Solar Boat

Two years ago when I bought my Hartley TS16 sail boat I dreamed of converting it to solar power. In January I installed a Torqueedo electric outboard and a 24V, 100AH Lithium battery back. That’s working really well. Next step was to work out a way to mount some surplus 200W solar panels on the boat. The idea is to (temporarily) detach the mast, and use the boat on the river Murray, a major river that passes within 100km of where I live in Adelaide, South Australia.

Over the last few weeks I worked with my friend Gary (VK5FGRY) to mount solar panels on the TS16. Gary designed and fabricated some legs from 40mm square aluminium:

With a matching rubber foot on each leg, the panels sit firmly on the gel coat of the boat, and are held down by ropes or octopus straps.

The panels maximum power point is at 28.5V (and 7.5A) which is close to the battery pack under charge (3.3*8 = 26.4V) so I decided to try a direct DC connection – no inverter or charger. I ran some tests in the back yard: each panel was delivering about 4A into the battery pack, and two in parallel delivered about 8A. I didn’t know solar panels could be connected in parallel, but happily this means I can keep my direct DC connection. Horizontal panels costs a few amps – a good example of why solar panels are usually angled at the sun. However the azimuth of the boat will be always changing so horizontal is the only choice. The panels are very sensitive to shadowing; a hand placed on a panel, or a small shadow is enough to drop the current to 0A. OK, so now I had a figure for panel output – about 4A from each panel.

This didn’t look promising. Based on my sea voyages with the Torqueedo, I estimated I would need 800W (about 30A) to maintain my target houseboat speed of 4 knots (7 km/hr); that’s 8 panels which won’t ft on my boat! However the current draw on the river might be different without tides, and waves, and I wasn’t sure exactly how many AH I would get over a day from the sun. Would trees on the river bank shadow the panels?

So it was off to Younghusband on the Murray, where our friend Chris (VK5CP) was hosting a bunch of Ham Radio guys for an extended Anzac day/holiday weekend. It’s Autumn here, with generally sunny days of about 23C. The sun is up from from 6:30am to 6pm.

Turns out that even with two panels – the solar boat was really practical! Over three days we made three trips of 2 hours each, at speeds of 3 to 4 knots, using only the panels for charging. Each day I took friends out, and they really loved it – so quiet and peaceful, and the river scenery is really nice.

After an afternoon cruise I would park the boat on the South side of the river to catch the morning sun, which in Autumn appears to the North here in Australia. I measured the panel current as 2A at 7am, 6A at 9am, 9A at 10am, and much to my surprise the pack was charged by 11am! In fact I had to disconnect the panels as the cell voltage was pushing over 4V.

On a typical run upriver we measured 700W = 4kt, 300W = 3.1kt, 150W = 2.5kt, and 8A into the panels in full sun. Panel current dropped to 2A with cloud which was a nasty surprise. We experienced no shadowing issues from trees. The best current we saw at about noon was 10A. We could boost the current by 2A by putting three guys on one side of the boat and tipping the entire boat (and solar panels) towards the sun!

Even partial input from solar can have a big impact. Lets say at 4 knots (30A) I can drive for 2 hours using 60% of my 100AH pack. If I back off the speed a little, so I’m drawing 20A, then 10A from the panels will extend my driving time to 6 hours.

I slept on the boat, and one night I found a paddle steamer (the Murray Princess) parked across the river from me, all lit up with fairy lights:

On our final adventure, my friend Darin (VK5IX) and I were entering Lake Carlet, when suddenly the prop hit something very hard, “crack crack crack”. My poor prop shaft was bent and my propeller is wobbling from side to side:

We gently e-motored back and actually recorded our best results – 3 knots on 300W, 10A from the panels, 10A to the motor.

With 4 panels I would have a very practical solar boat, capable of 4-6 hours cruising a day just on solar power. The 2 extra panels could be mounted as a canopy over the rear of the boat. I have an idea about an extended solar adventure of several days, for example 150km from Younghusband to Goolwa.

