[Q] how to run a phone without battery only by connecting charger

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Shrihari007

Senior Member
Apr 17, 2012
574
263
I think the question may be silly but I want to know the procedure for this. can I run the phone directly by connecting only charger and removing the battery...as I keep for downloads of movie over 3g it drains battery damn fast and if its kept charged the battery looses its power. so plz help me out.
 

speedee12

Member
Sep 14, 2010
39
13
Did you ever sort this out? I am looking to do the same thing on the same phone shortly. I previously did this on a few galaxy s2 and those were simple 2 wire removable battery replacements. This will be different being internal and only having 2 wire from the factory.


3.7v doesn't seem to work, even though the battery I'm trying to emulate has only 2 wires.

I have a Moto E 2nd gen model # 1526. The battery is 'non-replaceable' and there are only two wires emerging from the battery that connect to the phone. I can't post links, but if you google XT1526 battery you should see what the thing looks like. Anyway, because there are only two wires connected to the phone, I was under the assumption that simply applying ~3.8v across those two wires (with sufficient amperage) would allow the phone to work. Short answer, it doesn't, and I don't know why or what to do. Long answer:

I purchased a meanwell 150W PSU capable of supplying ~3.2 to 4.2V and controlled by potentiometer. Using this PSU, a breadboard, voltmeter and connectors, I tried operating the phone by supplying ~3.7 through ~4.2V directly into the battery connector, with no luck. I did notice a short voltage drop when trying to power on the phone. The screen would light up briefly (nothing displayed) and then shut off.

Next step, I disassembled the top of the battery and found a small, thin PCB. This board is wired directly to the battery outputs, and has a couple of surface mount things soldered onto it, and also has the two tiny output wires and battery connector that connects to the phone. I then tried wiring the Meanwell PSU to this board where the battery outputs connect, and then connected the battery connector to the phone, and applied the same range of voltage. Still no dice.

So it doesn't appear to be as simple as voltage/current, but I'm not sure what else to try. I have a test PSU from a computer than can supply 5v, 7v, 12v, but those don't seem likely to work, because that would mean that the tiny PCB in the battery is a voltage rectifier, and if that were the case, it seems to me that it would overheat.

Any ideas/suggestions?
 

Samcomeau

New member
Aug 7, 2018
2
0
I sort of know.

So some phones work without the battery on just the charger, but not many. What you have got to do is connect 3.7-4.2 to the battery terminals. This works for some phones, confirmed on original galaxy s. All phones have a battery management system (the middle 1-2 pins). Some phones refuse to start without a proper BMS signal. This may vary between phones and manufacturers. It may be as simple as connecting a resistor to ground. I'm going to try this right now and get back to you.

3.7-4.2V to pins, no other action(confirmed) :
Galaxy S, Samsung moment (seems to work well with three terminal devices)
 
Last edited:

Samcomeau

New member
Aug 7, 2018
2
0
3.7v doesn't seem to work, even though the battery I'm trying to emulate has only 2 wires.

I have a Moto E 2nd gen model # 1526. The battery is 'non-replaceable' and there are only two wires emerging from the battery that connect to the phone. I can't post links, but if you google XT1526 battery you should see what the thing looks like. Anyway, because there are only two wires connected to the phone, I was under the assumption that simply applying ~3.8v across those two wires (with sufficient amperage) would allow the phone to work. Short answer, it doesn't, and I don't know why or what to do. Long answer:

I purchased a meanwell 150W PSU capable of supplying ~3.2 to 4.2V and controlled by potentiometer. Using this PSU, a breadboard, voltmeter and connectors, I tried operating the phone by supplying ~3.7 through ~4.2V directly into the battery connector, with no luck. I did notice a short voltage drop when trying to power on the phone. The screen would light up briefly (nothing displayed) and then shut off.

Next step, I disassembled the top of the battery and found a small, thin PCB. This board is wired directly to the battery outputs, and has a couple of surface mount things soldered onto it, and also has the two tiny output wires and battery connector that connects to the phone. I then tried wiring the Meanwell PSU to this board where the battery outputs connect, and then connected the battery connector to the phone, and applied the same range of voltage. Still no dice.

So it doesn't appear to be as simple as voltage/current, but I'm not sure what else to try. I have a test PSU from a computer than can supply 5v, 7v, 12v, but those don't seem likely to work, because that would mean that the tiny PCB in the battery is a voltage rectifier, and if that were the case, it seems to me that it would overheat.

