How to Make a Very Cheap 4500 MAh Power Bank

Introduction: How to Make a Very Cheap 4500 MAh Power Bank

When I searched the stores for a power banks, the cheapest I could find was not always reliable so in this instructable I am going to show you how to make a very cheap power bank.


1 x 18650 Li-ion battery.

(If you can find a laptop battery pack you can take a working battery from inside.)

1 x USB battery charger.

1x 5V USB booster

(If you can find a dead powerbank ,you can take the regulator circuit instead of the usb charger and the 5v booster. )

1x 18650 battery base

1x toggle switch.

Step 1: Assembly

I glued two circuits together at the back of the base of the battery. If you are using a power bank circuitry then you will have to figure out for yourself a way to glue them.

Step 2: The Wiring

I first wired the batteries to the battery charger's B+ and B- pins. Then I wired the Out - of the charger to the In- of the booster. I put the switch between Out + of the charger and In + of the booster.

I am using a USB booster because the voltage of the battery is 3.7 v and phone's charge at 5v. So I boost the voltage to 5v using the booster.

That's all you need to do to make the power bank. This is the video for this instructable

Step 3: Going Further

I could only add 1 battery as my charger can only handle 1. But if you can buy a battery charger that can handle more than one you can have more than 1 battery wired as parallel.

If you want you can add another USB booster to have two power outlets.

Thank you!

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    2 years ago on Step 3

    how is this a 4500mAH power bank? most 18650 are around 2200mAH, few are 3000mAH.


    Reply 2 years ago

    I measured the capacity using a inaccurate way. So my results can be inaccurate but I have encountered batteries that do have more than 4000 mAH


    Tip 2 years ago

    Cool, but can you make high quality pictures?