4200mAh Nexus 4 - second internal battery!

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tommmtom

Senior Member
Apr 19, 2012
106
133
Just thought I'd share a mod I've done to my nexus 4..
After smashing the back glass on my nexus 4 and getting tired of glass shards in
my pocket/hand every day I decided to make a new back for it (£50 for a replacement is a bit excessive..)
I thought I may as well try and add in another battery too, as I don't mind a thicker
phone and would always opt for a fatter phone with more battery if I had the choice..!

Now I have a 4200mAh nexus 4!!!


a837ad5e-1f1f-4bdf-a794-9ecfe4d5736c_zps7322ede9.jpg
68cefde5-4894-45e3-bc71-1550541b1f88_zpsf89fcb23.jpg


e9fa2311-6b60-4852-a1fd-50bdc6e17aa4_zpsabb90a05.jpg
88003452-fec7-486f-9d81-ee03d8c14640_zps02f3f194.jpg
95d92be4-ec0c-4055-80f4-39c882931cbf_zps49a65945.jpg



How To:

-Remove the battery cover, and remove all the glass from it (its a pain...so much glue...but easy with blade to slide under)

-Solder a wire to the positive of the battery connector (disconnect the battery) and a wire to the negative side. Leave them fairly long for now...then reattach the battery connector to the phone

-Peel off the NFC/wireless charging coils from the battery cover and put to one side

-Solder a wire to each of the 4 gold spring contacts that connect to the coils...leave these fairly long too

-Put the battery cover back on the phone making sure all 6 wires are sticking out the back

-Now put the second battery (I used a Samsung galaxy S3 battery, 2100mah 3.8v same as nexus 4 (and cheap)) in place on the back of the phone and fix it in place (double sided tape, hot glue..)

-Measure the voltage of the second battery and then measure the nexus 4 battery voltage and either charge or discharge the nexus 4 until the voltages of the two batteries are within about 0.05v of each other

-Solder the positive wire coming from the nexus 4 battery to the second battery positive contact, and negative to negative

-Put the coils on top of the second battery and fix in place. Then solder the 4 wires coming from the gold spring contacts to the correct contacts on the coils

-Now mark out a thick piece of plastic (I used 12mm Acetyl) so it fits in the step where the glass sat. Then use a router or similar to cut out a pocket for the second battery to fit. I shaped the back using a router, and finished it off with a belt sander.

5f05b4ec-432b-4235-b8fb-a65714a0e1e2_zps6ae85d9e.jpg




-Fix the new back part to the phone using something sticky (I'm going to re stick mine with sikaflex, but hot glue or double sided tape work!)

cbc81dad-0f88-4767-bdfb-46b707a9ef77_zps1c9d37dc.jpg





-Now enjoy over 7 hours of screen on time!!



________________________________________________________________________________________________

Original post:

Hi there, I'm hoping to add a second battery or single larger battery to my nexus 4.

Can anyone see any problems adding another battery in parallel with the current one? The charging circuits are built into the battery so I guess it should work.....
Also I'm thinking of putting in a higher capacity single battery...from a note 2 maybe or one of these case batteries
I'm not bothered about the battery cover part of the phone..I can get that sorted after its working :)
 
Last edited:

tommmtom

Senior Member
Apr 19, 2012
106
133
I doubt it's going to work. Different batteries for different devices. Have you looked under the hood to see how the N4 battery is connected to the phone? Zerolemon is making a external battery that will allow us to snap and connect as it rides on it's back. It'll be up for sale in May.

Sent from my Nexus 4 using Tapatalk 2

Yeah I have the back off (it was smashed so I'm making a new one!) And its easy to add in small wires to the connector to get a battery in parallel. I've ordered a 3.8v 2100mah battery which is here tomorrow and I'm going to try it :) as long as I have both battery voltages identical before connecting them in paralell, there shouldn't really be a problem as the voltages should stay identical & both have separate charging circuits!
Yeah I was reading the thread about the ZeroLemon cases yesterday, they should be good!
 
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tommmtom

Senior Member
Apr 19, 2012
106
133
Okay I'm running with a sgs3 battery (3.8v & 2100mah) in parallel, so now have a 4200mah nexus 4 :D I'm just finishing off wiring the wireless charging/NFC coils then I'll try and get some pics....
 

username8611

Senior Member
Jun 9, 2012
696
231
Rapid City, SD
Okay I'm running with a sgs3 battery (3.8v & 2100mah) in parallel, so now have a 4200mah nexus 4 :D I'm just finishing off wiring the wireless charging/NFC coils then I'll try and get some pics....

pics would be awesome, im curious about this alternative back you are using since you said the stock back shattered. also pics of the inside showing how you mounted it all would be cool. i would never do this but it sounds really interesting so if its too much of a pain, no biggie
 
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tommmtom

Senior Member
Apr 19, 2012
106
133
pics would be awesome, im curious about this alternative back you are using since you said the stock back shattered. also pics of the inside showing how you mounted it all would be cool. i would never do this but it sounds really interesting so if its too much of a pain, no biggie
What I'm doing with the back: I've taken all the glass off the plastic bit(the rubberised surround is part of this..) And where the glass was there is a step where it sat. I'm putting a thick back (Plastic) with the inside milled out for the sgs3 battery to fit. It will Be rounded and look a bit like the HTC one back :) then I'll wrap it in carbon fibre effect vinyl so it looks nice and professional!
 

tommmtom

Senior Member
Apr 19, 2012
106
133
Battery life is epic......4 hours screen time with full screen brightness after 24 hours off charger!!!! Only problem is that the battery meter goes down as usual (same speed) but stops around 20% (~3.8v) and stays there for aaaaaages before starting to drop again....
There is a file in sys/class/power_supply giving the full capacity of the battery (2100mah). Is this used to calculate percent? I might try changing it to 4200 and see if I get better readings....
 

tommmtom

Senior Member
Apr 19, 2012
106
133
Battery just died... 7hr 15min screen time after nearly 35.5 hours off the charger :)))

Its actually really easy...only hard bit is getting a back cover to fit over the extra battery...3D printer would be nice
Cost me £5 for the battery & £3 for the plastic (acetal) block the back is made from!
I will get some pics of the back when its finished properly :)
 

Domenl

Member
Mar 18, 2013
17
5
Maribor
Could you use any other phone battery? As I have some old smartphones laying around. Might try get into this mod as I never say no to more battery life.

