Introduction: How to Use Phone Without Battery

Picture of How to Use Phone Without Battery

I made this for my next project.

How to connect phones with 4 pins, take a look into comments.

Step 1: "Battery"

Picture of "Battery"

I took pins from SD card adapter and glue them with Super Attak glue on piece of wood.

I used 82kΩ resistor.

Step 2: Power Supply

Picture of Power Supply

After couple of months I can say this is perfect power supply. It has enough power and it does not go hot! I bought it on Ebay for some bucks

Lithium Charger Step down 5A 5V-32V to 0.8V-30V Power Supply Module LED Drive 5A

Step 3:

Picture of


Zsolt0318 (author)2017-10-11


This is a nice project! I want to do a similar thing: I have a Samsung Galaxy Ace GT_S5830i phone with an almost dead battery. I could use it without a battery, but I'm not sure what's the difference if I want to use the USB socket of the phone for energy supply. So I'd like to avoid using a new cable for the power.

diy-master (author)Zsolt03182017-10-22

First I need to apologize to you for really late answer:(
Batteries are dangerous, so that is the reason why I made so wird project and remove battery from my phone.

GuillaumeB2 (author)2015-06-09


Thanks for the idea. I'd like to do the same with an S5 ( SM-G900WB )

but I have 4 battery terminals and not sure what should be the resistor value..

Thanks in advance. :)

diy-master (author)GuillaumeB22015-06-09


good question:)

If you have pins V+, ? , V-, ? I will try to put resistor on the middle one (between V+ & V-).

GuillaumeB2 (author)diy-master2015-06-14

Yea, the 4th pin is for the NFC... not sure for the 3rd one is for termals.. but..
Once I found the battery good pins, how should I mesure the right resistor value ?

Thanks !

diy-master (author)GuillaumeB22015-06-14

I used 82kΩ resistor.

I saw this on another similar project:)

GuillaumeB2 (author)diy-master2015-06-17


I got all my wires right, got a great step down power supply(from a 5volts to 3.85) but the phone seams to ignore the resitor 82K... the ''battery'' slowly drains.. have you experienced the same thing ?

Fresh plug I have about 68%... going down slowly.

I guess I should try a different resistor value ?

Any other idea ?

starcheng (author)GuillaumeB22017-08-20

Hi, would you please paste the picture of the correct pins with wires and resistor for 4 pins. I put 82k resistor between v+ and v- but it not work. My phone is samsung S2(I9100), thanks a lot!

diy-master (author)GuillaumeB22015-06-17

I think your power supply is not enough powerful.

You need more watts (amperes)

Paste link of your power supply.

GuillaumeB2 (author)diy-master2015-06-17

you where right. I was running my DC converter from usb 5v down to 3,85V then 4.0V

Right when I plugged into a computer 12v source, I got 100% with only two wires didn't plugged the resistor at all.

it's now on the bench with flashlight and 3hours long youtube video to try to drain it.. I think I'm good now.

Thanks for the kind help.

diy-master (author)GuillaumeB22015-06-17

of course didn't work ok, USB is only 0.5A or max 1A, but you need 5A;)

Please paste some pics what did you do;)

GuillaumeB2 (author)diy-master2015-06-17

Here is the one I've bought.

I've also increased to 5v flush. now I have like 80% battery..

if I unplug and replug, I get the 80% back...

but I'd consuming.. I'm watching 'longest youtube video' with flash light open to drain at maximum and see what happens when it reaches 1% or 0%..

I'm thinking it might be the 82K resistor ....

note my battery has 4 leads.. ( with one I believe to be the NFC )

diy-master (author)GuillaumeB22015-06-17


power supply looks enough powerful...

Buy the same one like me. So we will see if the problem in phone, resistor or power supply.

diy-master (author)GuillaumeB22015-06-17

or, you can test with higher voltage. Go step by step to max 1V higher like your battery.

AtisL (author)2015-06-10

How did you adjust the power supply unit? Which screw does what? Without load it gives out always approx 5 volts, and i somehow hesitate hooking up phone to it without first making sure i have correct voltage.

Also, what's the resistor value for the extra pin? Any hints on choosing it?

diy-master (author)AtisL2015-06-10

One screw is for Voltage, another is for load regulation (amperes).

If you always have 5V output, you doing something wrong or is your power supply broken.

Don't put 5V in your phone. Take a look on battery how many Volts have!

I have the same problem like you with some very similar power supply (LM2596). I have 3 at home from different seller, and no one works.

What type of volt meter do you have?

I used 82kΩ resistor.

falconzinx (author)diy-master2017-07-28

How did you know to use an 82k resistor?

Is it based on the your old battery's thermistor value?

diy-master (author)falconzinx2017-07-28

I found plan on internet and I try:)

falconzinx (author)diy-master2017-07-28

Good to know, thanks!

Billystubbsy (author)2017-07-23

Great project...

I can see your phone is connected up to the power supply, How do you restart the phone when you get back to your car?

