70 watt vs. 35 watt Apple Power Adapter for M2 Macbook Air - any performance increases?

[loby]

Other than faster charging with the 70 watt Apple power adapter vs. the 35 watt Apple adapter, is there any noticeable increases in power to the CPU or GPU's for any (noticeable) performance increases?

Anyone notice a difference or is the increase to 70W JUST for faster battery charging only?

Thanks ahead of time to anyone who might know.

 

[Apple_Robert]

There is no performance increase.

 

[iMacDragon]

No, on all macbooks the power adaptor does not dictate max performance, in extreme cases it can just cause battery to be drained if the PSU is smaller than needed for task. But I don't think this would apply to the air's at all with a any 35w+ power adapter.

 

[JPack]

No, because MacBook Air is thermally limited.

The CPU + GPU can use up to 30W but only if there is active cooling. That's why MacBook Pro 13 comes with a 67W adapter while the Air comes with 30W.

 

[loby]

So basically, the 70w adapter is for fast battery charging only.

I keep reading there is no effect on the battery as far as damage or quickly depleting the usage, but it is hard to believe it doesn’t. If you want the battery to last some years, I am still convinced it is better to use the 30w or 35w charger and just wait a little longer for the full charge.

I might be wrong, but maybe I am just old school as far as lithium batteries.

 

[Isamilis]

So basically, the 70w adapter is for fast battery charging only.

I keep reading there is no effect on the battery as far as damage or quickly depleting the usage, but it is hard to believe it doesn’t. If you want the battery to last some years, I am still convinced it is better to use the 30w or 35w charger and just wait a little longer for the full charge.

I might be wrong, but maybe I am just old school as far as lithium batteries.

Second this. I also use 15w charger for overnight charge.

 

[loby]

Second this. I also use 15w charger for overnight charge.

Humm...that is a good idea. I have a 20w Apple charger for my iPhone, I am curious if that would be better to use if I charge my M1 MacBook Pro or MacBook Air overnight.

If you are not in a hurry to charge your Macs, is a lower watt BETTER to use for battery health? Now I am VERY curious....

I prefer longer lasting batteries than fast charging. Even if it is just getting one more year out of Apple's stock batteries it is worth it for the wait....

 

[Isamilis]

I use lower watt is to avoid 100% charge too long during overnight charge. I also read somewhere that the lower wattage, the cooler the battery (which extend its life), but not sure whether it’s still valid for today’s battery.

 

[JPack]

MacBook Air has a 52Whr battery split into four cells encased in a large aluminum chassis. Chances are, the battery can dissipate heat well even if you used a 70W adapter. The biggest concern with notebook batteries is avoiding staying at 100% charge for extended periods of time.

iPhone is more affected by heat while charging because of how compact the chassis and due to it being a glass sandwich.

 

[AudiHeel]

I've been leaving my MacBooks plugged in virtually 100% of the time with the battery at 100% for 10+ years, and never had any issues. I may unplug it for a moment to move it upstairs, otherwise it's plugged in all the time. Maybe twice a year it comes unplugged and I notice the battery is at 88%, but I've never seen it below 80% I didn't think. And when I sell them after 2-3 years the battery cycle count is usually around 30.

 

[loby]

I've been leaving my MacBooks plugged in virtually 100% of the time with the battery at 100% for 10+ years, and never had any issues. I may unplug it for a moment to move it upstairs, otherwise it's plugged in all the time. Maybe twice a year it comes unplugged and I notice the battery is at 88%, but I've never seen it below 80% I didn't think. And when I sell them after 2-3 years the battery cycle count is usually around 30.

Many of my Mac laptops over the years will stay at 88% or 80% regardless of how long the battery life is now. Not sure if that is something programed or the real percentage.

Right before you sell your laptop(s), do you use it once in battery mode to see how long the battery lasts? That would speak a lot.

 

[Bacong]

you're too worried about your battery. if you wanna preserve its life and use it a lot plugged in, just get the app AlDente and set a limit of like 75%. when plugged in it will run off the power and not use battery. i've had this laptop for 3 months and it has 17 charge cycles even with me taking it to work every day.

 

[AudiHeel]

⬇️

 

[AudiHeel]

Many of my Mac laptops over the years will stay at 88% or 80% regardless of how long the battery life is now. Not sure if that is something programed or the real percentage.

Right before you sell your laptop(s), do you use it once in battery mode to see how long the battery lasts? That would speak a lot.

Good question. I do usually run it unplugged for a few hours just to make sure it's holding a decent charge. I may not go all the way to 0%, but I at least take it down to 50% or less and mention the battery holds x-hours when I tested it. It's usually a fairly old laptop at that point so if it's lasting 3-4 hours to 50% I mention that, which I'm guessing is a positive for buyers.

