Background Energy Consumption

Cardew

SavingNow wrote: »

OK, so you made me unplug the phone :rotfl:

Input 230V @ 40ma

2 outputs
5v @ 300ma
9v @ 300ma

Input wise, that should be 9.6w each, not 20w as guessed earlier, but if we recieve incoming voltage at 230 I'd be very surprised.

Looking at that Which article suggest I should consider replacing these phones.

The rating on an appliance does not mean it uses that power.

My laptop PC's power supply is rated at input 100 -240v @ 1.5 amps with an output of 19.5v @ 3.16 amps.

That doesn't mean it is drawing 360 watts from the mains and the output is 61.2 watts. Most of the time it draws less than 30 watts when operating, and when plugged in, but switched off with the battery fully charged it uses virtually nothing.

My desktop PC power supply is rated at 750 watts, the PC rarely uses more than 120 watts.

I have several BT cordless phones, - 2 x main phones, 4 used on internet and as an intercom - and they are drawing about 1 watt each.

Scrooge2

Sorry to pick this thread up so late as I have been looking for a topic on baseline/background consumption. I too have an OWL monitor, and my baseline is around 500W! - and I noted this in the middle of the night when everyone's asleep.

I still can't figure where this is going too. Like smartn, I have an old alarm system with around 8/10 PIR sensors - so, not sure if this is the one drawing all the power. I do have 4 DECT phones, a clock radio, microwave and oven timer light, an American fridge/freezer, Sky box, freeview box, 2 tellys on stand-by, left on during the night.

It's frustrating as I'd like to see this baseline go way down! It would be interesting to see what other people's baseline is, if a poll was done .....

jimjames

Our baseline is approx 250W. We only really have fridge & freezer on all the time, most other items are turned off when not in use and for TV etc standby isn't used.

I'd imagine at a guess that the American fridge freezer is the culprit although the range of items left on standby won't help. On the whole American items aren't exactly known for being efficient and green!

rogerblack

First step.

Un-clip the energy monitor from the cable - does it read about zero - if so - great, move onto the next step (after clipping it back on).

Turn off/unplug _everything_ - does it read zero(ish).
If not, then start switching off circuits at the breaker-box to identify which circuit(s) the loads are on.
Now, go and see if you can work out what stops working when you turn that off.
Remember to plug freezer back in.
(baseline ~100W)

don0301

the reason the energy monitor is giving a "ghost" reading is because it is measuring reactive power because it is an inductive meter.

it does not measure what you are charged for by the grid, or if on your PV system output the same.

the only sure fire way to measure is to individually switch off at the fuse box, or switch off individual electrical items on a particular fuse switch, and measure it that way.

ie turn everything off at the fuse box overnight, and take house meter readings before and after, then with individual items you may want to measure.

remember to turn essential items like fridge/freezer etc back on in the morning

hope this helps

Cardew

At very low consumption the readings on these monitors is just useless and is best ignored.


I have both the E.ON and BG Monitors and the readings over 7 days are pretty consistent when compared to my electricty meter(they over-read slightly)

However I cannot get my 'standing consumption' below 180 - 200 watts despite having everything off in the house. For an hour I had everything off, except of course the circuit in which the display was plugged in; the display was plugged in via a plug in monitor. At the end of an hour the plug-in monitor showed no consumption(so it wasn't the display using the 180-200w). Yet despite the E.ON monitor reading over 180 watts for the hour, the display on my meter hadn't changed - it displays in units of one tenth(0.1) kWh. It obviously should have changed by close to 0.2kWh.

rogerblack

Cardew wrote: »

At very low consumption the readings on these monitors is just useless and is best ignored.

It varies.
I have two energy meters - clipped onto the same cable.

Turning off all the loads - I think the only load at the moment is a timer for my solar heating pump (1w) - the 'currentcost' meter that I got free from Eon is bouncing between 30-32W.
The other meter reads 0.
On reading my meter, it goes 1/50th of a turn in 40s, so .55h, this is a reading of ~3 watts or so.

Turning on a 20W load, I now get the currentcost meter reading 60W, and the other one reading 24W.

So, in some cases, they can be not horribly inaccurate.

I just realised after typing this that I'd left a 11W light on during the test.

However, as accuracy seems to vary quite a lot between units, I'd recomend using them only after you've verified the reading is sane with the main meter, with the aid of a plug-in meter to measure individual appliances.

don0301

rogerblack wrote: »

It varies.
I have two energy meters - clipped onto the same cable.

Turning off all the loads - I think the only load at the moment is a timer for my solar heating pump (1w) - the 'currentcost' meter that I got free from Eon is bouncing between 30-32W.
The other meter reads 0.
On reading my meter, it goes 1/50th of a turn in 40s, so .55h, this is a reading of ~3 watts or so.

Turning on a 20W load, I now get the currentcost meter reading 60W, and the other one reading 24W.

So, in some cases, they can be not horribly inaccurate.

I just realised after typing this that I'd left a 11W light on during the test.

However, as accuracy seems to vary quite a lot between units, I'd recomend using them only after you've verified the reading is sane with the main meter, with the aid of a plug-in meter to measure individual appliances.

I'll just re quote my previous post

the reason the energy monitor is giving a "ghost" reading is because it is measuring reactive power because it is an inductive meter.

it does not measure what you are charged for by the grid, or if on your PV system output the same.

this was one of my first questions on joining this site, and this is the answer i got from Fronius company on the reasons why.

it has to be true, because i took the guys advice, turned everything off at the fuse box, for 11 hours at night. my owl monitor reads a constant 113W during non-generating time, and after 11 hours my house meter hadnt moved at all.

previously i had disconnected the sensor and placed it in the same place but not on wire and it still read 113W, removed it from where it was placed and it read zero.

this is the only plausible explanation.

hope this helps

rogerblack

don0301 wrote: »

I'll just re quote my previous post

the reason the energy monitor is giving a "ghost" reading is because it is measuring reactive power because it is an inductive meter.

One reason for inaccuracy of this sort of meter can be that it only measures amps - this can be misleading for some classes of loads.
However, this is not the sole cause of inaccuracy - there are others, from large currents in nearby wiring, to simple poor quality of manufacture.

Inductive loads with no power draw do not really exist.
Capacitive loads on the other hand do.

don0301

rogerblack wrote: »

One reason for inaccuracy of this sort of meter can be that it only measures amps - this can be misleading for some classes of loads.
However, this is not the sole cause of inaccuracy - there are others, from large currents in nearby wiring, to simple poor quality of manufacture.

Inductive loads with no power draw do not really exist.
Capacitive loads on the other hand do.

where do you get large currents in a household?

energy monitors working in their "threshold" are generally within 5% accuracy.

at very low currents, loads (however you want to define it, it makes no difference) it is as i stated.