Power an Android Phone Without Battery
Intro: Power an Android Phone Without Battery
This idea came to me when I built another project
For my needs, I had to have an Android alaways on but I didn't want to let it pluged on a wall with the battery cell inside. A battery that is 24/7 on charge can be damaged and start a fire ! So I wanted to bring power from a wall plug, directly in the phone.
Be careful ! Here we will play with electricity and battery cell. Those elements can be dangerous if you don't know what you're doing. I can't be responsible of any damage caused on your equipmentor on yourself. So please, read every documentation you can found BEFORE starting anything !
STEP 1: What Numbers Said
For this project, I use an "old" Samsung Galaxy S3. Numbers I'll give will just be correct with this model. Please check on your device the values you are looking for.
When I removed the battery cell of my device, I found a little label that said the device should be powerd at 3.8V. I found the same number wrote on the battery cell. But when I looked on the power plug, I saw it dispense 5.0V. We will need to reduce this voltage in order to not damage the device.
We can see on the device four little pins. Two of them are the +/- poles to power the device. To know exacly which one does what, you can look on the battery cell. It should be + and - symbols in front of the right ones.
STEP 2: Gathering Parts for Assembly
First of all, we will need cable between the power plug and the device. Took an old USB -> micro-USB and remove the micro-USB head.
If you remove the plastic protection you will see multiple wire. We only need two of them : the red one and the black one.
Here comes the hardest part. In order to make a good contact between our wires and the pins on device we will use a part of the battery cell itself.
With thousand precautions, you can start to remove the plastic sheet protection around the battery cell. You will expose the part we need : the one with four contacts. On my model, this part was protected with a little piece of plastic that I removed with a small pliers. With a small blade, you can detach this little part. See pictures to spot it.
STEP 3: Welding Parts
Using all those parts, if I measure output voltage I found 4.83V (don't mind the Arduino, it's not even plugged). It's less than the 5.0 wrote on the battery cell but it is still a bit high and it can damaged the device.
You will have to weld the red and black wires on the little battery cell part. The cell itself can be use as reminder to know where plugged which wire.
After all of that, the output voltage is still a bit high but it will do the thing.
STEP 4: Power the Device
Ok, now you just have to put your assembly into your device. For my part, I used a small piece of cardboard to hold our it in front of the four pins.
Hold your breath and... Yay ! The device starts \o/ !
Thanks to the Ampere app, you can control the device input voltage. On mine, it displays 4.2V. It's a bit high but I don't think it will damage my device.
46 Comments
geordief 8 months ago
I have an old Samsung xcover4 and the battery has gone .Can I use any old battery that will fit in the space and that applies the same voltage?
What damage can I do to my phone?
PaulVdB 9 months ago
I have a Galaxy S4 with swollen battery (was on the charger for more than a year, I use this only as clock.)
Went on the internet for solution but nothing really worked. So I started experimenting and came to this WORKING solution :
manta10 4 years ago
He just wired another cell phone battery to pins in the battery compartment, charging it via standard micro usb connector, so no need for Arduino or step-down converter.
So frankly speaking I am looking for an adapter to let me use any 3.7V ion cell battery for any smartphone ( outside or inside mounted).
Let me know your opinion
jack
manta103g@gmail.com
trutrvl 1 year ago
cristian.sto97 3 years ago
bassbindevil 1 year ago
trutrvl 1 year ago
bassbindevil 1 year ago
praporabnik 1 year ago
Use resistor with value calculated to achieve desired delivery voltage. At the same time the source must also be capable of at least the current needed by the device plus 5% higher of that value. Higher than needed is not a problem. But lower than nominal is!
As in this case voltage needs to be lowered from 5V to 3.8V. Use a resistor lin linear positive wire and with the value calculated via Ohms law R=U/I. R1=5V/1A=5Ohms. R2=3,8V/1A=3,8Ohms and finally R3=R1-R2=5Ohms-3,8Oms=1,2Ohms (the one you should use here). To be sure... U(V)=R*I=1,2Ohms*1A=1,2V. Which is a drop we need to get 3,8V of 5V source.
HOWEVER! This current is not sufficient for most of the smart phones nowadays.
USE a charger or DC power supply with 2A or higher. THAN RECALCULATE THE VALUE OF A RESISTOR NEEDED.
In any case of source it should match the specified voltage of the device as much as possible, if not rather exactly in any way. Better be sure of that.
WARNING! Do not use a power supply with too high values or to much power. Ussualy a very powerful power supplies eve would not work in this way. Then it needs a different aproach. More safety issues and not intended for such low power loads. Use a max. of 12V and 3A. Or a bit higher if it so happens.
DISCLAIMER: This is a direct instruction for thisws case, this post. In fact there are many facts surrounding this area and to consider. I Included them in to consideration, but did not mention them.
As to the link between the other two pins of the battery connections and the values and dependancies. For one example...
The procedure in this post by itself is technically correct. And the least complicated way to achieve the goal.
This will totally suffice to get what you intended here. As for the procedure itself and instalation of it all, that is for everyone to decide as it fits.
Tukan2 1 year ago
JJ88 2 years ago
The method you've outlined above gives the current to the device without using a battery. I've found a small device named "almac combo of 5v 1A Micro Usb input for 3.7v 18650 Lithium Battery Charger With Protection Module, best for robotics DIY kit" which seems to be doing the same thing:
https://www.amazon.in/almac-Lithium-Battery-Protec...
If I connect the red and black wires of the Nook to this Almac device, will it power on the Nook, without a battery and without connecting it to its own wall charger?
:)
raymondday61 2 years ago
ankitbittumahilane 3 years ago
raymondday61 2 years ago
Or can use a transistor to turn the power off and on fast with a capacitor Charge up the static in the capacitor just some till it get's to the right volts.
Adam_is_stupid 3 years ago
Rodribs 3 years ago
BanditQ 4 years ago
Has anyone tried it on their Samsung Android ROM version and were there any disadvantages ?
Some reading on the web suggests laptops power switches in parallel (battery/DC power charger) which is why they run just fine without a battery, and the design for MOST smartphone is a series connect (battery+DC power) hence the need to connect something to where the removable battery connectors. Obviously you need a phone model with removable battery (eg older Samsung models). Does what I read sound right?
More reading on "Dr Google" suggested that peek current (Amp spike) may not be sufficient with just a standard usb charger DC supply connected to the battery terminals. I am not sure if this was meaning your typical 5V 500mA charger - most Samsung chargers like one used in this Instructable are 1A is that accurate?
The "peek use", typically at power on, is worth testing with a 500mA charger. For me, that second phone might be plugged into laptop port (=500mA), or I want to plug it in to the closest standard USB charger I have available which is not always the Samsung supplied charger (1A). The usage at home will typically be WIFI connected, and streaming with a Chromecast; or an extra skype voice call; so this is probably low chance of hitting peek (I assume). Would a peek use case be one or all of the following: phone call using mobile network (assuming available); screen casting (mirroring) your screen and then watching stream content (e.g. Youtube); Whatsapp/Skype/(any other VOIP app) video call with phone brightness on full. It would be interesting to know if phone would keep running under these conditions. I am basing these examples on times my phone battery could not cope.
cristian.sto97 3 years ago
Rahul Ramachandran 3 years ago
cristian.sto97 3 years ago