Smartphones are very power hunger. Stock battery will last at most one day or less under normal usage. This guide will show how to double the battery, double time, double fun.


Playing with Lithium-ion battery has some risk. If you don't have the basic skill and knowledge, STOP!

Modifying Lithium batteries might violate laws in your country or region. It's all your own responsibility!

FAQs (possibly)

Q: Can I mix batteries, one new and the other old?

A: Short answer: YES! Long answer: Google it.

Q: Can I do this on non-Samsung phone/battery?

A: Yes. This Samsung Galaxy S Duos / S7562 is just an example. Almost any phone, which you can cut or rebuild the back case, can load more batteries than it's designed to.

Q: The best way to balance voltage between batteries?

A: My opinion: Discharge them to below 3.5V or use them until auto cut off. discharged battery has higher impedance and less energy, both are good for safety.

Q: What should I do when SHTF?

A: (not likely to happen if you follow this guide) Cut the wire if you have time and right tool. Drop the batt into water and step back. Inform people nearby. Do not touch the batt until it cooled off.

  1. Phone Battery Doubling Technique, Phone Battery Doubling Technique: 步骤 1 中的图像 1,1
    • WARNING: Soft-shell lithium-ion batteries are fragile. Damaging the batteries may result in spontaneous combustion.

    • First things first. Double batteries to double the capacity. There's no magic!

    Safe, retro-fitted double battery packs are sold. These safely enable two batteries to be soundly, neatly carried contiguously and, used consecutively by the phone. I'm astounded this dangerous, disreputable, frankly insane method is being demonstrated and recommended here. No. It is inadequate and disingenuous to state this method is being shown for informative/educational purposes. That is like Tucker Carlson saying he only asks questions and, what is wrong with asking questions ... ?

    Mrs. Cairns - 回复

    Why bother to ask me to provide a unique user name, only to use my actual name for display purposes? Has any other user had this experience on this website?

    Mrs. Cairns -

    This madness being displayed by iFixit is doubly disturbing. With one page iFixit has drastically reduced its credibility. Thereby allowing any company to use it as an example of why THEIR products really should not be repaired with advice and/or instruction from iFixit. Undoubtedly, there are many, many companies who are privately furious that the game of built in exclusivity/obsolescence, is finally moving into its end stage. They can claim that Oh Yes, they DO believe reducing consumer waste by allowing easier domestic repair and increasing product longevity, is a Great Idea ... But, consumers really ought to wait until THEIR company produces The Correct Models, instead of simply Attempting Dangerous Domestic Repairs/Mods. These companies can then state that naturally, in keeping with the Reduce, Reuse, Recycle ethos, what better way to help ecology in the meantime, than continuing to buy THEIR products which, decreases waiting time for the (secretly putative) release date of The Correct Model/s?


    Mrs. Cairns - 回复

    Fellas. This is a very old guide. Very likely obsolete. Modern smartphones have internal batteries very difficult to access, and parts gets ridiculously tinier and tinier. It's very not recommend to practice this guide if you are not a skilled DIYer or electronics guy. Please, be safe.

    Thank you for your support for years!

    -- The author

    Terrance - 回复

  2. Phone Battery Doubling Technique: 步骤 2 中的图像 1,3 Phone Battery Doubling Technique: 步骤 2 中的图像 2,3 Phone Battery Doubling Technique: 步骤 2 中的图像 3,3
    • Peel skin off, but not all the way off, from ONE battery.

    • Slice some skin off from the other. both sides. Until the black plastic PCB cover and be easily removed.

  3. Phone Battery Doubling Technique: 步骤 3 中的图像 1,1
    • Put 2 batteries together and aligned, belly to belly. Bind them with the peeled skin.

    • Not too tight!

    • Remove both black plastic PCB covers.

  4. Phone Battery Doubling Technique: 步骤 4 中的图像 1,2 Phone Battery Doubling Technique: 步骤 4 中的图像 2,2
    • Before bridge 2 batteries together, ensure voltage difference between them less than 50mV. New batteries will very likely have about 3.9V voltage, and varies very little.

    • Bridge one B+ to anotherB+ first. Use soldering iron and solder.

    • Then, P- to P-.

    • Leave Both B- open!

