Okay, a small update. We've received our plug-in adapter and quick release battery pack. When I did a bench test (not installing anything/drilling holes/up the ladder until I know it all works!) with the quick release battery fitted and the plug-in adapter powered up both of the lights (amber and green) on the battery pack lit up, and after several hours the amber light extinguished. So from that comprehensive experiment (!) I think I can conclude that @groundhogday was correct and the battery does indeed trickle charge from the mains. However... I'm not sure if it's just the app, or something I've done/not done, but the power status icons aren't showing what I expect. When I first plugged the adapter in it took ages for it to show the green lightning bolt on the siren's info page and then ages for it to disappear when I unplugged the adapter. I appreciate that when we've installed sensors we've seen a message saying "Changes might take XX hours to update" (why?) so I'm giving it a little bit of slack on that front. What is annoying is that the quick-release pack doesn't seem to exist according the app - there's just the battery symbol with the diagonal strike out across it, and it didn't change to show any indication of charging or that it was charged (i.e. no green battery symbol c.f. the sensors). When the D batteries were fitted the power symbol changed to a green battery as expected. What's confusing (to me) is that, as part of further tinkering/testing, I've now had the mains power switched off for a few hours but I can still run the LED tests (either via the app or by pressing the small black button on the siren next to the battery pack) and they work - so either there's another hidden internal/residual power supply to allow me to do this (which I doubt) or the quick-release pack is actually working but it just doesn't register with the app. Sorry for my rambling on. This seems like a good alarm system but the little niggles are beginning to irk... :slight_smile:

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