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Power supplies interchangable?

Message #1 - Posted 2009/07/08 - Richard Tobin

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

-- Richard

Please remember to mention me / in tapes you leave behind.

Message #2 - Posted 2009/07/08 - Ric Harris

On 8 July, 18:55, Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

-- Richard

--
Please remember to mention me / in tapes you leave behind.

Yes, and no. Works fine, charges slowly.

Message #3 - Posted 2009/07/08 - Jaimie Vandenbergh

On 8 Jul 2009 17:55:30 GMT, Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

It'll trip out if the MBP asks more power than it can supply.

I did this with an Air 45W psu and a MacBook, normally 60W. I was reinstalling the MB, and the Air psu kept it going all the way until Spotlight indexing started on first login. At that point the Air psu gave up and the overpower trip went.

Took the psu ten minutes to reset and carry on working, no obvious harm done. I've used it for more than a year since then.

Cheers - Jaimie

'Rings! Rings! Wherever they may be
I am the Lord of the Rings,' said he
'And I'll find them all, wherever they may be
And I'll bind them all in the dark,' said he -- Kevin Ahearn

Message #4 - Posted 2009/07/09 - David Empson

Ric Harris wrote:

On 8 July, 18:55, Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

Yes, and no. Works fine, charges slowly.

I've observed a situation where this combination wouldn't charge the battery while the computer was operating. It knows the adapater doesn't have sufficient power. You had to shut down or sleep the computer to charge the battery.

Incidentally, the 60W Magsafe adapter isn't "old". It is supplied with all 13" MacBook and MacBook Pro models. The 15" and 17" MacBook Pro models have always come with 85W adapters, but they started out bigger than the 60W one and got smaller in mid to late 2007 (about two weeks after I bought my spare one, of course).

David Empson
dempson@actrix.gen.nz

Message #5 - Posted 2009/07/09 - Richard Tobin

Previously, David Empson wrote:

Incidentally, the 60W Magsafe adapter isn't "old".

I just meant "old' in the sense of one I already had.

-- Richard

Please remember to mention me / in tapes you leave behind.

Message #6 - Posted 2009/07/09 - zoara

Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

Hannah and I (MacBook and MacBook Pro) just pick up whichever power supply is closest. No issues.

-z-

"And the tiny universe compiles."
http://powazek.com/posts/1655

Message #7 - Posted 2009/07/09 - zoara

David Empson wrote:

Ric Harris wrote:

On 8 July, 18:55, Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

Yes, and no. Works fine, charges slowly.

I've observed a situation where this combination wouldn't charge the battery while the computer was operating. It knows the adapater doesn't have sufficient power. You had to shut down or sleep the computer to charge the battery.

I've seen that too.

-zoara-

"And the tiny universe compiles."
http://powazek.com/posts/1655

Message #8 - Posted 2009/07/09 - Jim

On 2009-07-09, zoara wrote:

Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

Hannah and I (MacBook and MacBook Pro) just pick up whichever power supply is closest. No issues.

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Jim

http://www.ursaMinorBeta.co.uk http://twitter.com/GreyAreaUK Please help save Bletchley Park - sign the petition for Government funding at: (open to UK residents and ex.pats) http://petitions.number10.gov.uk/BletchleyPark/ Thank you.

Message #9 - Posted 2009/07/09 - James Dore

Jim wrote:

On 2009-07-09, zoara wrote:

Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

Hannah and I (MacBook and MacBook Pro) just pick up whichever power supply is closest. No issues.

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Good job it was two sentences then.

Cheers,

james dore
IT Officer,
New College, Oxford
http://www.new.ox.ac.uk/ it-support@new....

Message #10 - Posted 2009/07/09 - Jim

On 2009-07-09, James Dore wrote:

Hannah and I (MacBook and MacBook Pro) just pick up whichever power supply is closest. No issues.

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Good job it was two sentences then.

Grrrr. But fair point.

