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LED pulses on Smart Meter Landis & Gyr E470 type 5424

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Have been monitoring pulses out from the above meter BUT the LED pulses do not seem to show electricity consumption. It seems to track our rooftop solar panel production and does not coincide with the room display. Can anyone confirm this and is there any way of showing net usage - ie what we get charged for? Thanks

Welcome aboard, Seggy.

Have you got one meter or two? I presume two. Is the meter we’re talking about connected immediately after the supply authority’s fuse and neutral link, or is it one that was fitted when your solar panels were installed?

If you’re not sure, a photo showing the meter, consumer unit and the supply authority’s fuse and the wiring between them might help.

You could always add an emonPi!

Hi Robert, the way it has worked till now is that when solar panels were installed (3 years ago) we had a generation meter installed. We get paid for generation and export - but export was never measured - the payment assumed that we export half what we generate.

Our consumption meter was changed a month ago to a Smart Meter (free in the UK). The in-home display seems to work fine but does not give me fine detail.

I am trying a home grown solution which has been known to work before using the LED pulse output from the (old) meter. This pulses 1000 times for 1 kWh usage. The new meter also has an LED that flashes but does not seem to show usgae - way out when compared to the in-home display.

So I have 2 meters. 1 for generation the new one for usage (+export?).

OK, It would seem that your smart meter has been configured to show something, but it isn’t clear what. I very much doubt that you can reconfigure the LED to show anything useful - you can’t get nett usage out of it via the LED (because the LED can’t show the direction of energy flow), and it can’t know what the generation is. All you could possibly get from the LED (if your supplier will even let you change it) is either the import or the export or both (but without differentiating between them).

I think it’s either an emonPi, or if you’re up to building it, something very similar - using two c.t’s, one on the grid infeed and the other on the PV infeed. A simple subtraction will give you your usage, the Grid power can be separated (by the sign, you must monitor voltage to determine the direction of power flow) into import and export, and you’ve got all the information you need. The bonus is it’s all under your control.

Would every 5 or 10 s, or even less, be fine enough? That’s what you can have with analogue monitoring. Pulses are fine, but historical. All you know from a pulse is you’ve just used one quantum of energy (1 Wh in your case) - you can’t know whether it went to a LED light over the last n minutes, or an electric kettle for a fraction of a second before.

Hi Robert - that makes sense. I can easily connect a clamp to the incoming feed. Not sure about access to the solar power generation cable but this is not a priority.

I like to monitor led pulses as this gives me 100% accuracy - when it works. The current clamp can be out by 10% or more due to power factor not being 1.

Ironically, the generation meter has an LED that pulses.

Not if you do it our way - the emonTx and the emonPi both measure real power because they multiply current and voltage on a sample-by-sample basis and then average the power. We do it in a rather better way than a lot of the el-cheapo monitors on the market.

But, as I wrote - pulses are history, not the present. They’re good for calibrating against though.

Thanks for that info - that is impressive - you seem to have covered all angles.