Introduction: How to Use Phone Without Battery

I made this for my next project.

https://www.instructables.com/id/Install-phone-into-car-dashboard-Subaru-Legacy

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

Step 1: "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

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

http://www.ebay.com/itm/Lithium-Charger-Step-down-...

Step 3:

Comments

author
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?

author
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.

author
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?

author
diy-master (author)falconzinx2017-07-28

I found plan on internet and I try:)

author
falconzinx (author)diy-master2017-07-28

Good to know, thanks!

author
Billystubbsy (author)2017-07-23

Hi
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

Thanks

author
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.

author
RejinJ (author)2017-06-11

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

author
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?

author
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.

author
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?

author
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.

author
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:)

author
AdamA157 (author)diy-master2016-10-13

Do you have a link to the video?

author
diy-master (author)AdamA1572016-10-15

I have only this video https://youtu.be/fuLF84dqgxE

author
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

author
diy-master (author)AdamA1572016-10-15

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

author
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.

author
diy-master (author)rva19452016-12-08

Great!

Thank you for your comment!

author
mahitoshc6 (author)2016-10-27

Thank you for this valuable post.

author
diy-master (author)mahitoshc62016-10-28

With pleasure ;)

author
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?

author
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.

author
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?

Captura de Tela 2016-01-29 às 11.41.54.png
author
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?

author
WeslleyTorres (author)diy-master2016-01-29

I have the DC Power Supply DPS-305BM (http://www.amazon.com/DPS-305BM-Digital-Control-Laboratory-Adjustable/dp/B00ON8VPFY) . I set the voltage to 5V (less than that, the smartphone does not turn on).

Thank you for your answer.

author
diy-master (author)WeslleyTorres2016-01-29

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

author
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 ?

author
diy-master (author)luelusten2016-01-11

Hi

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

From usb on PC won't work.

author
Yonatan24 (author)2015-12-18

Great idea, My Aunt should need this!

author
Yonatan24 (author)2015-12-18

Great idea, My Aunt should need this!

author
rakeshkunnath (author)2015-11-14

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

temp_1603590251.jpg
author
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:)

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

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

author
rakeshkunnath (author)2015-11-03

Hi

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.

author
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.

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

hi,

today i got the step down module delivered frm amazon. With that i could adjust the volts. my question is how I can measure the amp of my car battery. i tried turning the amp screw clockwise and anti clock wise. cant find any diffrn in multi meter. not sure i chosed correct in multimeter. could you help me to figure out on how to measure with a multimeter..

thanks
rakesh

author
jimmyt15 (author)2015-10-19

hi.

thanks for the idea, I would like to do for my HTC Desire

I have 4 battery pinout.

for my battery pin 1 and 4 is v+ and v-

so may i know how can i do?

author
diy-master (author)jimmyt152015-10-20

Read comments below ;)

author
jimmyt15 made it! (author)diy-master2015-10-20

but that is different, in between the V+ and V- have 2 pin.

i found the battery is show symbol "T" and "DQ"

i think should put resistor on the"DQ" right?

nex-1-of-1.gif
author
diy-master (author)jimmyt152015-10-20

T is maybe for temperature.

So yes, try on DQ.

author
GuillaumeB2 (author)2015-06-09

Hi,

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. :)

author
diy-master (author)GuillaumeB22015-06-09

Hi,

good question:)

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

http://www.cpkb.org/wiki/Samsung_EB-F1A2GBU_battery_pinout

author
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 !

author
diy-master (author)GuillaumeB22015-06-14

I used 82kΩ resistor.

I saw this on another similar project:)

author
GuillaumeB2 (author)diy-master2015-06-17

Hi,

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 ?

author
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.

author
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.

author
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;)

author
GuillaumeB2 (author)diy-master2015-06-17

Here is the one I've bought.
http://www.dfrobot.com/index.php?route=product/pro...

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 )

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