Are Apple's power supplies interchangable?

[Wolfpup]

Apple's got a 90, 60, and 45 watt PSU for their various notebooks (unless they have larger I'm not aware of).

And...all three cost the same price.

I'm just wondering-are they interchangeable? Like a system that comes with a 45, can it use a 90? Or a 60 a 90?

I'm just thinking if they're all compatible, there would seem to be no reason for me to buy a 45 watt PSU for an air (or a 60 for a 13" Pro) if the 90 works, as then I might be able to use the 90 on more systems down the line?

EDIT: Sorry, I should clarify that I know I shouldn't use a smaller one to power a larger one, but I was hoping it was okay to use a larger one to power a smaller one, if that makes sense. Wasn't sure if Apple used the same connector, or was doing something else weird, but it sounds like they're all the same, so you can buy a 90 for the Air or 13" Pro!

 

[GoCubsGo]

I don't think so.

 

[Intell]

You can use an 85W to charge an Air. But cannot use a 45W to charge a 17" Macbook Pro. It will not damage the Macbook in anyway to use a higher rated wattage, but they should not be used with a lower rated wattage.

 

[HellDiverUK]

I'm just wondering-are they interchangeable?

Yes.

 

[wpotere]

You can use an 85W to charge an Air. But cannot use a 45W to charge a 17" Macbook Pro. It will not damage the Macbook in anyway to use a higher rated wattage, but they should not be used with a lower rated wattage.

What this guy said, not the poster above me.

 

[onthecouchagain]

My understanding is you can go one way, but not the other. And if I have it right, you can go higher to lower, but not lower to higher. Meaning, you shouldn't use the 45 to charge something that requires 60. But you can use the 60 to charge something that only requires 45.

Please correct me if I am wrong. This is my understanding, but I don't want you to ruin anything because of my misinformation.

 

[Wolfpup]

Cool, thanks! I'm semi-confused by why they bother selling the lower wattage PSUs then if they charge the same price, but thanks to you guys I'll just buy a 90! (Or an 85 I guess? Whatever the largest one is)

 

[HellDiverUK]

They're all interchangable. The lower wattage ones just take longer to charge a higher power laptop.

As the OP is looking to buy a 90W one, it'll work on all Apple laptops using MagSafe.

So, the answer is still yes.

 

[Intell]

Cool, thanks! I'm semi-confused by why they bother selling the lower wattage PSUs then if they charge the same price, but thanks to you guys I'll just buy a 90! (Or an 85 I guess? Whatever the largest one is)

The higher wattage ones get hotter, use more power, and are probably more expensive to make.

 

[416049]

They're all interchangable. The lower wattage ones just take longer to charge a higher power laptop.
.

um not entirely you can charge a laptop that needs a higher wattage charger i.e 85 watts with a lower wattage one but only if there is still charge in the battery and the battery is not completely drained. I have read it somewhere in the apple support discussions.

Official Apple Article quote :

For instance If you have a MacBook (13-inch Late 2009) that normally uses a 60W adapter, you can also use an 85W adapter with that computer. You would not use a 45W adapter with that computer; it would not provide enough power for that MacBook. Using an adapter of higher wattage than the adapter that came with the computer will not cause the computer to charge more quickly or otherwise operate any differently than using the adapter that came with the computer.

http://support.apple.com/kb/HT2346

 

[Wolfpup]

The higher wattage ones get hotter, use more power, and are probably more expensive to make.

Could get hotter...but only if they're drawing more power. Can use more power, but not really when connected to an Air or 13" Pro.

I mean PSUs tend to have loads under which they're most efficient, and maybe say the 60 watt one is the most efficient when powering an Air, or something...but I'd have to actually buy them all and test that, and it could be the 90 watt one that's most efficient for all I know, and I doubt it's a huge difference

 

[xraydoc]

The higher wattage ones get hotter, use more power, and are probably more expensive to make.

The 45 watt unit is much smaller/lighter than the 85 watt model that comes with the 17" MBP and higher end 15", and a bit smaller than the 60 watt.

 

[Intell]

The 45 watt unit is much smaller/lighter than the 85 watt model that comes with the 17" MBP and higher end 15", and a bit smaller than the 60 watt.

I thought they where different sizes. Wasn't quite sure. I guess you can add "shipping costs" to the list.

 

[Wolfpup]

Still tiny though. Wouldn't be an issue for me even if I carried it...which I don't, because I leave one at home, and one at work, which makes it much faster to just throw my PC in my bag, and faster to hook up too.

I still think maybe I'll need a 15 or 17" Pro though so I must get the larger PSU

 

[onthecouchagain]

Is there a difference between the 13" Air charger and the Pro 15" charger? Just wondering.

 

[Wolfpup]

Is there a difference between the 13" Air charger and the Pro 15" charger? Just wondering.

Yeah, the Air comes with a 45 watt PSU I think, and the 15" Pro comes with a 60 or 90 watt PSU, but you can use the 90 watt one on systems that ship with 60 or 45.