Emergency micro powerbank

Aug 08th, 2019 | by: Manuel Bonomi
Category: Electronics Basic Circuits
Views 601

We all know that our smartphone's battery is always out of juice when we really needed it, for example to make an important call or, in the worst case, to call for help or rescue. So, I designed and built a tiny and lightweight powerbank in a mint box that you could attach to your keys or throw in a pocket and it will be always ready to charge a little bit of your phone's battery.

If you are curious and you want to learn more about it please check the project page on my Instructables profile! There I explain step by step how I built it and how it works.


The final test!


  • Jason Meech

    about 4 years ago

    If i were to make a suggestion it would be to use something like a NiMH battery instead of lithium in the charger that way when you do go to need it after forgetting it exists for 3 months it still has some residual charge left

    Manuel Bonomi

    about 4 years ago

    Thank you for your suggestion! You are completely right, lipos tend to discharge over time.In fact, my original plan for this charger was to use 2 or 3 AA NiMh batteries connected in series and the same step up converter. The problem was how to charge them. Of course I couldn't use the TP4056 because lipos are different from Nimh and , as I saw on internet, Nimh has to be charged with a constant current source for several hours. I wasn't able to find a simple circuit that did all the works for me so I decided to go with a single lipo.

    Noob 19129

    about 2 months ago

    Please try Google before asking about Useful Product Blog aa023d9

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