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iMick
23rd March 2005, 10:04 AM
First n00b post!

Quick question: Is it possible to run the 65W 17" powersupply with a 12" PB and iBook that are rated for the 45W powersupply safely? I have a 17"PB for work and wonder if i can charge my 12" and iBook with it without toasting the batteries.

Cheers

karma
23rd March 2005, 10:09 AM
no worries

iMick
23rd March 2005, 10:34 AM
Thanks karma, I take it that it won't be a problem.

Martin
23rd March 2005, 11:07 AM
It won't be a problem. Why? Because the rated capacity of the power supply is irrelivant, unless of course it's UNDER-Rated. Then you're overloading the power supply obviously.

It doesn't matter if the power supply you have is 100-gigawatts, the simple matter is the laptop will only charge the battery at the rate it wants, and only draw the current it needs, it has a regulation circuit in it which handles all this.

Hope this helps.

Cheers,
Martin.

purana
23rd March 2005, 12:48 PM
The question they asked was valid.. as older generation machines (ibook I think, can't recall exact models concerned) had power adapters that you shouldn't mix with other machines. As it could damage the machine you used it with (as it wasn't compatible even though both machines were ibooks per se). For the life of me I can't recall the models, but I am sure you'd find the knowledge base article on apple if you searched.

iMick
23rd March 2005, 02:49 PM
Yeah thanks guys, I am pretty sure that it I will be ok to swap the power supplies. The apple knowledge base article I was looking at didn;t say you can but didn't say you can't.

I rang the local apple store for info and the guy said it would be fine, they do it all the time and it would charge my battery faster!! :P

pipsqeek
24th March 2005, 03:25 PM
You won't overload the Power supply by connecting an underrated one.. you will mearly be undercharging the battery.

Provided the voltages are the same (24.4V DC for example) then with most occasions you will be fine.

The fact that you are charging a 12" PB with a 17" PB charger logically tells me that the charger is overrated for the 12" and that it should cope just fine.

It won't charge your battery any faster as this is dependant on the battery capacity and Ampere hour rating. Also, above all, I would say (and I don't know this for sure... just from my electrical knowledge) that the DC board inside the machine will more then likely be controlling that sort of thing anyway. If the battery you are using is rated at 65Ah and the charger you are using is for a 75Ah battery. Then the battery will still only charge at whatever the previous (original charger) did. With 10Ah to spare. The charge rate varies and I am not sure what it could be on an Apple Book of any kind. But if it roughly takes 2 hours to fully charge a battery then I'd assume that the charge rate is about (for a 65Ah battery) 32.5A over two hours. Ofcourse this doesn't happen in real life because of the completely infinite variations in charging rates.

You can calculate how much current your machine draws by roughly calculating 65Ah/how many hours the machine runs for before it needs charging (goes to sleep). lets say 4 hours. Then the machine uses approximately ~16.25Ah

Repeating what I said earlier, Yes you can use it just fine. :)


pipsqeek

blueblue
13th January 2006, 06:06 PM
Originally posted by purana@Mar 23 2005, 12:48 PM
The question they asked was valid.. as older generation machines (ibook I think, can't recall exact models concerned) had power adapters that you shouldn't mix with other machines. As it could damage the machine you used it with (as it wasn't compatible even though both machines were ibooks per se). For the life of me I can't recall the models, but I am sure you'd find the knowledge base article on apple if you searched.
Hi - first post

I have a powerbook G4 15inch 550MhZ 'gigabit ethernet' model and the original power adapter broke (tip broke off). Can I use the new 65W power adapter? The repair place sold me one but when I tried it the area around where the adapter plugs in to the powerbook got very hot. Does anyone know if this will cause damage? The store says the 65W is backwards compatible and works with G4 Titanium powerbooks , however not sure if my model is technically speaking the same as the G4 Titanium (model listed as 'gigabit ethernet' on everymac), even though it is a greyish metal colour. Has anyone had experience of this? Should i buy a third party adapter?
Thanks

Squozen
14th January 2006, 09:10 AM
It's fine, don't worry about it. Power supplies only provide as much power as is demanded (until they reach their limit, naturally).

Ozi
14th January 2006, 09:15 AM
oh and the Power Supply Unit (PSU) is the board running inside the powerboard which sends power to the Mail Logic Board. I believe that Apple calls the external supply of power a power adaptor.

Squozen
14th January 2006, 09:25 AM
Same thing.