Adafruit has come out with an updated version of solar charging handbag to solar battery charger in the form of a backup, where the battery is rechargeable with the sun.The previous handbag project had attached solar battery but this project provides you a battery as a backup that can be carried anywhere.
It is suggested to read the following two links for better understanding of this project –USB, DC & Solar Lipoly Charger and Adafruit Power Boost 500 Basic. The equipment required for this project are USB/DC/Solar Lithium Ion/Polymer charger kit, Power Boost 500 Basic, 3D printer with filament, A large solar panel or a medium solar panel, 2000mAh lithium polymer battery, 2.1mm DC Barrel Plug, slide switch, A sturdy handbag or backpack, soldering tools and supplies and #4-40 3/8 flat Phillips machine screws.
The 3D Design Files and the customized design can be downloaded from here. The circuit is assembled by soldering the capacitor on the solar charger and then folded to give a more compact shape. Next, the leads of the capacitor is soldered to the board along with the JST connector to the solar charger. Once, the USB port is soldered onto the PowerBoos, a slide switch is prepared using two short silicone-coated stranded wires soldered to two adjacent pins.
The JST wire is plugged from the solar charger into the Power Boost along with lipoly battery, which is plugged into the BATT plug on the solar charger. AminiB USB cable is connected to the computer or an AC adapter for testing the circuit. The slide switch must turn the green Power Boost LED on and off.
The Solar Panel is prepared via Follow Method 2 for replacing your solar panel’s barrel jack. The circuit is tested by plugging it into the solar panel, then placing it in direct sunlight. If the red charging light is bright and solid, then this thing is working. For enclosure, a #4-40 3/8 flat Phillips machine is used to mount the circuit board, fit battery into the BATT port on the lipoly battery charger.
Place the lid with machine screws. Now, the solar panel when plugged in and taken into bright sun, the battery will start charging. Finally, just affix the power pack into your bag with the cable routed to your solar panel or just take the charged-up backup battery with you.
For more details, check the following link.