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Hi calypso_rae

I have Economy 7 with an afternoon boost so needed to add a relay to change over from the mains to your Mk2 mini when operational. I also wanted to use something that was fit for purpose and blended in with the other electrical equipment. So I used an empty consumer unit as I wanted to use the DIN rail inside. 

As I had relays to consider I went for DIN rail 20A Finder relays, 12V DIN rail power supply for Arduino and relay power, DIN rail bell transformer for the VT source, DIN rail kWh meter to record all diverted power and a 6A DIN rail circuit breaker for the protection of power supply and bell transformer.

The heat sink I mounted on the back of the consumer unit where fingers cant reach and a couple of wall spacers allow adequate ventilation. The unit was feed via a 16A circuit breaker in the main box and the existing immersion wiring diverted via the new unit.

As everything was contained within the consumer unit except the CT it made for a very neat installation and I would recommend it to anyone else. Very professional looking solution with smoked plastic front cover through which the power and trigger LED's can be seen.

Been working now since September 2012 with no problems. Regards, Solar Dumper.

Sounds an interesting solution, a bit pricey perhaps if everything has to be purchased from new.  I'm sure that many people will like the idea of your DIN rail kWh meter to record all diverted power.

Any chance of a photo, and maybe a link to the DIN items?

The triac has an isolated tab, in case of a critical fault arising I've earthed the heatsink  so any fault will cause the trip in the consumer unit to trigger. The signal to the optocouple is isolated by its nature but I would recommend the USB socket is sunk back by moving the arduino into the box and a cover stopping it being generally accessed, as is the supply plug to it, also the "wallwart" supplying the arduino should be double insulated.

However the unit is built our wonderful "nanny state" doesn't condone any interfering with our own electrical systems in our own homes by anyone not regarded as a competent person, so anything you connect up is at your own risk.

Hi All

Well my first bank holiday "hacking" has been, i think, a success

I will post and comment on the "Earthing" debate you have started above on a separate thread i think (i am pretty comfortable with this topic) but for now please see my build in the photo attached

I modified "Rich's kit" and used the spare 9V outputs along with a full wave rectification circuit to also provide the power supply to the Ardunio board, in addition I used the suppply from the Distribution board (via a small fuse) to power the ac-ac transformer and the power supply to the Ardunio  to avoid duplicating cables in and out of the board and multiple sources of supply being inside one enclosure

i cant see why any of this would cause a problem and the voltage to the board is OK and the board lights up but it got dark before i could actually test the unit

I uploaded the Rev 4 sketch but what i need to know (as an absolute beginner) is how i can monitor what goes on when the unit springs into life (im ever hopeful!)

if you could let me know that would be much appreciated

cheers

GTEC, I do hope you will be connecting the heatsink to earth before you (sorry for the pun) go live.

Good luck with using the second winding as a power supply, others have found doing so distorts the reference waveform and allows noise from the Arduino to have an adverse affect on low level readings compromising performance. And for the sake of a tenner for a separate wall wart not worth the bother.

Keeping the number of inputs down to a minimum makes a lot of sense.  The Arduino's power supply will not draw much current so may not affect the AC waveform in the other half of the transformer much.  Its effect, if there is any, would be to cause the voltage to droop slightly at the waveform peaks so the router would under-read.  But it would do this on every single cycle, not just when the dump-load is on, so may well have no overall effect on the router's ability to balance import and export flows.

The local mains voltage will undoubtedly droop during cycles when the dump-load is on, probably by a couple of volts.  This effect can be minimised by measuring as close to the meter as possible.  If the voltage were to be measured, say, at the live side of the triac, the reduction in voltage would be greatest.  Its effect would undoubtedly be to cause the energy content of 'on' cycles to under-read.  This would cause a bias in the direction of import, hence the likelihood of occasional charge pulses for the user.

It may be that this small amount of import leakage would be below the anti-creep threshold (around 15W for many meters) in which case this extra power could be consumed without risk of being charged.  It's essentially power that is being dissipated in the user's wiring between the meter and the point from where the load is being switched.

Any ideas for minimising the number of connections to the router (as SolarDumper has done so effectively) are right on topic here.  As are any reports re. the effectiveness of such techniques. 

GTEC: I uploaded the Rev 4 sketch but what i need to know (as an absolute beginner) is how i can monitor what goes on when the unit springs into life (im ever hopeful!)

Nice build.  If you have any questions about how my Mk2i_rev4 sketch works, the Mk2i thread is the best place to check.

I've insulated the triac, using a mounting kit, and earthed the box that functions as the heat-sink. So in my case there have to be two failures of the insulation before there's an earth fault.

Hi Both

thank you for the comments and replies, Rich, ill come back to Earthing and / or Bonding  of the parts / enclosures as te AC compliance side of things is an area that for my sins i have to say that i know an awful lot about, ive a few comments about the effectiveness of the OPD's with a reduced line voltage as well that ill put in the same posting.

