Introduction: Make 4 Useful Things From 9V Battery

Picture of Make 4 Useful Things From 9V Battery

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Are you thinking what to do with 9v batteries when they run out of juice? Don't worry,In this Instructable, I will show you 4 ideas to reuse your 9v battery parts.

I never throw my used 9V battery from various projects.Last week I saw, there are plenty of 9V dead batteries on my storage box.So I thought to reuse it.Finally I made the following stuff for my upcoming camping.

1. Flash Light

2.Battery Clip

3.Mini Hand Fan

4. Li Ion Battery pack

Step 1: ​Parts and Tools :


1. 9V Battery ( Amazon )

2. 0.5W Straw Hat LED ( Amazon )

3. 100 Ohm resistor ( Amazon )

4.Tactile Switch ( Amazon )

5. DC Motor ( Amazon )

6. Mini fan Blade

7. Wires ( Amazon )

8. Li Ion Battery ( Amazon )

Tools :

1. Wire Cutter ( Amazon )

2. Needle Nose Plier ( Amazon )

3. Soldering Iron ( Amazon )

4. Glue Gun ( Amazon )

Step 2: Prying the 9V Battery

Picture of Prying the 9V Battery

First identify the weak spot somewhere along the seams, and pry until the internal parts pops open.Slide the interior out and use a cutting plier to disconnect the batteries from the clip.

After opening the metal cover I found the following useful parts

1. Battery Clips

2. Battery Tabs

3. Metal Jacket

All of the above parts can be used for DIY projects.

In the following steps I will show you, how to make 4 useful things by using the above parts.

Safety Precaution :

Make sure that you, and especially your kids if they are doing it, are very careful cutting the jacket of the old battery. The chemicals inside are NOT user-friendly and can be nasty or toxic if spilled out.

Know more about 9V Battery

Step 3: 1. Flash Light

Picture of 1. Flash Light

This flash light is really good for emergency or a camping light. It's compact and runs by most common and versatile 9 Volt battery. You can switch it on and off and its so small you can fit it any where.

Glue the LED :

First trim the LED legs and then glue it to the battery flat battery clips

Step 4: Add the Resisstor

Picture of Add the Resisstor

Glue the 100R resistor to the side of the LED leg.

For more brightness you can use lesser value of resistor.

Calculate the resistor value by using this Online Calculator

Step 5: Add the Switch

Picture of Add the Switch

Straighten all the 4 legs of the tactile switch.

Trim the diagonal legs by a cutter.

Glue the Switch as shown in picture.

Then bend one leg of the resistor toward the LED leg and trim the other leg.

Step 6: Prepare the Clips Terminal

Picture of Prepare the Clips Terminal

Among the two terminal, one is projected type ( Negative terminal ) and other is flat (Positive terminal )

Flatten the projected parts by using a needle nose plier.

Step 7: Make the Circuit

Picture of Make the Circuit

Solder one leg of the resistor with the positive leg ( long leg ) of the LED and other leg with the switch.

Solder a metal wire to the clips terminal ( looks like Star ) and then to the Switch.I used the trimmed leg of resistor as a metal wire.

Step 8: Glue the Clips

Picture of Glue the Clips

After soldering, apply glue on both the surface and join them together.

Apply more glue, to insulate the conductive parts.

Now the Flash light is ready for test.

Carefully clip it on a fresh 9V battery and press the switch.

Step 9: 2. Battery Clip

Picture of 2. Battery Clip

You can make awesome 9V battery clip from the salvaged parts.Its pretty simple

Solder red and black wire to the the two terminal of the clips.Then apply glue to join them together.

Step 10: 3. Mini Hand Fan

Picture of 3. Mini Hand Fan

You can also make a portable hand fan by using the salvaged parts.It is great for relaxing outside and cooling off.

Make the battery clips as described in the previous step.

Solder the clips terminal wire to the motor terminals.

Glue the motor on the bottom surface of the 9V battery.

Install the fan blade.