Any ideas/suggestions?
You may have already tried this, but modern smartphones use over an amp of current on startup. Have you tried cranking up the current limit? 1.5A should be enough, assuming no battery to draw current. It seems very unlikely (but possible) that the battery is communicating via the power pins. That PCB you saw was the battery protection circuit. Every single lipo has one to prevent it catching on fire. If you hooked up to the battery output at 3.7-4.2V it should have no way of knowing your PSU is not a battery. Either you don't have the current or something is broken.
 

Vipindasu

Member
Aug 12, 2018
5
3
Samsung phone switch on only while external power is given

For accomplishing this task,
1) Download the "Auto Boot On Power" app from packagedisabler.com website to your phone.
2) Install the app.
This is a great service from packagedisabler team which allows android users to enjoy this amazing feature which was earlier
available only to the iphone users.

Use case: In showrooms and exhibitions, all the devices can be switched on and shut down easily.
output_wbSCk7_1000x1500.gif
 
Last edited:

zeroFILL

Member
Mar 26, 2009
33
1
For accomplishing this task,
1) Download the "Auto Boot On Power" app from packagedisabler.com website to your phone.
2) Install the app.
This is a great service from packagedisabler team which allows android users to enjoy this amazing feature which was earlier
available only to the iphone users.

Use case: In showrooms and exhibitions, all the devices can be switched on and shut down easily.
Thank you so much for sharing! But I wonder if there's a solution to fix the battery's percentage instead, so the phone won't turn off. Any ideas?
 

eGuru_new

Member
Dec 10, 2016
18
4
Does the "Auto Boot On Power" app work with non-Samsung devices?
Does it work with tablets?
Is it only useful when charging through the micro-USB port or does it work when the device has a dedicated charging jack?
 

kgbme

Member
Jun 27, 2017
28
4
45
Belgrade
Just btw., how difficult would it be to have the battery /hardware recognize when charge capacity is at 100% and have it switch-over to a mechanism that powers the device directly.

Likewise, such a system should allow for a mobile device to function normally w/o a battery, as there are decades-old laptop computers which can do the same.. I don't get it, whatever. :/

Same as with having: universal 1) batteries and /or 2) print cartridges (refillable, as well, ofc.)

By now, we would have: 1) absolutely amazing (!), brilliant battery technology, if it weren't proprietary and 3rd-parties were able to manufacture batteries for all sorts of devices and be able to invest profits into r&d and 2) probably, world-wide pollution numbers could decrease by (some crazy amount, like) 1% if all, those, obsolete cartridges weren't being discarded.

Not meaning to mix apples and oranges, but the cause and effect is completely the same: a) greed and b) failure, blah! :f
 
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Gegga

New member
Jan 14, 2015
3
1
Try this, i would say it works for most of the Sony Xperia series. only a guess, i have tested only Sony X10, Xperia E, Xperia Z1, Z2. for other models or even poket wifi etc, i would say they are working in the similar way, worth trying. again at your own risk.

do in this way, 3pins on the battery power connector inside the phone, connect the plus to the USB charging port plus(that 5v) - this is because i dont want extra cabling inside the phone, reuse the charging connector on the phone as power supply instead of charging. between the middle pin and the minus , connect a 20-30k resistor, connect the usb charging cable, connect the cable to a 5V power source. the phone will boot without a battery. monitor the fake temperature of the battery shown by a battery monitor app, need to be between a normal working temperature), try and adjust the value of the resistor if necessary.

-snip-

happy to share this experience with anyone interested and good luck to everyone coming across this problem.

Thank you! For anyone coming here looking for this solution I can confirm it works very well (model Sony E4G). I connect USB power to where battery power was, but have gone the more complicated way of powering with separate psu @ 4,3 Volt. Can confirm that the phone thinks it's charged and stays at 100% without reducing clock frequency. Without the extra wire between usb connector and battery/ power in the battery percentage reduced to 1% and clocks reduced to 936 MHz.

A prettier solution would have been to power with USB port which should work with the bridge between usb power and battery power. Beware that I only tested with 4,3 - 4,4 volt.

update 2020-12-23: Sadly this solution has stopped working, no idea why.
 
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    @zeroFILL Here's how to fix the battery percentage going down:
    -You have to be rooted
    -Use the terminal emulator app
    -Type SU (switches from $ to #)
    -Type this command to keep the phone at 100%
    dumpsys battery set level 100
    -Type this command to tell the phone that the charger is plugged in
    dumpsys battery set usb 1

    Everytime you reboot it reverts to stock settings. So I use a tasker script that runs the above commands on every boot.
    I've only tested all of this on an htc desire 510 running 4.4 so these may or may not work on your device.

