Question When charging my dead iPad with an ATX PSU, the wires got very hot. Why?

[s355]

I connected the 5V rail of the PSU to the VCC of the stripped USB cable, and GND to GND. What rail can I use instead of the 5V rail?

 

[fralexandr]

A picture of your cables might help determine why it's heating up.
Unless something else is wrong, the quality of the connection/solder/joint between the PSU 5V cable and the USB 5V cable is probably poor, resulting in high impedance/resistance and thus higher heat.

Depending on your ipad version it might support 12V charging. It's hard to say since you provided almost no information.

I would suggest just using a USB port on a computer, or a dedicated wall charger. Decent wall chargers aren't that expensive...

 

[s355]

A picture of your cables might help determine why it's heating up.
Unless something else is wrong, the quality of the connection/solder/joint between the PSU 5V cable and the USB 5V cable is probably poor, resulting in high impedance/resistance and thus higher heat.

Depending on your ipad version it might support 12V charging. It's hard to say since you provided almost no information.

I would suggest just using a USB port on a computer, or a dedicated wall charger. Decent wall chargers aren't that expensive...

When powering other USB devices, the temp was ok. Only charging the dead iPad made the cord heat up.

 

[fralexandr]

There's something wrong with the ipad then. Depending on the psu used the 5v rail could be capable of outputting ~100w which could explain why the cables are heating up. How long did you leave it plugged in for?

 

[s355]

There's something wrong with the ipad then. Depending on the psu used the 5v rail could be capable of outputting ~100w which could explain why the cables are heating up. How long did you leave it plugged in for?

1 hour

 

[fralexandr]

Was the ipad working before you charged it? And now it's dead or was the battery dead and you were trying to charge it? Was the ipad also hot to the touch after charging it?

 

[s355]

Was the ipad working before you charged it? And now it's dead or was the battery dead and you were trying to charge it? Was the ipad also hot to the touch after charging it?

Systems normal; battery dead. iPad battery temp normal. The battery died because it was unused for a long time.

 

[Fanatical Meat]

Gonna guess cheap/unbranded cable.
Don’t use that stuff. Totally worth the $10 extra to get something that won’t start a fire.

 

[mindless1]

What gauge is the wire? Break the connection, put a multimeter in series and measure current.

How did you connect the PSU wire to the USB? Needs to be a high quality solder joint or if crimped, HQ crimp and the right crimp tool for it. If you just twisted the wires together bare, no wonder...

 

[s355]

What gauge is the wire? Break the connection, put a multimeter in series and measure current.

How did you connect the PSU wire to the USB? Needs to be a high quality solder joint or if crimped, HQ crimp and the right crimp tool for it. If you just twisted the wires together bare, no wonder...

VCC to 5v pin, GND to GND, I soldered them together.