Electricity use at MHV

1

We’ve just paid two large electricity bills. We didn’t get them until just now because they went to our old PO Box, so we haven’t had a chance to think about ways to reduce/manage our use.

Electricity:

14/5 to 13/6    $256 
14/6 to 13/7    $388

We’ve also had a water bill: 5/3 to 6/06 $40

When we moved in, various people had ideas about ways to monitor our electricity use, and with bills this large it would be a useful project to progress. Is anyone willing to organise it?

With the high cost of heating, please use it as efficiently as possible. You can turn off the individual heaters when the room is warm enough instead of waiting for the 2 hour timer to turn them off. They also have thermostats which I don’t think anyone has tried to adjust to get the temperature right.

2

Hi Brenda,

I am happy to provide all my source code/bom/reference materials for the
power monitoring that I do at my unit. Note that given the size of MHV you
would prob have to look at multiple or a much larger clamp then what I use
(I only use a 20A and I’ve never hit saturation, even with hot water + ac
at the shed)

Other ways of reducing power use is try and avoid CRTs and CFL backlit
monitors, I also found that my baseload in the unit drops by about 60-80
watts when I unplug my desktop computer and switch off my printer (though
its using wifi)

As a temporary measure most good clamp meters will give you a good measure
so you can work out your baseload. Baseload can account for a large chunk
of your power use if you let it get too high (my average baseload is around
60-80 watts, which is in the noise of my setup, and it means my minimum
power use is around 3-4 kw/hrs depending on how active I am in the morning.)

Also be worth checking what the hot water is set at and how long it takes
to heat. I am not sure where it’s located but in the shed in the parents
backyard, my hot water system accounted for about 3-4kw/hrs a day, being
set to 45C (noting the HWS was so rubbish that when set to 60C it would
trip the TPV because the thermostat would let it overshoot by about 20-30C,
at that stage it was using nearly 10kw/hrs a day and using stupendous
amounts of water)

Given that MHV is NFP it might be worth talking with the power co to see if
we can get a discount and/or be switched to TOU metering (most of our use
is in the evenings so after about 8pm we would go to “SHOULDER” which is
about 3/4 to 1/2 the price of “PEAK”)

Also check if there is any averaging b/s, given where the space is I would
assume it’d be a bit of a pain to read our meter and thus wouldn’t put it
by the meter readers to go “uhh too hard”

Computers use a butt load of power too, chugging along at 100 watts (not
including baseload), will cost 2.4kw/hrs a day which adds up pretty quickly.

Also look at point heating instead of “area” heating. Whilst it is
inconvenient to wear gloves inside if you have bad circulation in the hands
like I do, it can save alot of power (my unit leaks so much that I can’t
heat it enough to get above ~18-19C with my current fan heater without
closing all the doors to the lounge room)

I will try and do a better write up (on a break atm) with more details, but
on week days I get by on ~10kw/hrs a day, but on days when I go to
classes/go out at night/work late it gets as low as 5kw/hrs a day (I have
tastics in my bathroom)

Note that in my unit, there is no hot water on my sub switchboard (which is
where my clamp is at)

The other secret is use the right heating for the building, my shed was air
tight, I could heat it with only 800 watt hours per hour. My unit leaks air
like a cieve (more so when its windy or i am cooking due to the range hood
drawing a bloody good vacuum) so its best to use fan based heaters such as
ceramic. In the shed it was so air tight I could use an oil column heater
with no problems. Of course ALL resistive heating has a coeffecient of
1:1, but some heaters handle some conditions MUCH better than others.

In theory a “wattsclever” might work too, but bear in mind they pick up
stray fields like no tomorrow and can give erratic readings.

Last thought before my break ends… How hard given the asbestos would it
be to get ACTPG to fit a reverse cycle heatpump to the space? they run on
the smell of an oily rag (the 3kw system in the shed used only 800-900
watts and provided a peak of around 3.5kw of heat) and are waaaaaaay more
effecient than resistive heating.

Many 73s
Max

3

I’ve got enough other projects on the go, so I’m not planning on joining in on the power one. But really hope there are people willing to run with it, I think it is important.

I’m not sure how ACTPG is working out the amount we are using. I’ll email them and see if there is a meter we can get some sort of access to. At the moment we have access to the fuse board but not a meter. We are being billed directly by ACTPG, not by a power company.

