60W Power supply for retina?

[rpg51]

Will the spare power supply from my old MBA work ok with my new 13 inch retina MBP if I get one of the $10 magsafe 2 adapters? Will there be enough power to get through a work day at the office if I arrive with a full charge?

 

[clyde2801]

If the charger is 60 watts, you'll be fine with the adapter. You can use a higher wattage charger with a lower wattage portable, but never the other way around.

And I'm pretty sure all macbook airs come with a 45 watt charger, not a 60 watt one. I'd check it out thoroughly first.

 

[rpg51]

Oooops. I got it wrong.

I meant to say can I use 45watt supply from my Air with new MBP retina?

 

[Wispy]

I meant to say can I use 45watt supply from my Air with new MBP retina?

What inch of Air and what inch of Retina? It is important.

 

[NewbieCanada]

I meant to say can I use 45watt supply from my Air with new MBP retina?

Yes, it will charge much more slowly though.

 

[rpg51]

13 inch air and 13 inch retina.

I assume it will work but charge more slowly as you say. Do you think though it would be strong enough to keep a full battery from discharging fully in an 8 hour day of continuous light use - word processing and e mail?

 

[rpg51]

Reply to my own thread!

I got my hands on a magsafe 2 adapter and I have been using my old MBA spare power supply (45 watt) with my newish 13 inch retina MBP and this is what I find.

Charging a depleted battery with the 45 watt supply takes a significantly longer time that it does with the 60 watt supply that came with the rMBP. But, on the other hand, the 45 watt supply works just fine if you are using the computer plugged in the entire time on a desk, as I will be during the day at my work station. The battery is maintained at exiting levels and does slowly increase its charge even while I am using the computer for basic tasks such as word processing, e mail, internet access, even watching a movie. So for me this is going to work fine.

 

[NewbieCanada]

13 inch air and 13 inch retina.

I assume it will work but charge more slowly as you say. Do you think though it would be strong enough to keep a full battery from discharging fully in an 8 hour day of continuous light use - word processing and e mail?

Yes, definitely. I have an MBA 13 charger that I use with a 15 rMBP. Under HEAVY use (like video encoding) you’ll see the battery slowly discharge, but under normal use it will maintain and charge. You’d definitely be back to 100% before the end of the day.