Introduction: 5 $ Solar Power Bank From Recycled Laptop Battery

Picture of  5 $ Solar Power Bank From Recycled Laptop Battery

As some of you know that my college was having a science exhibition , their was also a project display competition going for the Juniors. My Girl friend Meghla was interested to participate in that , they asked me what to make i suggested them this project and mentored them while making so their can be less photos as they were in a rush for the competition .

BTW this solar power bank won the contest as the grand winner of Inception 2016.

Do Congrats Them with a lovely comment. <3

Step 1: Components You Need

Picture of Components You Need

Here are the list of components

Tools you will need

  • Soldering Iron
  • File
  • Dremel or rotary tool
  • solder
  • glue gun
  • black tape
  • Double sided tape

Step 2: Preparing the Solar Panel

Picture of Preparing the Solar Panel

First step will be to attach the solar panel to the box for that we need to use double sided tapes.

I used 3M 's once as they are thin an also the bond is berry strong ,

You can find it in you local stores.

We drill two holes for the solar panel using our dremel.

We use a 0.8 drill bit for the work.

Then peeling off the wrap from the double sided tape we attach it to the box

Step 3: Preparing the Case for Mounting the Usb Slots

Picture of Preparing the Case for Mounting the Usb Slots

If the slots are not cut the USB in and out can't be fitted inside the case.

to make the slot we first drill a hole and then using our Dremel silicon carbide grinding bit.

take the rpm to 8k and slow grind the hole making it the shape of a micro USB.

for the USB Female slot we need a bigger slot we drill a couples of holes .

and then grind to make them joined and also bigger then by using the file we smooth it .

Step 4: About the Modules

Picture of About the Modules

About the charger module

last time i used a tp4056 without protection at output so that could have damaged the batteries if the where discharged below the under voltage specified by the manufacturer. the tp4056 comes with a DW01 IC which acts as a under voltage protection for the cell.

The Boost Connveter

A boost converter is a DC-to-DC power converter with an output voltage greater than its input voltage. It is a class of switched-mode power supply (SMPS) containing at least two semiconductors (a diode and a transistor) and at least one energy storage element, a capacitor, inductor, or the two in combination. Filters made of capacitors (sometimes in combination with inductors) are normally added to the output of the converter to reduce output voltage ripple.
Boost converters are easily available and they are cheap i bought a 1A 5V Boast converter.

Power input is equal to power output Input Voltage x Input Current = Output Voltage x Output Current

The Boost converter has two input just input + and input - Be careful with polarity

Step 5: Connecting Everything

Picture of Connecting Everything

Soldering the lithium Ion battery

Soldering Li-Ion may be a huge downside even for the knowledgeable techs out there.Many try and solder Li-Ion cells or phone batteries. it's not suggested by the battery makers to heat them up regardless the explanation.By victimization heat on Li-Ion cells, you'll be able to harm the plastic extractor, pressure protections or maybe the most internal metal layers.

if your hand tool takes quite an heap to heat up (30 sec +), take away it’s basketball shot favor of a diluent one. A 1mm wire tip can heat up considerably quicker than a 2mm wire tip. don't exaggerate tho'. If it’s too skinny, it'lls often.

I had to use and take away quickly to avoid harm. victimization pointed Tip is additionally higher


The Connections is giving in the diagram.


EmersonV10 (author)2017-01-22

Good, I have a question, my cell will be charged instead of charging, does anyone know what to do?

StrangerIV made it! (author)2016-06-14

Nice instruction, I made it quick and easy. The most long time was taken by the postal service :)

Batteries are 2200 mAh, salvaged from netbook accumulator. I have found a nice case for my device, Kradex Z34 (

Thank you!

geekrex (author)StrangerIV2016-08-15

that looks so awesome

Robert 7320 made it! (author)2016-07-22

Great Project

NickyB4 (author)2016-05-27

Nice build! Building my own now. I have 1 question though. What is white "thing" next to micro USB? Greets

Barkuti (author)2016-05-03

For the amount of money spent, great job. (-:


• You've been able to solder wires on the battery terminals because that one has tabs. Soldering a battery without tabs? Do not even try. Use frayed & flattened thin wire meshes under disc shaped neodymium magnets, and hot glue the thing. For 18650s I recommend ∅8×1'5mm magnets. For high currents: wrap the magnets on copper sheet.

• So-so diagram. I suspect the negative pole to the boost converter is not actually connected to the battery's cathode, or you'd have bypassed the protection circuitry (as the diagram suggests).


ThomasD39 (author)Barkuti2016-05-06

Cool idea with the magnets. If I do this, I'll use that method.

charliewinters (author)Barkuti2016-05-03

I have successfully managed to solder wires to packs without tabs, but I had to sand the end of the battery to rough it up, and use a very hot iron with flux. Tinning, and preheating the wire helps. I used non-coated solid wire (that can be left on a heat source to keep it warm) to join them, and cover the joints with hot glue to protect the ends of the battery afterwards.

