Geekzone: technology news, blogs, forums
Guest
Welcome Guest.
You haven't logged in yet. If you don't have an account you can register now.




108 posts

Master Geek


# 178976 21-Aug-2015 11:23
Send private message

Hi,
I have been trying to figure out a mysterious drop in power usage at home everyday.

I have a Effergy Engage power meter with the sensor on the main phase cable going into the meter outside, the usage it is reporting reflects what the meter is saying on the occasions I have checked.

There are a number of gadgets and stuff running 24x7, no electrical heating though (gas heating and hot water).  Idle load sits around 400w, which is a little high for my liking but seems to ring true to my IT and comms stack (about 100W), two aquariums with 100W heaters (not on all the time though) plus fridge and other idle stuff.

The screenshot below is fairly typical of power use, shows the idle then a jump when I get home from work and turn stuff on, there is often a peak in the morning too if I have time for a coffee :)

 

The strange thing is the 11am drop.  If I am not home it lasts from 11am to 9pm and is about 100W.  The only thing that I can find that changes in that time is the one of the aquariums, its lights turn on at 11am and switch off at 9pm, but that should result in an increase in power.  The lighting is 36W of fluros and 7.2W of LEDs.  I haven't measured real usage at the point yet on that though.

Now for the kicker.  I unplugged the timer and lights this morning to see what happens.  11am has been and gone and the power hasn't dropped today!

Now how on earth do those lights reduce power usage?  Surely they are not heating the aquarium more efficiently than the heater?  Probably worth pointing out that the heater is in the external filter so not exposed to the lights in anyway so doubt its the lights messing with the thermostat.

This is all very weird.




Create new topic
2914 posts

Uber Geek

Lifetime subscriber

  # 1371458 21-Aug-2015 11:27
Send private message

The only logical thing seems to be the timer... maybe its burning up a whole lot of power when the lights aren't on?


1670 posts

Uber Geek

Subscriber

  # 1371459 21-Aug-2015 11:28
Send private message

There will be others with a better knowledge of this, but from what I understand without a voltage sensor you are not able to measure real power, accurately. Those current-only sensors only measure power on resistive loads (i.e. filament lights, HWC elements etc). Anything with a reactive load will not be measure correctly and you could quite possibly see a drop in the reading - even though you are using more power.

Hopefully someone with more know-how can explain it a bit better!

 
 
 
 




108 posts

Master Geek


  # 1371460 21-Aug-2015 11:29
Send private message

frankv: The only logical thing seems to be the timer... maybe its burning up a whole lot of power when the lights aren't on?



I have wondered that too, but the timer is disconnected a the moment and there was no corresponding drop when I did that.



108 posts

Master Geek


  # 1371476 21-Aug-2015 11:31
Send private message

SumnerBoy: There will be others with a better knowledge of this, but from what I understand without a voltage sensor you are not able to measure real power, accurately. Those current-only sensors only measure power on resistive loads (i.e. filament lights, HWC elements etc). Anything with a reactive load will not be measure correctly and you could quite possibly see a drop in the reading - even though you are using more power.

Hopefully someone with more know-how can explain it a bit better!


Hmmm my electrician was telling me about power factors the other day as some new LED lights I had were particularity bad.  I wonder if its a situation like that?  I think there is another option to put a reader that reads the IR LEDs on the meter itself which is supposed to be more accurate.

3885 posts

Uber Geek

Subscriber

  # 1372640 23-Aug-2015 19:06

In short - it is to do with power factors. As different devices can have different power factors that can partially or fully cancel out. This is why you see an "apparent" drop in power consumption. You need to get a power measuring device that can measure power factors.

Also have you compared your monthly consumption as reported by your Effergy. With the consumption recorded by the power company meter. Due to the Effergy not being able to measure power factors. It should report higher than the meter. Also can you have a look at the power adaptor for the engage hub. Does it output DC or AC? As if it outputs AC it suggests that it is using the AC as a means of picking up the mains voltage waveform for power factor calculations.







108 posts

Master Geek


  # 1374603 26-Aug-2015 13:44
Send private message

I haven't managed to get a full month of monitoring yet on my Effergy.  My power company does not provide day by day usage or hour by hour usage so I wanted something to fill the gap, hence the Effergy box.

Pretty sure the engage hub is using DC but will check again...

Create new topic



Twitter and LinkedIn »



Follow us to receive Twitter updates when new discussions are posted in our forums:



Follow us to receive Twitter updates when news items and blogs are posted in our frontpage:



Follow us to receive Twitter updates when tech item prices are listed in our price comparison site:





News »

New AI legaltech product launched in New Zealand
Posted 21-Aug-2019 17:01


Yubico launches first Lightning-compatible security key, the YubiKey 5Ci
Posted 21-Aug-2019 16:46


Disney+ streaming service confirmed launch in New Zealand
Posted 20-Aug-2019 09:29


Industry plan could create a billion dollar interactive games sector
Posted 19-Aug-2019 20:41


Personal cyber insurance a New Zealand first
Posted 19-Aug-2019 20:26


University of Waikato launches space for esports
Posted 19-Aug-2019 20:20


D-Link ANZ expands mydlink ecosystem with new mydlink Mini Wi-Fi Smart Plug
Posted 19-Aug-2019 20:14


Kiwi workers still falling victim to old cyber tricks
Posted 12-Aug-2019 20:47


Lightning Lab GovTech launches 2019 programme
Posted 12-Aug-2019 20:41


Epson launches portable laser projector
Posted 12-Aug-2019 20:27


Huawei launches new distributed HarmonyOS
Posted 12-Aug-2019 20:20


Lenovo introduces single-socket servers for edge and data-intensive workloads
Posted 9-Aug-2019 21:26


The Document Foundation announces LibreOffice 6.3
Posted 9-Aug-2019 16:57


Symantec sell enterprise security assets for US$ 10.7 billion to Broadcom
Posted 9-Aug-2019 16:43


Artificial tongue can distinguish whisky and identify counterfeits
Posted 8-Aug-2019 20:20



Geekzone Live »

Try automatic live updates from Geekzone directly in your browser, without refreshing the page, with Geekzone Live now.


Support Geekzone »

Our community of supporters help make Geekzone possible. Click the button below to join them.

Support Geezone on PressPatron



Are you subscribed to our RSS feed? You can download the latest headlines and summaries from our stories directly to your computer or smartphone by using a feed reader.

Alternatively, you can receive a daily email with Geekzone updates.