Smart Meter using electricity

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I had my E7 mechanical meter swapped for a smart meter recently and I can confirm that it did under read. I know this as I took a reading everyday in my spreadsheet and can confirm that overnight usage has gone up by about 300Wh with only baseload compared to before the SM installation.

tRog67

Gerry1 said:

It seems that meter disks tend to rotate very slowly with no load, so they were tweaked to stop this.  The result was that extremely low consumption was under recorded.  Search on 'anti-creep' for the details.  Therefore, your 1kWh per year may well be an underestimate.

If you have sufficient patience you can check your smart meter by closely watching the red LED marked 1000 Imp/kWh or similar (Impulses = flashes), so if the alarm is using 1.5kWh per week and the LED is 1000 Imp/kWh then the meter should flash 1500 times per week (once every 8 minutes 56 seconds).

You could then disconnect the alarm and see whether the meter still flashes with no load, but it might make watching paint dry seem very exciting.

I would say it is this. The previous meter assuming it was mechanical will have been under recording.

If the burglar alarm is using 55mA (although that sounds quite high), that is roughly 13W at 240V

13W x 24 hours/day x 28 days is actually going to be more like 8 or 9 kWh (units) over the month., so seeing 6 would be no surprise.

scoittishmovies

Verdigris said:

My calculations makes the consumption 62.5W/hr on average. 55mA is about 13W, so there does seem to be a discrepancy, if that is the only load. Is there an outside light on a light sensor switch, or timer?

Online calculators didn't come up with those kind of figures, can you share how you got to that?
One I used at Amps to Watts (W) conversion calculator (rapidtables.com)  it's a 12volt device.

scoittishmovies

[Deleted User] said:

scoittishmovies said:

[Deleted User] said:

Just to be clear, we are talking about the smart meter and not the IHD? The latter uses a small amount of electricity from the supply side of the meter.

The meter reading is 00006, the hand held device is reading 00006.348  I only have the alarm plugged in, the smart meter device is charged at home.

If the IHD is plugged in, it is using electricity that you are paying for. The average energy use for a house alarm is:

Burglar Alarm

72 kWh/year

to 150 kWh/year

I would imagine that they use more power because they charge a backup battery as well. Mine is a 12volt device. No external lights, bell, nothing.

scoittishmovies

Gerry1 said:

It seems that meter disks tend to rotate very slowly with no load, so they were tweaked to stop this.  The result was that extremely low consumption was under recorded.  Search on 'anti-creep' for the details.  Therefore, your 1kWh per year may well be an underestimate.

If you have sufficient patience you can check your smart meter by closely watching the red LED marked 1000 Imp/kWh or similar (Impulses = flashes), so if the alarm is using 1.5kWh per week and the LED is 1000 Imp/kWh then the meter should flash 1500 times per week (once every 8 minutes 56 seconds).

You could then disconnect the alarm and see whether the meter still flashes with no load, but it might make watching paint dry seem very exciting.

next on the list to determine what's going on. Not particularly looking forward to it.

Verdigris

Is 55mA the output current to the alarm or the input from the mains? Very different by a factor of about 20.

QrizB

scoittishmovies said:

Verdigris said:

My calculations makes the consumption 62.5W/hr on average. 55mA is about 13W, so there does seem to be a discrepancy, if that is the only load. Is there an outside light on a light sensor switch, or timer?

Online calculators didn't come up with those kind of figures, can you share how you got to that?
One I used at Amps to Watts (W) conversion calculator (rapidtables.com)  it's a 12volt device.

I guess the question is, is that 55mA on the AC input to the device, or 55mA on the 12V output?

55mA at 12V is 0.66 watts which seems pretty low for a burglar alarm. Do you have a link to a spec sheet for the device?

Edit to add: 0.66 watts is still 6kWh per year, so your old meter was definitely under-reading.

scoittishmovies

QrizB said:

scoittishmovies said:

Verdigris said:

My calculations makes the consumption 62.5W/hr on average. 55mA is about 13W, so there does seem to be a discrepancy, if that is the only load. Is there an outside light on a light sensor switch, or timer?

Online calculators didn't come up with those kind of figures, can you share how you got to that?
One I used at Amps to Watts (W) conversion calculator (rapidtables.com)  it's a 12volt device.

I guess the question is, is that 55mA on the AC input to the device, or 55mA on the 12V output?

55mA at 12V is 0.66 watts which seems pretty low for a burglar alarm. Do you have a link to a spec sheet for the device?

Edit to add: 0.66 watts is still 6kWh per year, so your old meter was definitely under-reading.

my calculations, which could well be wrong, came up with just under 6 per year, currently running at 52 per year and can't understand the difference. It could well be that the previous meter was faulty although no reason to suspect it was. 

QrizB

scoittishmovies said:

QrizB said:

scoittishmovies said:

Verdigris said:

My calculations makes the consumption 62.5W/hr on average. 55mA is about 13W, so there does seem to be a discrepancy, if that is the only load. Is there an outside light on a light sensor switch, or timer?

Online calculators didn't come up with those kind of figures, can you share how you got to that?
One I used at Amps to Watts (W) conversion calculator (rapidtables.com)  it's a 12volt device.

I guess the question is, is that 55mA on the AC input to the device, or 55mA on the 12V output?

55mA at 12V is 0.66 watts which seems pretty low for a burglar alarm. Do you have a link to a spec sheet for the device?

Edit to add: 0.66 watts is still 6kWh per year, so your old meter was definitely under-reading.

my calculations, which could well be wrong, came up with just under 6 per year, currently running at 52 per year and can't understand the difference. It could well be that the previous meter was faulty although no reason to suspect it was. 

So what is the spec of the device? This one, for example, is rated at 55mA but that's just for the CPU; other parts (sensors, sounders, the battery maintainer) will need more power. I note the mains fuse is 125mA so the maximum power consumption could be something like 25 watts.

scoittishmovies

No external bell to support, just a small siren, mainly digital driven to text msg - GSM. Although it is plugged in 24/7 it doesn't have a backup battery so not the best as a security device but it does the job I need it to do.