Reading Further

Engage the Silent Drive
Lithium Cell Amp Hour Tester and Electric Sailing

Lithium Cell Amp Hour Tester and Electric Sailing

I recently electrocuted my little sail boat. I built the battery pack using some second hand Lithium cells donated by my EV. However after 8 years of abuse from my kids and I those cells are of varying quality. So I set about developing an Amp-Hour tester to determine the capacity of the cells.

The system has a relay that switches a low value power resistor (OK some coat hanger wire) across the 3.2V cell terminals, loading it up at about 27A, roughly the cruise current for my e-boat. It’s about 0.12 ohms once it heats up. This gets too hot to touch but not red hot, it’s only 86W being dissipated along about 1m of wire. When I built my EV I used the coat hanger wire load trick to test 3kW loads, that was a bit more exciting!

The empty beer can in the background makes a useful insulated stand off. Might need to make more of those.

When I first installed Lithium cells in my EV I developed a charge controller for my EV. I borrowed a small part of that circuit; a two transistor flip flop and a Battery Management System (BMS) module:

Across the cell under test is a CM090 BMS module from EV Power. That’s the good looking red PCB in the photos, onto which I have tacked the circuit above. These modules have a switch than opens when the cell voltage drops beneath 2.5V.

Taking the base of either transistor to ground switches on the other transistor. In logic terms, it’s a “not set” and “not reset” operation. When power is applied, the BMS module switch is closed. The 10uF capacitor is discharged, so provides a momentary short to ground, turning Q1 off, and Q2 on. Current flows through the automotive relay, switching on the load to the battery.

After a few hours the cell discharges beneath 2.5V, the BMS switch opens and Q2 is switched off. The collector voltage on Q2 rises, switching on Q1. Due to the latching operation of the flip flip – it stays in this state. This is important, as when the relay opens, the cell will be unloaded and it’s voltage will rise again and the BMS module switch will close. In the initial design without a flip flop, this caused the relay to buzz as the cell voltage oscillated about 2.5V as the relay opened and closed! I need the test to stop and stay stopped – it will be operating unattended so I don’t want to damage the cell by completely discharging it.

The LED was inserted to ensure the base voltage on Q1 was low enough to switch Q1 off when Q2 was on (Vce of Q2 is not zero), and has the neat side effect of lighting the LED when the test is complete!

In operation, I point a cell phone taking time lapse video of the LED and some multi-meters, and start the test:

I wander back after 3 hours and jog-shuttle the time lapse video to determine the time when the LED came on:

The time lapse feature on this phone runs in 1/10 of real time. For example Cell #9 discharged in 12:12 on the time lapse video. So we convert that time to seconds, multiply by 10 to get “seconds of real time”, then divide by 3600 to get the run time in hours. Multiplying by the discharge current of 27(ish) Amps we get the cell capacity:

  12:12 time lapse, 27*(12*60+12)*10/3600 = 55AH

So this cells a bit low, and won’t be finding it’s way onto my boat!

Another alternative is a logging multimeter, one could even measure and integrate the discharge current over time. or I could have just bought or borrowed a proper discharge tester, but where’s the fun in that?

Results

It was fun to develop, a few Saturday afternoons of sitting in the driveway soldering, occasional burns from 86W of hot wire, and a little head scratching while I figured out how to take the design from an expensive buzzer to a working circuit. Nice to do some soldering after months of software based DSP. I’m also happy that I could develop a transistor circuit from first principles.

I’ve now tested 12 cells (I have 40 to work through), and measured capacities of 50 to 75AH (they are rated at 100AH new). Some cells have odd behavior under load; dipping beneath 3V right at the start of the test rather than holding 3.2V for a few hours – indicating high internal resistance.

My beloved sail e-boat is already doing better. Last weekend, using the best cells I had tested at that point, I e-motored all day on varying power levels.