    • One more WARNING! Be very careful with B- test point. DO NOT MESS WITH THEM. B- are not protected by "Protection Circuits". Do NOT bridge B-, unless you know what you don't know!

    • Of course. NEVER short-circuit any B- to any B+, or P- to B+, or P- to B-!

  5. Phone Battery Doubling Technique: 步骤 5 中的图像 1,2 Phone Battery Doubling Technique: 步骤 5 中的图像 2,2
    • Cut 2 notches on each plastic PCB covers. At the position of bridging wires, and faces each other. So the wires won't lift the PCB covers.

    • These are not quite finished.

    • These are what I'm talking about.

    • Put both PCB covers back. If you bond batteries too tight, may need to loose a little bit, then tighten again later.

  6. Phone Battery Doubling Technique: 步骤 6 中的图像 1,1
    • Use the skin of the peeled bat to fully bond them.

    • Cover the notches and wires with some tape. Shown PI/Kapton tape will be the best choice, anything thin enough and isolate is ok.

    • The skin is a little short for 2 cells. The exposed metal should be covered also. They are the positive terminal. You don't wanna short-circuit something, do you? (not yet covered in these photos)

  7. Phone Battery Doubling Technique: 步骤 7 中的图像 1,3 Phone Battery Doubling Technique: 步骤 7 中的图像 2,3 Phone Battery Doubling Technique: 步骤 7 中的图像 3,3
    • Double battery vs single battery. :-P

    • The back case won't fit double battery. Cut them the way you like.

    • (Not quite) Finished. Maybe I should 3D print some extra cover and glue it to the back case.

    • Actually I did 3D print a frame, and glued a trimmed RFID card as back cover. They work well!


Double power, double juice.




6,193 声望



Good idea thanks :)

kaandonmeztf - 回复

Wow, i dont see pages like this anywhere else, i have a xolo phone, in india, its battery dosent have any b+/- or p+/- terminals, it just has + - and the middle one, can i wire + and - in parellel to get the doubled MAH?

Inzemam Zahidi - 回复

No no no thats is doubling the voltage and mah u just want to double mah. Because u double both and u now have a fried phone

jeremiah gyles -

In parellel, but only if two batteries are within very few mV of each other. They MUST be same mAH, or you will kill lower rated battery. First cut thin plastic or fireproof cardboard spacer, and place it between cells. Tape alined cells. Desolder top charging board from battery. Remove black plastic from top cell. Solder tabs + to +, then - to -. Nip lower black plastic, so tabs can fit under single charging board. Cover top battery tabs with tape or hot glue. Install pack same as you would single battery. Plug in phone charger. Fully charge battery pack, and enjoy. You now have a 1S2P 3.7 LiPo battery.


- Александр Борисович Мельников

Александр Мельников -

My battery hasn't got any b+ pin under the cover. Instead, it has p+ p- and b- pins.

What should i do? Should i connect p- to p- and p+ to p+? Or mine has a different way of doubling procedure?

hakansonmezz - 回复

Most LiPo cells have + and - markings below tabs. Follow instructions i posted, and you should be fine. Your phone will only read one BMS (charging board), so you don’t want two sending mixed information to your phone.

Александр Мельников -

in most Li-Ion/Li-Po batteries, B+ is P+. P- is switched by 2 N-MOSes to B-.

Terrance - 回复

No p+/- or b+/- minus indicted on each circles how can I locate the correct one

Please help. Thanks a lot.

Lloyd Edwin - 回复

how about you guys upload some photos of your batteries, if having trouble finding the right pads/pins. :-P

Terrance -

@Terrance, thank you; I’d forgotten about temperature sensing and identification.

I’ll have to do a dumpsys battery to see what info the OS is seeing from the combined battery.

I have paralleled one wire (other than the -ve line) and this seems to enable the NFC antenna (mounted on the S5 battery) to work

Richard WW -

please help me find the pins :) some foto i made http://lancercz.imgur.com/all/

LancerCZ - 回复

:-S "LancerCZ's images are not publicly available"

Terrance -

It should work now :) sorry

LancerCZ -

Sorry, I can't tell exactly which pad is which. But you can always combine 2 batteries by output contacts, +to+, -to-. And remember use as few solder as possible to avoid ruin the contacts too much. These gold plated contacts are very easy to solder.

