Hi there, someone on Discord asked me to post this here when it was done. It’s my latest solar enclosure based around a 3 watt solar panel and the RAK19004 Green Power module.
What I like about this one is that it can be used for lots of different solar projects. The carrier plate on the bottom can be customized to hold different components like a different board or battery. The usable interior space is 100x100x28mm.
Yeah, the RAK has super low power consumption. It’s about 10mA without a GPS. With a GPS it’s around 50mA. TBeams are power hungry at around 100-120mA. This is more a comparison of the nrf52 and the ESP32.
I messaged you about this unit over on Etsy this morning, I’m wondering how it reacts to a dead battery and how it handles super cold weather. I’m in Michigan and we get many cloudy days in a row and we also can experience below zero temps for a few days in a row. Will it self recover? I don’t want to have to climb a 60ft tower to bring it back to life.
Hi Dan, I saw your message on Etsy but I will reply here for others. The unit will come back to life without intervention if the battery drained all the way and the device shut off. So, you’re good there.
However, cold temperatures are a concern for lithium ion batteries. Charging a li-ion battery below freezing could damage the battery unless the charge rate is quite low (0.02C charge rate). I’m aware of this limitation and working on a solution that will allow safe charging at -40 degrees using a different type of battery, LTO (lithium titanate oxide).
I’m building a custom battery charging board for LTO batteries so we can take advantage of their great thermal performance. I’m probably 2-3 months out from having this produced and integrated into this 3W Solar Base Station. I will also offer the charger for sale by itself.
Nice! Yes, I’m working on the LTO solar base station. I have v1.0 of the charger board in hand. There were some critical issues with the first version so I’m updating the design. I have all the parts selected and the enclosure designed and tested. The only thing left is the LTO charger board. I’m currently working through the redesign for v1.1 to make it more useful and reliable. This new version is going to have a lot more capabilities. I’m expecting it to take a couple months until I have the new chargers.
I’ll make an announcement on Discord and here once it’s complete.