My laptop charger connector broke, so I bought a new connector. However, I noticed that the new connector's wires were thinner than that of the existing charger. The laptop charges, but the charger brick is getting very hot. Make note that I did not open up the brick, but rather just soldered the old wire to the existing wire.

EDIT: The charger does not get hot when it is plugged into the outlet and NOT plugged into the laptop, so essentially without a load it doesn't get hot. This is completely normal, but I suppose it suggests there are not shorts in my soldering work.

  • \$\begingroup\$ Is the wire getting noticeably warm? \$\endgroup\$ Commented Aug 5, 2015 at 2:52
  • \$\begingroup\$ Just FYI, decreasing AWG is the same as increasing the wire diameter. The smaller an AWG number, the larger the diameter. \$\endgroup\$ Commented Aug 5, 2015 at 3:08
  • \$\begingroup\$ Its not the wire that is getting warm, but rather the brick. It gets very hard to even touch. \$\endgroup\$ Commented Aug 5, 2015 at 14:43
  • \$\begingroup\$ Are you sure it wasn't as hot before? Mine runs pretty hot without modifications (almost too hot to touch after charging the laptop from empty to full). Maybe try adding additional wires in parallel and see if it has any effect? \$\endgroup\$
    – Justin
    Commented Aug 5, 2015 at 15:21
  • \$\begingroup\$ Unfortunatly, putting wires in parallel would be very tricky. Another thing I noticed what that the old wire was a silver color while the new one is copper. \$\endgroup\$ Commented Aug 5, 2015 at 15:42

1 Answer 1


Increasing the AWG number of your wire increases resistance. Higher AWG Has smaller area

$$R = (\rho *L)/A $$

Therefore, higher AWG has more resistance. And more resistance with the same current means more heat is dissipated.

The link below shows different diameters of AWG wire: https://www.tedpella.com/company_html/wire-gauge-vs-dia.htm

Here is also a link for the resistance per foot of different AWG wire:


  • \$\begingroup\$ But the brick is getting hot, not the wire/joint. Is that normal? \$\endgroup\$ Commented Aug 5, 2015 at 15:24
  • \$\begingroup\$ That's interesting, If you were using a higher AWG wire, it seems like the wire would heat up... \$\endgroup\$
    – Adam
    Commented Aug 5, 2015 at 15:35
  • \$\begingroup\$ After about 5 min of charging, it is getting to what I would consider a "normal temp", whereas 15 min in, it is getting unacceptably hot. Nothing is shorting because it is charging the laptop and I carefully insulated everything. \$\endgroup\$ Commented Aug 5, 2015 at 15:37
  • \$\begingroup\$ did you beep test to check for any shorts that could have occurred? \$\endgroup\$
    – Adam
    Commented Aug 5, 2015 at 15:58
  • \$\begingroup\$ Beep test? Like with a multimeter (I just want to check if that if what you are referring to). \$\endgroup\$ Commented Aug 5, 2015 at 16:05

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