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iphone external backup battery DIY with old nokia batteries as cells? Answered

i wanna charge my iphone via diy backup battery made from old nokia cells or ipad battery or even couple of iphone 4 batteries
i have a step up board and a cheap backup 18650 battery board
wich one should i use and how should i connect the batteries with the battery board or without


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Best Answer 6 years ago

You have two USB boards in the pic - if they are designed for 3.7V like the 18650 battery it can work.

Be aware that you need 2.0V on d+ and 2.7V on D-, otherwise your rotten fruit will only charge at a max of 100mA if at all.

Having said that using old batteries for this task is only feasable if they still hold a proper charge.

As the converter will use some energy old batteries might only give you a little top up before their voltage drops below what the converter can handle - only testing will tell.


Answer 6 years ago

thnx for the reply

as u can see in the pic there is a battery with the "charging" board and the other one is just a cell wich i discharged several times creating a spark, what kind of battery should i use just a cell or complete with failsafe boards (or whatever they`re called)

the one on top is step up input 1-5v to output 5v but i think it requires to many amps for it to be able to charge (it converts amps to volts, i think)
the one below it is the one designed to work with 3.7 18650 so i figured why not use several nokia batteries ( i can use new ones if i`m 100% sure it will work) or just buy one or two ipad battery and use that instead, i`m sure it has more then 2500mah.

as for the 2.0 and 2.7v on d+ and d- how should i solve that problem???