110V vs. 220V, which is better?

Question

Level 1

10 points

110V vs. 220V, which is better?

I'm going to be living for the next several months where I can use either 110V or 220V power. I know the charger is dual voltage, and I can use it with either voltage with a simple plug adapter. My question is, which is preferable? Will the battery charge twice as fast at 220V? Will using 220V create other issues like excessive heat in the charger or laptop? Any other reasons I'm not thinking of? I know the simple Watts = Volts x Amps, but I think that's more for DC current, and I suspect there are other more complex issues with how the charger handles voltage. Since I am not an electrical engineer I'm not really sure how it works. Thanks!

MacBook Pro, Mac OS X (10.5.6)

Posted on Jan 17, 2009 10:30 AM

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Answer 1

Kappy

Level 10

361,995 points

Jan 17, 2009 11:52 AM in response to Lee C.

It doesn't make any difference. The AC adaptor switches automatically to whichever voltage is used.

No, the battery won't charge twice as fast. The voltage may double, but the current will halve. Power resulting is the same.

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Answer 2

carl wolf

Level 6

14,631 points

Jan 17, 2009 3:17 PM in response to Lee C.

"Will using 220V create other issues..."
The power adpater places one-half of the line voltage onto the computer chassis. This results in leakage to the case. If you use 220V, the leakage is annoying.

"I know the simple Watts = Volts x Amps, but I think that's more for DC current..."
The formula works with AC, too.

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Answer 3

Jan 18, 2009 3:09 AM in response to Lee C.

Biggest difference will be how the 110 V and 220 V (most likely 230V nowadays) will be generated in the first place: are they from independent sources (which I doubt) or is your place fed with 110 V only which is then transformed into 230 V locally (or vice versa)?

Then you'd want to investigate there to avoid reverse transformation with transformation related losses (meaning if it's only 110 V you should use 110 V, if it's only 230 V that reaching your place, use 230 V)...

Best regards,
Michael

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Answer 4

capaho

Level 4

3,677 points

Jan 18, 2009 4:10 AM in response to Lee C.

Will the battery charge twice as fast at 220V?

No. The power adapter contains a power supply that steps down the input voltage and outputs the same amount of power to the MBP regardless of whether it's plugged into a 100V outlet, a 110V outlet, or a 220V outlet.

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Answer 5

Lee C. Author

Level 1

10 points

Jan 18, 2009 6:24 AM in response to Lee C.

Interesting discussion, thanks to everyone that responded. I will be somewhere where the "true" power is 220V, with European plugs, but is also being stepped down to 110 with American plugs for ease of use for American appliances. This leaves me with a dilemma, according to Carl, I should stay away from the 220 for case leakage reasons, but according to Michael better to stay with 220 to avoid issues related to power conversion. So the winner is....

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Answer 6

Jan 18, 2009 8:14 AM in response to Lee C.

Dear Lee,

As I live in Europe, I can share some additional advice: I'm running the MBP here on the standard 230 V without any problems; given the fact that it's the same model you get in the US (power supply wise, of course keyboards differ), there shouldn't be ANY issues.

With regards to leakage current, they should be within safety limits either way and - as usual - the voltage does not say anything about it, it is a question of total power; you can find some interesting reading here: http://books.google.com/books?id=h1YDVXADtiQC&pg=PA365&lpg=PA365&dq=IEC364Art.707.471.3.3.1&source=web&ots=6qb9-F0HLF&sig=fLlCqM9pU48pXc6WRWQ0SF8A8Wk&hl=e n&sa=X&oi=book_result&resnum=1&ct=result#PPA365,M1)

Best regards,
Michael

P.S.: When you're there, you can just meter the leakage between case an Earth in either case...

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Answer 7

Kappy

Level 10

361,995 points

Jan 17, 2009 7:44 PM in response to carl wolf

Only if it's single phase. Three-phase puts the the chassis at ground.

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