Solar Panel Backpack

Equipment -

Lenovo Laptop 15″ backpack ~$10

  • I found a deal on this from slickdeals.net , I made sure to use a backpack with a flat back so it was easy to attach the panels.

Solar Panel – $18.15 x 3 = $54.45

  • http://www.ebay.com/itm/220430473850?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649 These are the panels I purchased, the diode comes with the panels. [ Some people say that China can be hit or miss for panels, because they may use broken panels, but the ones I purchased seem to work great.]

18 Gauge wire

New Trent Battery ~ 20

  • Again I found a deal on slickdeals.net for this. Normally retail is higher price

Diode – IN5819

  • Comes with the panels

USB Female

  • Used a dremel to cut it off of a USB hub

 

Tools -

Soldering equipment

Multimeter

High temperature epoxy

Heat shrink tubing

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I used 18Gauge wire for durability. You can solder the wires anywhere on the negative or positive. They are all in parallel.

These are connecting to a usb port. The usb port has its data connections soldered together. Some phones needs these points soldered together so that it doesn’t limit itself at 500ma, and recognizes it as a wall outlet.

These panels are charging a 5v 5Ah LiPo battery. The battery can output 500mA or 1A. This battery does not have its data connections jumped, so I made an adapter that jumps that data connections.

This allows me to leave the backpack idle, and make use of collected solar energy at night.

Measuring the panels will show about 7 Volts, but when connected to the circuit the voltage drops to 5.5 with the diode in series.

In direct sunlight the highest charge, while connecting it directly to the multimeter, I was reading ~700mA at 7V (not connected to battery, just raw feed from panels).

I used hot glue to attach the panels to the backpack. (  I would recommend using an epoxy that can handle heats in excess of 180ºF )

27 Responses to “Solar Panel Backpack

  • sweet mod man! btw, lifehacker just featured ya too! may have to give this mod/hack a try for when i’m off the grid!

  • WOuld be could if you made a step by step “How to” for electrically challenged people like me… ;)

    Pretty awesome!

    • I’ll try to make a youtube video when I have some free time to show you how.

      • I also think that would be a great idea. I’m trying to follow the instructions, but I also am a little challenged electrically.

  • Could you give the links for the equipment you used? Thanks!

  • Do the panels have a built in charge controller? I don’t see that listed in your items. How do you find the max power point of the panels and make sure that you don’t over charge the battery?

    • The battery, and devices I plug into it have built in charge controllers. The max voltage and current is regulated from the people that make that panels.

  • Great DIY and a nice way to avoid overspending on a solar-powered backpack. I will be going backpacking next month and I plan to modify my camelback in a similar fashion.

  • Schematics?
    Or did you literally just hook up 3 solar panels and solder directly to a USB plug?

    • I did make a schematic, but its pretty basic. The solar panels are already regulated (solar panel design) at 5.5v with the diode in series. So the voltage will never exceed 5.5v. All the devices I hook up to it have built in charger controllers so I don’t have to worry about over charge. IMO its an efficient and cheap way to make this compared to the others I’ve seen using high voltage panels and voltage regulators.

  • This is Great! Where is the best place to buy the solar panels? I am slowly going to convert as many things as I can to solar powered, lamps, generator, coffee pot, and eventually whole house. Thanks for sharing your idea.

    • I updated my purchases. Let me know if you need more information. I would like to see how you projects turn out. Send me a link when you’re done.

  • Do you think this will be allowed for air travel (say international flights)? If yes then this would really be a great solution for everyone.

    • I looked up other solar panel backpacks online, and retailers say that “they get funny looks, but everything goes through”

  • I love the way you wrote this article. This is wonderful. I do hope you intend to write more of these types of articles. Thank you for this interesting content!

  • Nice work. I have been looking for a tutorial on this for a long time. I’ll be looking forward to your video instructions too, because I haven’t done much of this work.

  • Sweet build. Have you tried to take this backpack through security at an airport? I don’t see why it would be an issue JW. I have a Oakley bag I would want to mod like this but it’s my carry on and I travel like every other week. Thanks.

    • You shouldn’t have any issues. I looked up other companies and they said ” You will get weird looks, but no problems “

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