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shaharkadmiel

macrumors newbie
Original poster
Oct 17, 2017
2
0
Hi,

I have a 2016 TouchBar MacBook Pro 15". I have an old 85W charger with a MagSafe2 connector at the end. I need an extra charger for my current MacBook Pro and that requires a USB-C connector.

Is there a reason why I shouldn't be able to cut the MagSafe2 connector and solder a USB-C connector instead? Sure, I would have to check out the pinout of the connector and solder to the right terminals but did apple change anything internally in the power adapter itself? Are any of the other wires in the USB-C cable used for any kind of communication between the connector and the charging brick?

I would very much like to hear about someone who attempted this.

Cheers,
Shahar
 

negativzero

macrumors 6502a
Jul 19, 2011
564
55
Because MagSafe outputs voltage at 14V and higher while USB-C is 5V. It will blowout the MacBook. Nothing wrong with the connector end, its the power brick.
 

leman

macrumors Core
Oct 14, 2008
19,494
19,631
And you also need to add the chips for negotiating the USB power link... unfortunately, this is not the era of home-made radios anymore ;)
 
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shaharkadmiel

macrumors newbie
Original poster
Oct 17, 2017
2
0
Because MagSafe outputs voltage at 14V and higher while USB-C is 5V. It will blowout the MacBook. Nothing wrong with the connector end, its the power brick.

You are mistaken...

From the MagSafe2 charger:
Output: 18.5V - 4.6A, 16.5V - 3.6A

From the USB-C charger:
20.2V - 4.3A (USB PD) or 9V - 3A (USB PD) or 5.2V - 2.4A

so while charging, the voltage and the amperage are quite similar. I don't really know what the other values mean though...
[doublepost=1508308302][/doublepost]
Buy a new charger. Why would you even risk such an expensive device by soldering?
Because its a challenge!
[doublepost=1508308339][/doublepost]
And you also need to add the chips for negotiating the USB power link... unfortunately, this is not the era of home-made radios anymore ;)
CRAP!
 

Fishrrman

macrumors Penryn
Feb 20, 2009
29,177
13,225
OP --

Why don't you go ahead with your plans, and have a video camera aimed at the MacBook the first time you plug it in, to record the results? (and then post them here)
 

jerryk

macrumors 604
Nov 3, 2011
7,421
4,207
SF Bay Area
USB-C Power Delivery is not just providing power to certain pins. There are specs that have to be met and handshaking between the power supply and the device being charged to ensure that the power supply provides power at the right voltage and current. Voltage can range from 5V to 20 volts and current from 0.5 Amps to 5 Amps.

See this and subsequent links for the details http://www.usb.org/developers/powerdelivery/
 
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