DIY Solar Bag

Solar Bag recharges anything that can connect to a USB port. Solar energy is collected and stored in the battery pack while not in use. I use it to keep my power hungry cell phone and ipod running all day or in an emergency. You can buy these online for a few hundred bucks, but this one cost about $100 if you DIY.

The solar bag consists of a flexible solar panel, rechargeable Ni-MH batteries, and a few electronic components to tie it together.

The solar panel is a PowerFilm P7.5-150 producing 7.2V and 200ma in ideal conditions, more than enough to charge three nickel cadmium batteries.

Two circuits are used in this design. The first circuit employs a MAX639 step-down switching regulator to transfer all of the solar panels energy to the batteries as efficiently as possible. The second circuit uses a LT1302
Micropower High Output Current Step-Up DC/DC Converter to provide the necessary USB 2.0 power requirements. Both of these integrated chips are free from the manufacturer when you sign up on their websites.

All of the circuitry can be placed on a project board and fits into a small space. I found some garden solar lights on liquidation at Wallmart and it was easy to remove the existing circuit and incorporate my board into the design which evidently gave me a second solar panel which I can take out and place in a window when I'm indoors. With a full day of sunlight, enough energy is stored in the batteries to completely recharge my power hungry cell phone and ipod and I feel good about using renewable energy whenever I can.

1 comment:

  1. I really enjoyed the insign you bring to the topic, awesome stuff about the
    "Solar Energy Project"..Thanks for sharing it.... solar panels