Thanks for posting the article. I did not have a chance to post on this topic. You are correct and I used the 85 watt supply on several occasions without any problems.
Scott Howell Sent from my iPad On Aug 21, 2011, at 0:03, Chris Blouch <cblo...@aol.com> wrote: > If you try to run a 50watt device from a 25watt source the source power > supply is going to either overheat or be current limited such that the device > will get only 25watt of power. Apple supplies current limit. Just because > your MacBookPro can draw 85w of power doesn't mean the 45w supply starts to > overheat, it just gives it all it has and no more. So using a 45w or 60w > power supply for an 85w machine might be enough to limp along on but not > enough to charge your batteries at the same time. > > The reverse case is also safe. Using a larger supply on a smaller mac > shouldn't hurt anything. Just because your supply can crank out more amps > doesn't mean the device will make use of it. Just like the power available > from the power company has a lot more amps than you can (safely) use it > doesn't mean your coffee pot will start to melt. Only if they started sending > you the wrong voltage would things go awry. > > The main problem with DC power supplies is getting the wrong voltage. If your > device needed 6 volts and you plug in a 12 volt supply you may fry its > innards. Doesn't matter what the current draw is. So in the case of swapping > power supplies between models, all the voltages are the same. Apple has a FAQ > on this topic here: > > http://support.apple.com/kb/HT2346 > > and I recall a similar thread coming up elsewhere because the apple airplane > adapter apparently could only produce enough power to operate the machine > without charging the batteries. Apparently the airlines limited power on > their jacks to the point where drawing any more would pop their circuit > breakers. I guess it was designed with iPods, not laptops in mind. > > CB > > On 8/20/11 5:41 PM, Christopher-Mark Gilland wrote: >> Tim wrote: >> >> 3. You may get away with things for a while, but I recommend that you use >> the proper rated power supply, especially if you have any warranty left on >> the machine. >> >> I highly agree. It's never that great of an idea, in my opinion to >> mix-match chargers, that's only asking for trouble in the long run. >> >> Now, if you have to products same make same model same everything, then, >> that's a different story, but... >> >> Chris. >> >> ----- Original Message ----- From: "Tim Kilburn" <kilbu...@shaw.ca> >> To: <macvisionaries@googlegroups.com> >> Sent: Saturday, August 20, 2011 5:35 PM >> Subject: Re: charger Compadibility >> >> >> Hi all, >> >> They will all work with each other although, electrically, there are some >> things you should note: >> >> 1. If a unit is expecting a 45 watt power supply and you give it an 85 watt >> power supply, you may decrease the life of both the battery and the charging >> unit. consider that you're pushing almost twice the wattage into the >> charging unit as it is rated for. In some cases this will burn the unit out >> faster, and in some cases, it will simply burn it out immediately. Also, >> consider that heat is one of the most damaging factors in battery life, if >> an increased amount of power is being pushed onto the battery, it will heat >> up more, thus, the battery will get hotter during charging probably reducing >> its life. >> >> 2. The other direction, charging with a 45 watt when expecting an 85 watt >> power supply, does not hurt anything really. It will simply make the >> charging process take longer. >> >> 3. You may get away with things for a while, but I recommend that you use >> the proper rated power supply, especially if you have any warranty left on >> the machine. >> >> Later… >> >> On 2011-08-15, at 8:00 AM, Chris Blouch wrote: >> >>> While not quite the same setup my MacBook Pro charger works just fine in my >>> wife's old little MacBook and vice versa. Main thing is that her power >>> supply is not quite as big (physically and wattage) so it takes longer to >>> charge up my laptop if I'm using her power supply. I would assume similar >>> things with the Air and your MacBookPro where the Air uses a 45 watt power >>> supply: >>> >>> http://www.apple.com/macbookair/specs.html >>> >>> While the current MacBookPro has an 85w power supply >>> >>> http://www.apple.com/macbookpro/specs.html >>> >>> So I think whomever you passed the MacBookPro along to would appreciate >>> getting the correct larger power supply. >>> >>> CB >>> >>> On 8/14/11 7:55 PM, Mike Arrigo wrote: >>>> It should be, the macbook pro is a higher wattage charger, so, assuming it >>>> fits, it should work, though of course it won't charge any faster. >>>> On Aug 14, 2011, at 1:08 PM, Dan Roy wrote: >>>> >>>>> I am expecting my new macbook air to arrive tomorrow. Does anybody know >>>>> if the charger from the macbook pro is compatible with the 1 from the >>>>> macbook air. >>>>> >>>>> If I do sell the macbook pro, if the chargers are compatible, I can >>>>> package the macbook pro with the brand new charger. Knowing my luck, this >>>>> won't work. I just wanted to check and see if anyone knew for sure? >>>>> >>>>> If this is considered off topic, you can reply to me at: >>>>> d...@theroyhouse.com thanks. >>>>> >>>>> >>>>> -- >>>>> You received this message because you are subscribed to the Google Groups >>>>> "MacVisionaries" group. >>>>> To post to this group, send email to macvisionaries@googlegroups.com. >>>>> To unsubscribe from this group, send email to >>>>> macvisionaries+unsubscr...@googlegroups.com. >>>>> For more options, visit this group at >>>>> http://groups.google.com/group/macvisionaries?hl=en. >>>>> >>> >>> -- >>> You received this message because you are subscribed to the Google Groups >>> "MacVisionaries" group. >>> To post to this group, send email to macvisionaries@googlegroups.com. >>> To unsubscribe from this group, send email to >>> macvisionaries+unsubscr...@googlegroups.com. >>> For more options, visit this group at >>> http://groups.google.com/group/macvisionaries?hl=en. >>> >> >> Tim Kilburn >> Fort McMurray, AB Canada >> > > -- > You received this message because you are subscribed to the Google Groups > "MacVisionaries" group. > To post to this group, send email to macvisionaries@googlegroups.com. > To unsubscribe from this group, send email to > macvisionaries+unsubscr...@googlegroups.com. > For more options, visit this group at > http://groups.google.com/group/macvisionaries?hl=en. > -- You received this message because you are subscribed to the Google Groups "MacVisionaries" group. 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