iboost with another energy monitor

JimLad

Hi Everyone,

Ive searched on google but cant find anything about this.

We currently have an iboost installed and the transmitter is clipped on to the wire in the meter box.

If i install another transmitter in there which is for a normal energy monitor will it clash with the iboost? I wouldnt want for example the iboost to pick up the signal and use energy at the wrong times!

Cheers!

Dave_Fowler

JimLad wrote: »

Hi Everyone,

Ive searched on google but cant find anything about this.

We currently have an iboost installed and the transmitter is clipped on to the wire in the meter box.

If i install another transmitter in there which is for a normal energy monitor will it clash with the iboost? I wouldnt want for example the iboost to pick up the signal and use energy at the wrong times!

Cheers!

Most monitors have differently encoded transmit channels to avoid this sort of interference. This is needed, for instance, if both you and your neighbour had an iboost. Without this encoding, you could be using signals from your neighbour's monitor transmitter.

If you fit another power monitor clip to the cable, do not expect that the figures recorded on the new monitor would make any sense when the iboost is working. You get some weird and wonderful results! (which can be explained technically, but not in a short post like this).

Dave F

theboylard

Aha!

Thanks Dave - does this explain why my Wattson seems confused about net usage?

Do I just bin it and get an oem.org set up?!

Dave_Fowler

Power controllers (Iboost and Immersun etc) control the power to the immersion heater in one of two ways. They either work in 'burst firing' mode or 'phase angle' mode.

Most use burst firing mode as this involves less filtering of unwanted interference.*

In burst fire mode, the controller turns fully on and then fully off very rapidly. This on/off switching is done so rapidly that the electric meter is fooled into thinking that the power used is constant.

If we say the burst firing cycle lasts for one second, and you are generating 1kW of excess power and are sending the power to a 3kW immersion heater, the controller will turn ON for 1/3 second and OFF for 2/3 second. During the ON period you will be importing 2kW (3kW minus the 1kW you are generating) and during the OFF period you will export the 1kW being generated. The averaged nett effect on the electric meter will be a zero import/export.

A simple energy monitor would be upset by the switching. If it is the type which samples the energy at various times, it would either read 2kW or 1kW depending on the timing of the sample. Even if it were able to differentiate between exported power and imported power, the timing of the samples wrt the power controller's switching would give different answers.

A phase angle control system gives even more interesting results as the switching occurs during each cycle of the mains. In the example above, the switching between off and on would occur 2/3rds of the way through each positive and negative cycle of the mains waveform. With my relatively simple energy monitoring system the phase controlled current waveform causes the monitors to give completely false results, often showing that I'm importing and exporting at the same time. [I suppose I am really (looking within one mains cycle) if you consider that for part of each cycle I'm importing and for another part I'm exporting].

*There have been some instances where the burst firing on/off switching has caused lights to flicker rapidly at the switching frequency - both in the house where the controller is situated and in neighbouring properties - especially where there are long rural power lines.

Dave F