alt Hacker NewsThis used to happen to my MacBook Pro, although it was a non Apple Silicon one. The issue was that I had changed the DHCP lease time on my router from the default to a really low value. I believe I had set it to 15 minutes. What I believe was happening was the MBP was waking up to renew its IP address every 15 minutes and by the time it went to sleep again, it was probably waking back up to repeat the process. Changing the value on the router back to its default completely fixed the battery drain issue on my MacBook Pro. I'd never have guessed the cause-effect except I made the change around the same time I purchased that new MacBook Pro and was paying more attention to any issues that might arise.
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> I had changed the DHCP lease time on my router from the default to a really low value. I believe I had set it to 15 minutes.
What were you hoping to achieve by doing that?
That is so weird. How much mAh can a single “wake and renew lease” possibly take? Like it has to be milliamp-milliseconds (mAmS?). I mean my phone is chattering with the cell network probably all the time even in a fairly deep sleep mode. The laptop is lighting up the WiFi stack to send and receive (and process) like a few packets?
Like you said though, it’s pre Apple silicon so who really knows! Maybe it decided to do some other stuff while it was awake?
Woah just found out my router (mikrotik) defaults to 10 minute lease durations.
This is a macOS bug; it doesn’t need an IP address while it’s asleep. Waking up to renew a DHCP lease is crazy.
Closed source OSes are such a bane.
A functional DHCP client will request renewal of it's IP address 50% of the way through the lease, so it was probably worse than you thought.