    ---------- Post added at 12:41 AM ---------- Previous post was at 12:37 AM ----------

    What I'd really like to know is if anyone knows how to still use the USB port to power the phone (instead of hard-wiring to the battery terminals)? There has to be a combination of jumpers, or a resistor to mimic a fake battery, so that we can still use a standard cable and the normal phone connector. Anyone have any ideas?
    (Right now I have it working but I had to drill a hole through my back cover and splice a micro usb cable, so I'm hoping for a cleaner method).
    2
    Samsung phone switch on only while external power is given

    For accomplishing this task,
    1) Download the "Auto Boot On Power" app from packagedisabler.com website to your phone.
    2) Install the app.
    This is a great service from packagedisabler team which allows android users to enjoy this amazing feature which was earlier
    available only to the iphone users.

    Use case: In showrooms and exhibitions, all the devices can be switched on and shut down easily.
    output_wbSCk7_1000x1500.gif
    2
    For Sony Xperia Series Hardware

    Try this, i would say it works for most of the Sony Xperia series. only a guess, i have tested only Sony X10, Xperia E, Xperia Z1, Z2. for other models or even poket wifi etc, i would say they are working in the similar way, worth trying. again at your own risk.

    do in this way, 3pins on the battery power connector inside the phone, connect the plus to the USB charging port plus(that 5v) - this is because i dont want extra cabling inside the phone, reuse the charging connector on the phone as power supply instead of charging. between the middle pin and the minus , connect a 20-30k resistor, connect the usb charging cable, connect the cable to a 5V power source. the phone will boot without a battery. monitor the fake temperature of the battery shown by a battery monitor app, need to be between a normal working temperature), try and adjust the value of the resistor if necessary.

    Pay attention to these :

    1. if you think apply 5v power source to a 3.7v battery plus pin, it will damage your phone and make you feel uncomfortable, dont try this at home. you can try 3.7v-4.0 with extra power wiring inside the phone.

    2. phone requires very high current(300mA - 1.8A) and varies all the time compared to that a normal charger can provide, dont expect it will boot if u use a "ebay charger" or a PC USB port. i would say , most of the ebay chargers,if not all, will not be able to boot up a phone for current's sake regardless what they claim or be printed on the description. USE A RELIABLE HIGH CURRENT STEP DOWN CONVERTER, get from a powerful and reliable power source (a laptop power charger 19v, up to 3A, for example), keep monitoring the current when you boot the phone. Any car cigarette lighter socket normally can provide enough current, if it fails to boot, check the current your step down converter can provide. The step down converter i m using is just about $6-$7. not expensive one but need to find the right one(i bought more than 10, but only one useful for this purpose, they are all cheap $1-$10).

    i came across this issue when i started making my own car onboard GPS system by using an old Sony Xperia X10, then Z1, then later, tested E and Z2 for fun . currently my system evolves to an Android X86 on a normal PC platform bluetooth, wifi and onboard video recording system connected. its all just for fun.

    if you are looking for making your onboard phone boot with the engine key, dont need to worry too much about the switch on off, battery charging etc., Another idea is to use or modify a voltage step down converter(12V->5V), make its output voltage vary , say 3v-5.5v by a potentiometer (get it from an old PC speaker), then connect it to the onboard phone as a charger, you dont need to modify you phone, just change the charging voltage so as to the charging current, that means charging the phone while using the phone. if u charge more than you use , then the battery will increase when u drive,if u lower the voltage, the more u drive the more the battery decreases. u never need to take out the phone to charge. of course, you need to automate the phone on off with the engine key, to boot up GPS application automatically etc. i found this very interesting, currently an Xperia Z is running in this way, i found you need to adjust the charger voltage only once for months. theoretically, you have a balance point, always can make when u drive you car, keep the charging equal to your phone using.

    happy to share this experience with anyone interested and good luck to everyone coming across this problem.
    1
    Just btw., how difficult would it be to have the battery /hardware recognize when charge capacity is at 100% and have it switch-over to a mechanism that powers the device directly.

    Likewise, such a system should allow for a mobile device to function normally w/o a battery, as there are decades-old laptop computers which can do the same.. I don't get it, whatever. :/

    Same as with having: universal 1) batteries and /or 2) print cartridges (refillable, as well, ofc.)

    By now, we would have: 1) absolutely amazing (!), brilliant battery technology, if it weren't proprietary and 3rd-parties were able to manufacture batteries for all sorts of devices and be able to invest profits into r&d and 2) probably, world-wide pollution numbers could decrease by (some crazy amount, like) 1% if all, those, obsolete cartridges weren't being discarded.

    Not meaning to mix apples and oranges, but the cause and effect is completely the same: a) greed and b) failure, blah! :f
    1
    very helpful

    this forum thread was helpful! :) thanks!