Step 11: Li Ion Battery Pack

Picture of Li Ion Battery Pack

The salvaged tabs can be used to make Li Ion Battery pack.

Remove the paper coating on the tabs.You can first wet it and then pilled up.

Apply glue on the battery surface and join them together.

Clean the terminal surfaces thoroughly then apply soldering flux on it.

Solder the tabs carefully.Your battery pack is ready.

You can parallel as much you need. I used to two just for the demonstration.

Safety Precaution :

Solder the tab carefully or you may use a Spot-Welder to do that.Excess heating of Li Ion Battery may leads to thermal runaway where it shorts inside, heats up, emits hazardous fumes, catches fire and potentially explodes.

Follow me for more DIY projects and ideas.

Thank you !!!


afridave (author)2016-09-22

when I was an appy i welded a spanner to two terminals of a 24 v truck battery with my hand stuck got really hot and very unpleasant and painful very quickly....I still have the semi melted spanner 30 years later which I keep as a reminder never to do such a silly thing again...

NiytOwl (author)2016-08-04

While I applaud the author for making something from trash, this is NOT economical! I don't think a light or a fan makes sense when the purchased alternative costs about the same and lasts significantly longer. Around here 9v batteries go for about $2 a pop. For the same $2 I can buy a little AA flashlight that lasts 3x as long on a 50-cent battery. The same goes for the fan. I picked one up a few years ago from the dollar store. It uses two AA batteries for a grand total of $2 and I'll bet it runs 5x longer than the 9v equivalent. As far as the parts go, I have 9v battery clips I bought off eBay at 99 cents for 10. If you made minimum wage disassembling batteries you would lose money trying to disassemble 90 batteries an hour.

That said, when I needed ONE clip I did take apart a 9v (to make the LED flashlight 12 years ago when such things were still a novelty item). It made sense considering the time it would take to order them and the wait 2 weeks to get them.

clark5113 (author)2016-07-30

That's not too bad and a good way to "test" if you don't have a meter. DO NOT UNDER ANY CIRCUMSTANCES however, use this method to check a 6 volt lantern battery.

andrew.mead.1253 (author)2016-07-26

A 5th use is of course a paper-weight. The standard 9 volt "transistor" battery is well suited to this task having nicely rounded edges that will not damage paper.

The 6th use is for the positive terminal on another dead 9 volt battery. It can be used to contain and store minute quantities of water--perhaps as a water bowl for one's pet cricket.

I just spewed a minute amount of my beverage when I read this. Thank goodness I had a spare 9 volt handy.

deba168 (author)cnaughtin2016-07-28

Enjoy !

Congratulations on being finalist! You instructables are really awesome!! :-)


Same to you too :)

deba168 (author)andrew.mead.12532016-07-26

Awesome ideas..I really like it.

Thanks for the suggestions.

KISELIN (author)2016-07-26

Me 65+ to age... worked all my llife within elec. back in those golden years we did not have these fancy multimeters, we checked out the wall outlet (230VAC) for to check if the wire was"hot" or not, this is how it goes: 1. have the unicolated end of the wire to be checked 2. be grounded 3. lick one of your fingers to be wet enough 4. tap the unicolated wire with a "wery" fast wipe. 5. If it tickles some, then the wire is hot

This story is "TRUE"

Phil_S (author)KISELIN2016-07-26

Not to be recommended, but as an industrial electrical person, I have more than used up my nine lives. The fact that I am here now is down to good fortune and thick layers of dry skin. More than once I have had hold of a UK 240-V wire and felt nothing, but the bang when it touched neutral or earth tells otherwise. The golden rule if you want to try this insane method is one hand only and wear some thick rubber-soled shoes. Also avoid cheap power supplies with floating outputs. A 12-V DC PSU can put out 120-V relative to earth - using a metal-cased laptop on bare legs can give you a bit of an unwelcome tingle. An implanted cardiac device makes me much more wary now.

charliewinters (author)Phil_S2016-07-26

Not really a response to you, but your comment inspired my thought.

