Solar Charging Wireless Battery Bank (A 3d Printer Required Hack)




Introduction: Solar Charging Wireless Battery Bank (A 3d Printer Required Hack)

Ok you will need some skills and a 3d printer or access to someone with a good operational one. You need some rudimentary soldering skills and you will also need about $25 in supplies for a Chinese Solar power bank (Suggest a minimum of 20000 mah) and a small disk type QI charger available for under $5.00 also on Aliexpress.

If you shop Aliexpress carefully and look for this chassis type the 3d printed .STL file I am providing will fit providing the printer producing it is properly calibrated. I do not want to leave a link for any particular vendor because I have found a few different ones for each of the Items used.

I have waited until I have used my unit for over 3 months before setting up and posting this instructable. I wanted to prove out the print design and the performance. Since that time I have now seen similar function devices selling retail for over 100USD on many sites for units at and under 10000mah. Best part is if you loose your nerve about building this before you recieve the parts you can always use the power bank to simply power the QI charger.

Step 1: Removing the Back Cover of the Power Bank.

These units are assembled using 8 small screws. simply remove the 4 holding the back of the device on to access everything you need to work with

No other disassembly of the unit should be necessary.

Step 2: 3D Printing.

Get the 3d file at Thingiverse. and print (I use a .4 nozzle and .2 layers for most of my projects) NO raft and NO supports. I also use PLA this print. If you are using ABS, I recommend you use a 1.02 scale to account for shrinkage as I made the tolerances fairly tight so things do not move around.

Fit the completed and cooled shell on the rest of the chassis to position the screw holes which I recommend you use a 1mm drillbit and work by hand so you do not drill through to the batteries and short them.

Once that is complete you should be able to re-use the original screws (If you have 4 matching screws max length 5 mm with a head at 2.5mm they will work better but make sure the shaft of the screw is under 2mm)

Step 3: Adding the QI Charger Disk.

Disk style QI chargers are cheap and easily available for this project you simply need to open the plastic case and remove the QI unit which is generally a single unit as shown in the photos above.

All that is required from this stage is to make a direct paralell connection from the 2.1A output of the Power bank directly to the same points of the QI unit.

Place the coil in the position shown in the 2nd and 4th pictures so the printed back will fit properly.

Step 4: Place and Secure the 3d Printed Cover to the Rest of the Chassis.

Fit the back of the cover first so you can position the charging unit if necessary (I made allowances in the printed back cover for different placement needs) and test for function before securing screws.

I did confuse the polarities on the first try and got tagged by this problem so be aware.

If you see the lights on both the QI unit AND the power bank your connection should be good next try your QI device to be certain that it is working correctly.

Once that is complete and everything works it is safe to secure the new back cover with all 4 screws. (With some less expensive QI units they are thinner than the one I used so you may want to try a piece of 2 sided tape to secure so no rattling and movement occurs).

Note that if you use almost any other color than black to print the New backpiece you should be able to see the glow of the LED on the QI disk. I did not make allowances for the LEDs because I liked all arounf effect of the glow. Feel free to modify the back cover in Thingiverse and let us all know how yours came out!

The unit is essentially and functionally complete. I leave mine on the dashboard to charge and keep my cell phone off the USB charger completely. This is an off the grid option for almost anything that can be charged via QI. cellphones, tablets, GPS units LED flashlights can all be hacked to mount a QI charging coil inside.

Step 5: Bonus Option I Found VERY Helpful...

I had a couple of these cheap pads that claim to make anything stay in place on your dashboard and the charger tended to bounce around on my dash while driving so I combined the two.

I superglued and trimmed the Sticky Pad to the QI charging side of the Power bank and now there is NO sliding on the dash, Also I have found that I can use the charger by sticking it to the back of almost anything to charge OR use the USB ports.

For a $5.00 investment at the corner gas station I recommend it.

ENJOY AND INSTRUCT ON! Feed back to me and I will add on options for this instructable!

Yours truly


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    Just4Fun Media
    Just4Fun Media

    7 years ago

    Great instructable! It totally deserved my vote!

    How long does it take to fully charge the onboard battery?

    Have a great day!


    Reply 7 years ago on Introduction

    Solar it takes 6 or 7 hours of full sunlight on the dash to charge 10000 mah of capacity (Rough estimate) Or about 4 hours on USB charging from a PC.

    If you get 20000 or higher capacity units the charging time will increase.


    Reply 6 years ago

    I had the same 10K pack and even at full sun on it at 12am etc. It didn't even charge 25% ... the original solar cell that comes with it doesn't generate any useful power when it comes to charing the pack, if anything, it's a gimmick


    Reply 7 years ago on Introduction

    That shouldn't be possible with a solar cell of that size. Either your battery is way smaller than reality, or the solar cell is rated way higher than reality.

    From the solar cells we have in shop of that size, I'm guessing it's at MOST half an amp of power. Which means 500mA (probably more like 250mA if its the same model we tested). That would take a MINIMUM of 20 hours to charge up a 10,000mAh power bank. (Also assume a certain amount of energy lost in conversion, adding more time.) 40 hours if it's 250mA. AKA five days of full sunlight.

    We've had some of those exact same power banks in shop before and they work great as power banks, but their solar cells are just too small to be of any practical use. Half the companies we get products for outright lie about the power of their solar panels or size of their lithium batteries.

    Love your project, but I want to make sure people are not getting the wrong expectations or information about solar panels. It's something we deal with every day.


    Reply 7 years ago on Introduction

    I agree, with your statement completely so I will footnote the following information. I live in South Florida and for almost the entire time I have been testing I have let the unit on my dash 7 to 9 hours a day and charged my Nokia 822 every night Empiracally the unit shows full charge (4 lights) after a sunny day and 3 out of 4 on a cloudy or rainy day. I do not want people to think that there is magic charging these batteries. I am stating from reasonable use where I do not discharge it completely every day I am able to maintain a high charge with a day on the dashboard. I am sure you can agree with these ammendments and I DO apologize to anyone who may have been misled by the earlier statement. I will also ammend the instructable to include this information.



    7 years ago on Introduction

    I just wanted to say thank you for making it clear in the title that a 3D printer was required, I often have been disappointed by seeing a cool title then finding out I need a 3D printer, laser engraver, or CNC router if I want to make the same thing.
    also, I like the instructable


    Reply 7 years ago on Introduction

    Thanks, I am big on that as well.

    But keep in mind that you can actually go to most of the 3d Printing model sites and find a service to reasonably print a model for you that is how I finally went out and built one for myself for a very reasonable price. I have since spent 3 times the amount of cash on filament for the thing.