Introduction: DIY Portable Power Bank and Table Fan
Being a Do It Yourself guy does means that I am having a good supplies of tools and stuff …. Well thats true but with good things comes great challenges ….. and in my case, right now, I am dealing with alot of unwanted/excess stuff that is lying in each corner of my workspace and believe me its just a burden on my mind that is getting heavier as the passage of each DIY project …..
Well not any more! as In this Instructable we are going to built up a Portable Desk Fan + a battery bank (13200 Mah capacity) to charge any USB powered device while enjoying the cool gusts of air. The best part of this project is that we are going to built this useful Gadget using most of the materials that is laying around my workspace…..
As you follow this article, I hope you will enjoy the built and please don't forget to vote my Instructable in the Unusuall Uses challenge ( https://www.instructables.com/contest/unusualuses... ) and also put your suggestion for enhancing this gadget.
So it the time to use some unusable things in Unusual ways to get the things done in our way :) ...... Lets get building ........
Step 1: The Required Components
As i have stated earlier, most of the components that are going to be used in this project are from the old stuff that is lying around my workspace.
The List of the stuff that is used in this project is as follows:
- Lithium polymer battery 11.1v 4400 Mah (extracted from an old 2003 MacBook)
- A standard speed 550 12v DC Motor (Fetched from a broken Remote Controlled car)
- A slow speed three blade plastic fan (New)
- A battery bank circuit with dual 5v 2A USB outputs (Ebay)
- A simple 12v 6A On/Off switch (New)
- Few yards of 22 gauge insulated wire (New)
- 20mm Aluminium tubing (A leftover piece from curtain holder)
- 3mm plywood sheet (used for packaging in automobile spare parts)
- Various size Phillips screws (from different broken devices)
The major cost is cut down while reusing the old stuff, so this project wont cost me much.
Step 2: Making the Battery Pack
I love this part ….. making the battery pack from one of the finest batteries out there and that doesn't even cost a penny ….
The battery pack that is going to power the fan and the charging unit is made up of lithium polymer battery that is extracted from an old MacBook (2003 model) lying in computer scrap near to my house. Physically the battery pack is in flat condition and thats a good symptom considering you are getting an used lithium polymer battery. Then I teared down the battery pack and found that the whole battery pack is made of 6 cells each cell have a terminal voltage of 3.7v at a capacity of 2200 Mah. There are three pairs each of which have a parallel connection and later they are connected in series thus forming an output of 11.1v 4400Mah.
After tearing the battery apart i have checked the individual voltage of each cell and it was founf that none of the cell is above 1.5v. I was quiet disappointed as a voltage below 3v is the sign of a dead lithium battery because the lithium pollymer batteries are highly sensitive considering their voltage range.
Still i kept the hope and charged the battery and I was highly surprised toind out the the battery pack is still holding its stated capacity!!!!
Now with the currently available speed 550 DC motor running at 11.1 we are going to have an enormous RPM (Rotation per minute) so we can rotate a much smaller fan at a higher speed, resulting in a much lesser amount of air at a greater speed and all of this happens at a very low efficiency.
So to make the whole unit efficient we are going to rewire the current battery pack so that it results an output voltage of 3.7v at 13200 Mah, thus resulting in much slower Motor rotation allowing it to spin a much bigger fan and hence propelling a good amount of air at a moderate speed. Moreover we are also going to reassemble the cells so to make it fit inside a smaller box.
Now we assembled the six cells side by side and connected them in parallel. The resulted battery pack is a 3.7v at a capacity of 13200Mah. Considering this huge amount of battery capacity it can power both the fan and charge two USB powered devices for 2 3 hours.
Step 3: Making the Main Body
This step consists of three sub steps that elaborates the making of the main body. This body works as the base as well as the enclosure for the battery pack and the charging circuit.
The whole enclosure is made using a 3 mm plywood sheet. The Dimensions of box are as follows:
Height : 40mm
Width : 60mm
Length : 110mm
The dimensions of this box is decided so that the battery pack fits nicely into the box and the overall built quality improvises and the base feels solid. In case if you are using some other batteries the decide the dimensions as per your requirments.
All the pieces are cut down using my DIY table saw. The dimensions and the no of pieces cut down for the box are as follows:
All the pieces are then glued together using CA glue except of the top plate.
PLACING THE BATTERY AND CHARGING CIRCUIT:
First the battery pack is glued down the box using hot glue and then the groves are made so that the box enables the access to the input and output ports.
These groves are made using small files so that each grove fits perfectly. Moreover a hatch is cut down right below the charging circuit so to mount the switch.
First the switch is put into place by pushing it in its hatch and after that the charging circuit is glued down in place ensureng that both the input and output charging ports are easily assessable.
