Category Archives: Green


Been real busy at work with a project proposal. We finally got it submitted last Friday.  Consequently I do not have as much done with the new machine to replace the dell dimension desktop. I started look at it today and I realised I had run out of spare sockets on the RIGrunner in the shack. So I need to sort that out first but it will require me pulling everything off the desk to do a bit of rewiring (sigh).

So rather than tackling that today, I first installed a 190 Litre Single Water Saver Kit that I got from It is 1/4 full already with todays showers. After that I moved my battery bank to its new home (with help from EI8JA). This is also going to require some rewiring to get the Inverter output back to the garage to hook back into the house wiring (where it moved from).

PV Panels are hooked up again, and the bank is being charged, but no AC available back in the house yet. Oh, lucky me, I’m “off” tomorrow,  I wonder what I will be doing?

“Gorilla” Update

I’ve not been in the shack all that much recently (being part of the organising team the the Irish IPv6 Summit kept me busy) so I have not been doing much checking up on the PV installation and how it is working.  Today, after assisting the South Eastern Amateur Radio Group set up a station for the EI2GEO special event station, I got to sit down and do some investigations. I have a second 60 Watt solar panel that I mentioned before. We hooked it into the battery system on Jim, EI8IG’s camper van to keep the battery topped up via solar power, and ran the radio from the same battery bank.  This evening I dropped out my little 850 watt generator to keep the battery topped up overnight (and to give it a good run).

Today over a 12 hour period between approximately 08:00-20:00, my rrdtool graph says the system produced an average of 148 watts. 148 x 12 gives 1776kw, or approximately 28.5 cents of electricty (including vat). If we have about 7000 more days of sunshine like today  (unlikely) then the system will have “paid for itself”.  While it doesn’t seem like a whole lot, it is currently averaging about 1/6 of the ESB bill (over 30 days).

That is the first part done. Next I intend to replace my power hungry dell dimension desktop (approx. 125 watts, 24/7 or approx. 48 cents per day ) with a more efficient machine (approx 20 watts or approx. 8 cents per day). To do this I have purchased an Intel Pine Trail base D510MO a 40GB SSD drive, 4GB of ram and a DC powered case (I already have a DC supply in the shack, plus I can experiment with it in the car as well).

Thus far the machine seems to be able to do most of the tasks I need it to do, time will tell though as I need to get 6 RS-232 ports operational on it to control all the items I have running.

As an aside, we recently replaced the old washing machine (at least 10 years) with a super duper A rated new one.  Initial testing seems to suggest that it is no more efficient than the old one. My suspicion is that I tested the old one (which I no longer have) in late Autumn, where it would have the benefit of taking hot water from the cylinder (Central Heating). The new one doesn’t have a Hot water input, so has to heat the water itself.

Ramblings about PV and going “Gorilla”

Ok I admit, I’m a bit of a solar power junkie.  I’ve been experimenting with PV panels a while now (here, here, here, and here). I have a small 10 watt waterproof solar panel (the irony eh?) which I got a number of years ago that I use to keep a few GEL Cells topped up by leaving it in the window of the upstairs bedroom.  I have a pair of Evergreen ES-180RLs (24volt) which have been mounted on the shed roof for quite a while now, also, last year I picked up a pair of 80 Watt Panels (12 volts, off ebay) and a second hand 60 (12 volt) watt panel.

At the moment I’m using them to keep a battery bank charged. I have a 1500 Watt inverter/charger that I can run off the bank.  I split one of the circuits in the house so that I can plug it either into the consumer board, or the output from the inverter.  This circuit has on it, the central heating pump and burner, fridge, fridge freezer and one double socket in the kitchen, i.e. an extension lead can be run to the TV/Radio Shack.  This is just the way the house was wired, so I took advantage of it. I also have an external 220v connection that I can feed in the output of a generator. The inverter is plugged into this, and if it is receiving power from a generator, it can power the house circuit mentioned above and re-charge the battery bank simultaneously.  My only issue with the inverter is that when the charging circuit is running, it generates an awful racket on the HF bands. I’ve used it a few times during power outages, Watching T.V. when the rest of the housing estate is in darkness is interesting, and generates interesting questions afterwards (how come you had lights on etc.). I also can run the items in the shack directly from the battery bank, but, to be honest, it’s a bit messy, and not very efficient.

