Magsafe replacements

Hi,
Apple power chargers go broken all the time, always due to frayed rubber coating close to the Magsafe connector. The Apple way to fix them is to buy a new one for $80 (I don't mind doing that but I am reluctant to do it every two years... now it would be the fourth time). There are ebay replacement cables available, for varying price $5-$20. They are often named "universal 45W/60W/85W magsafe 1"

Could anyone enlighten me how do the replacement cables for magsafe power adapter work? I find this puzzling: Power adapter with different wattage has a different Voltage (e.g. 60W has 16.5V 85W has 18.5W etc..).

My understanding is that:
- after connecting magsafe to the socket the computer reads the id form the magsafe, and what the chip has read can be later read in SystemReport->Power->AC after os boots. At this point brick delivers 6.8V (no matter the type)
- a second later the brick changes the 6.8V voltage to the target voltage.

The replacement cable in my opinion has no way of knowing to what power adapter it is attached to. So is Mac being lied to by the IC in the magsafe connection, about the voltage it is going to receive?

So what scenarios follow:
- Mac gets say 18.5V although it has just been sent an magsafe id through one-wire which would imply 16.5V (or vice versa) -
- I noticed that Chinese replacement switches on power immediately, not one second later - this is unsafe, right?

Are there any tech manuals available to figure that out?

Sometimes (depends on the store) Apple will replace a frayed or broken MagSafe Charger for free even it's out of warranty. At least that has been our experience. Anyway, I don't profess to know all the technical specifications of how the charger is supposed to work. What I do know is that Apple has done away with it with the newer MacBook Pros and MacBook.

And, Welcome to our forums.

marcin said:

Apple power chargers go broken all the time, always due to frayed rubber coating close to the Magsafe connector. The Apple way to fix them is to buy a new one for $80 (I don't mind doing that but I am reluctant to do it every two years... now it would be the fourth time).

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Yes...the Apple power adapter cables are prone to failure/damage. Most of the time this is caused by the cable being repeatedly bent at too sharp of an angle:

- Winding the cable too tightly which cause's failure at the brick end.
- Bending the cable at too sharp an angle at the mag-safe end.

I'm VERY VERY careful how I treat my Mag-Safe cables. And fingers-crossed...have not had a problem in over 45 years of experience with Mag-Safe cables (I've always had at least 3 MacBook Pro's/MacBook Air's in my household since 2006 when Mag-Safe cables were first introduced...3 x 15 = 45 years experience).

- Nick

chscag said:

Sometimes (depends on the store) Apple will replace a frayed or broken MagSafe Charger for free even it's out of warranty. At least that has been our experience. Anyway, I don't profess to know all the technical specifications of how the charger is supposed to work. What I do know is that Apple has done away with it with the newer MacBook Pros and MacBook.
And, Welcome to our forums.

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Thanks. I think I am out of luck - this cable replacement program was US-only and it has already expired. And I think there is no Apple Store in my country

OWC among others sells the "genuine" adapters and cords, usually at a fraction of the price that Apple charges:
https://www.macsales.com

Moshi also makes some excellent adapters and cables and often cheaper and better IMHO.
https://www.moshi.com/power-charger-rewind2-usb-dual-port-wall
others at:
https://www.moshi.com




- Patrick
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pm-r said:

OWC among others sells the "genuine" adapters and cords, usually at a fraction of the price that Apple charges:
https://www.macsales.com

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Thanks. I feel that in the end I will buy stuff from this site.

Anyway, I am still interested in getting answers about how this power adapter and magsafe plug matching works in practice

I like Nick am VERY careful and myself have never had one fail. I have a friend who won't listen and gets rough with his MBP and Magsafe and breaks them yearly! His MBP 2011 looks like it was drug behind his car on a rope! Amazing.

And yes there is a small IC Chip in the Mag Safe end. I had one I worked on for a friend where he shorted the pins and popped the IC chip! Voltage was there but Chip controls charging and it would not charge.

dtravis7 said:

I like Nick am VERY careful and myself have never had one fail. I have a friend who won't listen and gets rough with his MBP and Magsafe and breaks them yearly! His MBP 2011 looks like it was drug behind his car on a rope! Amazing.

