portlandstone Posted November 25, 2008 Share Posted November 25, 2008 hi all I am new so don't flame me if I do something daft! I was asked the power consumption of an old (1996?) burglar alarm system with 4 PIRs. The customer has one of these 'Owl' devices that measures realtime household electricity usage and reckons the alarm uses Link to comment Share on other sites More sharing options...
Cubit Posted November 25, 2008 Share Posted November 25, 2008 hi allI am new so don't flame me if I do something daft! I was asked the power consumption of an old (1996?) burglar alarm system with 4 PIRs. The customer has one of these 'Owl' devices that measures realtime household electricity usage and reckons the alarm uses Link to comment Share on other sites More sharing options...
luggsey Posted November 25, 2008 Share Posted November 25, 2008 I don't understand how you seem to correlate maintenace fee to the cost of electricity drawn by the system. A bit like saying my car service cost ----------------------------------------------------------------------------------------------------------------------------------- Life is like a box of chocolates, some bugger always gets the nice ones! My Amateur Radio Forum Link to comment Share on other sites More sharing options...
portlandstone Posted November 25, 2008 Author Share Posted November 25, 2008 Point taken. I assumed that annual electricity cost should be much cheaper than the cost of skilled British labour. But petrol and service fee analogy makes sense. But how about this alarm that makes up 30% of this domestic customer's annual electricity bill? Can't be right shurely? Link to comment Share on other sites More sharing options...
james.wilson Posted November 25, 2008 Share Posted November 25, 2008 it could be 70w i suppose if its very old and not very efficient. Those meters arnt very accurate though. Best way is to meter (with a calibrated meter) the current draw on the ac input side. id say a modern panel should draw around 10-20w but if its running warm, has old high current use components and an inefficient transformer etc then yes its possible. But id still say its too high (ie the reading) also how have you calculated that is securitywarehouse Security Supplies from Security Warehouse Trade Members please contact us for your TSI vetted trade discount. Link to comment Share on other sites More sharing options...
portlandstone Posted November 25, 2008 Author Share Posted November 25, 2008 70 watts X 24hours X 365days = 613.2KWhrs per year Electricity price varies, but estimate 14p per KWhr charged for first 900 units per year. Burglar alarm is one of the few things that can't be switched off ever, so you need to use this higher electricity price for it. 613.2kWhrs X Link to comment Share on other sites More sharing options...
lawandorder Posted November 25, 2008 Share Posted November 25, 2008 it could be 70w i suppose if its very old and not very efficient.Those meters arnt very accurate though. Best way is to meter (with a calibrated meter) the current draw on the ac input side. id say a modern panel should draw around 10-20w but if its running warm, has old high current use components and an inefficient transformer etc then yes its possible. But id still say its too high (ie the reading) also how have you calculated that is Link to comment Share on other sites More sharing options...
hpotter Posted November 25, 2008 Share Posted November 25, 2008 An old optima (eg) panel only has 125mA mains fuse = 30W max (hence need fully charged batt to deliver 1A @ 12v). Wouldnt expect the panel to draw that unless charging a flat/knackered bettery. Modern PSU's work differently. Link to comment Share on other sites More sharing options...
SystemQ Posted November 25, 2008 Share Posted November 25, 2008 Hi all. Must admit, I thought that the figures sounded too high. But based on 10p per kwh, a single 100W bulb uses a tenth of a kilowatt per hour and therefore costs 1p an Hour to run. So if it System Q Ltd. Link to comment Share on other sites More sharing options...
lawandorder Posted November 25, 2008 Share Posted November 25, 2008 Hi all.Must admit, I thought that the figures sounded too high. But based on 10p per kwh, a single 100W bulb uses a tenth of a kilowatt per hour and therefore costs 1p an Hour to run. So if it Link to comment Share on other sites More sharing options...
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