The short version
- Tend doesn't control the charger. It never stops or starts charging, never discharges your battery while plugged in, and doesn't change any low-level hardware settings.
- macOS can limit charging on Macs with Apple silicon running macOS 26.4 or later. That's the real limit, and Tend takes you to it.
- The Battery Coach looks at how you actually charge and tells you whether a limit would help, and how much.
How the Battery Coach works
Tend keeps a small log of your battery on your Mac: the charge level, whether you're on power, whether it's charging and the battery temperature. It adds an entry every 5 minutes and whenever you plug in or unplug, and keeps 60 days. Nothing in the log leaves your Mac.
After about 3 days, and at least 20 hours with your Mac awake, the coach looks at the last two weeks and shows:
- Time on power: how much of the time your Mac is awake, it's plugged in.
- Near 100% per day: hours a day spent plugged in at 95% or more.
- Warm per day: hours a day with the battery at 35 °C (95 °F) or warmer.
- Typical unplugged use: how far the charge usually drops before you plug in again.
Then it gives one of four answers:
- A charge limit will help. You're plugged in most of the time and sit near 100% for hours. That's the pattern that wears a battery fastest, especially when it's warm.
- You don't need a charge limit. You use your battery regularly, so a limit would mostly cost you runtime.
- A light limit is worth it on desk days. You split your time. A limit of 85–90% on days you're plugged in, and a full charge before you head out, gets you most of the benefit.
- Your battery is already well looked after. You're on power a lot, but macOS's Charge Limit is already on (the coach then says your charge limit is already doing this), or your battery rarely sits near 100%, usually thanks to Optimized Battery Charging. There's nothing to change.
The coach is free. If your battery hasn't reached 100% for a month, Tend suggests one full charge so your battery percentage stays accurate. With macOS's Charge Limit on, macOS takes care of this itself, so Tend doesn't send that reminder.
The science here is genuinely debated, so the coach doesn't give one rule for everyone. Read the reasoning and sources.
Setting macOS's Charge Limit
On a Mac with Apple silicon and macOS 26.4 or later:
- Open System Settings › Battery. When the Battery Coach suggests a limit, its Set macOS Charge Limit button takes you straight there.
- Click the info button (i) next to Charging.
- Choose a Charge Limit between 80% and 100%, then click Done.
According to Apple, your Mac then charges to within a few percent of the limit and stops. If the charge drops more than 5% while plugged in, it charges back up to the limit. Now and then macOS charges to 100% anyway, to keep its battery estimates accurate. When you need a full battery for a trip, choose Charge to Full Now from the battery menu. Source: Apple, About Optimized Battery Charging and Charge Limit on Mac.
With Tend Pro, the Battery page shows whether the limit is on and at what level, and has a button that opens the setting.
On macOS 15 to 26.3
These versions have no manual charge limit. They do have Optimized Battery Charging in System Settings › Battery, which learns your routine and delays charging past 80% when it expects you to stay plugged in for a long time.
If you'd like to stop at a level yourself, Tend Pro's unplug reminder sends a notification when you reach the level you choose (50–100%) while plugged in. It's a reminder only: charging continues until you unplug.
Unplug reminder and heat warning
Both are part of Tend Pro and live on the Battery page under Battery care.
- Unplug reminder: a notification when you reach your chosen level on power. It pauses on its own while macOS's Charge Limit is on, because the limit already stops charging.
- Heat warning: a notification if the battery stays at or above your chosen temperature (40 °C by default) for 5 minutes while charging. It comes at most once per charge. Charging while warm speeds up wear, so it's a good moment to unplug or move somewhere cooler.
Battery health numbers
Tend shows the same Maximum Capacity as System Settings › Battery › Battery Health whenever macOS reports it. Otherwise, Tend divides the battery's full-charge capacity by its original design capacity, as reported by the battery itself, and rounds down the way macOS does, so the two can differ by a point or so. When deciding whether to get your battery serviced, Apple recommends going by what macOS reports (Apple).
Apple rates the batteries in MacBook Air models from 2020 onward and MacBook Pro models from 2021 onward for 1,000 cycles, and designs them to keep up to 80% of their original capacity at that count (Apple, Determine battery cycle count). Tend shows how much of that rated cycle life you've used.
Why doesn't Tend control charging directly?
Controlling the charger needs a privileged helper that changes low-level power settings, and those settings change between macOS versions. Since macOS 26.4, Apple's own Charge Limit does the job safely and survives updates, so Tend leans on it instead. If you want features such as discharging while plugged in or holding a precise level on older macOS versions, an app like AlDente does that. Tend and AlDente compared.