I'm having trouble with particular problem


diy-master (author)Billystubbsy2017-07-23

Phone was turned on non-stop. But if I needed I can restart it like every phone on on/off button.

RejinJ (author)2017-06-11

what should be the minimum volts and amps to power the power supply model

DevinN2 (author)2017-01-12

Hi Trying to connect a LG V909 3D tablet , works while plugged in but switched off from time to time, how did you connect the black and red wire , is it connected to the 12v straight?

diy-master (author)DevinN22017-01-12

If tablets goes off, I think you have problem with power (watts or amps). You need more powerful power supply or just turn the button. I have 2 buttons/screws on power supply, one for Voltage, and another for W.

Wires from power supply goes direct to 12V into the fuse box. You can see on pictures.

TL15 (author)2016-10-10

Hi, thanks for the post. So when there's three pins in the cellphone, the left and right are plus/minus, and middle's probably temperature-sensor. I don't get why the resistor connect to the middle pin?

rcrusem6 (author)TL152016-12-13

Our smartphone has thermisistors or resistors that varies resistance upon heat intensity of battery, doing that will give the smartphone idea that it is actual battery not a power supply. Especially a Samsung smartphone i detecting the thermal resistance of batteries.

diy-master (author)TL152016-10-10

I also don't know. I just do it, like they do it on the "Discovery channel" :)) I saw on internet and it works:)

AdamA157 (author)diy-master2016-10-13

Do you have a link to the video?

diy-master (author)AdamA1572016-10-15

I have only this video

AdamA157 (author)diy-master2016-10-15

That's a nice video, and I like what you have done to it. However I meant the link to the video from the Discovery Channel

diy-master (author)AdamA1572016-10-15

:)) This was a joke with D.C. This is part from one old and very popular song ;)

rva1945 (author)2016-12-07

I'm powering my old Samsung GT-S5310L with a cell charger and a diode in between (the chager's open voltage is around 6.2V). The middle terminal is not connected. It works fine.

diy-master (author)rva19452016-12-08


Thank you for your comment!

mahitoshc6 (author)2016-10-27

Thank you for this valuable post.

diy-master (author)mahitoshc62016-10-28

With pleasure ;)

Damnaed (author)2016-10-12

hi. my idea is to power the phone with 4 AA lithium batteries in parallel and to charge this "battery pack" from the phone charger via phone. will it work?

diy-master (author)Damnaed2016-10-15

I don't understand why do you like to use extra batteries? I think, that would be better to use real power bank.

WeslleyTorres made it! (author)2016-01-29

Hi, thank you so much for your post. I tried it in a Samsung J7 but unfortunately it did not work =/. Actually I just need to turn on the smartphone in a external power supply. However when I try it, the smartphone shows a message about low battery and then it turn off. Can you help me?

diy-master (author)WeslleyTorres2016-01-29

i think you don't have enough power on power supply. You need more amperes. what power supply do you have?

WeslleyTorres (author)diy-master2016-01-29

I have the DC Power Supply DPS-305BM ( . I set the voltage to 5V (less than that, the smartphone does not turn on).

Thank you for your answer.

diy-master (author)WeslleyTorres2016-01-29

This is too much powerful :)) Set more Volts. Step by step.

luelusten (author)2016-01-11

I am not sure if you still view this but could I use a 5V rail from a PC power suplie and add some kind of reziseter to it to step it down ? I don't want to over kill my build but it would have a PC in there two so makes sence to use that power ?

diy-master (author)luelusten2016-01-11


I don't know. You must to try:)

From usb on PC won't work.

Yonatan24 (author)2015-12-18

Great idea, My Aunt should need this!

Yonatan24 (author)2015-12-18

Great idea, My Aunt should need this!

rakeshkunnath (author)2015-11-14

this is the multimeter i hold to measure. pls assist.

diy-master (author)rakeshkunnath2015-11-14

I don't know:)

Just adjust volts.

Ampere adjust with test.

Connect phone to the step down module, turn phone ON and run some "heavy" app, Youtube with HD and put to play half hour. Run browser and open few tabs. Open navigation app... If the phone will not turn off, than is OK:)

diy-master (author)diy-master2015-11-14

And put battery percent on 95-100%. This you will reach with adjusting screw for amperes.

rakeshkunnath (author)2015-11-03


Thanks for sharing your effort. I wud like to take some advice from you. Am planng to integrate my phone to car dash like wat u did. From where sud i take the power, so that my phone will switch on and off when i turn the keys.

diy-master (author)rakeshkunnath2015-11-04

I think turning phone on&off with car is not good idea. Because duration is too long.

I dont know how to make that phone will go ON when receive power.

For shutting down phone when lost power, you can use some tasker app (macrodroid, tasker...)

For wiring you can use car lighter with car phone charger.

Or Cable with fuse (Add A Circuit Fuse Tap Piggy-Back) and Lithium Charger Step down, like I did it.

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