USB Charging

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Technofreak

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#93416 21-Nov-2011 10:51

I have two devices a Nokia E7 and an HP Touchpad both of which are charged using the USB port.

They will both charge using the provided AC adapter and from a computer USB port using either the provided USB cable or any other USB cable. However they will not charge from a generic USB power supply, I have two an AC one and a car one. It would be very handy to have just one unit that works in the car ad be able to use what I already have.

It appears that the Nokia will charge from the Touchpad charger but the Touchpad will not charge from the Nokia charger.

How do you get a generic supply to work? I'm guessing that there is some sort of R/C network hung across the bus connectors on the proprietary chargers which the device recognises as the charger or a computer.

Sony Xperia XA2 running Sailfish OS. https://sailfishos.org The true independent open source mobile OS
Samsung Galaxy Tab S6
Dell Inspiron 14z i5

Technofreak

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#553495 4-Dec-2011 14:31

Google is indeed your friend.

I had done a Google search prior to my first post without any success. I finally had some more time to devote to this today. The answer is to connect the data pins (pins 2 & 3) together.

On one the thread that I found some posters suggested splicing a USB cable to join the data pins together. I don't like this method since the cable is then only good for charging and useless as a data cable.

I carefully pried apart the car USB supply that I have and soldered a piece of wire between pins 2 & 3 and hey presto I was able to use that supply to charge my phone using a standard USB cable.

Job done.

Sony Xperia XA2 running Sailfish OS. https://sailfishos.org The true independent open source mobile OS
Samsung Galaxy Tab S6
Dell Inspiron 14z i5

bazzer

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#553910 5-Dec-2011 10:19

I wonder if this would work for my PSP Go too? Are there any downsides? I'm assuming the phone has the smarts to know when it's finished charging and doesn't rely on some kind of "smart" charger that communicates via the data lines?

Do you think that the only difference with the other chargers is that they already had those pins connected?

Edit: Google is my friend too. Looks like the PSP Go wall charger has a 0 Ohm resister (read piece of wire) connecting the data pins. I might do the same thing to my car charger then.

Technofreak

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#554027 5-Dec-2011 13:34

bazzer: I wonder if this would work for my PSP Go too? Are there any downsides? I'm assuming the phone has the smarts to know when it's finished charging and doesn't rely on some kind of "smart" charger that communicates via the data lines?

Do you think that the only difference with the other chargers is that they already had those pins connected?

Edit: Google is my friend too. Looks like the PSP Go wall charger has a 0 Ohm resister (read piece of wire) connecting the data pins. I might do the same thing to my car charger then.

I think the "smarts", if any, are in the device to control the charging.

I figured that if the devices are happy to charge off any old USB outlet on the computer there must be a way to get them to charge off a generic USB charger.

One thing to remember is most consumer devices like these chargers are pretty basic and cheap so there's normally nothing too fancy in them. Shorting out pins 2 & 3 seems to be the way its done. Cheap and nasty, though different enough to get you to buy the branded item when the generic item doesn't work.

Sony Xperia XA2 running Sailfish OS. https://sailfishos.org The true independent open source mobile OS
Samsung Galaxy Tab S6
Dell Inspiron 14z i5