One neat trick, explained to me by Matt, is motor-sailing. Using a little bit of outboard power, the boat overcomes hydrodynamic friction (it gets moving in the water) and the sail is moved out of stall (like an airplane wing moving to just above stall speed). This means to boat moves a lot faster than under motor or sail alone in light winds. For example the motor was registering just 80W, but we were doing 3 knots in light winds. This same trick can be done with a stink-motor and dinosaur juice, but the e-motor is completely silent, we forgot it was on for hours at a time!

Reading Further

Electric Car BMS Controller
New Lithium Battery Pack for my EV
Engage the Silent Drive
EV Bugs

Engage the Silent Drive

I’ve been busy electrocuting my boat – here are our first impressions of the Torqueedo Cruise 2.0T on the water.

About 2 years ago I decided to try sailing, so I bought a second hand Hartley TS16; a popular small “trailer sailor” here in Australia. Since then I have been getting out once every week, having some very pleasant days with friends and family, and even at times by myself. Sailing really takes you away from everything else in the world. It keeps you busy as you are always pulling a rope or adjusting this and that, and is physically very active as you are clambering all over the boat. Mentally there is a lot to learn, and I started as a complete nautical noob.

Sailing is so quiet and peaceful, you get propelled by the wind using aerodynamics and it feels like like magic. However this is marred by the noise of outboard motors, which are typically used at the start and end of the day to get the boat to the point where it can sail. They are also useful to get you out of trouble in high seas/wind, or when the wind dies. I often use the motor to “un hit” Australia when I accidentally lodge myself on a sand bar (I have a lot of accidents like that).

The boat came with an ancient 2 stroke which belched smoke and noise. After about 12 months this motor suffered a terminal melt down (impeller failure and over heated) so it was replaced with a modern 5HP Honda 4-stroke, which is much quieter and very fuel efficient.

My long term goal was to “electrocute” the boat and replace the infernal combustion outboard engine with an electric motor and battery pack. I recently bit the bullet and obtained a Torqeedo Cruise 2kW outboard from Eco Boats Australia.

My friend Matt and I tested the motor today and are really thrilled. Matt is an experienced Electrical Engineer and sailor so was an ideal companion for the first run of the Torqueedo.

Torqueedo Cruise 2.0 First Impressions

It’s silent – incredibly so. Just a slight whine conducted from the motor/gearbox pod beneath the water. The sound of water flowing around the boat is louder!

The acceleration is impressive, better than the 4-stroke. Make sure you sit down. That huge, low RPM prop and loads of torque. We settled on 1000W, experimenting with other power levels.

The throttle control is excellent, you can dial up any speed you want. This made parking (mooring) very easy compared to the 4-stroke which is more of a “single speed” motor (idles at 3 knots, 4-5 knots top speed) and is unwieldy for parking.

It’s fit for purpose. This is not a low power “trolling” motor, it is every bit as powerful as the modern Honda 5HP 4-stroke. We did a A/B test and obtained the same top speed (5 knots) in the same conditions (wind/tide/stretch of water). We used it with 15 knot winds and 1m seas and it was the real deal – pushing the boat exactly where we wanted to go with authority. This is not a compromise solution. The Torqueedo shows internal combustion who’s house it is.

We had some fun sneaking up on kayaks at low power, getting to within a few metres before they heard us. Other boaties saw us gliding past with the sails down and couldn’t work out how we were moving!

A hidden feature is Azipod steering – it steers through more than 270 degrees. You can reverse without reverse gear, and we did “donuts” spinning on the keel!

Some minor issues: Unlike the Honda the the Torqueedo doesn’t tilt complete out of the water when sailing, leaving some residual drag from the motor/propeller pod. It also has to be removed from the boat for trailering, due to insufficient road clearance.

Walk Through

Here are the two motors with the boat out of the water:

It’s quite a bit longer than the Honda, mainly due to the enormous prop. The centres of the two props are actually only 7cm apart in height above ground. I had some concerns about ground clearance, both when trailering and also in the water. I have enough problems hitting Australia and like the way my boat can float in just 30cm of water. I discussed this with my very helpful Torqueedo dealer, Chris. He said tests with short and long version suggested this wasn’t a problem and in fact the “long” version provided better directional control. More water on top of the prop is a good thing. They recommend 50mm minimum, I have about 100mm.

