Charging European MBP in USA ("step-up" conversion?)

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Level 1

4 points

Charging European MBP in USA ("step-up" conversion?)

I know MagSafe handles step-down conversion for USA->EU charging, so all you need is an adaptor. That makes sense, since we're removing voltage to bring 220v down to 110v. But how does it work the other way around - charging an EU MBP in USA? In my mind you can't add volts to perform step-up conversion (110 -> 220). Is it just that all MBPs, EU or USA, require the least common denominator of 110v?

Backstory: my MBP is breaking while I'm on vacation, may have to buy a new one in EU. Safe to bring home and charge forevermore?

MacBook Pro with Retina display

Posted on Sep 1, 2016 7:10 AM

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Answer 1

Sep 1, 2016 7:40 AM in response to lefnire

Th Apple adapter select by sensing the input voltage. It does not ADD voltage it selects whether to chop up the input voltage (it chops it up if its higher) and does not if it's lower.

The AC adapter is fine for US and EU. You will simply need to correct plug adapter

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Answer 2

Sep 1, 2016 7:51 AM in response to lefnire

I just looked at the charger for my older MacBook and its rated output is 16.5 V. In other words pretty much any domestic electrical source is going the be reducing the voltage to a much lower one which is the voltage at which the battery is really charging. What your charger does is automatically detect the voltage at the source and within a certain range automatically reduces it to the correct output voltage.

Incidentally, a transformer can transform any voltage into any other voltage, including stepping up 110 V to 220 V. The main difference between European power supply and US domestic supply is supplying a certain number of amps at each voltage which results in a greater wattage output (actual total power = volts x amps). This is why electric kettles boil water faster in Europe.

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Answer 3

Sep 1, 2016 9:28 AM in response to Limnos

The AC Conditioning filters the incoming voltage and steps the voltage down (whether 120 or 240 VAC). After the rectifier, the DC voltage will be one value when the input is 120VAC and about double when the voltage is 240AC. The DC/DC (DC to DC converter) will regulate the rectified voltage to the specified output voltage whether it is 20VDC or 40VDV. That was what I was referring to as "Chopping" the voltage.

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Answer 4

lefnire Author

Level 1

4 points

Sep 1, 2016 10:09 AM in response to lefnire

Thanks for all the replies, appears I'm in good hands! Excuse my hardware newbiness, I'm having trouble following. What I think I'm hearing is (1) step-up is possible, so this wouldn't be a problem theoretically; and (2) MBP consumes less than either EU or USA provides, so we're stepping down anyway. That is, it wouldn't be a problem to bring EU MPB to USA?

Partly why I ask is I was using my wife's Air charger (45w?) to charge my MBP (85w?), which actually damaged my battery. This contrary to what they told me at the Genius Bar ("it's no problem, they can all charge each other w/o issue"). In my newbie mind I relate these two - that is, USA outlets not providing enough juice to EU MBPs. Sounds like I should be fine though?

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Answer 5

OGELTHORPE

Level 9

57,329 points

Sep 1, 2016 10:37 AM in response to lefnire

lefnire wrote:

Partly why I ask is I was using my wife's Air charger (45w?) to charge my MBP (85w?), which actually damaged my battery.

Not a good idea. Get an 85w Charger for the MBP. The MBA charger is way under powered for the MBP.

Ciao.

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