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I think I do not want to be VERY careful with the cable. The portable power adapter is portable when it does not get broken just like that. I carry it in separate compartment in my suitcase. I take care when unplugging it and I have never seen my magsafe with large strain at the end of the connector. I think this is reasonable precautions and I do not want to center my life around the cable. And I my company these magsafe charger cables are common, not matter whether the macbook is company property (and likely mistreated) or whether it is a private property.

dtravis7 said:

And yes there is a small IC Chip in the Mag Safe end. I had one I worked on for a friend where he shorted the pins and popped the IC chip! Voltage was there but Chip controls charging and it would not charge.

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Replacements magsafe connectors I have bought from ebay work and charge, but I would like to understand how this happens on the lower level. I am reluctant to assume that green light means everything is fine, just because the green light is green.

I would like to understand how this happens on the lower level. I am reluctant to assume that green light means everything is fine, just because the green light is green.

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Maybe these articles would help:
Teardown and exploration of Apple's Magsafe connector
http://www.righto.com/2013/06/teardown-and-exploration-of-magsafe.html

Macbook charger teardown: The surprising complexity inside Apple's power adapter
http://www.righto.com/2015/11/macbook-charger-teardown-surprising.html

and more at:
https://www.google.ca/search?client...&oe=UTF-8&gfe_rd=cr&ei=78oyWayHOPPs8wfc_pPACg

BTW: we have several Apple adapter power cords that have failed with fraying and split cord covering that have a permanent position at a power receptacle and certainly don't get any rough treatment or handling, but basically just sit there in a neat coil. Bottom line, the materials Apple uses is plain cheap CRAP. Period. At least for most of their cords we have. Unfortunately they don't seem to want to change or improve things either!! ;P

PS: The "green light" is only to provide an indication that the battery has a designated charge. Nothing else. i.e.: it won't provide any other indication like the "full" charge will only last ten-twenty minutes etc. that an old battery may provide.





- Patrick
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pm-r said:

- Patrick
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Hi,
thanks. Indeed the links you have provided touch the very essence of the the things I would like to read/figure out.
I will play around with the replaced power cable. To some extent it suffices to use the notebook normally - seems that the buck converter inside the macbook is controlled properly and assures the computer gets a proper voltage.

Do you know what does the mac do with the info it reads from the magsafe plug? (as described in the first link you have posted)? For sure this info is displayed in System Report->Power->Ac Adapter, but is it actually used to do power management?

At the very least if computer overloads the charger (e.g. because SMC thinks it is 85W) it would trigger the overload protection and DCIN(16.5V) will shut down, then the LIO_DCIN_ISENSE will trigger the battery and in the end 3.425V G3HOT will be powered from the battery. But will then the adapter restart and be used just enough to trigger the overload again? I do not want to think that everything is in order while in reality the power adapter is being tortured.
Actually I could just monitor the voltage on the power adapter and run some sort of stress test, but perhaps someone already knows

Do you know what does the mac do with the info it reads from the magsafe plug?

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I'm guessing that it may send the info to the power utility company and a copy to the CIA and maybe some of the other US snooping agencies, but not to worry as I believe Apple encrypts such info and will not allow any password forcing to access any of the info, so the user is quite safe and protected…

However, Tesla does have authority to access and use the info in order to further develop better charging methods and to help improve battery development, as long as it can be used for peaceful purposes. North Korea is not authorized to access ANY such info that may be sent out over the charging power lines.

But, no, in actual honesty I do not really know other than it's to provide the user some indication that the device's battery is sufficiently charged. And yes, I was just making up the story above. Honest.

PS: No device can draw more current than a charger/adapter can provide and neither can a charger/adapter provide more power than a device can accept or use. Honest. A basic law of electricty.

I'd just connect the devices and let them charge assuming they, the adapter, the cables and the device being charged are in proper working condition.






