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2nd-generation magnetic AC power adapter for MacBook products, first released in 2012. Not compatible with previous generation systems. Available in 45W, 60W, and 85W versions.

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Hack magsafe 2 to use as generic PSU

Hi,

I. have an 85W Magsafe 2, which had the cable damaged.

As I don’t need it to power a mac, would it be possible to use it as a bench power supply?

Measuring the voltage with no load, shows 3V on my multimeter. How can I make it work? I read somewhere that it needs to see 40kohm, to activate.

I’ve tried to put a 40kohm resistor there and it doesn’t wake up to max voltage.

Cheers,

Pedro

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It’s not designed to be a generic power supply. Its circuitry is designed to charge a Li-Ion battery that’s it.

A bench power supply needs the ability to select a voltage and control the current draw. Without that you risk damaging the device if over powered.

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Thanks Dan.

What if I want to use it as an USB-C charger for my phone/tablet. Is that possible?

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@pcardoso73 - Sorry Apples charging system is unique to them.

One of the biggest benefits of the USB-C standards effort was to define a charging standard.

The Apple MagSafe charger won't offer the needed connections and the temperature feedback system which uses a one wire conn connection won't work within the USB-C device.

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@pcardoso73 sure you can. You just have to be careful and follow instructions like this. One of the issues that I see coming at you, is something like this “with no load, shows 3V” which should not even be there.

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@oldturkey03 - This is not something I would recommend.

Besides I doubt Pedro is advanced enough to get this deep and likely doesn't have the rest of what's needed and lastly a cracked open charger is not very safe!

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@danj I am not going to guess the skill level of @pcardoso73 but it can be done. It is not the design of the Magsafe that would be an issue. @pcardoso73 can check the video and see if that is what he wants to do and only he knows his comfort level when it comes to a project like this.

So yes, it CAN be done.

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40k ohm resistor in how many watt?

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if you cant calculate power dissipated by 16V power supply into a 40kohm resistor you shouldnt be asking.

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