I don't know if you have checked out my profile but you may like to download the book a co-wrote recently, the links on my profile page, i think its great, but them i am biased!

Calpso_rae, I'm afraid that i've read the page that you have linked to over the last few days and sort of get it, what i am interested in is more fundamental than that i am afraid!

I have seen your Youtube clips and you are able to monitor the "realtime" out put / behavior of the sketch - this is what i am interested in - ie id like to hook it up during darkness and see if i have the ct coil the right way round but dont know what settings / software will allow me to view the output, and in addition will the ardunio store data and if so for how long (with its limited RAM etc)

so many questions and so little sleep..........................

thanks in advance

cheers

GTEC, Checking the operation of a PV Diverter system during the hours of darkness is very straightforward.  All it takes is an extension cable from which the outer insulation has been removed.  You wrap one of the conductors around the CT at least twice, and the CT will then detect any current flow in that cable as PV.  The current has to be flowing in the opposite direction to the normal flow.

The diagrams on page 8 of my article at http://openenergymonitor.org/emon/mk2/build should make this clear.  This technique is also shown in several videos on my summary page.   Look for  Simple demo of Mk2 PV Router (1 of 2) and How to check that PV Router is set up OK 

None of my Mk2 sketches store any long-term performance data in the Arduino.  Their sole purpose is to divert surplus PV power to one or more dump-loads. 

Hi again

Thanks for the reply, what I was wondering was how you can hook up the laptop / computer to show "realtime" the functions that are being performed?

After a late night last night (I didn't get in until 8pm) I managed to get the rev.4 loaded onto the Leonardo board but there was no output to speak of, I tried the coil in different orientations (i had it mounted on my "meter tails" where there was 17A of load) but to no avail

After thinking that i may have clumsily deleted something in the code that I shouldn't have whilst selecting the functions in rev.4 (ADC time etc) i thought id try rev.2

Success - well sort of, the Triac now functions and I get full output to the immersion, but this state doesn't alter no matter what orientation the CT was mounted on on the meter tail

any suggestions .....

thank you in advance

GTEC, it sounds as if you need to check that your basic setup is working correctly.  The first two tools on my summary page are ideal for this.  You will then know that your rig can measure AC voltage and current correctly.

If you are trying to divert surplus PV power, why not use a simple Mk2 Router sketch such as Mk2_PV_Router_mini_2, as linked from the same page.  This sketch operates with floating-point maths and is probably the easiest one to understand.  There are no interrupts or strange scaling aspects for integer maths.  Moreover, it uses analogRead(), just as per the standard OEM sketches,  As posted, that sketch displays each second how much the level in the energy bucket has changed by.

If you wish to continue this discussion, please could you do so on the relevant thread, ie. http://openenergymonitor.org/emon/node/841 for the basic Mk2 operation or http://openenergymonitor.org/emon/node/1912 for the interrupt-based version.

This thread is intended for enclosure-related topics only.  Thanks.

To put this thread back on track I have attached a photo of my remote energy diverter in action controlling the primary load which is an immersion heater.

The heatsink is one of these. The triac case temperature is reaching 53 deg C when the unit is running at full tilt. I can only assume that others who have used smaller heatsinks and plastic boxes must be seeing higher temperatures.

Personally I see no sense in housing steaming hot mains voltage electronics in anything less than a class 1 rated enclosure.

Brian that box looks really professional and very safe.  As we are back talking about enclosures, get yourself one of the traditional cylinder jackets to go over the foam insulation, you will raise the insulation effect from 85% to 98% not a bad gain.

I prefer metal container to enclose my routers because earthing is easy with them unlike with plastic ones.

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I prefer my containers to be a bit smaller than the room-sized ones that you are suggesting  !!!

I used one of these from mouser.com http://www.hammondmfg.com/1554FSLP.htm#1554CL_F

I have used the metal back panel to mount 2 emonTX and a emonGLCD

Ian

Looks a neat box, Ian, especially the corner mountings.

Are you transmitting data between three Atmel processors, all in the same enclosure, by radio?  If so, I wonder whether the SPI interface (hope that's right) would be able to do this using less hardware.

Not sure what a SPI interface is!

I am using wireless for all my data transfers

One of the emonTX is collecting house, Solar and immersion dump data via CTs
The other enonTX has a CT on the house incoming neutral line and is controlling a SSR to divert power - it also gets tank temperatures and has a software off at 75C
I have a emonTX at the hot water tank monitoring the temperatures at the top and immersion heater point - the tank had a spare sensor pocket at the immersion heater point.

I have two emonGLCDs one in the box and one in the kitchen - they both get data from all three emonTXs
I also have a nonodeRF - it only pushes out the date and time at present.

I have attached another picture of my setup

Ian
 

Ianjm: look at MartinR's Full Fat monitor to see how to link many units using the SPI bus. http://openenergymonitor.org/emon/node/1170