We only just got the hot water fixed, so no hot water in those bills.

I don’t think we can get reverse cycle units fitted, and given we are only heating at the coldest times not sure that we’d get high efficiency?

4

I have a PCB here for a professional 8 circuit clamp on power meter with WiFi. It is one of the development projects I am working on for Redshift Wireless. I also have a cloud based controller for IR based Air Conditioners that I would be happy to donate to the group, if it is useful.

Darryl

5

Hi I am new.
I would be keen on helping out with energy efficiency and energy monitoring.

Aaron

6

Hello Aaron,

As you can tell from the dates on the emails/posts, the project didn’t progress - be great for you to run with it if you are interested. I’m happy to help you :slight_smile:

regards,

Brenda

7

I might dig around in my setup find some source code for reporting/logging. Its a bit of a mess because of epic scope creep (added to the minute voltage logging to see why stuff keeps going pop in my unit).

I would recommend avoiding the use of a raspberry pi for this application as the SQL database performance is poor when it comes to reporting although it does work for capturing and basic automated reporting

It worked very well over the winter with some minor error ( about 30 kW out of over a thousand or so unaccounted for )

Though during the warmer periods I found that its accuracy goes down the drain pipe (under reads by nearly 50%), I suspect that its to do with the signal being down in the noise as the peak power use is around 300 watts unlike before where I had 6 hrs of 1000watts + in addition to this I suspect there is some nonlinearity in the code I used which is causing some calibration error

The annoying thing for me with my setup is actually the lack of room in my consumer switch box, and the great big fat bus bar (that is connected to active) that makes poking around in there a little precarious. Thus making any attempts to calibrate it a pain

One more tidbit, make sure that the clamp fits the wire snugly. This is because measurements can swing a fair bit just by it moving.

Also always keep the current transformer loaded otherwise it vibrates like mad and can generate some stupid high potentials ( minute currents)

8

S/minute/tiny/

9

Just wondering if anyone checked if the space has a “smart” meter with an LED to indicate consumption? Some (most?) have a LED that flashes once per watt hour.

Just makes for a very easy way to track consumption if it does (i.e. just a photo-diode to pick up the pulse…) No need for current clamps etc.

10

From memory I am not sure we have actual access to our meter, it’s behind a
locked switch board that ACTPG reads

Though I do vaguely remember seeing a power meter? on the side of our pole
pig so that could be it too.

Although a smart meter with a flashy led would make life WAY easier

11

I don’t think we know where our meter is, or even if we have one. That was something that was going to be checked with the ACTPG - not sue if that has happened? We have a large, old style fuseboard in the corridor to the bathroom.

12

Yeah I had a look in that one, no power meter :frowning: it’s just one of those
consumer switchboards (i.e. having all the breakers accessable to avoid
call outs )

I suspect it’ll be in the switchboard opposite of the stairs on the ground
floor (though that part of the space is fuzzy in my head so I may be wrong)

Though for all we know there may be no power meter at all and ACTPG is just
making a wild guess

13

I’m going in tonight for the workshop, so I’ll have a look around if there’s enough light.

1 Like
14

Looked around, nothing…

Could we get key access to the meter box by chance? Surely it’s got to be the large metal box downstairs.

Even if the meter is the old rotating electromechanical type, I reckon it would be easier to do some sort of pattern matching off that rather than introduce further current measurement devices.

15

The electricity use at MHV was checked today by an electrician sent out by the ACTPG.

He used a two prong meter to measure the amps on each circuit, and on each phase overall. I made notes of some of the results.

The overall finding is that nothing seems to be wrong with any of the circuits. He adjusted the lights timer so that the outside security lights were on, and that circuit is only using 0.9 amps (this is the always on at night ones, not our led spotlights). The heaters upstairs do use a lot - each wall unit uses about 10 amps when it is running. The big fridge downstairs uses 5.6 amps when it is running - which seems to be quite a lot of the time.

I’ll give my notes to Adam for the committee/anyone who wants to try to work out why our overall power usage is so high. Adam also has the details of electricity usage for each month that the ACTPG has now provided.

I’ve turned off all the individual heaters upstairs, so as well as pressing the timer switch you will need to turn on any heater you want to have running. The one in the bathroom is easy to forget to turn off, and I’m not sure it is necessary to heat that area.

regards,

Brenda