C
clivep
Monday was the best day we have had (in Yorkshire) for generated electricity since the install in November. For the 3 hours from 10am to 1pm we were generating above 2.5kW peaking at nearly 3kW at 11am (monitored using Sunny Explorer).
My energy usage monitoring device (supplied free by a utility company a couple of years ago) is clamped around the outside of the cable from the import meter to the fusebox and works fine but now shows the net import from/export to the grid and cannot distinguish between import or export power (to establish this I can turn on/off a light bulb and see whether the reading goes up or down). This device showed that I was exporting at about 1.5kW for the period 10am-1pm. I was therefore not expecting the import meter to change it's reading over this 3 hour period and was surprised to see it had gone up by 5kWH i.e. by the amount I had exported.
I contacted my supplier (EDF) who said they were unaware of any problems with this meter so I said I'd check again.
I then Googled the meter "Siemens S2AS-100" and found postings on the Moneysavingsexpert forum warning about this problem.
Apparently this meter holds both import and export figures in separate registers. There is a software "anti-tamper" setting which if set adds the two figures together and only displays the total. This is to prevent fraud by a customer reverse wiring the meter. This setting is totally incompatible with solar panels but must be how ours is set.
I re-checked yesterday (also a good generating day) that my import meter was indeed functioning in this way then contacted EDF again. They said they were aware of this problem on Siemens pre-pay meters but not on the S2AS model. They contacted the metering company and have booked an appointment to change the meter in a fortnight's time. The problem could be resolved simply by sending out someone with suitable equipment to change the anti-tamper flag (in which case the display would immediately switch to the correct import figure) but I expect them to put in a new meter. The correct import reading will be available to them if they use an optical reader to interrogate the meter but I won't rely on them doing this so I'll note my generation meter reading when they take the old meter away. As they estimate 50 % of generated electricity is exported then I would be happy for them to reduce the final import meter reading by the same numers of estimated export units.
I don't blame the installer for not picking this up as it's only recently that we have been generating enough to be consistantly exporting over a long enough period to be able to identify the problem.
My energy usage monitoring device (supplied free by a utility company a couple of years ago) is clamped around the outside of the cable from the import meter to the fusebox and works fine but now shows the net import from/export to the grid and cannot distinguish between import or export power (to establish this I can turn on/off a light bulb and see whether the reading goes up or down). This device showed that I was exporting at about 1.5kW for the period 10am-1pm. I was therefore not expecting the import meter to change it's reading over this 3 hour period and was surprised to see it had gone up by 5kWH i.e. by the amount I had exported.
I contacted my supplier (EDF) who said they were unaware of any problems with this meter so I said I'd check again.
I then Googled the meter "Siemens S2AS-100" and found postings on the Moneysavingsexpert forum warning about this problem.
Apparently this meter holds both import and export figures in separate registers. There is a software "anti-tamper" setting which if set adds the two figures together and only displays the total. This is to prevent fraud by a customer reverse wiring the meter. This setting is totally incompatible with solar panels but must be how ours is set.
I re-checked yesterday (also a good generating day) that my import meter was indeed functioning in this way then contacted EDF again. They said they were aware of this problem on Siemens pre-pay meters but not on the S2AS model. They contacted the metering company and have booked an appointment to change the meter in a fortnight's time. The problem could be resolved simply by sending out someone with suitable equipment to change the anti-tamper flag (in which case the display would immediately switch to the correct import figure) but I expect them to put in a new meter. The correct import reading will be available to them if they use an optical reader to interrogate the meter but I won't rely on them doing this so I'll note my generation meter reading when they take the old meter away. As they estimate 50 % of generated electricity is exported then I would be happy for them to reduce the final import meter reading by the same numers of estimated export units.
I don't blame the installer for not picking this up as it's only recently that we have been generating enough to be consistantly exporting over a long enough period to be able to identify the problem.
