What does the solar panel do?

[Anna Black]

Some Dragino end devices are solar powered like the PS-LS pressure sensor. 

Does the solar panel actually charge the battery? Or does the device just use solar when it's available and switches to battery when solar is not available but the solar doesn't charge the battery?

Thanks

AB

[Matthew B]

Charges the battery.  Note the battery capacity is smaller on units that have solar on them.  

[Anna Black]

Thanks Matthew.

I've had one of those solar units deliberately kept in the dark since before Christmas - so about two months now - and according to the battery voltage data transmitted it hasn't dropped battery voltage whatsoever in two months. That battery is smaller but not small and it certainly shows that the solar panel isn't needed on a daily basis. 

I was hoping to prove to myself though that the battery voltage would drop and then I can see the panel charging it back up again, but I guess I'll have to wait longer. Or the other explanation is that the battery voltage data point sent is not accurate.

AB