Computing stuff tied to the physical world

Energy tracking with Cost Control

In Hardware on Nov 14, 2009 at 00:01

The ELV Cost Control is a set with two power measurement units and a display:


Every 5 seconds the base units transmit their readings over 868 MHz, each with a unique 4-digit ID. The display shows actual and aggregated results for up to 5 units. You have to press a button to get an update, i.e. the receiver is only activated on request – for about 6 seconds.

Setup is trivial. Tracking current power consumption, peak power consumption, projected monthly & yearly cost, and hours on vs. total is extremely straightforward.

This is a very convenient setup because you can put the sensor in the outlet, way down deep behind everything if needed, and then take individual appliances out to see what effect each one has on the total consumption.

I found out that my 5-port Ethernet hub draws 3W (of which 2W in the adapter), and an old monitor I’m only using occasionally uses 4W (both asleep and “off”).

Our TV + amplifier + speakers + satellite receiver is drawing 6W when idle. Most of this is the Mac Mini (used as TV), due to an energy saver which cuts power to all other appliances when the Mac sleeps.

At €12.95 per outlet, this is the cheapest good-working solution I’ve found so far for tracking power use at individual outlets. I’m thinking of getting several more of these for the refrigerator, washing machine, and other intermittent power consumers.

Does anyone know whether the Cost Control wireless protocol has been documented?

  1. Does this unit only do power measurements, or can you also use it as a remote switch? :) I’m currently using plugwise, which can also do switching and even upload schedules into a plug. but that’s a lot more expensive :( They only thing which I’m missing in the plugwise plugs is a button on the plug itself, to switch it on again.

    • No switch. I’ve tried plugwise (I find the software horrible and the range abysmal) and yes – a remote switch with no local button is very inconvenient. Same reason why I prefer FS20 units over KAKU.

      It only does power measurement, but it seems to do so very very well, with 0.1 watt precision in the lower range. It also tracks/sends total consumption, so occasional packet loss is not an issue.

      If there is no documentation, I’ll try to analyze the protocol. This unit sends out readings every 5 seconds – it really would make a great power monitor if I can integrate it into JeeMon.

  2. Price is very nice, certainly a big plus! Do you know how much power the plugs itself use? sending every 5 seconds is quite often, if you have a lot of these modules :)

    • It says 0.6W standby on the plug. And yes, that’s what I get when I plug one plug in the other :)

  3. I think the protocol is explained in:

    I couldn’t figure out the product code of the ELV things, but the above address appears to relate to the same product.

  4. I’m not sure. I’m already decoding EM10 packets. Have just “loosened up” the decoder to report any packets with a similar 8-bit + 1/0 continue bit it might be seeing, but no luck so far. The Cost Control seems to be using a different encoding – it’s sending packets out every 5 secs, not every few minutes as most of the other ELV units are doing.

  5. conrad has almost the same , only for up to 9 units, maker voltcraft .

    • And it includes on/off remote control. Here’s the direct link:

      Operates at 433 Mhz. Hm, on closer inspection this looks like two separate packages: a non-RF power meter plus 4 RF-controlled switches. No wireless transmission of power usage. I think it’s just a power meter + 4 KAKU-like units.

  6. Yes (no),that is not the rigth one , this is the right ordernummer 125353 .

    pdf =

    Type: Energy Count 3000 Uitvoering: Voor stekkerdoos Officieel bekrachtigd: Nee Aanduiding: LCD Max. registratieduur: 19999 h Werkzaam vermogensbereik: 0.2 – 3600 W Afleesbereik: 0.001 – 9999 kWh Frequentie: 50 Hz Eigen verbruik: 0.3 W Overige technische spec.: Frequentie: 868 MHz · Indicatie looptijd: 0,001 – 19999 h · Kostenweergave: 0,001 – 9999 € · Tariefweergave: 0,001- 9,999 €/kWh · Weergave van de besparing 0 – 100% Voedingsspanning: 230 V

    specs are almost the same

    • Oops, yes – looks like a good alternative. Almost the same indeed. Now all I have to do is figure out what the RF protocol is…

  7. Maybe different pulse widths ,then FS20 and EM , or and maybe different sync ,but i think you tried that already.

Comments are closed.