MagSafe LED does not reflect user-defined charging limit (optimized battery charging)

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Created 3w

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I recently noticed a UX inconsistency while using the battery charge limit feature on my MacBook with a MagSafe charger.

With the optimized charging feature, users can set a custom maximum charging limit (for example, 95%) to improve battery health. However, the MagSafe LED indicator continues to show the charging state (amber) even after the device reaches this user-defined limit.

Previously, the LED would turn green when charging reached 100%, clearly indicating a “fully charged” state. But now, when charging stops at a user-defined limit, there is no clear visual feedback that charging has effectively completed based on the user’s preference.

This creates confusion, as the LED suggests that charging is still ongoing even though the system has stopped charging at the configured limit.

A possible approach to improve this could be to treat the user-defined limit as an effective “fully charged” state during charging. For example:

if is_charging: if battery_percentage < user_defined_limit: LED = AMBER else: LED = GREEN

This would align the physical LED indicator with the system’s charging behavior and improve clarity for users without requiring hardware changes.

Has anyone else observed this behavior, or is there any existing workaround?

Answered by DTS Engineer in 885180022

Perfect, thank you. I can't comment on our release plans or schedules, but this is something I do expect us to address.

...and this should be fixed in the most recent beta seed, macOS 26.5 beta 3 (25F5058e). More specifically:

The light should now turn green when the device reaches the charging limit.
The light should now turn back to amber if/when power drain causes charging to resume.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

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Answer 1

DTS Engineer OP

Apple

2w

I recently noticed a UX inconsistency while using the battery charge limit feature on my MacBook with a MagSafe charger.

Have you filed a bug on this and, if so, what's the bug number?

Has anyone else observed this behavior, or is there any existing workaround?

I haven't looked into the issue in detail, but I wouldn't expect there to be any sort of workaround. My guess is that the reason the issue exists at all is that the LED is being controlled at a VERY low level, possibly through direct interactions in the charging hardware and not through the normal "system" (so the machine doesn't have to actually be "on"). That would also mean it's largely outside of the system’s normal management/configuration.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

1

Answer 2

DTS Engineer OP

Apple

2w

Yes, I’ve filed this as feedback — FB22468514.

Perfect, thank you. I can't comment on our release plans or schedules, but this is something I do expect us to address.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

0

Answer 3

DTS Engineer OP

Apple

1w

Accepted Answer

Recommended

Perfect, thank you. I can't comment on our release plans or schedules, but this is something I do expect us to address.

...and this should be fixed in the most recent beta seed, macOS 26.5 beta 3 (25F5058e). More specifically:

The light should now turn green when the device reaches the charging limit.
The light should now turn back to amber if/when power drain causes charging to resume.

__
Kevin Elliott
DTS Engineer, CoreOS/Hardware

1

Answer 4

late_cat OP

3d

I would love to hear how you solved it;😊

0

Answer 5

DTS Engineer OP

Apple

3d

I would love to hear how you solved it;😊

Truth be told, it's actually pretty simple. You've been thinking of the LED as part of the "charger", but that's not how it actually works. With a bit of searching, you can find teardowns and pinout descriptions of the MagSafe connector, and the "trick" here is that one of those pins uses a very simple and low-power protocol to pull identifying data about the adapter/cable... and to control the charging LED.

That process is essentially independent of the entire charging process and, in fact, I believe it's possible to light up the LED without the cable even being attached to power. In other words, the LED is more like a light bulb that happens to be "attached" to the charging cable, not an integral component of the actual charging process. Theoretically, the Mac could make the LED do anything it wants, but the hardware is involved is so slow[1] that making it blink like a strobe light is probably impossible.

In any case, with all that context, the fix here was simply adding an additional check into the code that sets the LED color so that it accounted for virtual charging limit, not just the true physical state.

[1] There's no reason for it to be fast, particularly since the MagSafe handshake process is intentionally fairly slow for safety reasons.

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Kevin Elliott
DTS Engineer, CoreOS/Hardware

0