Jim

http://www.ursaMinorBeta.co.uk http://twitter.com/GreyAreaUK Please help save Bletchley Park - sign the petition for Government funding at: (open to UK residents and ex.pats) http://petitions.number10.gov.uk/BletchleyPark/ Thank you.

Message #11 - Posted 2009/07/09 - Simon Slavin

PreviouslyRichard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

You won't fry the supply. I'm fairly sure you won't even blow the fuse. I've plugged one in by accident myself and didn't notice for a few hours.

It will, as you suggest, charge more slowly. So much more slowly that if you're using a lot of power (playing a real-time 3D game) it may still have a net discharge.

--

I'm using an evaluation license of nemo since 192 days. You should really try it!
http://www.malcom-mac.com/nemo

Message #12 - Posted 2009/07/10 - zoara

Jim wrote:

On 2009-07-09, zoara wrote:

Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

Hannah and I (MacBook and MacBook Pro) just pick up whichever power supply is closest. No issues.

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Hur. Point taken.

-z-

"And the tiny universe compiles."
http://powazek.com/posts/1655

Message #13 - Posted 2009/07/10 - Roger Merriman

Jim wrote:

On 2009-07-09, zoara wrote:

Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

Hannah and I (MacBook and MacBook Pro) just pick up whichever power supply is closest. No issues.

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Jim

well at least he didn't say ibook...

roger

www.rogermerriman.com
Capital to Coast
www.justgiving.com/rogermerriman

Message #14 - Posted 2009/07/10 - Roger Merriman

Jaimie Vandenbergh wrote:

On 8 Jul 2009 17:55:30 GMT, Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

It'll trip out if the MBP asks more power than it can supply.

I did this with an Air 45W psu and a MacBook, normally 60W. I was reinstalling the MB, and the Air psu kept it going all the way until Spotlight indexing started on first login. At that point the Air psu gave up and the overpower trip went.

Took the psu ten minutes to reset and carry on working, no obvious harm done. I've used it for more than a year since then.

Cheers - Jaimie

I used to end up buying the higher spec powersupplys for my old 12inch powerbook as it would over heat and trip out the correct ones, at least if working hard anyway.

roger

www.rogermerriman.com
Capital to Coast
www.justgiving.com/rogermerriman

Message #15 - Posted 2009/07/10 - Jim

On 2009-07-10, Roger Merriman wrote:

Hannah and I (MacBook and MacBook Pro) just pick up whichever power supply is closest. No issues.

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Jim

well at least he didn't say ibook...

Heh. Good point.

Jim

http://www.ursaMinorBeta.co.uk http://twitter.com/GreyAreaUK Please help save Bletchley Park - sign the petition for Government funding at: (open to UK residents and ex.pats) http://petitions.number10.gov.uk/BletchleyPark/ Thank you.

Message #16 - Posted 2009/07/10 - Jaimie Vandenbergh

On Fri, 10 Jul 2009 10:13:09 +0100, Roger Merriman wrote:

Jaimie Vandenbergh wrote:

On 8 Jul 2009 17:55:30 GMT, Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

It'll trip out if the MBP asks more power than it can supply.

I did this with an Air 45W psu and a MacBook, normally 60W. I was reinstalling the MB, and the Air psu kept it going all the way until Spotlight indexing started on first login. At that point the Air psu gave up and the overpower trip went.

Took the psu ten minutes to reset and carry on working, no obvious harm done. I've used it for more than a year since then.

I used to end up buying the higher spec powersupplys for my old 12inch powerbook as it would over heat and trip out the correct ones, at least if working hard anyway.

Coo. Mine never did that. Still doesn't, according to my sister.

Cheers - Jaimie

Okay, it works now. Or at least it malfunctions in all the expected ways. -- Mark Edwards, asr

Message #17 - Posted 2009/07/10 - Roger Merriman

Jaimie Vandenbergh wrote:

On Fri, 10 Jul 2009 10:13:09 +0100, Roger Merriman wrote:

Jaimie Vandenbergh wrote:

On 8 Jul 2009 17:55:30 GMT, Richard Tobin wrote:

Is it safe to use an old 60W Magsafe power supply with a new 15" Macbook Pro (which comes with an 85W one)? Will it just charge more slowly rather than, say, frying the power supply?

It'll trip out if the MBP asks more power than it can supply.

I did this with an Air 45W psu and a MacBook, normally 60W. I was reinstalling the MB, and the Air psu kept it going all the way until Spotlight indexing started on first login. At that point the Air psu gave up and the overpower trip went.

Took the psu ten minutes to reset and carry on working, no obvious harm done. I've used it for more than a year since then.

I used to end up buying the higher spec powersupplys for my old 12inch powerbook as it would over heat and trip out the correct ones, at least if working hard anyway.

Coo. Mine never did that. Still doesn't, according to my sister.

Cheers - Jaimie

mostly playing games for a few hours that would do it, you'd notice when either you'd hear the bleep of battery out of juce or when it just went to sleep though once given some power it wouldn't crash just carry on, with killing zerg or what ever.

roger

www.rogermerriman.com
Capital to Coast
www.justgiving.com/rogermerriman

Message #18 - Posted 2009/07/10 - Jaimie Vandenbergh

On Fri, 10 Jul 2009 10:36:05 +0100, Roger Merriman wrote:

Jaimie Vandenbergh wrote:

On Fri, 10 Jul 2009 10:13:09 +0100, Roger Merriman wrote:

I used to end up buying the higher spec powersupplys for my old 12inch powerbook as it would over heat and trip out the correct ones, at least if working hard anyway.

Coo. Mine never did that. Still doesn't, according to my sister.

Cheers - Jaimie

mostly playing games for a few hours that would do it, you'd notice when either you'd hear the bleep of battery out of juce or when it just went to sleep though once given some power it wouldn't crash just carry on, with killing zerg or what ever.

That would do it - I rarely played games for a great length of time on it, though I did knock off quite a lot of Stubbs the Zombie.

Cheers - Jaimie

If it's not worth doing, it's not worth doing well.

Message #19 - Posted 2009/07/10 - Jim

On 2009-07-10, Gwynne Harper wrote:

Jim wrote:

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Does that include running them the other way around (ie 85W on a 60W machine)?

I'm almost completely sure you meant to reply to someone else.

Jim

http://www.ursaMinorBeta.co.uk http://twitter.com/GreyAreaUK Please help save Bletchley Park - sign the petition for Government funding at: (open to UK residents and ex.pats) http://petitions.number10.gov.uk/BletchleyPark/ Thank you.

Message #20 - Posted 2009/07/10 - Gwynne Harper

Jim wrote:

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Does that include running them the other way around (ie 85W on a 60W machine)?

Gwynne

My real email is net, not line.

Message #21 - Posted 2009/07/12 - Gwynne Harper

Jim wrote:

Does that include running them the other way around (ie 85W on a 60W machine)?

I'm almost completely sure you meant to reply to someone else.

I think you're right, however I'm an equal opportunities replier.

Gwynne

My real email is net, not line.

Message #22 - Posted 2009/07/12 - zoara

Gwynne Harper wrote:

Jim wrote:

I have problems with any sentence you write containing the words 'MacBook' and 'no issues'.

Does that include running them the other way around (ie 85W on a 60W machine)?

Yep.

Though the caveat already mentioned about my luck with Macs does apply...

-zoara-

"And the tiny universe compiles."
http://powazek.com/posts/1655

Message #23 - Posted 2009/07/13 - Gwynne Harper

zoara wrote:

Though the caveat already mentioned about my luck with Macs does apply...

Goodo - I did it a few times without even thinking about it, then thought the better of it until such foolhardiness passed the UCSM litmus test.

Moving house next week - wish me luck...

Gwynne

My real email is net, not line.

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