Inside the well known altoids tin lies three 2,200 mah lithium ion batteries. All three are ran in parallel to create a 6,600 mah or 6.6 amp battery. Which triples the charge time! Meaning if one battery can charge your phone 75 percent than three can triple that! 75x3=225 percent!
This project was made using three individual 'powersticks' which had one 2,200 mah battery on the inside. I picked up three of these for a very nice price and decided to see if I could maybe combine all three batteries to create a longer lasting USB battery bank and I did just that. I know that working with lithium ion batteries can pose a risk when being worked on so let me clarify that I did take extreme caution when making this. After I made it I tested everything I could to ensure a safe hack.
Since the battery size has now evolved to 6,600 mah it will charge my phone longer which is good but it will also triple the charge time for the battery bank. The charge controller is rated at 1 amp and the package also suggests using a charger no higher than 1 amp to charge the battery. Since it is now a 6,600 mah battery it could take a few hours to charge depending on the charger used, but charging it while you sleep helps pass the time.
Be careful and do this project at your own risk!
Step 1: Things needed
3 equal sized power stick phone chargers
wire clippers/ snippers
Step 2: Taking apart the power sticks
These came apart in an easy but hard way. They actually unscrew at the top and the easiest way to unscrew them is to use a clamp or vice. I however lacked those tools and had to resort to using my needle nose pliers which took some time and damaged the USB ports. Not to worry! I have plenty of extras on deck.
Do this carefuly, unscrew the cap and slowly work the charge controller and battery out. Try keeping one charge controller in good shape as we will be needing it later.
Step 3: The batteries.
Remove each battery from the charge controllers by clipping the connections then connect all three batteries together by joining all the positive leads together then all the negative leads together.
Since the negative leads on each battery were long enough I just folded them to join all three in the middle and soldered them together then soldered a black wire (for negative) to the joint as well. For the positive leads I had to strip a wire and join the leads by soldering that wire to each positive lead, I used a red wire for positive. After, I then wrapped some electrical tape over the exposed connections to insulate. The red and black wire will be soldered to the charge controller.
Running batteries in parallel is very easy, as I described. Simply combine all the positive leads together then combine all the negative leads together. I have included a simplified picture. Running batteries in parallel increases the run time. When joining batteries in parallel it is important to use batteries that have the same ratings. Never mix! Mixing unlike batteries can lead to fires.
Step 4: The charge controller.
We now need to solder the red and black wire from the 3 batteries in parallel back to a charge controller. Simply strip and tin the red and black wire then solder it to the controller keeping watch on polarity. Positive to positive, negative to negative.
In short we took apart three USB power sticks apart, freed the batteries from the charge controller, wired the batteries in parallel to triple the charge output time and resoldered the three batteries in parallel back to one charge controller. Pretty easy stuff :)
Step 5: Putting everything inside of an enclosure.
The final product is far to big to fit back into the nice flashlight like tubes and we need an easy way to carry it. I decided to use an altoids tin because they are very common amongst the community here and it is easy to carry! I have seen a ton of pocket USB chargers formed inside of an altoids tin and I have always loved the look :)
insulate the tin with electrical tape and cut holes where needed. I had to cut a hole for the female USB and micro USB ports. Move the electronics in and hot glue to secure.
As I mentioned earlier I did extensive testing to ensure the safety of this build. It charges fully and discharges safely and emits very little heat when doing so. I am just saying this because I know there will be a few people saying that what I did was dangerous and all that jazz so I am trying to avoid that :)
Thats all folks! Thanks for viewing!
Check out my facebook page dedicated to DIY projects if you would like :)
Step 6: Test it. (added step)
I would take a picture of it charging my phone but I use my phone (galaxy note2) to take the pictures for my projects. The multimeter reading 5 volts dc should suffice :)
The easiest way to test to see if everything works is to test the output with a volt meter. I would advise testing with a meter before a usb device such as your phone