Keith Woody's Technology Blog


Keith Woody Welcomes You

Welcome my technology rant!

My name is Keith Woody – with 25 years in engineering, solar energy and electronics, my friends suggested i started a blog – here we go!

Solar Power – Hmmmm

We recently bought a house in Brisbane with an old(1979)solar water system. It has two 4 x 8 panels bolted to the (2 story)roof. The huge exchange tank itself was rusted out with no hope of repair, but the rest of the system looks okay. It used coolant pumped through the tank with a pump and electronic control box that basically compared the temp of the heater with the temp in the panels and pumped accordingly. We brought in a local solar panels expert who was actually involved in the original installation. He said the new systems circulate water through the panels. The panels are vertical and the water is actively pumped up into them when needed and drained back out when off, making freezing impossible. (it really does freeze in Brisbane occasionally) So basically nothing of the old system was reusable and we can not afford $6k for an entire new system so we put in a cheap electric heater for now. We now plan to remove the old panels from the roof, relocate them to a sunnier area(trees have grown up south of the old location anyway) and mount them
vertically so they will drain as the new ones do. The plan is to use them for heating water for the hot tub(not yet acquired) or maybe house water. We’ll make sure it is thoroughly flushed but don’t plan to
use it for potable water anyway.Tom the solar guy says they weigh no more than about 150 kg, so hopefully we
can wrestle them off the roof with pulleys and a big overhanging branch. My experience or observations on this is that with power prices rising Brisbane will see a huge uptake in solar

Transient Voltage Suppression

James Allen at Electrician Inner West has installed 3 TVS‘s to stop the noise coming down the Sydney Electricity power lines from reeatedly blowing our SMA solar inverter.

It was installed in 2010 as part of our 5KW solar system which has run flawlessly for 5 years. 2 months ago it failed. Why did it fail? Well, my theory is that is was due to poor electrical filtering on the power lines in inner west Sydney caused by the inner west light rail system which began operating 2 years ago. The light rail runs of power cables that arc on occasions and my theory is these arcs inductively couple spikes into the electricity grid. Because the line transformers do not have ant transient suppressors installed the electrical spikes go straight into residences electrical circuits, including my SMA solar inverter!

James is an electrician with 20 years experience and has not seen these type of failures before recently. Again, my theory is that the power spikes from the light rail is the culprit!


From Wikipedia:

transient voltage suppressor or TVS is a general classification of an array of devices that are designed to react to sudden or momentary overvoltage conditions. One such common device used for this purpose is known as the transient voltage suppression diode that is simply a Zener diode designed to protect electronics device against overvoltages. Another design alternative applies a family of products that are known as metal-oxide varistors (MOV) that protect electronic circuits and electrical equipment.[1]

The characteristic of a TVS requires that it respond to overvoltages faster than other common overvoltage protection components such as varistors or gas discharge tubes. This makes TVS devices or components useful for protection against very fast and often damaging voltage spikes. These fast overvoltage spikes are present on all distribution networks and can be caused by either internal or external events, such as lightning or motor arcing.[2]

Plumbing Goes 21st Century

I have known Paul Myers for 27 years. He is a licensed plumber in Inner West Sydney, running 888 Plumbing Solutions. Paul came around last week to take a look at our hot water system that was seemingly on its last legs. It was a Rheem stellar  stainless steel skinned electric hot water system. I told Paul that the flow of hot water had been steadily decreasing over a period of about 4 to 6 weeks – to the point where having a hot shower was increasingly frustrating! The flow rate seemed only related to the hot water system, as the cold water flow was fine.

Technology To The Rescue

Paul produced a miniature CCTV camera that is capable of looking inside standard copper water pipes. These cameras were developed by the CSIRO to enable scientists to locate metal fatigue in steel structures, jet engines and internal combustion engines. It was later realised that the small size of the cameras lead themselves to uses in other industries, like plumbing. Paul runs a thriving plumbing business based in Rozelle, in Inner West Sydney. He does a lot of blocked drain work and uses a standard drain CCTV camera to feed into the problem drain and see what the issue is (typically tree root invasion into the drain in Sydney’s sandy soil in the inner west).

