Battery drain during standby on iPad & iPhone

I loose about 10% per day in standby mode.

That sounds pretty normal. Even when the screen of the device is locked, the device is still doing things. These things include syncing to iCloud, receiving notifications and other background processes.

Nothing about what you're describing sounds unusual. Unless your wife has exactly the same apps and the same data and uses her device in exactly that same way as yours, it may be different. Still normal.

Make sure that you're plugging your device in at night, making sure that it's connected to WiFi and lock the screen. It will do the bulk of the backing up overnight. And, your iPad will be fully charged and ready to go in the morning.

You’re clearly adept with your network analysis - so I’ll not delve into the basics which you’ve already covered in some detail.

I’m sure you should appreciate that if you are using your iPad as a HomeKit hub, it’ll be responding to and processing traffic for all your HomeKit devices - and this must have some impact on battery usage, even when apparently inactive with screen off.

As an alternative to using your iPad as your HomeKit hub, have you considered offloading the hub function to your AppleTV?

Your iPad has the abilty to provide hub functionality in abscence of alternatives - if it is permanently present on the network - but it may not be the most appropriate device to provide HomeKit hub services if you have an AppleTV or an Apple HomePod - both of which are effectively “static” devices with permanent connection to power and are intended to provide HomeKit hub services.

Out of curiosity, what App are you using in your illustration to measure activity on your iPad?

Okay, so you’re using the AppleTV as your HomeKit hub. That’s cleared-up one variable.

Given the nature of multicast traffic, all devices on your local network (assuming a “flat” network with a single subnet) are going to receive and potentially process these packets; we know that whilst the iPad is apparently sleeping, many background tasks (such as email push and fetch) are still accessing the network - and is likely monitoring multicast and other traffic. All this processing consumes battery power, especially if the iPad NIC is never allowed to sleep because of a “chatty” device.

You could try looking through the Apple Developers documentation for clues as to what the iPad is “up to” when apparently idle.

Another throught - your home router may have some configurable multicast settings that you can tune - such IGMP Snooping. Not all home routers have such options, especially ISP-supplied “domestic” kit which tends to be kept as simple as possible for the “general masses”. You may have to consider being creative in segregating network segments - perhaps having a seperate subnet for your HomeKit devices.

Absolutely so. IGMP snooping being active on the network switch allows the switch to only send IGMP traffic to hosts that require it - rather than flood the entire subnet with multicast traffic.

This has two significant benefits, in that:

• it reduces traffic on a contended nerwork segment (remember, unlike wired ethernet, a WiFi cell is a shared/contended half duplex network segment)

• it eliminates packet processing overhead for devices that don’t need to see the multicast packets (for battery operated devices, extending battery life)

So, in conclusion, if your iPad must be a member of the broadcast domain, you’ll need to accept that the processing overhead associated with multicast traffic will have a negative impact on battery life for battery operated devices. If it were me, to improve network performance, I’d certainly attempt network segmentation by subnet or VLAN in addition to employing IGMP Snooping.

If the Hue bridge, necessary for protocol conversion, cannot be be “tuned” to reduce what appears to a polling interval - and network sementation impractical - there appears to be little else you can do with what you have.

Have you contacted Philips technical support to discuss your issue?

I hope that our conversation has provided some help and/or insight into possible improvements to your setup.

One final thought comes to mind...

If your iPad exhibits increased battery consumption when configured to interact with HomeKit devices while it is configured to sync with your iCloud account, have you tried disabling iCloud for “Home”?

Settings > [Your AppleID/iCloud account] > iCloud > Home - set to OFF

Perhaps, despite wanting to control HomeKit devices from your iPad, you don’t actually “need” to allow it to sync to your iCloud account? If multicast packets are triggering an iCloud sync (pending additional research, speculation on my part) every time your iPad is polled, this would introduce an additional processing and consequent battery overhead.