see.
Hiking, cross country skiing, snoeshowing. Out on the snow mobile. I hear them go up and down my street all hours of the night.
It would be a shame if the midpoint coms went out when the sun goes down and your just wondering out.
Does anyone know if there a command to turn off the board LEDs from the meshtastic CLI?
I assumed --set-router would do this, but doesn’t seem to affect it. I couldn’t find anything obvious in the docs. Currently trying to squeeze every last bit out of an 18650 for a Lora32 board (v2 1.6) and do some runtime tests with the LG HG2s I have lying around from flashlight projects.
Maybe people that have been using the python interface can help update the wiki with things that have been added, mentioned here, but not documented well.
If it is not part of the API already you would need to check the schematic to see if the LED is attached to a GPIO pin, and if it is you can try adding code to change that pin.
Unfortunately I don’t know that board so he best I can offer is a potential general starting point.
You will likely get better replies, and help the community by starting a new topic that is focused on this question. Most people will not find this as it is deep in a long thread that covers a lot of topics related to solar charging.
The LED is turned on/off from setLed() in sleep.cpp
If you don’t want the led to turn on, you can update that function.
Gotcha. So I’ll need to build it in PIO instead of just using in one of the pre-compiled bins to flash it if I want to customize LED behavior?
You got it and when you’re in there, you can make other changes too.
There are parts of winter where there are only about 3 hours of diffuse daylight when the sun isn’t strong enough to harvest power with an oversized panel (within reason) at all. With no storage, there are basically two months of the year I would be totally offline, and another 4 months that I would be mostly offline.
My use-case isn’t recreational hiking.
I have a question. Can I input a 5V solar panel directly into a T-Beam? The input voltage might drop due to the T-Beam loading the 18650 until it’s fully charged right?
I’m just not sure if an additional charging circuit is necessary?
It will work. If you live in a sunny place it may even work well.
If you want to do things like have it work in winter in northern latitudes or sub-zero temperatures then you may need a more sophisticated setup.
Hiking in the summer, somewhere sunny, then the simple approach should work fine
How is this currently running? Id love an update before I try it out. Thanks
Yes that right. I would suggest using a 50 watt solar panel with a charge controller like he said. I use morningstar for a charge controller they reliable in my opinion.
I used your idea and I realized that if I just solder the battery leads from the Lora32 to the battery pins on the built in charger board, it will still function as a solar light and charge the battery. This theoretically improves it’s ability to “hide in plain sight” since it can still function.
I’m in San Diego too. Do you have your node up and running?
Hey Grayham, haven’t had one up for a while but I’ve got a couple laying around if you want to test. I’m in Normal Heights.
Yeah that would be great. I think I could reach that far. I have found a few other users with nodes so I think we can make working mesh.
these might be able to solve all charging and cooling heating insulation problems for router nodes 
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