I’ve been talking to the person that builds and sells these as an option for keeping nodes operating remotely.
What are the pitfalls here utilizing this type of system? Do you think it’s a good idea? I know it’s expensive, however I’m going to play around with this solar panel for other stuff (like trail cameras).
I have been using a similar (much cheaper) 10W setup with a sizable ~20,000mah lithium pack to keep a Tbeam running for a while partially shaded by the trees. I really want to keep some tbeams around in my remote mesh nodes, I paid a good amount for all those
Any nrf52 device will definitely make this setup overkill for anything but trying to outlast long winter months + heater.
I have always had firmware issues unrelated to batteries cause me to need to visit nodes almost weekly. This has allowed me in testing to simplify down and cut out the solar entirely. Much easier to have a fat lithium pack that lasts 2 weeks that you recharge yourself over the course of visiting and testing. When 2.0 is out and gets nice and stable, I can envision returning to these 10W setups.
Thanks for the thoughtful reply. I can understand the pragmatism associated with just swapping out battery packs when you check on the devices due to the firmware or infancy of this stage of development. Is there a timetable for 2.0 being released?
My hopes were that it was more stable at this point in time. Is there anything specifically that you keep returning to do to them that I should be mindful of before I set a bunch of these up?
Garth, what would you consider for the application that is necessary? The framework being this node should be up 24/7 being the best case scenario (with regard to energy being a limitation, not issues with the firmware)
Maybe I was being a little misleading, I know some folks have stable nodes up for many months. I have had most stable use on 1.2.6x releases. Mainly there are only stability issues when dealing with many nodes in earshot (~more than 5) and when sending many messages per minute. Low channel utilization meshes should be much more stable than some of my stress tests. Definitely stick to the more tried and true firmware versions though.
You can see the future 2.0 changes in the 1.3 alphas which will culminate in the eventual 2.0 release. The progress is moving fast and features have been getting better and better. The compression and new channel defaults really help with average use cases.
Not the master Garth here but my input would be it really depends a lot on your climate and where you plan to place the node.
To get through a dark week or so in the cold winter, a large batter may be required even when the same setup would be more than sufficient in the summer. If it gets really cold, you may also need to add some heating for both your battery and even board to keep the crystal at proper temperature. These all mean bigger battery and larger panels and unfortunately there isn’t one catch all solution or prediction without some real world data for where you expect your deployment.
With a 18650 and a ~10 watt panel a NRF without GPS should easily run continuously with a rak board and the green power add on or one of their new modular power supplies like @kalestew said the firmware is more likely to need updating right now.
The RAK solar panel enclosure with a 1200mah lipo runs continuously in my testing, but it is tight. I don’t really have to manage much cold which is nice because lead acid batteries are heavy. Everything gets bigger with cold as you need to manage the batteries themselves much more actively.
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So, unfortunately I seem to have purchased the t beam models. Reading through a bit of what you linked I see t beams are not particularly well suited for unattended solar, the caveat being if its going to run out of juice. I think im definitely going to stick with a 10watt panel.
Battery heating is an issue I havent considered though. What is the general group concensus regarding this? I wonder if I can wrap and insulate the battery with some sort of micro heater tucked inside. The north east usa can get pretty darn cold.
A 10-Watt panel is plenty, at least that’s my experience here above 45° N. I’d be more concerned about battery capacity, as even with moderate sun a 10-Watt panel will charge it pretty quickly, while three days without sun could eat up a fully-charged 18650 Li-ion cell. Hence, more cells are recommended.
Having said that, my home node is powered by a 5-Watt panel and a single 18650 cell.
On my remote node I’ve simply put several layers of bubble-wrap around batteries and radio, to preserve heat while being easy to unwrap for service.
