About: Passionate developer and creator of first and last hour ;-D Love to try to do what people say you cannot do, to see if it still possible to do. ;-D Interests: Programming languages in general, love OP, C…

Welcome to my first instructable! With this instructable you are able to transform a dodgy/cheap solar powerbank (with some extra parts) into something useful. Something you can use every day, like I do, because it is really great to use! Most of available portable PSUs don't have a multi voltage output and if they had it, it is pretty expensive. But hey! We are makers, right? Let's built one ourselfs.

Step 1: How It All Started......

As a gift I received this large solar powerbank, however very dodgy powerbank. It was rated 4000mah but yeah..... not true at all. I decided to take a look inside.

It is easy to take apart, just put some creditcard between the solar panel and the case. The panel is glued to the battery, construction of quality :-) Found a small battery positioned centered in the case, the reason it doesn't hold a charge for a long period of time. No rating on this battery, nothing. This is an excellent example of fake and cheap or cheap and fake, however the circuit board is pretty nice.

Time to replace it with something else and to discover how to modify it.


If cannot find or you don't have such case and charger, you can buy one similar here.

Step 2: The Transformation, Design Idea

Because there is huge gap/hole when the solar panel is removed, I was thinking of to use it as a case for something else. After some thinkering and experimenting I decided to make it a case for a component tester. I use the component tester alot, very handy tool however requires a clunky 9V battery to operate. With this I can make it rechargeable. The component tester fits perfectly.

I don't want to reuse the 'original' battery so needed a 'new' and better one. Had some spare lipo laptop batteries lying around, very slim design and very thin and powerful. Used the Sanyo UPF3768111, 3.7V - 3800mAh - 14Wh. However the component tester needs at least 9V to operate. I use a MT3608 boost converter board to achive the voltage required.


Before using the MT3608, you have to fine tune it first. Connect the battery to the MT3608 board and check the output voltage with use of a multi-meter. It must be around 9V.

Because there was still some empty space available, I was thinking of adding some buck-boost converters, to make it a multi-voltage power supply. Found two that fits the design perfectly when desoldering the USB male connector.

Added some switches to the design and that's it. A device with many possibilities. Nice.

Step 3: List of Parts

Take a look at the picture to see what parts you will need. I don't specify where you can purchase all the components you need, just google it and it can be easily found by using the description of the components or go to your local hardware store. You only need a few parts to make this handy tool.

One exception tho, the buck-boost converter I use can be purchased from aliexpress by following this link. However at this time of writing the link still exists however can be obsolete in future. I didn't found one that fits this case perfectly without desoldering the USB male connector.

If cannot find or you don't have such case and charger, you can buy one similar here.

Step 4: The Circuit

The circuit is pretty straight forward and simple. Be sure you connect the red wire to the positive (+) terminal and connect the black wire to the negative (-) terminal. Double check every step you make to keep it safe!

Just follow the red lines to connect the positive (+) connections (red) and connect all the ground connections (black). Use shrink tubing on any connection to a switch. The kapton/sticky tape can be used to isolate the mainboard its connections and when components stack together inside the case. Use the rubber pads to minimize scratching (of sharp solder connections on a PCB) and pressure on the battery.

First start with all connections between components and after this check the connections with a multi-meter. When you are sure there are no shorts, test this first for example with two/three AA batteries in series or a protected power supply before connecting the battery. Check the circuit is working correctly. After this you can solder the final connections, the battery to the PCB. Double check the polarity of the battery (with a multimeter) carefully before soldering. Do this carefully, you are warned!

Step 5: Finally: Assemble All in the Case

Make sure no connections can short while assembling it. Fit the battery with the main board first and on top of it all other components. Use capton/sticky tape to isolate and rubber pads to avoid sharp solder connections poke into the battery minimize pressure on the battery (when pressing a button while using it).

You can use the borders of the case to hide the wires. Use some glue where needed however keep in mind you can still disassemble it, for example to replace the battery when is required. Take your time to do it carefully because you are 'playing' with power!

Step 6: That's It!

There you have it, a nice multi-voltage PSU and component tester in one! Like noticed in the images, you can add more features if you wish. For example the extra headers and cables I made. It is up to you. Hopefully you like it like I do. Thanks for watching!

- Do not use all of the added functions when charging. Fully charge it and after this use it.

Battery Powered Contest

Participated in the
Battery Powered Contest