To get started I made up a 24V battery pack using a plastic tub and 8 x 3.2V 100AH Lithium cells, left over from my recent EV battery upgrade. The cells are in varying conditions; I doubt any of them have 100AH capacity after 8 years of being hammered in my EV. On the day we ran for nearly 2 hours before one of the weaker cells dipped beneath 2.5V. I’ll sort through my stock of second hand cells some time to optimise the pack.

The pack plus motor weighs 41kg, the 5HP Honda plus 5l petrol 32kg. At low power (600W, 3.5 knots), this 2.5kWHr pack will give us a range of 14 nm or 28km. Plenty – on a huge days sailing we cover 40km, of which just 5km would be on motor.

All that power on board is handy too, for example the load of a fridge would be trivial compared to the motor, and a 100W HF radio no problem. So now I can quaff ice-cold sparkling shiraz or a nice beer, while having an actual conversation and not choking on exhaust fumes!

Here’s Matt taking us for a test drive, not much to the Torqueedo above the water:

For a bit of fun we ran both motors (maybe 10HP equivalent) and hit 7 knots, almost getting the Hartley up on the plane. Does this make it a Hybrid boat?

Conclusions

We are in love. This is the future of boating. For sale – one 5HP Honda 4-stroke.

New Lithium Battery Pack for my EV

Eight years ago I installed a pack of 36 Lithium cells in my EV. After about 50,000km and several near-death battery pack experiences (over discharge) the range decreased beneath a useful level so I have just purchased a new pack.

Same sort of cells, CALB 100AH, 3.2V per cell (80km range). The pack was about AUD$6,000 delivered and took an afternoon to install. I’ve adjusted my Zivan NG3 to cut out at an average of 3.6 v/cell (129.6V), and still have the BMS system that will drop out the charger if any one cell exceeds 4.1V.

The original pack was rated at 10 years (3000 cycles) and given the abuse we subjected it to I’m quite pleased it lasted 8 years. I don’t have a fail-safe battery management system like a modern factory EV so we occasionally drove the car when dead flat. While I could normally pick this problem quickly from the instrumentation my teenage children tended to just blissfully drive on. Oh well, this is an experimental hobby, and mistakes will be made. The Wright brothers broke a few wings……

I just took the car with it’s new battery pack for a 25km test drive and all seems well. The battery voltage is about 118V at rest, and 114V when cruising at 60 km/hr. It’s not dropping beneath 110V during acceleration, much better than the old pack which would sag beneath 100V. I guess the internal resistance of the new cells is much lower.

I plan to keep driving my little home-brew EV until I can by a commercial EV with a > 200km range here in Australia for about $30k, which I estimate will happen around 2020.

It’s nice to have my little EV back on the road.

8 Mega Watts in your bare hands

I recently went on a nice road trip to Gippstech, an interstate Ham radio conference, with Andrew, VK5XFG. On the way, we were chatting about Electric Cars, and how much of infernal combustion technology is really just a nasty hack. Andrew made the point that if petrol cars had been developed now, we would have all sorts of Hazmat rules around using them.

Take refueling. Gasoline contains 42MJ of energy in every litre. On one of our stops we took 3 minutes to refuel 36 litres. That’s 42*36/180 or 8.4MJ/s. Now one watt is 1J/s, so that’s a “power” (the rate energy is moving) of 8.4MW. Would anyone be allowed to hold an electrical cable carrying 8.4MW? That’s like 8000V at 1000A. Based on an average household electricity consumption of 2kW, that’s like hanging onto the HT line supplying 4200 homes.

But it’s OK, as long as your don’t smoke or hold a mobile phone!

