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View Full Version : Safe to use a 60w Magsafe with Macbook Air?




Gadgetman99
Sep 6, 2009, 06:27 AM
I ask because the voltage is higher (16.5v vs 14.5v). I would assume the 60watt would charge faster, but not sure if the voltage increase will do damage.



Barbie
Sep 6, 2009, 07:04 AM
some have reported that the charger will cause the Air's battery to swell, as the charger can also swell the Pro machines' batteries too.

obviously any inflation inside the MacBook Air will damage the very tight hardware packed inside the thin notebook

JFreak
Sep 6, 2009, 07:53 AM
Yes it is safe. but if you're buying, why not buy the 85W version to begin with? That one can be used with MBP's as well.

The power supply is not outputting constant amount of power at all times. The Watt rating only defines the UPPER limit of what the brick can do. The laptop defines the amount of power it DRAWS from the brick and if that is within the capabilities of the brick, then it's all good.

That said, you can also use a 45W power brick with MBP's, just that it's not providing enough power which means that either the battery is not charging (fast enough at least) or the brick itself might overheat. I wouldn't try my luck, but it's not that the brick would suddenly make the battery explode.

Gadgetman99
Sep 6, 2009, 08:37 AM
Yes it is safe. but if you're buying, why not buy the 85W version to begin with? That one can be used with MBP's as well.

The power supply is not outputting constant amount of power at all times. The Watt rating only defines the UPPER limit of what the brick can do. The laptop defines the amount of power it DRAWS from the brick and if that is within the capabilities of the brick, then it's all good.

That said, you can also use a 45W power brick with MBP's, just that it's not providing enough power which means that either the battery is not charging (fast enough at least) or the brick itself might overheat. I wouldn't try my luck, but it's not that the brick would suddenly make the battery explode.

I agree with all you said, in regards to wattage, but what about voltage? If the MBA requires 14.5v and the 60 watt adapter is 16.5v, then I would think there could be an issue.

SeaneyC
Sep 6, 2009, 09:15 AM
Used a Macbook Pro adapter a few times with no issues. Other than the fact you need to have it on the edge of something so the connector isn't being leant upon, as the wire comes out straight, unlike the angled air connector.

alphaod
Sep 6, 2009, 01:17 PM
I often see Apple stores charge their MacBook Air computers with the 60W and 85W adapters, so if they do it, I don't see why it's bad for the computer.

JFreak
Sep 6, 2009, 01:25 PM
I agree with all you said, in regards to wattage, but what about voltage? If the MBA requires 14.5v and the 60 watt adapter is 16.5v, then I would think there could be an issue.

As I said, the bricks specify the MAXIMUM they can output, which is not necessarily what they need to output. Wattage is simply product of voltage and current, a number of how much power is consumed.

NC MacGuy
Sep 6, 2009, 01:40 PM
Been mixing and matching magsafes w. different models for a long time. Zero casualties have resulted.

Gadgetman99
Sep 6, 2009, 02:12 PM
Ok, so the consensus is, a little extra voltage is not an issue. So now I will explain the real reason I asked. I have been looking for an external battery solution that will not break the bank, but at least get me an extra batterys worth of power when traveling etc. So, I bought one of these:

http://www.thetechstop.net/?p=579

and one of these, just for the magsafe plug/cord combo:

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=110423202494&ssPageName=STRK:MEWNX:IT#ht_3357wt_1167

Both together cost me $42 (including shipping!). But the battery's lowest output setting is 15v, so if a 60w magsafe charger puts out 16.5v and works fine, then the extra .5v this setup will put out should not be an issue at all.

So now I will have a thin battery that will slip into a case with the MBA and at least double my battery run time (if not triple). Plus it will look good ok as well.

JFreak
Sep 6, 2009, 02:37 PM
Mixing and matching voltages is not like "square peg does not fit into a round hole" thing. If you have under-powered power brick for charging a battery, it does no harm but will take longer. Inversely, if you keep using your laptop while charging the battery with an under-powered charger, your battery will eventually lose its charge thus the laptop would power down.

And if you charge a battery too fast, it might overheat and explode. Properly designed power brick fits nicely in between.

Scottsdale
Sep 6, 2009, 11:13 PM
I have tested other more powerful charges on multiple occassions and there is NO DIFFERENCE in charge times! The only difference is it's a pain to use MB/MBP chargers with the MBA because they easily come loose as don't fit right.

I have read many people who claim it charges faster but my tests have shown ZERO differences. However it does make a difference to try to charge MBP with MBA charger.

Get the MBA charger for simpler connection and same charge time.

Good luck.