I don't have the time as I would do this myself. All I need is to get some help to find a chip that is similar to the one being used like in the product from this link. The chip must be fairly similar and functional just like the JUMP cable by Native Union.
This is just a research job. :)
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9 freelancere byder i gennemsnit $62 for dette job
I saw what you need, you need a current detector to change the flow to the battery or cellphone and a voltage booster to charge the cellphone from the batteries.