The 60 Watt I bring with me on AREN events, as its useful at keeping the battery in my X-Trail or the Mobile Command Post (MCP) topped up:

The 60 Watt panel works surprisingly well for this purpose.  On several (rare) sunny events in the last 12 Months, we didn’t require any generators or external power at all on the day.

Anyway, back to my main point.  I happened to visit John Ketch a few months back, and he was particularly happy with the advice he got from Nigel in as to panels and other items. As I had been thinking about getting a grid-tie inverter to experiment with, I took Nigels details and in February I rang him.

Our initital conversation was not what I expected. I outlined the various bits and pieces that I have, what they were doing etc, and said I was interested in getting a grid-tie inverter.  Nigel said to go away and think long and hard about what I’m trying to achieve and come back to him after I’d done that.

So, I go away and re-examined what I wanted to do.  Between the server and radio gear I leave running 24×7, plus the usual stuff like alarm clocks etc, I have about approximately a 400 Watts of continuous load in the house.  So I decided to do several things. Replace the server with something that uses less power, more intelligently use the radio equipment i.e. only switch it on when a satellite is visible, and see what contribution a grid-tie inverter could make to offsetting the usage.

Typically, I’m tackling the last one first.  So my plan was to split the panels, and use the two 24 volt panels with a grid-tie inverter, leave the two 12 volt panels to charge the battery bank.  So I rang Nigel again about a week ago. This time things went better, in that I actually convinced Nigel to see me an inverter! I went with a Steca Grid 300 from

Now,before agreeing to the sale Nigel pointed out that though the inverter does automatically shut down should the grid fail, it does not conform to EN50438, which the ESB require in order for any installation to be approved. I looked at the specs, and decided that in the grand scheme of things, my (potential) 300 watts isn’t going to make much of a difference, and that if he didn’t tell the ESB, then neither would I.

This morning at 08:00 when I plugged it in, the inverter was producing approximately 60 Watts, which I think is very impressive given the low light levels. It will peak somewhere between 180 and 200 Watts (based on yesterdays performance) about 13:00, and still be putting out 60 Watts at 20:00. I’m monitoring both the general house consumption and the output of the inverter with an Envi CC128, so it will be interesting to watch it over time.

So there you have it, I’ve gone “Gorilla”. Many thanks to Nigel in for the advice and assistance.

Electricity Usage.

I’d been meaning for ages to purchase something to measure power consumption in the house. Earlier this week, a work colleague reminded me about it, so I went and purchased one. My Current Cost Envi arrived just before 8am this morning (thanks Mr. Postman) so I hurriedly plugged it all in before going to work.

This evening after dinner I found the data cable and plugged it all in.

[3383512.421973] usb 1-2: new full speed USB device using uhci_hcd and address 3
[3383512.580255] usb 1-2: configuration #1 chosen from 1 choice
[3383513.033716] usbcore: registered new interface driver usbserial
[3383513.034024] drivers/usb/serial/usb-serial.c: USB Serial support registered for generic
[3383513.034271] usbcore: registered new interface driver usbserial_generic
[3383513.034276] drivers/usb/serial/usb-serial.c: USB Serial Driver core
[3383513.146668] drivers/usb/serial/usb-serial.c: USB Serial support registered for pl2303
[3383513.146703] pl2303 1-2:1.0: pl2303 converter detected
[3383513.146930] usb 1-2: pl2303 converter now attached to ttyUSB0
[3383513.146942] usbcore: registered new interface driver pl2303
[3383513.146946] drivers/usb/serial/pl2303.c: Prolific PL2303 USB to serial adaptor driver

Excellent, the device was recognised to begin with. I found this web page by Paul Mutton, describing how to generate graphs from it with RRDtool. Some minor modifications, courtsey of “Q” and we have a result.

1 Hour in Meadowbrook

To quote from Paul’s page:

Then you can sit back and be amazed at how much electricity you waste when you leave a computer on to monitor how much electricity you are using 🙁

Power Consumption.

Here are some rough figures that I’ve come up with for ‘annual’ usage.

  • PC/UPS/Dsl Router, 990kWh
  • Fridge/Freezer, 525kWh
  • Work Laptop(at home)/Screen/Wireless Router , 235kWh
  • Chest Freezer, 182kWh
  • Kettle, 182kWh
  • Sky Box, 142kWh
  • TV/DVD/Speakers, 118kWh
  • Washing Machine, 93kWh
  • Printer/ancillaries, 89kWh
  • Projection Alarm clock, 34kWh
  • Toaster, 6Kwh

Biggest surprise for me was the small chest freezer, it seems to be very efficient.  I’ll have to think a bit more about the rest.