I agree with you. Soldering is not a good choice, but it can be done, if one takes the time to prep the metals, and works fast so the battery wont overheat.

geekrex (author)Barkuti2016-05-03

Thanks You
What is the tabs actually ?

i took the output from the tp 4056 module , from the protection pins,

the diagram was made for the competition and i didn't remember to change those.
thanks for showing it.
i will update it soon .

Barkuti (author)geekrex2016-05-03

Laptop pack pulled batteries usually have spot-welded tabs.

Now that I'm seeing it more carefully your battery only had the cathode tab (-). The tabs are those “fins”. :-D

A correct solder joint is performed by steadily joining the surfaces to be soldered and then uniformly heating the joint with a pre-tinned soldering iron tip (heat transfer surface maximization); when all the surfaces reach fused solder temperature, solder flows easily and the joint is well done if cooled in a stable way (i.e. do not shake the stuff). If the surfaces to be joined do not reach solder temperature, a fragile cold joint will result (and it'll break sooner or later).

Check the photos. (-:

Hope it helps.


geekrex (author)Barkuti2016-05-03

thanks :D

Kinnishian (author)2016-05-03

Hi, a small tip is not a good for soldering 18650, because you get worse heat transfer (less surface area) and a big tip acts as a thermal capacitor.

Soldering direct to tabs is doable but needs to be done very carefully. You first tin the taps with a HOT big iron and 10-ish seconds. Then I use tinned solder braid as my connection. Again very few seconds (absolute minimum.) Between tinning and soldering allow cell to fully cool.

geekrex (author)Kinnishian2016-05-03

will try it soon thank

ninadt23 (author)geekrex2016-05-04

Dear friend,

Good work. i just want to know

1) the life of solar panel what you had used.

this is epoxy mini solar panel.

2) also some the li-ion 18650 battery are available with PCM/PCB (for cutoff for low discharge & overcharge protection circuitry ) then we don't want to use tp4056.

attached image shows li-ion with PCM/PCB

geekrex (author)ninadt232016-05-04

Thanks For the pic

Unfortunately i don't know the lifespan i bought that on ebay , where it was not written .

if your has inbuilt protection you can use that only just get a USB break out for the connection.

ninadt23 (author)geekrex2016-05-04

thanks for replay. i just want to know through 3V to 5V boost converter can we use total charge from 2.2Ah battery to charge our mobile?

Kinnishian (author)geekrex2016-05-03

If you're an electronics guy, think of the big iron and heat as a higher RMS current, allowing faster localized heating. If you're not an electronics person, or just dislike the metaphor, ignore my side point :p.

In all cases, you want heat getting in FAST and you want to avoid buildup to the max. has a 50+ page thread about making battery packs from 18650 cells, tho most ppl making a big pack invest in a cheapo capacitor spot welder.

The thread has great info about sorting cells too, since especially if your source stop is crappy recycled cells you really want to get the good ones. As much as more would seen always better if you tolerate weight and size, any cells with self discharge are particularly important to exclude from your pack

LetL1 (author)2016-05-04

Nice Work Congrats to the Winners. I'm interested in trying to make a Solar Panel so I can see if i can make them for my Home Any Suggestions? ?

geekrex (author)LetL12016-05-04

yes you can do that in my next coming project i would make one Home only. Stay tuned :D

rrMuraliR (author)geekrex2016-05-04

I use electricity for only 1 CFL lamp, one table fan, plug to charge mobiles. I want to use solar . Let me know if you have a product.

meghla.banik (author)LetL12016-05-04

thank you :)

ToolboxGuy (author)2016-05-03

Yay for reduce, reuse, recycle! How long does it take to recharge a cell phone, from the SolarBank?

geekrex (author)ToolboxGuy2016-05-04

500 ma that is around 4-5 hours for 2200 battery phone

Treknology (author)2016-05-04

Nice little project that re-uses the functional cells from a dead laptop battery. I'm glad it won a prize!

You're wise to caution people about soldering to Lithium Cells. In your case, there are tabs on each end. Hold the tab in a pair of pliers. This means you only heat the solder joint (although you may need a stronger iron) and the pliers absorb the heat before it reaches the cell. I have cells without the tabs which means that I have to find "A"-size holders to be able to use them.

charliewinters (author)2016-05-03

I've built one of these several years ago using completely salvaged parts for free (unless you count the solder, and electricity). I used two usb ports from a pc, added a voltage controller, and capacitor, LED's from a PC to indicate whether it was in charging mode, and use mode. A low profile toggle switch to turn it on and off from charging to output. I put it on a shelf to finish later when I tried adding a small fan to cool the batteries off while they were sitting in direct sunlight. I had multiple battery packs that I made that could be swapped out of the unit when charged for backup power.

