Given my problem with battery consumption, oncoming winter and my latitude…
Would it be possible to turn of the WIFI-module and starting saving data on SD-card, starting WIFI-module and resending data as a function of battery status?
Regards/M
Hi @MaxHeadroom! You can use the SD card to do data logging by uploading the software that you can find here: https://github.com/fablabbcn/Smart-Citizen-Kit It is possible to send the data via wifi or saving it in the SD card, but no both at the same time. At least not now, with the hardware we have. Maybe in the future this will be possible as we will have chips with higher capacity and it is a quite interesting feature. Thanks for the tip. Best. 
My question was not about wi-fi and SD-Card working simultaneously.
Rather, it was using either wi-fi or SD-Card as a function of energy from solar panel.
When too little solar energy, you write to the SD-Card & turn off the wi-fi.
Once sun comes back and the solar cell produce enough energy, you start the wi-fi, deliver saved data from the SD-Card and resumé normal wi-fi-operation.
Hi @MaxHeadroom. Maybe i did not express myself correctly. Sorry for that. That feature you are asking for it is not possible with the current microchip. You can not switch between the two operation modes (sd vs wifi) automatically. There is not enough space to put that code yet. Thanks for your support. Best.