The pipe camera Paul used was around 6mm in diameter and connected to a fibre optic cable only 7 mm in diameter. This fibre optic cable was 20 metres long allowing for visual inspection in virtually all household water pipe systems. This opens up huge possibilities for plumbers to check what is going on inside your pipework even if it is set in brick cavities in your typical double brick home. Using the pipe camera Paul was able to find the problem with a dwindling hot water supply. He fed the camera through the outlet pipe from the hot water system to discover a large rust flake had partially blocked the copper water pipe feeding the hot water from the tank to the house (and the shower!!). It was, fortunately, only 20 cm away from the end of the pipe, so by feeding a small wire into the pipe he was able to dislodge the rusty flaky metal causing the obstruction – problem solved!

Technology continues to revolutionize all facets of our lives. plumbing used to be seen as a very ‘mechanical’ trade – where the standard plumbing toolkit consisted of wrenches, welding equipment and pipe cutters. how things have changed. plumbers now carry a range of ‘high tech’ electronic equipment that make fault finding a plumbing system far more accurate and definitive than was ever possible 15 years ago. We live in interesting times!

  • drain camera

A.C.T. Solar – Canberra solar installation company Profile

The latest 22 percent efficiency solar panels are being installed in Canberra A.C.T. I spoke with Bob Ryan from A.C.T. Solar - call Bob on 0419 592 801).

Companies like Sunpower (http://us.sunpowercorp.com) and several Japanese solar companies have been steadily increasing solar power efficiency. From levels around 14% a few years ago, it is expected that solar efficiency of up to 40 percent may be possible in a few years Bob says. In Canberra Bob’s company is doing several solar panel installations per week and the need for high efficiency panels is becoming more important with Townhouse and smaller residence construction in the A.C.T. with commensurately less roof space available to install the solar panels. Bob mentioned a 5kw system they installed in a 45 metre square north aspect roof – amazing given 30 percent roof space would have been needed a few years ago.

Solar Water pumps

Solar Water Pumps

A google search for the title “solar water pumping in Home Power magazine ” lead me to this article:


Solar Water-Pumping

Water is an important consideration for any property. I secured water rights to artesian springs on my property, but they are below the building. I placed an 1,100-gallon (4,160 l) tank on a ridge above the building. Next, I built a weir with drilled plastic pipe for the input. From there, the water flows slightly downhill to a 5-foot-diameter (1.5 m) concrete well tile, dug into the ground and floored with concrete to serve as a reservoir.

The springs’ flow rate varies from 1 or 2 gpm (4–8 l) in summer to 25 gpm (95 l) in winter. The reservoir has a 4-inch overflow pipe near its center that returns excess water to the ground stream. From this reservoir, I pump up to the storage tank on the ridge. I use the same 1 1/2-inch line up from the pump as an intake for the building. The overall head is about 90 feet (27 m).

The available pressure at the building is about 26 psi. A booster pump and expansion tank raise the pressure to about 50 psi before the water enters the plumbing distribution system. This booster pump operates intermittently, for a duration of two minutes per cycle.

I use a Conergy (formerly Dankoff) Slowpump attached to a Conergy controller and a single, 24-volt solar-electric module to pump the water. The pump is rated at 3 gpm (11 lpm) at a 400-foot (122 m) head. It produces about 2 gpm (8 lpm) under average conditions at my site. I use a float switch in the reservoir to shut down the pump as the water level falls, since it is not good to run the pump dry.

The reservoir holds about 325 gallons (1,230 l). But it can be easily pumped down on a strong solar day. I have a control switch in the building that triggers the pump upon my demand. I simply watch my water level and pump up the storage tank when needed.

Often I clean the concrete reservoir and charge its contents with chlorine before pumping. A cup of bleach works fine. A microbiologist friend of mine assures me that contained clean water stays clean indefinitely. I don’t drink this water, but tests lead me to believe that I could. Interesting video follows: