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Magsafe 60watt vs 85watt

rkriheli

rkriheli

macrumors member
Original poster
Dec 11, 2002
72
0
new york, ny
Apple recommends using the 85watt with a Macbook Pro. I am considering purchasing a second one that I can leave at work without carring it around and I see some used 60watt macbook magsafes at good prices.

Questions are:
1 - Will it work?
2 - If so, will it cause any problem?
3 - Has anyone tried using a 60w magsafe with their macbook pro's? if so, can you let me know how it works out for you?

Most appreciated!
 
Do NOT use a lower power magsafe power adapter. it is for the Macbook. NOT Macbook pro.

it will not work properly with your mac. if it works, it will not actually allow for charging your battery. also, it will not provide the full amount of battery power your laptop needs.

a macbook doesnt have a full power graphics chip nor the needs of a MBP. on top of that it may actually harm your laptop
 
It DOES work and it works fine. I use my wifes MB power adapter with my MBP almost ALL THE TIME. It DOES charge my laptop and I have NOT experienced a single problem in the 5+ months that I have been doing this.
 
wow - 2 different replies. i dont know what to think. anybody else with experience? i am leaning towards using one since it has worked fine for kingjr. anyone else?

:confused: :confused: :confused:
 
Apple2Mac said:
I glad it works, but that makes me feal uneasy to risk my MBP....
Click to expand...

The way I understand it, its fine to underpower a device but never ever ever try a power supply that exceeds your devices requirements. This is why I won't use my MBP adapter with my MB, although I believe I read that it auto switches down to the MB power requirements.
 
I've read somewhere that they can be used interchangeably on both machines, but that it takes longer to charge an mbp with a 60 watt adapter.
That said, I wouldn't want to risk my own unless I was absolutely certain.
 
Has anyone solved this mystery yet of the Macbook and Macbook pro Magsafe interchangability?

Pretty inconvenient if you have two Magsafe adapters looking exactly the same in the same place.

Any help appreciated
 
hi, i have had two macbook pros, the old 2.16 17" and now i have the new c2d 17" and i have used both with the 60W power adapters at times, basically using friends @ school etc. Works fine, takes a little longer 2 charge but i can still use it and charge the battery at the same time, no harm done!
 
rkriheli said:
Apple recommends using the 85watt with a Macbook Pro. I am considering purchasing a second one that I can leave at work without carring it around and I see some used 60watt macbook magsafes at good prices.

Questions are:
1 - Will it work?
2 - If so, will it cause any problem?
3 - Has anyone tried using a 60w magsafe with their macbook pro's? if so, can you let me know how it works out for you?

Most appreciated!
Click to expand...

Switching PSU's like the ones provided to charge the MB/MPP's are designed to be like ideal voltage sources. i.e. whatever the load the supply will keep the same output voltage, hence the power supply will supply as much power as is needed by the device.

The reason there are two types of adapter are that the more power is drawn the larger the heat dissapated in the PSU. The components in the 60W device will only be rated for dissapating 60W's worth of heat. If you pull 85W through it it will probably work for most of the time, however. There is a chance that it will overheat and kill itself.

Most modern switching PSU's come with a feature called a "crossbar". This electronic device is designed to shutdown the power supply in the event of a malfunction. These are put in place because one of the most common failure modes for a switching PSU is to dump mains voltage DC on the output and trust me your MBP won't like 230V DC :-D.

So in conclusion, using a 60W adapter once in a while is fine. Using one regularly is *probably* going to be ok. IF you're really paranoid only ever use an 85W.

HTH

Chris
 
Wow, I really went deep into the archives to find this thread, but I want to know if anyone has anymore info on this.

I just bought a MacBook Pro and I want to know if I can use my old MacBooks MagSafe to charge it while its at my desk. This way I can have one always plugged in at my desk, and one always in my case with my MBP.

Thanks!
 
hey NYR, my girlfriend had a macbook but dumped water on it and it broke. so she got a macbook pro to replace it. long story short she's been using the macbook charger (not the new charger, never unpacked from the box... :p) for almost a year now and no problems to report (with the power supply area, anyways...).

hope this helps!
 
Thanks for the info. I don't think it'll do any bad either but I just want to be sure. Anyone think it its a bad idea?
 
NYR99 said:
Thanks for the info. I don't think it'll do any bad either but I just want to be sure. Anyone think it its a bad idea?
Click to expand...

I just checked and my 2009 model 2.53 15inch MBP, that I bought a week before the refresh (d'oh) came with a 60w PSU.
 
NJuul said:
I've read somewhere that they can be used interchangeably on both machines, but that it takes longer to charge an mbp with a 60 watt adapter.
That said, I wouldn't want to risk my own unless I was absolutely certain.
Click to expand...

Ya exactly. It would be fine, but it would just take much longer to charge the MBP with a 60Watt (MB) Charger.
 
So, I was doing some research trying to figure this out a couple of weeks ago trying to figure what works on the plane... This is what I learnt:

1. On the 2009 15" 2.53 w/o the 9600 (i.e. only on board 9400), the 60W charger works fine and charges as well. In fact they come with a 60W brick.

2. On the ones with both dedicated and on-board video, if running the dedicated 9600, the 60 watter does work, but will only either charge or power, not both at once. (Combining both these points would lead me to conclude that if running on just the on-board 9400, it should do both... but I don't know the answer to this.)

btw, lots of people do buy the 60W charger to use onboard international flights (on united first and biz, you don't need special adapters), as most aircraft power points are only rated for 75W. I do know of cases of the 85W brick blowing the circuit breakers on planes.
 
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