TED – The Energy Detective

Having a photovoltaic solar system that can run your whole house is awesome. Not having a way to monitor it while you are away sucks. This is where my good friend Ted comes in. Ted is not really my friend in the human sense but in the TED-5000 (The Energy Detective http://www.theenergydetective.com/ted-5002-g ) sense.

TED can measure AC voltage directly and AC current via inductive coupling current clamps. These signals are fed into an MTU (Monitoring and Transmitting Unit) which digitizes them and sends them over the power line in bursts each time the A/C voltage crosses zero. At that point, (for what seems like thousands of micro-seconds to TED), there is effectively no current flowing on the line and a data is sent on a 132KHz channel from the MTU to TED. TED then uses his built in Internet gateway and relays this information to the Internet where I can log into Google power meter and monitor my home energy usage. TED also has an optional $80 handheld unit that receives info from TED via a Zigbee wireless signal. I opted not to get one of these displays when I already have an Apple itouch because, well, there’s an app for that.

I actually bought TED’s schizophrenic brother, TED 5002G, which contains two MTU units. One set of voltage leads and current clamps can monitor the total power coming from and going to the grid while the other set monitors just the inverter’s production. Using the provided software, I can see exactly how much power my house is consuming during any point in time (within 2 seconds).

This also provides a way to monitor actual usage (within 1 watt) of all appliances in the house, including ones that run on 240 volts and/or are hard-wired (like the dish-washer).

To the shock and surprise of my 7-year old son and 9 year old daughter, I requested they turn on every light in the house. We also turned on all four burners on the electric range, the oven, the toaster oven, the microwave oven, the waffle iron, the electric griddle and Kitchen Aid mixer. Last but not least, I turned on some work lights, the table saw, shop-vac and drill press. Ahh. TED reports back that we are currently using 22,300 watts. A quick math calculation reveals we are drawing almost 93 amps at 240 volts. Wow! That’s a lot of power. That is approaching Clark Griswold levels of power consumption.
In the movie Christmas Vacation, Clark Griswold (Chevy Chase) used 25,000 Italian imported lights (assuming 7 watt bulbs). That works out to be 175,000 watts.

Here is an EKG of my electric Oven. What you are seeing here is the preheat cycle followed by the oven coming up to temperature (flat line) and then re-heating caused by a batch of cold cookie sheets with dough being placed in the oven. Awesome! Snort, snort.

You might think that my wife is not too fond of me knowing exactly when lights get left on and when she is baking bread or otherwise using copious amounts of electricity. Actually, she is quite pleased that I got TED because now she doesn't have to run outside into the garage to read the display on the inverter every time I call her on the phone from work.