Terrance -

It looks OK but what will happen when you charge the batteries??! Is there any risk that the batteries will explode?

Also, is the charger able to charge this double battery?

Ma Ro - 回复

1. Nothing is 100.000% guaranteed 'safe'. Even stock Galaxy Note 7s explode. But if you know what u'r doing, and do it right, it will be safe enough.

2. Yes, a stock charger is able to charge double battery. It take ~2x time to charge them full.

Terrance -

Awesome! I have weekend project! Thanks for your great tutorial!

Redd Z - 回复

any feedback from people who have done this?

Lawrence S - 回复

Wonderful tutorial, what of doubling 4 pin Samsung battery

henry salvatore - 回复

for 3-pin or 4-pin batteries, only tie + and - pins. (very likely the first and the last pin. Do NOT manipulate other pins, or temperature sensing or battery ID will be ruined.

Terrance -

I did this a while back, but the phone wont regognise the higher mah and battery meter runs down as normal, when it says the battery is flat i disconect and reconnect the battery and im back to full charge. any ideas how to fix this.

I have an s3 mini running on 20 18650 li ion batterys, lasts for ever as long as i restart the phone when it says its flat.

Simon Saddler - 回复

Hi! I was thinking of doing just that for my S2 (maybe turn it into a mobile 3G hotspot, with an USB-powered fan + CNC-milled heatsink around the camera/CPU area. So, even if I had 2+ Samsung 18650 batteries (the 2.9Ah ones), the phone would “die” / require a restart after it runs through 1.6Ah of the power???

BlackDoomn -

Can i do it with lg g3 ??

zaheer abid - 回复

i saw some zero lemon batteries for g3 on the internet. of course you can. i have a long weekend so maybe ill give this a shot. i have 4pins batteries tho,

jake esguerra -

Yo thanks for the info! it's very helpful, i'll try this later. One question tho. does this work on all types of 3 pinned batteries? I have 2 batteries for my phone and i HATE charging them one at a time .Any response will be appreciated!

Jan Talape - 回复

for 3-pin or 4-pin batteries, only tie + and - pins.

Terrance -

wonderful, i have a question. if my phone stock battery is 2000mAh if i connect both battery as you showed. will my phone recognized the higher mah like 4000mAh on phone display? or it will say 2000mAh like before ?

menafa siam - 回复

if you tie P- to P-, It will still report 2Ah, and measured current consumption will be 1/2 of real value. If you tie B- to B-, it might report 4Ah, but not for sure.

Terrance -

sir if i connect 1 battery 2000 mah and other is 4000 mah of other company then what will happen

zeshan - 回复

Short answer: yes. Long answer: the 4Ah might be fake or mis-labled.

Terrance -

Awesome job done. I have a damaged Nexus 7 battery (the pbc is dead but the battery pack itself still retains charge) I'll try to bridge directly the battery ports and see it that works.

Alan W. G. Meraz - 回复

My battery has p- p+ b- , which one will i leave open? Thanks

mervin marcelino - 回复

must connect p+ to p+, and either one or both (p- to p-) and (b- to b-) works well enough. with tiny little bit technical difference.

Terrance -

Great battery.

Filbotres - 回复

Wonderful! Extended batteries are available but often pricey. For phones with removable batteries, this is a very good solution to double up multiple spare batteries and extend life/usefulness of your phone. Thanks!

coldspring21 - 回复

Hi Terrance,

I checked under the cover of the battery but i can’t locate the PCB. Please for advice.. can i connect only + and - pins which are visible on the picture ?

Veli - 回复

Hi Terrance,

I can’t locate the PCB under the cover of my cell battery. Can i connect only the + and - which are visible on the picture and still get the double capacity ? Please for advice. txh


Veli - 回复

nice work , what if i want to combine the original samsung battery with a some LIPO cell that can be found inside laptop batteries

i mean .. these cells doesn’t have B+ or B-

how it’s going to work ?

Ahmad Tarek - 回复

Would it be crazy to add an external battery to a phone (like iphone) routing two cables to the outside of the phone and soldering them to the outside battery on the correct poles? Thanks!

pere carrizo - 回复

isn’t a powerbank a better choice?

