rMBP 13 charges faster with 85W Magsafe?

[scooby321]

Does the rMBP 13 charge faster with a 85 W Magsafe adaptor? Has anyone ever benchmarked?

If I understand correctly, size difference between 60 W and 85 W is minimal but I could not find any information on weight difference. Any information would be greatly appreciated!

 

[justperry]

Most likely it will not charge faster, the Wattage is the maximum the Power Supply delivers, it does not mean it will deliver that much, it would not be good for a charger to be charging at 100% capacity.

The Laptop is the one asking (controlling) for Power, so if it asks for 2 Amps it won't matter if the power supply can deliver 10 Amps.

 

[Stetrain]

I use an 85w charger with my 2008 13" aluminum Macbook. As far as I can tell the charging speed difference is negligible, but the charger does stay much cooler since it isn't being used at max capacity.

 

[justperry]

I use an 85w charger with my 2008 13" aluminum Macbook. As far as I can tell the charging speed difference is negligible, but the charger does stay much cooler since it isn't being used at max capacity.

You confirmed what I was thinking, and yes it should stay cooler since the load is less.

Thanks

 

[drambuie]

The one situation where the 85W charger could provide quicker charging than the 60W one, is when you are using the MBP at high CPU load while charging the battery.

 

[justperry]

The one situation where the 85W charger could provide quicker charging than the 60W one, is when you are using the MBP at high CPU load while charging the battery.

You don't know, the MBP internal SMC might prevents higher charging, there is very likely to be a maximum Amp set so it won't matter.

 

[drambuie]

You don't know, the MBP internal SMC might prevents higher charging, there is very likely to be a maximum Amp set so it won't matter.

I know the maximum charging rate is fixed. I was referring to situations where the battery charges much more slowly, or even drains, especially with USB peripherals attached, if the MBP is being used at high load while charging.

My 15" MBP charges a lot faster if powered off during charging. The 15" could probably do better with a 100W power supply.

 

[justperry]

I know the maximum charging rate is fixed. I was referring to situations where the battery charges much more slowly, or even drains, especially with USB peripherals attached, if the MBP is being used at high load while charging.

My 15" MBP charges a lot faster if powered off during charging. The 15" could probably do better with a 100W power supply.

Of course it will charge faster if off, then all the power from the charger is available for charging instead of half to the System half for charging, a 100 Watt charger would not do anything or very little as confirmed by Stetrain.

 

[dusk007]

According to a thg article the 15" charges at 35W when off max and never more than 30W when on.
The 13" has a few cells less so it is probably a little less. Everything past that it won't do because the battery pack doesn't like to be charged too quickly. Afaik it is always a bit of a tradeoff between longevity and fast charging. Or was it capacity. Anyway usually how fast a given battery is supposed to be charged is limited. You can always charge lower but not faster, at least it ain't smart to do.
Between 80 and 100% the charge rate sinks dramatically. Once it is mostly full it needs less.

If the supply can deliver those 30W on top of what the machine consumes while you are using it, charge rate will be as good as it can be.