Burglar alarms

[Dave Plowman (News)]

Is that how all your crashes have occured?

[alan_m]

Especially useful for finding all the other metal in ones home such as the nails and screws holding the building and fittings together, pipes, electrical wires, radiators, foil backed insulation, the kitchen sink etc. etc.

[Huge]

Actually, most false alarms are caused by user error.

[Huge]

Quite. Given how useless my stud detector is, I suspect that's an urban legend.

[Martin Brown]

Depends on the bat - ours are a maternity roost in summer at peak insect availability so lots of youngsters. You can hear them crashing about in the loft for a couple of days a year first learning to fly. They vanish about now going off to a much cooler winter roost to hibernate. Bat conservation come and do a count every now and then.

Vaseline on any identified weak spots seems to be a preferred field engineering solution. Its the small spiders that get in.

[Huge]

Our chap blocked the holes up with Blutak.

[Andrew Gabriel]

My system tests the batteries every day (it switches off the power supply and checks it can run on the battery for a while, cutting back to mains if the battery voltage sags too much, and generates a dead battery alert). I've never got more than

5 years from the standard 7AH SLA batteries. The battery probably has to drop to 1/20th or less of its new capacity before it actually reports as dead, so even long before that, you won't get full capacity from it (just like with a UPS).