Deals: Take Up to 25% Off Anker's New USB-C Wall Chargers

[orev]

Does anyone know if fast charging degrades the life of the battery?

Yes, it degrades the battery. If you charge your phone overnight, just use the original small 5W charger, and/or make sure Optimized Charging is enabled in the battery settings.

Fast charging is good if you need to charge quick in an airport, or larger devices like laptops need them as those need more power.

 

[gbynum]

The MBA only uses 30 watts unless it's the new M2 version with fast charging (which requires 60+ watts).

I'm going to (politely) call you on that one. I have the Anker 45W Nano II which I use when away from home, and the Apple 30W at home. I've been of the opinion that my M1 MBA charged faster with the Anker. Tonight I used my "KILL A WATT" on my mostly discharged MBA. No USB-C connected, each read 0W. With the Apple, load from 118VAC line ramped up over perhaps 7 or 8 seconds to 30W. With the Anker, similar ramp, but to 46W.

I monitored VA as well, and it was in similar proportions.

I don't have a higher power charger to try, but am confident the MBA doesn't limit charge to 30W and will accept near 45W. Conversion efficiency is not, of course, 100%, so I'd estimate charge rate based on these numbers being accurate at probably 28 and 42 Watts. The meter is at the bottom of its range, so I won't guarantee my data.

 

[jaytv111]

I'm going to (politely) call you on that one. I have the Anker 45W Nano II which I use when away from home, and the Apple 30W at home. I've been of the opinion that my M1 MBA charged faster with the Anker. Tonight I used my "KILL A WATT" on my mostly discharged MBA. No USB-C connected, each read 0W. With the Apple, load from 118VAC line ramped up over perhaps 7 or 8 seconds to 30W. With the Anker, similar ramp, but to 46W.

I monitored VA as well, and it was in similar proportions.

I don't have a higher power charger to try, but am confident the MBA doesn't limit charge to 30W and will accept near 45W. Conversion efficiency is not, of course, 100%, so I'd estimate charge rate based on these numbers being accurate at probably 28 and 42 Watts. The meter is at the bottom of its range, so I won't guarantee my data.

I had no idea about that, but I do know for the M2 generation Apple calls it fast charging only with 67 watts or more (I think 60 gets close enough).

Fast charge your MacBook Air or MacBook Pro - Apple Support

You can fast charge your MacBook Air introduced in 2022 or later and 14- and 16-inch MacBook Pro models introduced in 2021 or later up to 50 percent battery in around 30 minutes. Learn which power adapters, cables, and displays can fast charge your Mac.

support.apple.com

But the M1 generation does not have fast charging according to Apple, but if it can use more power than all the better.

 

[gbynum]

I had no idea about that, but I do know for the M2 generation Apple calls it fast charging only with 67 watts or more (I think 60 gets close enough).

But the M1 generation does not have fast charging according to Apple, but if it can use more power than all the better.

I just dug into the M1 MBA battery specs' 49.9 WH. A quick Google search suggests rechargeable LiON cells return 80-90% of what is put into them, so let's PROPOSE that it would require 60 WH of charge to fully charge that 49.9 WH battery.

Given those "facts", it appears that a 67 (or 60) W charger could theoretically fully charge a 49.9 WH battery in an hour. (In reality, the charge rate of all cell chemistries with which I'm familiar is usually tapered down for the last 10% or so of capacity for the good of the battery)

I've read in multiple sources that for most cell chemistries it is best to charge at 0.1 of capacity for 12 hours. I've read in multiple sources that "fast charging" reduces the life of a cell more rapidly than "slow charging".

So, so, so I think the Apple 30W charger is better for the battery than my Anker 45W or Apple's 67W. Indeed, if battery life (measured in cycles, not hours/charge) is the number #1 criterium, something like a 10W would be better. BUT, how much does the system use running. Other than Apple's estimate of hours/charge, more than 5, less than 15, and wanting to be sure the charger could easily charge the battery while the system was in full operation, I would propose that it would need a charger capable of supplying about 20W. Apple selected 30W, covering all bases.

But there is another issue to consider. USB-C chargers "offer" different voltages depending on power rating. To get the voltage required for our MBAs, I ____BELIEVE____ a charger must be rated =>27W. I'm unable to find my source for that memory.

That's more than I know.