Ways to use my lecky monitor

Andy_WSM

Got mine showing import, export and on site usage now Dave: http://wattson.energyhive.com/dashboard/AndyW

Only just replaced the broken clamp, so not much data yet - and it's another dull day!

matelodave

I'm impressed, it's very informative especially if you can download all that info into your own spreadsheets as well.


keep us updated

Andy_WSM

matelodave wrote: »

I'm impressed, it's very informative especially if you can download all that info into your own spreadsheets as well.


keep us updated

Notice how the usage and generation is closely tied? Immersun

The hot water tank stores surplus (a few kW worth anyway), which is less work for the heat pump to do when it comes on later.

Andy_WSM

Dave, question about the multisensor - Is it any good? I notice one of yours is saying it's -300C at the moment. Whilst it is chilly...Gosh!

Is it a bare board as it shows on their website?

Ideally I'd like just the temperature module, but can't find them for sale anywhere.

polymaff

matelodave wrote: »

It's not everso accurate anyway. Clamp on sensors can't accurately measure your consumption - mine works out about 5-7% high compared with the electricity meter.
My voltage fluctuates between 243-249 which adds to the inaccuracies and the heatpump has an inverter driven compressor and fans which probably plays havoc with the power factor as well.

These clamp-on sensors make assumptions about both voltage and power factor - which can result in significant errors. The best monitors I've seen are those which stick onto the front of your meter and then time the rate at which the meter's LED flashes.

True, the LED has to be there - but this system can compute very accurately what you are currently and cummulatively using.

Providing that the meter isn't faulty

Andy_WSM

polymaff wrote: »

These clamp-on sensors make assumptions about both voltage and power factor

The software for this kit allows you to put the mean grid voltage in to the settings, which can be derived from the solar inverter software. So granted, whilst not 100% accurate it's accurate enough for monitoring purposes. I can't use the LED type as my incoming meter is configured incorrectly and flashes on both import & export, but only registers import on the the display.

Is power factor an issue for domestic billing?

polymaff

Andy_WSM wrote: »

Is power factor an issue for domestic billing?

Not directly for billing, but it does affect those energy monitoring devices that rely on current sensing. 50+ years ago, most loads were power-factor=1 - incandescent lights, electric fires, immersion heaters etc. Now that we have so many bits and pieces that involve power factors less than one, trying to deduce the power from the current is becoming more and more difficult. Even when, as you mention, you can input the voltage - that varies, and even then, you end up with the VoltAmps, not the Watts. A lot of entirely bogus figures for the standby power of modern TVs etc. has been published by those who don't know the difference between VA (voltamps) and W (watts)

There is an indirect effect on the billing, BTW. It costs more to supply power when the power factor is less than 1.

Andy_WSM

Ah well, regardless, it's an indication, not a scientific experiment. I can't do any different anyway thanks to the incoming meter being set as it is - not something I can change. Also as my generation meter and supply meter are at different ends of the house it would be a challenge connecting to both optical ports - whereas clamping the cable is easy and can happen anywhere.

polymaff

Andy_WSM wrote: »

Ah well, regardless, it's an indication, not a scientific experiment. I can't do any different anyway thanks to the incoming meter being set as it is - not something I can change. Also as my generation meter and supply meter are at different ends of the house it would be a challenge connecting to both optical ports - whereas clamping the cable is easy and can happen anywhere.

As long as folk treat it as "for indication only" that is fine. To give you some idea of the accuracy, the algorithm to derive the power displayed in watts from the current sensor in a widely used monitor is that the calculated value to be displayed is scaled down by a factor which is slipped from 0.6 at 0W calculated power to 1.0 at 750W - i.e. above 750W no attempt is made to allow for Power Factor, below 750W calculated the figure displayed is progressively reduced. This is a reasonable approach as most PF < 1 equipment is lower powered.