I don't recommend it, but I've put my finger right on a hot main to prove a point with a live 470v main. If you are not grounded on your body elsewhere, and have good boots, it's not going to kill you. IF YOU ARE NOT GROUNDED. That's the important part. Ground out, and you're not going to be a happy camper if you survive.

I am an ex-electrician. I can attest to working live wires, and surviving, yet having them blow up when the tip hits ground due to incorrectly labeled breakers. I've been shocked more times than I can count. The worst feeling of them being an overloaded, and unbonded neutral wire (yes, the white wire can shock you on older or inproperly installed services that are not up code).

No matter how well you trust your partner, always test the wires with your meter/ticker. Always question your ticker. They're handy, but I've had several that would chirp on dead wires, and not chirp on live ones. When in doubt, get the meter out.

That's why birds can sit on 220,000V lines and live, they are not grounded or connected to another phase. (do they get a static shock as their bodies charge?)

Awhile ago, a raven was pecking at a power pole, while sitting on the wire! he was lucky that if he hit it, it would be only 220 or so volts! I still think that would kill the bird.

Phil_S (author)AlphaOmega12016-07-28

More birds get killed htting the wires.

They must have some capacitance. If only they knew what a stunt they are pulling. When the linesmen are working on live overheads, the protective gear is impressive. On the "millies" thing, frequency is also important. Humans can survive quite high amperages if the frequency is high enough. DC is the killer causing spasm. I've just had a nerve conduction test involving many thousands of volts. One of the most painful procedures I have ever had and won't volunteer for that again.

rufus.wallaby.9 (author)KISELIN2016-07-26

One would think it was a 117V mains and not 240V otherwise you may not be telling us this story.

Until sometime in the 1970's areas of Bristol had a 110V supply. As a kid I had a Saturday job at vacuum cleaner repair shop (some miles from Bristol) and we had a 110V supply for that very reason.
BTW "it's the volts that jolts and the millies that killies" - so providing the time was short and the resistance high.... But not a smart way to test ;) Having said that, as kids we used a long length of grass to test cow fencers. Touch the wire with the tip and slowly slide the grass stem, making the distance to your hand shorter until you felt a jolt, or not!

As far as I know, only US has low voltage mains. Normal mains voltage as in Australia & Europe is somewhere between 220V & 240V.

Possum Living (author)Jeyroslave2016-07-26

At a quick count, I found 47 countries other than USA that have a 100-130V standard.

In Australia now the nominal mains supply is 230V and up to 250V 50 Htz . In the US it's 117V nominally at 60 htz. In Europe it is 220V nominally at 50 Htz.

As a sparky in au i have many tales of being belted by the mains.. Im still here only because i never got hooked up. Its the current that will cook you the volts only make it more likely to sting

RainerG1 (author)2016-07-26

When I was a kid my black Labrador retriever found a 9v battery on the floor and proceeded to lick it. Jumped in the air and yelped. Then proceeded to attack it with intermittent yelps and growls. Finally figured out how to hold it in her mouth without getting zapped and proudly walked around showing everyone the proper way to carry a 9v.

michael2718 (author)RainerG12016-07-27

Might have been a lot more :"pet friendly" too immediately substitute a pet toy and save the pup from further shocks and additional yelps.

studleylee (author)2016-07-27

Yes! I used to joke I had a calibrated tongue. For guitar effects: this was useful to tell if your battery was good enough to get through a gig.

gorbkeller (author)2016-07-26

Warning: that doesn't look like a 0.5W capable resistor there! More like 0.25W max. Being that this setup will likely draw approx. 70mA approximating a 2V drop across the LED, it's dissipating upwards of 0.45W, so be careful. Lil' bub could burn out and start a fire!

LaserDave (author)gorbkeller2016-07-26

I really don't like when alarmists reach for the "it could start a fire" card whenever something electrical is suspected of having even the slightest risk.

First - the forward voltage of most white LEDs (in addition to blue, purple, pink etc.) is more than 3 volts, so that leaves us with 6 volts to deal with. The current through a 100-Ohm resistor at 6 volts is a mere 60mA, which is 0.36 Watts - MAX.