Magic Smoke!

Unfortunately I accidentally released the magic smoke (sorry Scott, didn’t mean to hurt it) from the venerable OT-1 that I was using to measure my PV array (see my earlier post). So I’ve parked that experiment for a while. As we get closer to the solstice, its amazing (to me) to watch the amount of ‘sun hours’ available to the panel decrease. I’ll have to begin negotiations with SWMBO for a better location for them next year.

PV Measurement

I’m still going through the various items in the house, trying to get average usage profiles is quite difficult, so far the biggest hog is the Ubuntu Server I have running under the desk, so I might have to re-visit my choice of machine in the future.

Something I’ve wanted to do ever since I installed the PV Panels was to get some data on them. I’ve started it at least, here (login required) you can see some data. The top graph is the air temperature in the office. The second is the battery bank voltage as seen at the charge controller. The third is not yet connected, but I’m hoping to get a current measurement from the panels as well over the next few days.

The device doing the measurement is an OT1 (discontinued) from Argent Data Systems. The radio is a Yaesu FT-1500M (also discontinued) with a transmit power set to 5 Watts. I had to make a minor modification to the OT1. The potential divider circuit is set-up for measuring up to 15 Volts, I had to change one resistor to allow measurement up to 30Volts.

Power hogs.

I flirted with measuring the power consumption around the house last year, but got side tracked.  Now that we’re getting a 17.5% increase in Electricity prices, I think its high time I revisited this area. Co-incidentally, I happened to be running the TV ‘stuff’ through a Kill A Watt meter for the past week.  Total  consumption was 2.25kWh (approx €0.33).

I’m going to slowly go through the house and get a handle on what everything consumes.

The PV panels I put up are silently working away.  Unfortunately ‘operator error’ reset the counters a while back, and I’ve not been as diligent since. However, in the time between the 27th May and the 28th of June, the panels produced approximately 1500Amp Hours, 36,000 Watt Hours (1500 x 24), 36kWh or about €5.25 worth of electricity.

Guilt free Radio!

Eamonn seems to be enjoying his holidays. With R$15 all-you-can-eat dinners and R$1 for a beer, I’m not surprised. I, on the other hand have been so busy recently it just was not funny.

AREN has been soaking up my spare (ha!) time, with meetings, documentation, and other stuff that comes with trying to organise volunteers. AREN was also involved in recent exercises with other Voluntary Emergency Services in South Tipp,


and last weekend AREN members aided the Glen of Aherlow Fáilte Society with communications for the Glen of Aherlow Walking Festival, as the weather was forecast to be good, numbers were quite high. Communications from both sides of the mountain were provided and everything seemed to go without a hitch (other than the torrential shower just before walkers got to the buses on Saturday afternoon). Bernard, EI8FDB, has a few pics up on flickr taken during the event. Finally though, things are slowly getting under control (even on the DIY Front!) AND we found that shim6 bug I was talking about, so I can make some headway in work.

Now, as to the title of the post (Thanks Seamus!). I’ve been collecting bits and pieces for a while (2 years or so), batteries, solar panels, charge controllers etc. I finally got the panels installed, (sub optimally unfortunately, but wife friendly) two weeks ago. I let the batteries charge up fully, then I switched off my 13.8Volt PSU, and switched on the (slightly adjusted) 24v-12V DC DC converter. That was the 27th of May. Since then I’ve had my radio gear running from it just the battery bank and the panels (some of it 24×7). At this moment in time (approx 11 days later), the panels have put 204Ah into the battery bank, the DC-DC converter has consumed 350Ah.

Miguel was asking me to work this out during the week, so here goes (its late, and I’m tired so I could easily be way off here)

554 * 24 (volts) = 13.296 (KWh)

13.296.5 /11 * 365 = 441.18kWh for the year.

My last bill says a unit costs 15.02 cent (incl vat), so I should ‘save’ about €66.26 on the ESB Bill over the course of 12 months. Or to put it another way, it will never pay for itself, economically speaking.

I’m still experimenting, and will probably add more panels (and more ‘load), but so far, I’m happy as a pig in the proverbial with it. The problems will arise however as winter descends (and that €66.26 total will be in doubt). In those (in)famous words, A lot done, more to do.