The irony is that while I was sitting on 60 litres of high explosive, spraying fumes along the Princes Highway and bitching about petrol cars I was enjoying the use of one. Oh well, bring on the Tesla charge stations and low cost EVs. Infrastructure, the forces of mass production and renewable power will defeat the evils of fossil fuels.

Reading Further

Energy Equivalents of a Krispy Kreme Factory.

Fuel Consumption of a Pedestrian Crossing

WTF Internal Combustion?

At the moment I’m teaching my son to drive in my Electric Car. Like my daughter before him it’s his first driving experience. Recently, he has started to drive his grandfathers pollution generator, which has a manual transmission. So I was trying to explain why the clutch is needed, and it occurred to me just how stupid internal combustion engines are.

Dad: So if you dump the clutch too early the engine stops.
Son: Why?
Dad: Well, a petrol engine needs a certain amount of energy to keep it running, for like compression for the next cycle. If you put too big a load on the engine, it doesn’t have enough power to move the car and keep the engine running.
Dad: Oh yeah and that involves a complex clutch that can be burnt out if you don’t use it right. Or an automatic transmission that requires a complex cooling system and means you use even more (irreplaceable) fossil fuel as it’s less efficient.
Dad: Oh, and petrol motors only work well in a very narrow range of RPM so we need complex gearboxes.
Dad thinks to himself: WTF internal combustion?

Electric motors aren’t like that. Mine works better at 0 RPM (more torque), not worse. When the car stops my electric motor stops. It’s got one moving part and one gear ratio. Why on earth would you keep using irreplaceable fossil fuels when stopped at the traffic lights? It just doesn’t make sense.

The reason of course is energy density. We need to store a couple of hundred km worth of energy in a reasonable amount of weight. Petrol has about 44 MJ/kg. Let see, one of my Lithium cells weighs 3.3kg, and is rated at 100AH at 3.2V. So thats (100AH)(3600 seconds/H)(3.2V)/(3kg)=0.386MJ/kg or about 100 times worse than petrol. However that’s not the whole story, an EV is about 85% efficient in converting that energy into movement while a dinosaur juice combuster is only about 15% efficient.

Anyhoo it’s now possible to make EVs with 500 km range (hello Tesla) so energy density has been nailed. The rest is a business problem, like establishing a market for smart phones. We’re quite good at solving business problems, as someone tends to get rich.

I mean, if we can make billions of internal combustion engines with 1000’s of moving parts, cooling systems, gearboxes, anti-pollution, fuel injection, engine management, controlled detonation of an explosive (they also make napalm out of petrol) and countless other ancillary systems I am sure human kind can make a usable battery!

Internal combustion is just a bad hack.

History is going to judge us as very stupid. We are chewing through every last drop of fossil fuel to keep driving to and from homes in the suburbs that we can’t afford, to buy stuff we don’t need, making plastic for gadgets we throw away, and flying 1000’s of km to exotic locations for holidays, and overheating the planet using our grandchildren’s legacy of hydrocarbons that took 75 million years to form.

Oh that’s right. It’s for the economy.

Degrowth Economy

Just read this article: Life in a de-growth economy and why you might actually enjoy it.

I like the idea of a steady state economy. Simple maths shows how stupid endless growth is. And yet our politicians cling to it. We will get a steady state, energy neutral economy one day. It’s just a question of if we are forced, or if it’s managed.

Some thoughts on the article above:

  • I don’t agree that steady state implies localisation. Trade and specialisation and wonderful inventions. It’s more efficient if I write your speech coding software than you working it out. It’s for more efficient for a farmer to grow food than me messing about in my back yard. What is missing is a fossil fuel free means of transport to sustain trade and transportation of goods from where they are efficiently produced to where they are consumed.
  • Likewise local food production like they do in Cuba. Better to grow lots of food on a Cuban farm, they just lack an efficient way to transport it.
  • I have some problems with “organic” food production in the backyard, or my neighbours backyard. To me it’s paying more for chemically identical food to what I buy in the supermarket. Modern, scientific, food production has it’s issues, but these can be solved by science. On a small scale, sure, gardening is fun, and it would be great to meet people in communal gardens. However it’s no way to feed a hungry world.
  • Likewise this articles vision of us repairing/recycling clothing. New is still fine, as long as it’s resource-neutral, e.g. cotton manufactured into jeans using solar powered factories, and transported to my shopping mall in an electric vehicle. Or synthetic fibres from bio-fuels or GM bacteria.
  • Software costs zero to upgrade but can improve our standard of living. So there can be “growth” in some sense at no expense in resources. You can use my speech codec and conserve resources (energy for transmission and radio spectrum). I can send you that software over the Internet, so we don’t need an aircraft to ship you a black box or even a CD.

I live by some anti-growth, anti-consumer principles. I drive an electric car that is a based on a 25 year old recycled petrol car chassis. I don’t have a fossil fuel intensive commute. I use my bike more than my car.

I work part time from home mainly on volunteer work. My work is developing software that I can give away to help people. This software (for telecommunications) will in turn remove the need for expensive radio hardware, save power, and yet improve telecommunications.

I live inexpensively compared to my peers who are paying large mortgages due to the arbitrarily high price of land here, and other costs I have managed to avoid or simply say no to. No great luck or financial acumen at work here, although my parents taught me the useful habit of spending less than I earn. I’m not a very good consumer!

I don’t aspire to a larger home in a nice area or more gadgets. That would just mean more house work and maintenance and expense and less time on helping people with my work. In fact I aspire to a smaller home, and less gadgets (I keep throwing stuff out). I am renting at the moment as the real estate prices here are spiralling upwards and I don’t want to play that game. Renting will allow me to down-shift even further when my children are a little older. I have no debt, and no real desire to make more money, a living wage is fine. Although I do have investments and savings which I like tracking on spreadsheets.

I am typing this on a laptop made in 2008. I bought a second, identical one a few years later for $300 and swap parts between them so I always have a back up.

I do however burn a lot of fossil fuel in air travel. My home uses 11 kWhr/day of electricity, which, considering this includes my electric car and hence all my “fuel” costs, is not bad.

More

In the past I have written about why I think economic growth is evil. There is a lot of great information on this topic such as this physics based argument on why we will cook (literally!) in a few hundred years if we keep increasing energy use. The Albert Bartlett lectures on exponential growth are also awesome.

Energy Equivalents of a Krispy Kreme Factory

My 15 year old son is rather excited at the prospect of Adelaide’s first Krispy Kreme factory. This factory will be pumping out 5,000 donuts an hour.

Now a donut contains about 1000 kJ of energy. This is chemical energy, in the form of fat and sugars and carbohydrates. Our bodies are designed to run by “burning” this chemical energy. If we don’t need more energy when we consume the donut then some of the excess will be stored as fat.

Now energy comes in different forms, for example as electricity, mechanical, solar, thermal, or potential energy. It’s possible to convert between one form and another using a machine, for example a petrol motor converts chemical into kinetic energy. A solar panel converts the energy in the suns radiation to electricity.

Energy is measured in Joules (J), lots of energy in kilojoules (kJ), or megajoules (MJ). Power is the rate we use (or produce) energy. If I use 1 J/s in my LED torch, that is 1 Watt (W). My electric car uses 5 kW when I cruise along at 60 km/hr. So 5,000 J/s is moving from my batteries to the electric motor of the car.

The average human uses 8700 kJ per day. That means we need to injest roughly 8700 kJ of energy, and our body uses about the same amount of energy. This energy runs our body, and gives us some energy for moving about. There are 24(60)(60) seconds in a day. So the power consumption of the average human (energy/second) is 8,700,000J/(24(60)(60))=100W. About the same as a large incandescent light bulb.

So as we know the energy in a donut, and the rate at which the donuts are produced, we can measure the Power Output of the Krispy Creme factory. Then compare that to all sorts of other power producers and users in our lives.