Deduct from this value... the battery's internal resistance, the additional fraction of a volt for the LED's forward voltage (3.3v), and that these values were based on a full 9v battery.

So, yes, a 0.25W resistor would be entirely appropriate. Fire? Have you ever seen a (sub 2W) resistor fail under extreme overload conditions? They turn black and burn out, sometimes with smoke, maybe even a 'crackle', but they don't burst into flames or produce enough thermal energy to ignite something nearby. Resistors are manufactured out of non-flammable materials designed to withstand heat.

studleylee (author)LaserDave2016-07-27

@ LaserDave Agreed 100% They kinda suck the fun out of life.

stevesigma (author)LaserDave2016-07-26

I would not recommend to use this flashlight to inspect car petrol tank.

gorbkeller (author)gorbkeller2016-07-26

Note: this is disregarding internal resistance which I know is not necessarily negligible, but worst case scenario.

JRFrogman (author)2016-07-26

The music on the video is tooooooo fn loud. If you aren't going to narrate, why does everyone have to put such loud music on their tutorials. Is everyone that deaf???

deba168 (author)JRFrogman2016-07-26

I am really sorry for that.The problem is that when I edited, the volume is pretty low.But after processing and saving, it is somewhat amplified.Anyway I will try to reduce the sound level in my upcoming videos.

Thanks for the valuable feedback.

claudg1950 (author)deba1682016-07-27

Very nice job. Apart from that I have another idea for your upcoming videos. NO music. I've lost count on how many instructive videos I stopped watching just because I couldn't stand another second of the deafening hysterical heavy metal rock guys for some reason deem necessary to add.

Flyboyron (author)2016-07-26

Maybe it's just me, but would any of these things work with a "Dead" 9v battery?


I assume you're just talking about one that has lost the ability to power a full 9V device, but a dead battery will ONLY be useful for a paperweight, as Andrew says.

oldmanbreadboard (author)2016-07-26

Read all the details on the Amazon website regarding the strawhat leds. The leds from Amazon are listed as 150 watt beside the picture but click "see more product details" and you will find in the additional details are listed as 0.06 watt and use 3.0--3.2v at 20 uA. A 100 ohm resistor at 3.2 volts would give 60uA current from a 9v battery. This is 3 times the rated limit and will surely burn out the diode, who knows how fast, but it will do it. They can tolerate some over abuse but it greatly shortens the lifespan even if they don't immediately die on you. If I had purchased these, I would let Amazon know that the seller has posted false and misleading information up front and hiding the real details in the fine print and I would want my money back. 0.06 watts is a heck of a long way from .5 watt. Off by a factor of almost 10.

KISELIN (author)oldmanbreadboard2016-07-26

Actually... the power of the led is P=U*I. U (V) in this case would be 9V minus the initial V 3.0 ~3.2V = ~5.8V thats to be "destroyed" by the resistor. You write "60uA" that would be "60 microamps", you surely mean "60mA" that is "milliamps... ;). A standard led stands for appr. 20mA, them powerfuller ones stands for much more, take notice on them tech. specs.

oldmanbreadboard (author)KISELIN2016-07-26

Yep, I have been working with capacitors today and the uF transformed in my brain to uA, you are perfectly correct, I should have said milliamps. I was checking out this instructable while I stopped work on the project for a rest. I just wondered about the 0.5 watt leds as that is a very large power rating for any normal leds and I found conflicting information on the sellers page. I hurried to comment before people ordered some and got less than they expected. These leds would need a 290-300 ohm resistor for operation at their max ohm rating, and would not be nearly as bright as a true .5 watt.

deba168 (author)KISELIN2016-07-26

You are right.

I used 100R to make the current below the rated value, so that it will run longer.I have tested if these LED runs @ more than 100mA ,after few hours,it starts to loose the brightness.

deba168 (author)oldmanbreadboard2016-07-26

You are right, the information given in the details are not at all for the straw hat LED.