- Patrick
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pm-r said:

But, no, in actual honesty I do not really know other than it's to provide the user some indication that the device's battery is sufficiently charged. And yes, I was just making up the story above. Honest.

- Patrick
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For a minute there I was thinking it was time to break out the tin foil hats.

Slydude said:

For a minute there I was thinking it was time to break out the tin foil hats.

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LOL, I sure would like to see you wearing a 10 gallon tin foil hat!

chscag said:

LOL, I sure would like to see you wearing a 10 gallon tin foil hat!

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Just needs a bit of tinfoil… :Blushing:





- Patrick
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pm-r said:

I'm guessing that it may send the info to the power utility company and a copy to the CIA and maybe some of the other US snooping agencies, but not to worry as I believe Apple encrypts such info and will not allow any password forcing to access any of the info, so the user is quite safe and protected…

However, Tesla does have authority to access and use the info in order to further develop better charging methods and to help improve battery development, as long as it can be used for peaceful purposes. North Korea is not authorized to access ANY such info that may be sent out over the charging power lines.

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This is attempted humour?

pm-r said:

But, no, in actual honesty I do not really know other than it's to provide the user some indication that the device's battery is sufficiently charged. And yes, I was just making up the story above. Honest.

pm-r said:

What magsafe connector would have to do with the battery? Battery has its own circuitry and sensing the battery for sure has little to do with the adapter input. At some point battery output and adapter meet in the power system of the mac, but for sure there is not data transfer between the adapter and the battery.

pm-r said:

PS: No device can draw more current than a charger/adapter can provide and neither can a charger/adapter provide more power than a device can accept or use. Honest. A basic law of electricty.

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But it may attempt to do so - and trigger overload protection. Just as if it shorted the output of the adapter. In this case it would not be shorting but lowering the input impedance below value accepted by the charger. And of course I have written about that, but you decided to be condescending.

Moreover I have described the possible mechanism: mac hardware and software could limit the load the computer has on the adapter based on wrong information. Just any dummy load device can do that. In case of computer it is more complicated as many systems draw power, but I would imagine e.g changing the frequency of the CPU as a way to limit power drain (again based on wrong information). Apple's product feature vertical integration and fancy chips such as SMC, so I would imagine something like could be possible. And I would ask someone with acutal knowledge to comment on the issue.

pm-r said:

I'd just connect the devices and let them charge assuming they, the adapter, the cables and the device being charged are in proper working condition.
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Yeah this works.

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pm-r said:

BTW: we have several Apple adapter power cords that have failed with fraying and split cord covering that have a permanent position at a power receptacle and certainly don't get any rough treatment or handling, but basically just sit there in a neat coil. Bottom line, the materials Apple uses is plain cheap CRAP. Period. At least for most of their cords we have. Unfortunately they don't seem to want to change or improve things either!! ;P
- Patrick
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In fact in my opinion there is more to the story. Somehow there are defects with Apple products that are sold and branded as quality products. This is perfectly normal, but I do not appreciate how quite often the accountability for the mistakes made is not taken by the manufacturer, and instead they shift blame on the user. In case of the power cords there was a limited to the US replacement program for exactly that issue, that has already expired, despite the fact that the same power cords were sold worldwide, and to my knowledge they are still manufactured exactly in exactly the same way.

Off topic case: our iPhone is great, you are just holding it in a wrong way - seriously? Not to mention susceptibility to mechanical damage.

In fact in my opinion there is more to the story. Somehow there are defects with Apple products that are sold and branded as quality products. This is perfectly normal, but I do not appreciate how quite often the accountability for the mistakes made is not taken by the manufacturer, and instead they shift blame on the user.

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Unfortunately there are also a lot of Apple fanboys and fangirls spewing forth how great their Apple God is who can do no wrong.

There are also some that can find independent reviews and consider and purchase with their guidance as well as any from their own wallet or bank account. Then it's Apple's concern as to whether they listen or make any changes or not.





- Patrick
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