Whenever my phone is connected to my home Wi-Fi, my battery is dropping by about 5-10% every hour. After a night of staying on Wi-Fi, my phone will drop from 100% to nearly 60%, sometimes worse. When using the stock Pixel OS briefly before installing Graphene OS I was not experiencing this problem at all, with standby drain on Wi-Fi at less than 1% per hour, and maybe 2-5% overnight. This is similar to what i've gotten on my 4g mobile data connection on both stock Pixel OS and Graphene OS.

Some observations:

  • When looking at my "Battery usage" stats, the Wi-Fi module is showing as the top battery draining process, and there are clear changes in the slope of the battery percentage curve when I go on and off Wi-Fi.
  • Going on "Data saver" doesn't make a difference.
  • Changing the Wi-Fi configuration from Unmetered to Metered or Restricted doesn't make a difference.
  • I have barely any other apps installed in my main profile. The only apps that could be using the internet are Vanadium and Element, both of which are set up to behave exactly the same on Wi-Fi and mobile data.
  • I've reset my modem and router, and my router is configured with the same SSID and password on both the 2.4Ghz and 5Ghz bands. Changing this and forcing my phone to use either one or the other also doesn't make a difference.
  • Changing the DTIM Interval setting on my router from 1 (the default) to 3 didn't make a difference. The rest of my router settings are at the default. My router is an Asus RT-ACRH17.

Happy to provide any diagnostics that might be useful and really hoping to find a solution to this, since using my phone at home for high data consumption tasks is really a drag right now!

Bumping this because I'm still facing this issue completely.

I installed RethinkDNS + Firewall to monitor my traffic and it's showing that "Dynamic System Updates + 11 other app(s)" are hitting the network every 10 seconds on Wi-Fi, but not on mobile data. Those apps are:

  • Android System
  • com.android.localtransport
  • com.android.wallpaperbackup
  • com.google.android.iwlan
  • Dynamic System Updates
  • Fused Location
  • Input Devices
  • Key Chain
  • Phone Calls
  • Settings
  • Settings Storage
  • Setup Wizard

as these apps are all blocked by Rethink if I block the app shown as transferring data. I haven't gone to manually check them all, but most of the ones I checked have network permissions and those permissions can't be removed through the app settings.

I'm going to try blocking their network access through Rethink's firewall and see if that fixes my battery drain problems. If so, I assume something is either messed up with my hardware or software because these apps aren't really configurable and shouldn't be causing this kind of problem. I guess I'll try a factory reset in that case. Some crude guess as to what might be happening: maybe some update checking process got confused and is checking every 10 seconds instead of at the normal interval?

Blocking network access through Rethink solved my battery drain problems, and there were four IP addresses that were being interchangeably used for data transfers every 10 seconds; just blocking those IPs solved the problem too. The data being sent every 10 seconds are an ISAKMP request over UDP on port 500 followed by a request over UDP on port 4500.

Checking the IP addresses, they were associated with my mobile provider, which is quite weird, given that this issue wasn't happening on mobile data only, and still happened when I was just on Wi-Fi (in addition to happening when both Wi-Fi and mobile data were toggled on). Why would my mobile data provider be establishing a connection every 10 seconds but only when I am connected to Wi-Fi?

Luckily I have a second SIM card and when I switched to it, the problem went away as well (even though I remember the battery drain problem happening on both SIMs, but who knows). I'll try swapping my new SIM back in and doing some other debugging related to the SIM card and see if I can't get my first SIM to behave properly. This may still be some GrapheneOS-specific issue -- maybe my mobile service provider is trying to do some kind of hardware attestation which is repeatedly failing -- but I'm starting to doubt it.

You really shouldn't be tinkering with system apps. If you've got battery drain through those ports and having checked the apps you listed it would look more to me that your carrier is the issue.

The ISAKMP on Port 500 from what I can determine is for VoWIFI. Which would explain the increased drain on WiFi.

My carrier is definitely triggering the problem (since it doesn't happen with my other SIM card), and I also came to the conclusion that VoWIFI could likely be the source of it. But this isn't normal VoWIFI behavior, right? I don't think enabling VoWIFI shouldn't be resulting in these constant pings to my phone I don't know how VoWIFI works but this feels broken. Maybe there's a mismatch between my carrier and the Pixel 6a hardware. I am fairly certain that GOS doesn't touch the VoWIFI implementation, but I think it's premature to completely rule out the fact that GOS might be playing a role. Like I said, this issue wasn't present on the vanilla Pixel OS.

I had set this aside and hadn't done any debugging for a while, but (after writing the above) just plugged in my problematic SIM and disabled VoWIFI, and voila, the requests stopped happening! More interesting though is that when I re-enabled, it, my phone seems to be doing exponential backoff with these requests now rather than sending a request every 10 seconds. I'm still sitting here and watching it to be sure, but I got gaps between the requests of 10, 20, 40, 80, and then 160 seconds so far. This should be far less problematic for my battery life than the much weaker backoff (if any) that I was seeing before, where I had pings consistently for the whole night while my phone was totally unused.

Also, I totally agree that "tinkering with system apps" is definitely not a permanent solution. I'm doing it as a debugging step to figure out what's wrong so I can solve the problem. Without Rethink or some similar app or program I wouldn't have been able to tell that there were these requests happening in the first place. From there, I wanted to see if those network requests were really the cause of my battery drain. Before taking that step, for all I knew, the battery drain could have been due to a totally different cause.

Seems that I've got a full understanding of what's going on now, though! So I'm happy to mark this as resolved, though I would still like to confirm that this ISAKMP+UDP request pair with exponential backoff are expected behavior for VoWIFI, and I'm curious if GrapheneOS does make any changes to VoWIFI (couldn't find anything on the website pages about that -- seems to just say that it should work with the normal caveats about carriers limiting it).