The typical rating is


Vf = 3.2 to 3.8V

I = 120 to 150mA

SteveA35 (author)2016-07-26

Sticking my 10-y/o finger into an empty 110V lamp socket was the kick-off for my life-time career.

charliewinters (author)SteveA352016-07-26

For me, it was a paper clip in a socket. I stuck it in, and watched it vibrate. Touched it, and the circuit popped. I was maybe 4.

SamG91 (author)2016-07-26

I still do that. It's an easy way to know if the battery is dead or not. Does it hurt? Great, that's a good battery.

charliewinters (author)SamG912016-07-26

I wouldn't say it hurts, but it is unpleasant. To me, it's like tasting something very bitter.

Lee Wilkerson (author)2016-07-26

Great 'able.

I would offer one word of caution about connecting batteries in parallel. It usually doesn't work out well.

BobS135 (author)2016-07-26

What am I missing with the fan? Solder clip to motor; OK. Glue motor to dead(?) 9-Volt battery; Why? Glue motor to fresh 9-Volt battery; Have a fan that runs for a while, after which you're left with a motor glued to a dead battery.

Why not glue the clips to the motor and add a non-momentary switch to turn it on/off? That way it can be clipped to a fresh battery as needed, like the flashlight.

deba168 (author)BobS1352016-07-26

Good idea BobS.

I appreciate it.I will make the changes in my future build.

Thanks for the suggestion

WmPerry (author)2016-07-26

I just recharge my standard "Heavy Duty", non-alkaline batteries - it works a treat. 9volt, 1.5volt with no problems like heating (which i sort of expected). I was hesitant to try it but now i do it routinely. Never with any but standard carbon batteries. The others would blow up

rufus.wallaby.9 (author)2016-07-26

Yes, I wasn't tricked by anyone just a what if in my own head, but my most unfortunate experience was when I first started in radio in 1962 with a radio B battery of 90V. Lucky I wasn't silly enough to put that on my tongue but two wet fingers were enough. I commenced an apprenticeship in electrical and radio trades in 1965 and found out 240 & 415V shocks were much much worse. You learn to respect electricity otherwise you don't last long on this earth working with electricity, 30mA through the heart are the requirements for ventricular fibrillation followed closely by a trip through the door of no return.

Quantumdust (author)2016-07-25

Ideas are good....just a couple of comments. Make sure that you, and especially your kids if they are doing it, are very careful cutting the jacket of the old battery. The chemicals inside are NOT user-friendly and can be nasty or toxic if spilled out.

The second not is do NOT EVER solder to Li-Ion batteries with a soldering iron. These cells are not meant to be heated like that. Links are always attached with a spot-welder which does not invade the internals of the cell. If you heat it with solder you may be lucky and nothing will happen except a soldered connection, if you are unlucky you get a thing called thermal runaway where the battery shorts inside, heats up, emits hazardous fumes, catches fire and potentially explodes. Unless you like calling 911, do not do this.

Speaking as one that has many many... many... real world experience in soldering I can vouch for the relative safety when soldering closed li-ion cells. I say relative because I doubt anything good will happen if you gouge an iron into the cell for 10 minutes... I have, and probably will in the future, soldered these cells together. Definitely use flux as described in this instructable and be intentionally "quick" about it. Get in, get out, enjoy. I have even soldered to li-po cells and this is easily doable as well just... not as "safe".

KISELIN (author)xKOBAYASHIMARUx2016-07-26

Agree with you. But it comes to pretty much of having "good" soldering experience. I have soldered many Ni-Mh, (not the same as Li-Ion), and I can do the soldering in say less than 3 seconds, (apply the tin the "right way"). That shouldn't corse any damage? Flush, flush, flush, thats the key to the thing, ( not to flush 3 times but you know what I mean)

About This Instructable




Bio: I am an Electrical Engineer.I love to harvest Solar Energy and make things by recycling old stuffs. I believe ""IF YOU TRY YOU MIGHT ... More »
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