Terrance -

@Terrance, I don’t think a power bank is a good idea here. All they can do is ‘charge’ the battery and in my experience they

barely keep the mAh from falling when the phone is in use, let alone putting more charge into the battery.

I think what pere carrizo wants is to ‘run’ the phone, possibly without even a battery present, bypassing the charging logic completely.

I’d like to see a variation on this idea: provide connectors for a 9v(?) battery, which you attach temporarily in parallel with the

extant, so you can change the battery without having to reboot the phone. What this’ll do to the Coulomb-counting, I don’t know.

Richard WW -

can we tripple them

Dang Dao - 回复

sure … XD

Terrance -

I’ve just successfully paralleled two Samsung Galaxy S5 batteries. It works but it’s too early to tell what the additional capacity will be in practice.

The voltage of the two batteries reported by my DVM is 4.8v (!)

I couldn’t relate the pin names to what I could see under the PCB cover, so I soldered the two + terminals

together with a solder blob. I also connected a wire between the two negatives (pin 3; there are four pins)

On this model, the NFC inductor is laminated to the battery to get it as close to the outside world as possible; I got this working

as well by removing the NFC inductor from the “inner” battery and wiring together one of the other pins, so as to connect it to the

outer battery. I’ll try and get some pictures but I don’t know to upload them in comments.

I am also going to try and put in an aftermarket wireless charging pad. I’ve had one before, but the thicker battery in this case will

change the geometry a bit.

Richard WW - 回复

I have a cell phone that isn’t charging - and no new batteries are available. I’m going to try to jumper through the case via a long wire that I can connect indirectly to an external charger. It’s 800ma. I am planning to use a second battery as a terminus and place that in the charger as needed or even long term as the charger has over-charge protection. I expect the original battery voltages to be lower - but I think the innate resistance of the original battery will prevent over-charging, and an equilibrium balance will just find itself without any rush of current, b/c al the potential max voltages are safe, all the potential max charging amperages are safe, and nothing evil can happen. The power genie is safely bottled up. I only expect the new battery to heat up based on current draw from phone as it does normally.

iOn-Christopher DiMeglio - 回复

i have 1200mAh. 3,8V asus a400cg battery combine with my 2200mAh. 3,8V lenovo battery. it work well!! 8hours last for nonstop activities, before then it just last for 3-4hours only.

next day, i accidentally short-circuited my lenovo battery. does it reduce the battery current power??

now it feel like im using 2000mAh power only ;(

smeogla - 回复


By connecting in parallel we are practically increasing the current. wouldn't that be injurious to the PCB itself?

Sunday Michael - 回复

What if we only connect the +ve and -ve terminals?

Cyber Quicksilver - 回复

Putting the cells in series does not increase the mah capacity it only increases the voltage!

This hack is very dangerous…accidentally short circuiting a li-ion battery can cause it to explode!

I think it is out of character for ifixit to support this kind of hacking!

Armand Francoeur - 回复

Sir. Is it gonna work on realme 2 pro! I mean the batteries, if I bought two realme batteries? Thinking bout doin something weird

Ojimin Yao - 回复

Can we do the same for iphone

Lerin Sebastian - 回复

Can wie try that with an Iphone too (Iphone SE 2016). I have two quite fresh batteries and I would like to combine them. After all I’ve seen it seems to be a totally different thing with an iphone.

bernhardschaller - 回复

Hi. I have samsung S10e and 2 original batteries, 3000 mAh, both 2 yo and capacity is 2300 mAh now. I buyed one used and one is in my phone. How to add or join togerher 2 same batteries to work normal? Keep one controller and which wires to solder?


Ivan Martinko - 回复

"FAQs (possibly)

Q: Can I mix batteries, one new and the other old?"

NEVER! Always use new cells with same voltage when connecting parallel. If not fire hazard, atleast new battery degrades way faster than normally.

ken villa - 回复

hmm, technically and scientifically you can (mix lithium-ion batteries in parallel, not in series).

Terrance -

This has got to be one of the most irresponsible things I've seen in a long time. If one needs to be shown how to do this, it should not be attempted. This is why bomb disposal is not a 10min tutorial.

Martin Cairns - 回复

Thanks for your reminding. This is really a very old guide written back in 2015, not much practical these days.

Terrance -



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