Introduction: Double Altoids Solar Charger

Picture of Double Altoids Solar Charger

Hi! After returning from Active Duty training with the Air Force I wanted to build something that could charge my phone on the go and i always had wanted a Solar Charger so I decided to make one myself!

(A small Disclaimer) I pretty much threw this little guy together in about a day and kinda forgot to take pictures of what it looked like during construction. So for that I apologize!

Essentially it is a USB Battery/Solar Power Charger that switches between two battery banks to provide power to a USB MintyBoost Charger. The reason for having two separate banks is that i wanted to be able to charge my phone while also utilizing the wonderful sun to charge the battery bank. So I quickly decided that the simplest solution would be to use a DPDT switch to swap between battery banks and then using two SPST switch to allow solar panel power to flow to whichever battery bank was not currently being discharged. 

Supplies

- Electrical Wire (Copious Amounts)
-Altoids Tins (2)
-DPDT Switch (1)       https://www.sparkfun.com/products/11139
-SPST Switch (2)        https://www.sparkfun.com/products/10727
-Rechargable AA Battery (5)    https://www.sparkfun.com/products/335
-MintyBoost Kit (1)     https://www.sparkfun.com/products/10094
-Solar Panels 0.5W (2)     http://www.radioshack.com/product/index.jsp?productId=12609999
-AA Battery Holder (Any kind will do, long as you have 2 holders that hold between 2 or 3 AA's)
-Packing Foam to Pad the Mintyboost and other Components
-Paint For Making it look pretty!

Tools

-Dremel Tool
-Hot Glue
-Soldering Iron

So in a nutshell what we have here is two Altoids Tins Hot glued together with on each "door" there is a Solar Panel. I used a dremel tool to make a opening in between the two tins, as well as a opening for the mintyboost and sockets for the switches.  one Tin we have the Switches and a 2 AA battery holder and on the other Tin we have the MintyBoost and a 3 AA holder. As Shown By my crude Schematic the battery banks are separately energized by the panels with the two SPST switches and the DPDT switch swaps between banks. Its important not to plug a device in while charging the batteries as the combined voltage from the two power sources could damage the mintyboost since it was designed to step up voltage not step down. 

I hope this was helpful in any way, if you have any questions feel free to ask, as i know i sorta just winged it. Thanks!



Comments

jmichels2 (author)2014-11-16

Your rough schematic does not have the charge indicator light. Where would that be placed? Also does this light indicate full battery charge or just that a charge is happening? I am looking for a design to place an indicator light that states full charge.

Mr_Rep (author)2014-08-27

so i have a 4 AA battery holder, and a 7.2V NiMh RC heli battery. which would be more effective with the use of a 6V solar cell?

jtrim (author)2014-08-20

Can you make a video on YouTube or something and post a link to it because this design, idea and practicality of this is so innovative!!! Keep it up ! :)

rsantos24 (author)2013-07-08

I have a 6 V 50 mA Solar panel wired to 2 rechargeable batteries, and the battery wires and solar panel wires are soldered to the USB connector. The USB connector is lit up so there is some power going to it but the device is not charging.

Solarcycle (author)rsantos242014-03-07

You're essentially charging two devices, the external backup battery and your phone, at the same time. This instructable explains what kind of charge controller and power is required to perform this task and give constant phone charge even under non-ideal conditions: https://www.instructables.com/id/DIY-Solarpad-Kit-...

Mickey_Boy (author)rsantos242013-11-24

I hope you have already found your answer. If so maybe someone else will read this and go aha :P
Some devices require you to have a specific voltage across the data pins on the usb connector. This is so your device can know how much current it can draw.
Shorting the data pins tells the device to draw as much current as there is.

Sethaulton (author)rsantos242013-07-08

Do you have a DPDT switch between the solar panels/batteries and the USB? As the combined voltage of the batteries and the panels will usually produce a voltage higher then the USB boost converter can handle, most USB chargers are meant to step up a voltage as opposed to stepping down one. Hope this helps, if not i will continue to provide aid good sir!

CreationBoy- (author)2014-02-26

I freaking LOVE the way it looks and functions. You have not failed at making an awesome instructable mate.

CreationBoy- (author)2014-02-26

Brilliant.

rallison22 (author)2013-12-01

Is there any specifications on the solar panels? Besides it fitting on the can?

decc1954 (author)2013-06-23

Love it! Want those details though...

Penolopy Bulnick (author)2013-06-12

Awesome design!

About This Instructable

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Bio: Working with an interest in Space Exploration and Sciences, I am a highly motivated worker, tinkerer, and aspiring Astronautical Engineer that wants to continue my ... More »
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