 

[Isamilis]

I've been leaving my MacBooks plugged in virtually 100% of the time with the battery at 100% for 10+ years, and never had any issues. I may unplug it for a moment to move it upstairs, otherwise it's plugged in all the time. Maybe twice a year it comes unplugged and I notice the battery is at 88%, but I've never seen it below 80% I didn't think. And when I sell them after 2-3 years the battery cycle count is usually around 30.

No offense. But I did this on my MBP back in 2009 (my first Mac). The battery health was dropped to ~70% after 1.5 years.

 

[krspkbl]

I went with the 35W charger. I don't need it to charge super fast so I think I should be fine with 35W. Plus I can use it to charge another device at the same time.

No offense. But I did this on my MBP back in 2009 (my first Mac). The battery health was dropped to ~70% after 1.5 years.

I used to run my MacBook at 100% as well but I'd also let it drain right down to 0% before charging. I can't remember what the battery health was but it was probably quite low after about 4 years lol.

At least back then you could replace the batteries... I was going to get a new one before the MacBook completely died lol.

 

[AudiHeel]

No offense. But I did this on my MBP back in 2009 (my first Mac). The battery health was dropped to ~70% after 1.5 years.

I've had this base M1 plugged in for about 2 years, and the battery health is currently at 97%.

 

[Ifti]

I have my MacBook Pro 16 (M1 Max) plugged in all the time while in use since its my desktop machine, but use AlDente to keep it at 80%.

I never use my MacBook Air plugged in. I use the 70w charger to top it up as and when needed (when battery reaches around 15-20%). I do have AlDente installed on the machine and charge to 80% most of the time, but I also regularly let it go to 90-100%. I just never leave it to sit at 100% - as soon as its close I will usually catch it and unplug.

In this day and age, the most dangerous thing for battery health is keeping it sitting at 100% for long periods - in my opinion anyways.

 

[snipr125]

I have my MacBook Pro 16 (M1 Max) plugged in all the time while in use since its my desktop machine, but use AlDente to keep it at 80%.

I never use my MacBook Air plugged in. I use the 70w charger to top it up as and when needed (when battery reaches around 15-20%). I do have AlDente installed on the machine and charge to 80% most of the time, but I also regularly let it go to 90-100%. I just never leave it to sit at 100% - as soon as its close I will usually catch it and unplug.

In this day and age, the most dangerous thing for battery health is keeping it sitting at 100% for long periods - in my opinion anyways.

Apple should include a 'Direct power' mode where you can turn off battery charging and just use the A/C power. Would be so easy to implement and probably increase the life of the internal battery.

 

[rocketbuc]

Apple should include a 'Direct power' mode where you can turn off battery charging and just use the A/C power. Would be so easy to implement and probably increase the life of the internal battery.

This is essentially what is happening when a Macbook is plugged in and the charging is stopped. With Al Dente you can achieve this state of "battery charging stopped" also below 100%, then your MacBook runs off wall power without generating any battery cycles.

 

[za9ra22]

Apple should include a 'Direct power' mode where you can turn off battery charging and just use the A/C power. Would be so easy to implement and probably increase the life of the internal battery.

Apple do include battery management algorithms which operate without user intervention. On my M1 13-inch this shows up as cycling the battery to around 80% after a day or two on the charger, but that system is over 3 years old. The M3 doesn't seem to behave this way, but it's only a month old so battery health is still 100%

There is a support document that somewhat explains how it works: https://support.apple.com/en-us/102589

I use lower watt is to avoid 100% charge too long during overnight charge. I also read somewhere that the lower wattage, the cooler the battery (which extend its life), but not sure whether it’s still valid for today’s battery.

You have to be a bit wary because there's a mathematical relationship between voltage, power (wattage) and current (amperage) which means that as one varies, the others do too.

The computer and battery will draw whatever current it needs up to the maximum capability of the power adapter - it won't draw more. For example, my G4 PowerBook requires a 120volt 35watt power adapter which calculates to a maximum current of about 400mAmps. But I can use a 120volt 65watt power adapter that can deliver 550mAmps. It will still only draw the current needed to power it and charge the battery (measurably about 320mAmps).

However, if I think that to charge the battery slower I should use a 20watt adapter, the computer will still attempt to draw that 320mAmps, when the adapter can actually only provide a little over 150. This creates an 'over voltage' in the power adapter, which can cause significant heating in the adapter and the computer's power regulator circuit.

Meaning that - assuming voltage is correct - you can't over run a system with too much power because it will only draw what it needs, but you can under run it, with too little.

There's a neat calculator at https://www.omnicalculator.com/physics/watt that allows you to see how it works.