Here are a few energy equivalents (spreadsheet):

More

A related analysis is Fuel Consumption of a Pedestrian Crossing.

Aspitech E-waste Recycling Tour

Yesterday Robert Hart was kind enough to take a group of local hackerspace members on a tour through Aspitech, and Adelaide e-waste recycler. The Australian government has mandated that all importers must pay to recycle 33% of their products (by weight), which has created a new, high growth industry. The South Australian government is unique is requiring zero landfill from old TVs and PCs which I think is pretty cool.

Aspitech currently processes 200 tons per month. The TVs and PCs are disassembled into broad categories, such as plastic, copper wire, circuit boards, metalwork. These are then bagged up and shipped off to other companies that can use them as raw materials, for example melting down the copper, or using glass from CRTs as road base. Aspitech is a social enterprise that employs a number of disabled people.

Robert is looking for entrepreneurs who have ideas and most importantly the passion to create spin off businesses from e-waste resources.

Busting Teenage Partying with a Fluksometer

On New Years Eve 2011 I was in Geelong at a restaurant, 800km from my home in Adelaide. This year I happened to be away from my children, who were staying elsewhere in Adelaide while I was interstate. My home was supposedly vacant. However I knew it was very hot in Adelaide that day (40C) and I wondered if this would affect my power consumption, for example an increased duty cycle on the fridge. I am just that sort of power-geek.

So I checked my Fluksometer via my 3G android phone. I was surprised to see 1000W being used since 1pm – about what my Air-con uses. I also noticed that around 7pm the power jumped by a few 100W, just like the lights had gone on, or perhaps the TV.

Looked like some one was in my home. On New Years Eve. Hmmmmmm.

The 24 hour plot below just was captured on (1 Jan) at 5:30pm, so it actually shows the tail end of the Dec 31 festivities. You can see the 1000W consumption until it shoots up around 1900 hours, then the rapid, parentally-induced decline at around 2030 hours as explained below…..

I was fortunate to be at the restaurant with a couple of people expert in these situations. Teenagers. They suspected “Party”. I was unsure. I called my beloved 16 year old daughter Amy to see if she “knew” anything about this phantom power problem. My gut feel was to call my mother (Amy’s grandmother) and ask her to visit my home but I thought I’d give Amy the benefit of the doubt. Amy said that she was at a friends house but would go around and check my house. She was not keen on using her grandmother to resolve the issue. Exactly 30 minutes later I received a text from her saying the air con and TV was on but she had switched them off.

By this stage half the restaurant (I was with a friend’s extended family) were crowded around my phone, watching the next development with excitement. My teenage brains-trust were calling “Party” but there was no way to know for sure. Sure enough the power drops, down to about 180W. About what the fridge motor uses. However curiously, there was none of the regular fridge cycling on and off. It was as if all the lights were off in the house but the fridge motor was running all the time to cool or freeze something.

I returned to Adelaide the next day (1 Jan). My home was very clean but I found a few tell-tale signs: disposable cups with sticky red liquid in them in one of the bins, a trace of the same red sticky stuff on my sink, and post it notes accidentally left on my fridge saying things like “Molly, you may have to open up another bottle”.

What happened to Amy? Well to be honest I wasn’t very mad, just curious about the mystery. I actually enjoyed the detective work side of guessing what was going on and finding supporting evidence. Bart, the inventer of the Fluksometer, was rolling on the floor laughing when I told him the tale.

All my friends knew about the incident so when Amy joined me in Geelong for the next week she was teased relentlessly. Eventually she came clean, and said:

“All my friends who didnt know Dad said ‘How could he do that? Who measures power from across the country’? Those that did know Dad said ‘He knows. Dont worry!'”

“When I realised we were busted there was a mass exodus. I was the last one out and could see a continuous line of teenagers stretched up the street over three blocks.”

One of Amys friends put it well: “You gotta get dumber parents Amy.”

Links

Flukso Web Site
Flukso – Wifi Household Power Logging
Buying a Fluksometer in Australia