My aging Apple power adapter requires either a new cable or being replaced
all together. Cable was replaced twice already.
I would like to take advantage of compact newer power adapters which
invariably offer a USB-C socket and digital Power Delivery (PD) controls.
Was reading about USB-C PD triggers/decoys which present fixed voltage one
side and PD interface on the other (*). So I thought USB-C to MagSafe 1/2
adapters available on the market implement that.
Then read about a MagSafe plug tear down revealing the connector itself
provides a power adapter ID to the Mac laptop (**). Even if those cheap
cable adapters implement this feature, which I doubt, I am not sure it will
be the correct one. It may simply return the ID of the most powerful Apple
power adapter of the line and leave it at that. As far as I know they don’t
offer users any configuration option.
To be considered also third party power adapters are known to work with old
Mac laptops. But I don’t know if they also affect battery lifespan.
What are your thoughts about safety - for both user and equipment - of such
solutions? Thanks.
* https://learn.adafruit.com/usb-pd-hacks/things-to-know
** http://www.righto.com/2013/06/teardown-and-exploration-of-magsafe.html
I have a couple of those adapters - both Magsafe 1 and 2. I haven't used
the 1 yet but the 2 works fine. From Aliexpress - the listing is gone but
looked like this:
https://www.aliexpress.com/item/1005003915958424.html
According to the manuals, the Apple power supplies emit the following:
https://cdsassets.apple.com/live/6GJYWVAV/user/locale/en-gb/ma1986_apple-magsafe-2-power-adapter-ug.pdf
Specifications
45W Power Adapter
* Input: AC 100–240 volts (V), 50/60 hertz (Hz)
* Output: DC 14.85V, 3.05A
60W Power Adapter
* Input: AC 100–240 volts (V), 50/60 hertz (Hz)
* Output: DC 16.5V, 3.65A
85W Power Adapter
* Input: AC 100–240 volts (V), 50/60 hertz (Hz)
* Output: DC 20V, 4.25A
The Magsafe 1 supplies are fractionally lower voltages/higher currents:
https://www.allion.com/tech_syst_magsafe/
So in principle the Macbooks are capable of taking 20 volts. USB-C is only
capable of generating 15V (typically 45W chargers are 15V at 3A) and 20V
(60W chargers and up) unless using PPS mode which most power supplies won't
support. I expect the adapters just ask USB-C for a fixed 20V
and they may not work with a 45W supply.
The Macbooks will have their own independently controlled DC-DC converter to
charge the battery so the battery won't care what the input voltage is. If
anything a higher voltage might help as it reduces the current and makes
things run slightly cooler.
I wouldn't worry about it.
Theo
| Date | Sujet | # | Auteur | |
| 9 Aug03:34 |  MagSafe 1 | 7 | Wu Ming | |
| 9 Aug16:29 |   Re: MagSafe 1 | 1 | legg | |
| 9 Aug22:38 | Re: MagSafe 1 | 2 | John Robertson | |
| 10 Aug02:39 |   Re: MagSafe 1 | 1 | Wu Ming | |
| 9 Aug23:30 | Re: MagSafe 1 | 3 | Theo | |
| 10 Aug02:39 |  Re: MagSafe 1 | 1 | Wu Ming | |
| 11 Aug04:00 | Re: MagSafe 1 | 1 | Wu Ming |
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