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Phone Battery Doubling Technique

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  1. Phone Battery Doubling Technique, Phone Battery Doubling Technique: step 1, image 1 of 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!

  2. Phone Battery Doubling Technique: step 2, image 1 of 3 Phone Battery Doubling Technique: step 2, image 2 of 3 Phone Battery Doubling Technique: step 2, image 3 of 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: step 3, image 1 of 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: step 4, image 1 of 2 Phone Battery Doubling Technique: step 4, image 2 of 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: step 5, image 1 of 2 Phone Battery Doubling Technique: step 5, image 2 of 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: step 6, image 1 of 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: step 7, image 1 of 3 Phone Battery Doubling Technique: step 7, image 2 of 3 Phone Battery Doubling Technique: step 7, image 3 of 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.

118 other people completed this guide.


Member since: 11/17/09

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17 Guides authored


Good idea thanks :)

kaandonmeztf - Reply

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 - Reply

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 -

Actually, paralleling batteries. Does not necessarily require them to be same capacity (if within reasonable range, e.g. 1Ah + 3Ah, is ok, 500mAh + 100Ah, probably not). But requires them be same voltage spec, 4.35V // 4.35V is ok, 4.35V // 4.25V is not good.

Terrance -

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