Hack Together a Powerful Pocket USB Charger. (6.6 Amp Hour Battery)




About: My name is Taylor, I am an electrical repair tech by day and an engineer by night, after work or free time.

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

soldering iron

wire clippers/ snippers

hot glue+gun

electrical tape

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



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    25 Discussions


    4 years ago on Introduction

    why did you rip the top off ,because they screw off lolz


    4 years ago

    Hi nice job how was the micro usb wired to charge cells ?


    Can I just replace the lithium battery that is around 2300 mAh with a Panasonic 3000 mAh lithium ion battery?


    4 years ago

    This is a good project


    4 years ago

    I just made a project similar to this,.but i made my own case,altoid tin was nice,but unable to find it here.anyway thanks for giving time to check mine:
    DIY Links:

    iPhone/Smartphone DIY Powerbank


    Mobile link:



    4 years ago on Introduction

    Agreed with Kurt. Project is cool, but you may want to consider redesigning the power source.

    Here are few reasons why:

    1) Running batteries in parallel is always a bad idea

    2) The controller board is only able to handle so much current. The limiting diode will blow, if it exceeds the limit(usually 1A for a regular charger).

    You can actually replace all 3 units with cheaper alternative: my local radioelectronics store has 3.7V 5800mAh Lithium accumulators(~$4). In combination with really cheap 5V step-up converter and a simple resistor bridge to set output voltages for D+ and D- on your USB output will make it safer, smaller and lighter.

    1 reply

    Reply 4 years ago

    I understand your addressed concerns but since I have made this I have charged my phone well over 10 times and have yet to notice any issues. even after several tests.

    While I applaud your creativity and enthusiasm, I have to warn you that this is not an ideal use of Lithium batteries.

    To start, Lithium batteries are not something to play around with unless you really know what you are doing. I know you know this, and I know you mentioned it, but I still have to say it. They tend to explode when they are unhappy. Just saying.

    Charge controllers for Li-on are specified for a certain number of cells, meaning they will not work correctly (long term) for more or less than they were designed to charge. Parallel batteries typically demand a special charge controller with multiple outputs. One or more of the cells will eventually settle at a different voltage level than the others, causing discharge from the other batteries into it. This is a recipe for disaster. You can sometimes combine other types of batteries in parallel without consequence, but definitely not Lithium based ones.

    Although you didn't mention this, I have to state it because people are always confused on the matter...The mAh rating only specifies the capacity, not the discharge rate. In fact, it has absolutely nothing to do with the discharge rate. You can often estimate what the correct charge rate of the battery will be based on the mAh rating, but the discharge rate is a whole different animal, typically based on the internal architecture. For example a AAA cell can only source a fraction of the current that a D cell with the same voltage and Ah rating can.

    True, combining three 2.2Ah in parallel does (somewhat) create one 6.6Ah battery pack. However, it does not in any way increase the discharge rate into a circuit, just the potential for a higher discharge. Your device itself has a charging circuit built in that determines how much current it wants to draw while charging. You can put an infinite number of batteries in parallel and it will not charge your device any faster. Again, I know you didn't say that it would speed up the charging time of the device (just the time to charge the battery pack itself), but I have to mention this because most people have absolutely no idea how any of this stuff works.

    As for insulating the tin, you should look into a product called "plasti-dip" which is basically liquid plastic in a spray can. It is perfect for this type of application.

    5 replies

    I never said it would increase the discharge rate. it I outputs one amp. I said it would triple the charge time. meaning if one battery can charge your phone say 50 percent than three can charge it 150 percent. as I have proven that to be true. one unmodified battery charged my galaxy note 2 about 65 percent now with three it charges it to 100 percent plus some. 65x3=195 percent. I have monitored this closely and it discharges and charges without any problems. I do understand your concerns though. I have done my research on the application and its looking pretty good as of right now. I will look into plastic dip! kinda like flex seal?

    I know you didn't say that, hence this: Although you didn't mention this, I have to state it because people are always confused on the matter...
    And yes, plasti-dip is similar to flex seal, but it is a bit less expensive. Either will probably work fine. Also, plasti-dip usually sprays on smooth while flex-seal can leave a very rocky looking finish.

    What do you mean by "it outputs one amp?" Do you mean it is capable of sourcing one amp? Just clarifying... Like I mentioned before, it's the device itself that decides how much current to draw. It's why you can often safely use different USB chargers from difference devices, as long as they can each source the minimum amount of current.


    the charge controller will output 1 amp meaning it's the most a device can draw. I'll have to look into plastic dip for future projects

    I notice you are in school for electronics, which is really the only reason I have said much of anything - trying to teach you something that will help in the future. With that said, this isn't a constant current driver, so it will not output 1 amp. However, it can source up to 1 amp. It's not the same thing, and the wording can get you into trouble, especially if you get it in you head that something like this actually is sourcing 1 amp all of the time.


    4 years ago on Introduction

    Thank you for the Instructable. I may give this a try soon. I've seen these sticks around, I take it that one would re-charge the stick via a USB connection to say, a laptop or desktop? Have you considered adding, or someway intergrating solar technology to re-charge your battery sticks? That would be pretty cool!

    1 reply

    Reply 4 years ago

    you're welcome. :) I would advise using a usb port from a wall charger. I haven't tested the current draw and if it's higher than 600 ma it could damage the usb port on a computer. I would love to incorporate solar power to recharge this but maybe for another build. since the battery capacity is 6,600 ma it would take weeks of direct sunlight to charge using a panel that would fit on top of the tin. maybe in the future it would be possible :)


    Reply 4 years ago on Introduction

    You can also insulate the inside of the tin with plastic dip, sold at your local hardware. You can apply it with a brush, or using their spray on cans. They also have various colors too; red, blue, white, yellow, etc. I personally like the one I can apply with using a brush, I get better control.


    Reply 4 years ago

    with anything that won't conduct. :) I used electrical tape.