macOS battery scale inaccurate at lower percentages #16

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adam · 2025-12-30T01:32:03+01:00

adam commented

2025-12-30 01:32:03 +01:00

Originally created by @peterlewis on GitHub (Jun 5, 2020).

Howdy, no rush on a fix, but just wanted to highlight (and note down, before I forget) where AlDente appears to get 'macOS battery scale' percentages slightly wrong, lower down the charging scale. All measurements done on 2020 MacBook Pro 13" (A2257).

AlDente 53% = Real 51%
AlDente 50% = Real 48%
AlDente 80% = Real 81% (was at 80%, but crept-up)

I'll update this as I find more. Maybe a pattern can then be established! :)

Originally created by @peterlewis on GitHub (Jun 5, 2020). Howdy, no rush on a fix, but just wanted to highlight (and note down, before I forget) where AlDente appears to get 'macOS battery scale' percentages slightly wrong, lower down the charging scale. All measurements done on 2020 MacBook Pro 13" (A2257). AlDente 53% = Real 51% AlDente 50% = Real 48% AlDente 80% = Real 81% (was at 80%, but crept-up) I'll update this as I find more. Maybe a pattern can then be established! :)

adam closed this issue

2025-12-30 01:32:04 +01:00

adam commented

2025-12-30 01:32:04 +01:00

@davidwernhart commented on GitHub (Jun 9, 2020):

Hi @peterlewis,

thank you for your involvement and feedback! (And your generous donation!)

You are right, the new macOS battery scale feature is still not 100% exact for all percentages. In fact, enabling the checkbox simply removes 3% from the set value and sets the SMC with that, which is admittedly quite a hack.
It appears that the conversion between the real charging values and the ones displayed by macOS is not that simple. The gap seems to get bigger the higher the value is, but I have not figured out the pattern yet. Also, I don't know if this conversion difference is the same for all MacBooks or changes when the battery ages.

Anyway, I will keep my eye on this.

Best regards,
David

@davidwernhart commented on GitHub (Jun 9, 2020): Hi @peterlewis, thank you for your involvement and feedback! (And your generous donation!) You are right, the new macOS battery scale feature is still not 100% exact for all percentages. In fact, enabling the checkbox simply removes 3% from the set value and sets the SMC with that, which is admittedly quite a hack. It appears that the conversion between the real charging values and the ones displayed by macOS is not that simple. The gap seems to get bigger the higher the value is, but I have not figured out the pattern yet. Also, I don't know if this conversion difference is the same for all MacBooks or changes when the battery ages. Anyway, I will keep my eye on this. Best regards, David

adam commented

2025-12-30 01:32:04 +01:00

@peterlewis commented on GitHub (Jun 10, 2020):

Yeah that's fair enough! To be honest, if it were me, I'd probably remove the feature, or at least set it to disabled, by default. Don't mean that to seem rude, I just think there are likely so many variables and when you're dealing with not just code, but chemistry (battery health) and hardware (model-specificity) it's likely a battle that would not be easy to win! :)

Speaking of which, when I disable the macOS 3% feature, it doesn't appear to last longer than a session. Looks that the setting is not being saved in prefs. I'll open a separate issue for that, though, so you can keep track!

Thanks!

Peter

@peterlewis commented on GitHub (Jun 10, 2020): Yeah that's fair enough! To be honest, if it were me, I'd probably remove the feature, or at least set it to disabled, by default. Don't mean that to seem rude, I just think there are likely so many variables and when you're dealing with not just code, but chemistry (battery health) and hardware (model-specificity) it's likely a battle that would not be easy to win! :) Speaking of which, when I disable the macOS 3% feature, it doesn't appear to last longer than a session. Looks that the setting is not being saved in prefs. I'll open a separate issue for that, though, so you can keep track! Thanks! Peter

adam commented

2025-12-30 01:32:04 +01:00

@peterlewis commented on GitHub (Sep 5, 2020):

@davidwernhart Just to re-visit this. Just over two MacBooks (16-inch 2019 and 13-inch 2020) I've noticed discrepancies, both between the two, as well as on each individual machine when setting maximum at varying percentages.

Also, applications such as 'Coconut Battery' report a more accurate battery percentage anyway, so even if it were to be consistent across different percentages/models, it doesn't feel like it's adding benefit.

Please can I suggest that the 'Use macOS battery scale' is either removed or at least that the setting is honoured across re-launch?

I hope that doesn't sound like a rant. Both I and my battery adore this application and keen to see grow! 👍

Many thanks!

Peter

@peterlewis commented on GitHub (Sep 5, 2020): @davidwernhart Just to re-visit this. Just over two MacBooks (16-inch 2019 and 13-inch 2020) I've noticed discrepancies, both between the two, as well as on each individual machine when setting maximum at varying percentages. Also, applications such as 'Coconut Battery' report a more accurate battery percentage anyway, so even if it were to be consistent across different percentages/models, it doesn't feel like it's adding benefit. Please can I suggest that the 'Use macOS battery scale' is either removed or at least that the setting is honoured across re-launch? I hope that doesn't sound like a rant. Both I and my battery adore this application and keen to see grow! 👍 Many thanks! Peter

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Reference: starred/AlDente-Battery_Care_and_Monitoring#16