56% battery drain by Mobile Network without a simcard

SovereignCopper

I have been using my phone without any simcard for the last week.

After charging to 100% (= reset of battery stats), I see that the Mobile Network still has a share of 56% of the battery drain among the view by systems.

Could anyone explain to me how this is possible?

Possibly related (although searching within topics is basically impossible with Flarum):
https://discuss.grapheneos.org/d/13708-battery-usage-shows-mobile-network-using-battery-while-on-airplane-mode (I always have Wi-Fi Calling set to disabled)
https://discuss.grapheneos.org/d/21909-extreme-battery-drain-from-mobile-network/116

Johnnyloans

SovereignCopper Could anyone explain to me how this is possible?

Phones with no sim or the cell plan expired can still make emergency calls.

I'm pretty sure the phone still searches for cell towers. You can enable Wi-Fi after turning on airplane mode to negate this :)

56% battery use from mobile network:

For exmaple, if your battery drained 80% in this time, we don't know how much power is attributed to apps (x) and system (y).
x + y = 80%
mobile network power usage = 0.56y
y and x are unknown.

apps could have used 60% battery and system 20% (mobile network = 11.2% battery)
or apps 79% and system 1% (mobile network = 0.56% battery)
unknown.

SovereignCopper

You're right, I didn't set it in Airplane mode. I'll retest with that enabled.

But why would it connect to cell towers before ever trying to call an emergency service?

Also, the app Privacy Cell then states there's no connection whatsoever.

Johnnyloans

SovereignCopper

Might be better to ask another forum like privacy cell if we don't get an expert to reply here but I think:

1) for faster connection for emergencies. Or maybe even: the signal range to connect is less than the signal range to place a call? So it scans early.

2) the app is asking the OS via an API and the OS replies with the same info we see in settings and the top bar of the screen: No sim. No internet. No connection. no calls. (except emergency)

The app won't have direct access to the modem to inquiry for itself.

SovereignCopper

Okay, so to close this, after putting it into airplane mode, I didn't see any drain by Mobile Network anymore.