Sent from my Nexus 4 using xda premium
 

tommmtom

Senior Member
Apr 19, 2012
106
133
Could you use any other phone battery? As I have some old smartphones laying around. Might try get into this mod as I never say no to more battery life.

Sent from my Nexus 4 using xda premium

Yep i guess you could...each battery has its own protection circuit in so the batteries can't over charge etc
I will whack some pictures up of my neuxs tonight...its all done now :)
 

paul c

Senior Member
Nov 15, 2006
1,696
526
Madrid
Nice one! Another option is to buy a 5000mAh battery pack, a good one like NewTrent often costs $25 - price varies quite a lot for some reason. It's a black rectangle about as big as the phone, and you just connect from the USB port to the phone with a normal charging cable. And you charge it up from a PC/wall charger.

Obviously a bit messy when you actually have to connect, but when you are not charging the phone is still the original size.

Hope I didn't spoil the fun :)
 

Domenl

Member
Mar 18, 2013
17
5
Maribor
That would break this in the root. We are trying to add a battery not charge the existing one. I own a 12000mAh battery but this is very interesting as it would improve the battery capacity directly.

Sent from my Nexus 4 using xda premium
 
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  • 71
    Just thought I'd share a mod I've done to my nexus 4..
    After smashing the back glass on my nexus 4 and getting tired of glass shards in
    my pocket/hand every day I decided to make a new back for it (£50 for a replacement is a bit excessive..)
    I thought I may as well try and add in another battery too, as I don't mind a thicker
    phone and would always opt for a fatter phone with more battery if I had the choice..!

    Now I have a 4200mAh nexus 4!!!


    a837ad5e-1f1f-4bdf-a794-9ecfe4d5736c_zps7322ede9.jpg
    68cefde5-4894-45e3-bc71-1550541b1f88_zpsf89fcb23.jpg


    e9fa2311-6b60-4852-a1fd-50bdc6e17aa4_zpsabb90a05.jpg
    88003452-fec7-486f-9d81-ee03d8c14640_zps02f3f194.jpg
    95d92be4-ec0c-4055-80f4-39c882931cbf_zps49a65945.jpg



    How To:

    -Remove the battery cover, and remove all the glass from it (its a pain...so much glue...but easy with blade to slide under)

    -Solder a wire to the positive of the battery connector (disconnect the battery) and a wire to the negative side. Leave them fairly long for now...then reattach the battery connector to the phone

    -Peel off the NFC/wireless charging coils from the battery cover and put to one side

    -Solder a wire to each of the 4 gold spring contacts that connect to the coils...leave these fairly long too

    -Put the battery cover back on the phone making sure all 6 wires are sticking out the back

    -Now put the second battery (I used a Samsung galaxy S3 battery, 2100mah 3.8v same as nexus 4 (and cheap)) in place on the back of the phone and fix it in place (double sided tape, hot glue..)

    -Measure the voltage of the second battery and then measure the nexus 4 battery voltage and either charge or discharge the nexus 4 until the voltages of the two batteries are within about 0.05v of each other

    -Solder the positive wire coming from the nexus 4 battery to the second battery positive contact, and negative to negative

    -Put the coils on top of the second battery and fix in place. Then solder the 4 wires coming from the gold spring contacts to the correct contacts on the coils

    -Now mark out a thick piece of plastic (I used 12mm Acetyl) so it fits in the step where the glass sat. Then use a router or similar to cut out a pocket for the second battery to fit. I shaped the back using a router, and finished it off with a belt sander.

    5f05b4ec-432b-4235-b8fb-a65714a0e1e2_zps6ae85d9e.jpg




    -Fix the new back part to the phone using something sticky (I'm going to re stick mine with sikaflex, but hot glue or double sided tape work!)

    cbc81dad-0f88-4767-bdfb-46b707a9ef77_zps1c9d37dc.jpg





    -Now enjoy over 7 hours of screen on time!!



    ________________________________________________________________________________________________

    Original post:

    Hi there, I'm hoping to add a second battery or single larger battery to my nexus 4.

    Can anyone see any problems adding another battery in parallel with the current one? The charging circuits are built into the battery so I guess it should work.....
    Also I'm thinking of putting in a higher capacity single battery...from a note 2 maybe or one of these case batteries
    I'm not bothered about the battery cover part of the phone..I can get that sorted after its working :)
    9
    It's the other way around. If you wire them in parallel, you double the current. If you wire them in series, you double the voltage.
    8
    Sorry but i dont need it ... My nexus 4 stats are.

    2d 10h + 5 h screen.

    The rest of us use our phones. Why even post here?
    8
    First of all, you're brilliant
    You gave me the idea of trying this, then I remembered I work in an electronics shop at a University, and we have a 3D printer
    Printing off a back right now
    If anyone is interested in the results I'll post when I am finished
    8
    man....watch your language!!!!
    i haven`t insulted anybody!
    if u want i can start right now...but i`m sure mi IQ is way better than this!so...please watch your language!!!

    Mi IQ. Gold!
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