FINISHING THE TOP PLATE:
Since the charging circuit has indication for the battery level and it also has a SMD push button to start charging the connected USB devices, we need to drill the holes in the top plate to monitor these indication lights as well as accessing the charging button on our ease.
The position of these holes are carefully marked on the top plate using a vernier calliper. Using a 2mm drill bit, holes were drilled as neatly as possible as the margin of error is quiet small here.
The top plate is then put down in place and thereafter we checked that all holes align with the indication LEDs and the SMD button as after this the whole thing in unacessable because everything is going to be glued.
Later the top plate is glued down and the box is sanded with a 500 grit sand paper to roundup all the edges and give the box a neat basic finish.
Step 4: WIRING EVERYTHING
The wiring of this unit is quiet simple.
This particular battery charging circuit have have a mini USB input that is used to charge the battery pack that is connected to the circuit. The charging can be done using any smartphone charger.
On the other hand the charging circuit has dual USB output, each of which offers a output of 5v at 2A which is good enough to power or charge any USB powered device. The efficiency of the overall circuit is very good as nothing seems to heat up.
On the bottom of the charging circuit, connection are marked on the PCB with positive(+) and a negative (-) sign which indicated the connection for the lithium polymer battery pack.
This is a boot converter circuit which is specifically made to operate with a single cell (3.7v) lithium pollymer battery
After identifying the input points on the charging circuits the positive and negative leads coming from the battery are soldered to the circuit.
To power the motor the negative wire is directly soldered to the motors negative lead. While the positive lead from the battery pack is first soldered to to switch then the wire from the second terminal of the switch goes to the positive terminal of the motor.
Connect the positive and negative leads on the motor terminals such that the motor spin in a way to propell the air in forward direction.
Step 5: The Motor Mount
To mount the motor, we have used an Aluminium pipe that is usually used to hang curtains. It has a 20mm outer dia. To give the whole thing an elegant look I have decided to cut the aluminium pipe at a slight angled which give a bit more grip on both ends and thus providing a firm support and a good blade clearance near the base unit as well as from the bottom.
This aluminium pipe is the glued to the top plate and we have added a triangular plywood pieces to give is some more area to hold onto providing a rigid base to work as supporting pillar for motor mounting.
Later on the motor mount is made using two layers of 3mm plywood sheets. First I have cut down four square pieces out of 3mm plywood and the alternately gluing them so to have a better grip between the angled joints. Following this the front end is trimmed down using a file to five it a neat look. To mount the motor to the motor mount we have drilled a centre hole so to pass the motor shaft through such that the front end bushing sits in the front plywood plate.The motor is held in place using two 3mm Phillips head screws passing through the front plate.
Two wires are passed through the aluminium pipe by drilling a 4mm hole in the base plate so that the wires are traveling inside the aluminium pipe from the base. These wires are then soldered to the motor and then insulated by applying heat shrinks at both the soldered motor terminals.
Step 6: FINISHING TOUCHES
After putting everything together, initial testing is done and as everything seems to work fine, its time to finish the whole unit.
The whole unit is carefully sanded with a 500 Grit sand paper.Both the base and the motor mount is sanded so to round up all the edged and rough corners.Later the whole unit is cleaned with a cotton cloth to remove wood dusted that is collected over the surface during the sanding process.
Then we have applied multiple coats of clear varnish mixed with staining powder. This time i have applied a relatively darker shade which gives the wooden parts a seemingly attractive yet sleek looks.
After the varnish is dried, motor is again mounted and fitted with the fan. Everything is tested and assured to be in fluent working order.
Step 7: FINAL RESULTS
Everything comes together so nicely that is remarkable!!!
At first look this thing just seems like a classy handmade table fan, nicely built with an elegant look of metal and an aesthetic feel of wood. As you get to the mind blowing battery capacity which is 13200 Mah this unit is quiet impressve as on a full charge it can easily charge my smartphone down from 0 to 100% for more than two cycles and at the same time running the fan for over a period of almost 3 hours.This unit can be charged by using any smartphone charger and requires an overnight charging period.
The best part is that this thing almost cost me nothing and this project helped me to use some of the unusable thing to create such a useful gadget. This whole project proved to be a good exercise of using thing that were laying around for creating awesome projects by learning the Unusual Uses of different materials.
So Guys if you like my project then don't forget to support me by voting in the Unusual Uses Challenge here at Instructable.
Put you suggestions and comments down below in the comment section and don't forget to visit to my youtube channel for the videos of my upcoming projects.
Link to The main Contest Page to vote: https://www.instructables.com/contest/unusualuses...
Youtube Channel: https://www.youtube.com/user/falconsamad
Participated in the
Unusual Uses Challenge 2017