Future design plans included making the solar panel input into an odd shaped port so it could be set out remotely in order to keep the battery pack cooler, and working out the problem I had with the fan (which might not be necessary if I make the solar panel remote).

Those large batteries are difficult to solder to. You will need an iron with high wattage so that you can heat your joint quickly. A low wattage iron will cause you to have to heat the battery for longer in order to make your connections. This will degrade the battery. A possible solution for this is to make a battery holder that uses springs to connect the batteries, rather than having to solder them in and out of the pack.

I've used laptop batteries for many projects over the years. When the pack goes bad, it's often just one of the cells that went bad, so It's a good source of rechargeable batteries.

If you don't want to wait until you find an old laptop battery, you can purchase them new online, or at a specialty store like batteries+.

Unfortunately for me, I am not an electronics master. I learn as I go. I have several marketable ideas, but don't know how to design the circuits well enough. If anyone is interested in chatting with me some time to work out some problems I run into, I'm game to talk. Just send me a message.

I was using it to charge my battery packs during the daytime, then recharged my usb devices such as my phone, or my old tablet, with the charged battery packs at night.

You'll want some diodes in there to prevent backflow off your device into weaker charging packs. Some devices like phones are going to be sensitive to overvoltage, so you definitely need something to regulate your voltage to a clean 5v output.

CorneliusV1 (author)2016-05-03

Great project with limited resources! Since you are already using a soldering iron, it might be worth getting or making a hot knife tip ( ) also purchaseable for less than the dremel. The dremel on this type of plastic is very rough. Using a hot knife will offer a cleaner result with more control. You can also use a very fine soldering iron tip but expect lots of cleaning.

geekrex (author)CorneliusV12016-05-03

will go through your ible soon
Thanks in advance

CorneliusV1 (author)geekrex2016-05-03

Sorry for the confusion. Not mine but something that makes sense.


systemBuilder (author)2016-05-03

I would recommend that you use 2 batteries and a 2A 5v converter to have higher power for flagship smartphones and tablets :

geekrex (author)systemBuilder2016-05-03

will use it in next build, thanks man

electronic_artist_ (author)2016-05-03

bhai, nice work. accha kiya hai. neat and clean.
next time try upgrades with this.
for example, u can use more batteries because, i guess one battery is equals to approx 2000mah, so it may not full charge a phone. also try to decrease charging time. if u dis this it will be very usefull.
aur jarurii bat. agli bar circut apnehat se bana... akhir ham hindustani hai! dont use ready made charging circuit ??
overall awsome work. :)

the battery is 2200 mah not 2000 .

AleemA1 (author)2016-05-03

This has been done before. But because it's a 6v solar panel, you need to be in direct sunlight at full blast. You could have used two panels with a 5volt regulator to charger the 18650 battery, then it would have been more efficient.

geekrex (author)AleemA12016-05-03

that you be would be cool ,but the surface are will increase too. which is not desirable ,find better cell replacement option

kavish laxkar (author)2016-05-03

how much time did it take to build..;P

1 hour

meghla.banik (author)2016-05-03

thanks for helping us making the project and making it win :)

irun4fundotca1 (author)2016-05-03

good luck fully charging one cell if its high rated ,i can leave mine on for days and its still not fully charged

geekrex (author)irun4fundotca12016-05-03

whats is current rating ,this one charges fully in sunny day

Chaka23 (author)2016-05-02

if you have 5V solar cell why do you need boster from 3V to 5V? is it just to reduce output voltage ripple?

geekrex (author)Chaka232016-05-02

the boost converter is for the li ion battery , we are not using it directly rather storing it and using it .:)

JasonB195 (author)2016-05-01

Love this idea, i might try it But just a correction.

Step 2: Preparing the solar panel

I used 3M 's once as they are thin an also the bond is berry strong

"berry" I just wanted to ponit that out so you could fix it

geekrex (author)JasonB1952016-05-01

Thank you ,i am really sorry i made a very careless mistake in a rush :(

josh (author)2016-04-30

Quite clever!

geekrex (author)josh2016-04-30


discostu956 (author)2016-04-30

how long does it take to charge the cell via solar?

geekrex (author)discostu9562016-04-30

10 hours with 220 mah

5 hours with 500 mah

About This Instructable




Bio: So basically i am a crazy person, who loves to think the most odd way ever possible,who makes what he thinks and also let ... More »
More by geekrex:DIY 3D Printed Desk Lamp$200 DIY 3D Printer Build$1 DIY Fidget Toy
Add instructable to: