Do I have to have 85w magsafe ?

[biggun]

I have two Macbook Pros. One is a 17 inch 2.4 c2d. The other is a new 15 inch i7 2.0. I lost one adapter and mistakenly bought a 60w unit. Am I correct in my thinking that the 60w will work on either but will just charge the battery slower?

 

[fr]

Yes. I also sometimes use a 60w instead of the 85w. There were times when encoding video when it would still drain the battery, but no ill effects yet.

 

[rugby]

It will power the machine just fine, but it might not charge it while the machine is being used.

 

[TheStu]

It will work, and an 85W will work on the lesser machines, but as others have pointed out the 60W will charge it but it will take longer, and I think that it will make it run hotter than usual.

 

[wantedSpidy]

It will work, and an 85W will work on the lesser machines, but as others have pointed out the 60W will charge it but it will take longer, and I think that it will make it run hotter than usual.

I'm not sure about the 'run hotter than usual', but as other pointed out it'll take longer to charge, and may not even charge while you're using it for intense power draining work.

 

[TheStu]

I'm not sure about the 'run hotter than usual', but as other pointed out it'll take longer to charge, and may not even charge while you're using it for intense power draining work.

I seem to recall my MacBook power brick running hotter than usual when my friend was using it to charge his MBP. Not a whole lot hotter, but a little.

 

[biggun]

I appreciate all the responses. Eases my mind.


Thanks for your time.

 

[wantedSpidy]

I seem to recall my MacBook power brick running hotter than usual when my friend was using it to charge his MBP. Not a whole lot hotter, but a little.

Oh sorry I thought you were saying the laptop would run hotter than usual. I can see the lower watt rated power brick getting hotter, surely.

 

[JC86]

The charger definitely runs hotter although it still charged, albeit much slower.

 

[Emulex]

macbook's exceed 85w anyways. so they clock down when on the charger and cranking out to prevent battery total drainage.

for slow charge = sure.

85w is underrated for the high line macbook pro's already. throttling is what you get.

 

[nerp]

I tried a 60w magsafe on my 13" Macbook Pro and it just flat out didn't work. Had to return it for the 85w. No charge, no light, nothing. I'm surprised to hear you guys had it working on a 15". Whatever.

 

[TheStu]

macbook's exceed 85w anyways. so they clock down when on the charger and cranking out to prevent battery total drainage.

for slow charge = sure.

85w is underrated for the high line macbook pro's already. throttling is what you get.

They throttle all the time anyway, but they do not limit you when you are on the charger.

My roommate ran a series of tests on his MBP, running the same benchmark that stressed the CPU, he got identical times in all but one circumstance, these are the setups;

Battery In, Battery Power (some score that I cannot recall)
Battery In, Mains Power (same score as above)
Battery Out, Mains Power (same score as above)
Battery Out, Battery Power (no result here obviously )

 

[TheStu]

I tried a 60w magsafe on my 13" Macbook Pro and it just flat out didn't work. Had to return it for the 85w. No charge, no light, nothing. I'm surprised to hear you guys had it working on a 15". Whatever.

See that's weird, because I thought the MBP13 was 60W.

 

[Emulex]

They throttle all the time anyway, but they do not limit you when you are on the charger.

My roommate ran a series of tests on his MBP, running the same benchmark that stressed the CPU, he got identical times in all but one circumstance, these are the setups;

Battery In, Battery Power (some score that I cannot recall)
Battery In, Mains Power (same score as above)
Battery Out, Mains Power (same score as above)
Battery Out, Battery Power (no result here obviously )

http://appleguru.org/blog/2011/04/12/2011-macbook-pro-battery-not-charging-under-gpu-load/

90W full load - how do you expect it to operate at 90W forever?

 

[TheStu]

http://appleguru.org/blog/2011/04/12/2011-macbook-pro-battery-not-charging-under-gpu-load/

90W full load - how do you expect it to operate at 90W forever?

Well, to be fair, you never specified the 2011 MBP specifically as having this problem. My roommate has the '09 unibody.

 

[nerp]

See that's weird, because I thought the MBP13 was 60W.

Mine (work issued) came with the 80w one. I bought the 60w one as a backup/road adapter. Was driving back to Best Buy for an exchange a few hours later. This is the previous gen macbook pros, c2d.

 

[TheStu]

Mine (work issued) came with the 80w one. I bought the 60w one as a backup/road adapter. Was driving back to Best Buy for an exchange a few hours later. This is the previous gen macbook pros, c2d.

Still confused...

The official page for the 13" MacBook Pro states that it comes with the 60W adapter. And the current MacBook which is equal to the old 13" MacBook Pro, also comes with the 60W.

Not saying that it didn't happen, but like I said... confused.

 

[nerp]

I am too. I'll take a second look at my stuff, but I swear I had to swap the adapter at Best Buy for the higher wattage one because it just wouldn't charge. There is a possibility that the 60w one I got was defective.

 

[Suspicious-Teach8788]

I used a 60W just to charge. Felt like the brick was gonna blow up. It was so hot. I'm sure you can get away using a 60W and surfing, but any encoding, you might actually drain the battery.

I realise there is a fear of exceeding 85W which is why when you unplug the battery which a lot of ppl used to do for fear of excessive charging, the CPU throttles to 50% speed. However, I've NEVER seen my MBP exceed 85W using my Kill-a-Watt.

 

[TheStu]

I used a 60W just to charge. Felt like the brick was gonna blow up. It was so hot. I'm sure you can get away using a 60W and surfing, but any encoding, you might actually drain the battery.

I realise there is a fear of exceeding 85W which is why when you unplug the battery which a lot of ppl used to do for fear of excessive charging, the CPU throttles to 50% speed. However, I've NEVER seen my MBP exceed 85W using my Kill-a-Watt.

They throttle all the time anyway, but they do not limit you when you are on the charger.

My roommate ran a series of tests on his MBP, running the same benchmark that stressed the CPU, he got identical times in all but one circumstance, these are the setups;

Battery In, Battery Power (some score that I cannot recall)
Battery In, Mains Power (same score as above)
Battery Out, Mains Power (same score as above)
Battery Out, Battery Power (no result here obviously )

Unless of course you are referring to the latest gen that emulex showed actually pulled 90W at load. But I can point to actual tests that demonstrate that the system is not throttling any more aggresssively than it would normally, and is not limiting the user if they actually need the power.

I don't care if it throttles the CPU 90% if the system isn't doing anything.