This works perfectly with two 18650 cells wired in series(7.2v). I actually used 4 cells all together, two pairs wired in parallel(3.7v) to give extra capacity then wired the pairs in series to give me the required voltage(7.2v). Easily charges my HTC One M9 and my sons iPad.

This works perfectly with two 18650 cells wired in series(7.2v). I actually used 4 cells all together, two pairs wired in parallel(3.7v) to give extra capacity then wired the pairs in series to give me the required voltage(7.2v). Easily charges my HTC One M9 and my sons iPad.

This works perfectly with two 18650 cells wired in series(7.2v). I actually used 4 cells all together, two pairs wired in parallel(3.7v) to give extra capacity then wired the pairs in series to give me the required voltage(7.2v). Easily charges my HTC One M9 and my sons iPad.

I wanted to use it with this solar panel: https://www.banggood.com/Portable-5W-12V-Polysilicon-Solar-Panel-Battery-Charger-For-Car-RV-Boat-W-3m-Cable-p-1449442.html?rmmds=myorder to power a wemos d1 mini using the power hat and a 18650 battery. Unfortunately the 14V open circuit voltage of the solar panel drops to around 4V when connected to this charge panel and it cannot provide power on the USB output as the minimum working input voltage is rated to 6V. So this panel cannot be used in this situation. I cannot decide now what is wrong, the solar panel, the charge panel, or the planed usage type.

I wanted to use it with this solar panel: https://www.banggood.com/Portable-5W-12V-Polysilicon-Solar-Panel-Battery-Charger-For-Car-RV-Boat-W-3m-Cable-p-1449442.html?rmmds=myorder to power a wemos d1 mini using the power hat and a 18650 battery. Unfortunately the 14V open circuit voltage of the solar panel drops to around 4V when connected to this charge panel and it cannot provide power on the USB output as the minimum working input voltage is rated to 6V. So this panel cannot be used in this situation. I cannot decide now what is wrong, the solar panel, the charge panel, or the planed usage type.

I wanted to use it with this solar panel: https://www.banggood.com/Portable-5W-12V-Polysilicon-Solar-Panel-Battery-Charger-For-Car-RV-Boat-W-3m-Cable-p-1449442.html?rmmds=myorder to power a wemos d1 mini using the power hat and a 18650 battery. Unfortunately the 14V open circuit voltage of the solar panel drops to around 4V when connected to this charge panel and it cannot provide power on the USB output as the minimum working input voltage is rated to 6V. So this panel cannot be used in this situation. I cannot decide now what is wrong, the solar panel, the charge panel, or the planed usage type.