WARNING SOLAR PANELS & some Siemens S2AS-100/ Siemens S1AS-100 Meters

ChrisJD

John_Pierpoint wrote: »

Couple that with the UK grid tending to run at over the European standard of 230 volts for single phase. Historically the UK used to aim for 240 - 250 volts., then you could be paying well over 5% too much.
It is as bit like running a two star car engine on 5 star petrol.

I am told that this over voltage effect is worse if you are the last property out in the wilds at the end of the circuit (as I am).

Would any electrician care to comment?

There is a very small degree to which you are right, and there are companies who market voltage reduction equipment, claiming to save you money based on this theory. View them with caution.

However, to simplify greatly, most of the heavy power consumption, meaning the items that contribute significantly to your domestic bills, are not really influenced.

Power = amps x volts, and this is what you pay for. (For those who know about it, I don't think it is helpful to wander off to worry about power factor in this discussion.)

For instance If you need to heat the water in your washing machine, then the temperature control will ensure that you use the same amount of energy throughout the permitted voltage range. If the volts are a bit low, slightly less curernt will flow, less power will be drawn at any instant, but it will turn the heater off later, having used the same amount of energy in total as the slightly faster higher voltage situation.

At the end of a long line, they need to ensure sufficient voltage at times of high current flow, without exceeding limits at times of low demand. This can mean that you have high volts in the middle of the night, but low volts at breakfast time. Keeping the whole network within limits can be quite tricky.

Cardew

ChrisJD wrote: »

There is a very small degree to which you are right, and there are companies who market voltage reduction equipment, claiming to save you money based on this theory. View them with caution.

However, to simplify greatly, most of the heavy power consumption, meaning the items that contribute significantly to your domestic bills, are not really influenced.

Power = amps x volts, and this is what you pay for. (For those who know about it, I don't think it is helpful to wander off to worry about power factor in this discussion.)

For instance If you need to heat the water in your washing machine, then the temperature control will ensure that you use the same amount of energy throughout the permitted voltage range. If the volts are a bit low, slightly less curernt will flow, less power will be drawn at any instant, but it will turn the heater off later, having used the same amount of energy in total as the slightly faster higher voltage situation.

At the end of a long line, they need to ensure sufficient voltage at times of high current flow, without exceeding limits at times of low demand. This can mean that you have high volts in the middle of the night, but low volts at breakfast time. Keeping the whole network within limits can be quite tricky.

Above is spot on and this has been covered a few times.

In domestic use it makes little difference, lower the voltage and heaters will give out less heat, lights will not be as bright etc.

Motors however will generally run OK on lower voltage so you will save pennies on fridge/freezer consumption.

So supermarkets with banks of fridges and freezers will benefit.

dunloadin

dunloadin wrote: »

John_Pierpoint, milking the information from the meter will not give a correct reading of the consumption used. The meter has only one recording element, it also only has one live in and out, and all it can do is detect the flow through the meter.

If, for instance, the customer has used 3 units in an hour, but the cells have generated 2 units, then the meter will advance by only 1 unit. If in the next hour the cells generate 3 units but the customer only uses 2 then the meter will advance by 1 unit and record this in its little chip as 1 unit of reversed flow. So, in the two hour period the meter has only recorded 2 of the 5 units the customer has actually used and generated.

Using the same figures on an older type meter will see the meter advancing one unit in the first hour, then reversing for one unit in the second hour giving a total used as zero in the two hour period.

Other meters just stop and display ReD on the screen, so you can’t get a read at all.

Sorry, no excel stuff from me. Just a little ‘what if’.

I reckon it would be best to take readings 12 hours apart, say 8 or 9 in the morning and then again in the evening. As you’ll then be able to see the majority of the imported electricity being used through the evening/night, and the majority of the exported through the main part of the day.

Subtract the previous totals from the new reads on each meter each time to give you the units used in each 12 hour period.

If, as suspected, the Siemens meter is recording the exported electricity as a positive, then subtracting the units used from the check meter from the units used on the Siemens meter will give you the amount that has been exported.

Subtracting the amount that has been exported from the amount that has been generated on the PV meter will give you the amount you consumed through the day that was ‘free’.

Still think theres a big can of worms opened up here for PV installers and Suppliers alike....I would think that if theres a possibility to generate more electricity than you can use the fitment of import/export meters by the DNO would be a must.

furndire

At the moment I've been checking the meter more or less hourly - big discrepency while the sun was shining, but I also think there is a discrepency while its not! We will know more in a few days.
I have been reading the meters as soon as I get up - usually about 7.30 - the solar is producing a bit then, and I read it last thing at night. I've been doing this since 25th April.
We will be going for an export meter when this is sorted. I doubt if we will export much in the winter. but we will make up for it in summer.
I agree re can of worms - after talking to to the guys who came today the whole lot is a shambles - even the smart meters they are supposed to rolling out have problems. The technology has moved so quickly & they've all been caught napping.
The young man who fitted the meter said ours was the first one that he personally had come across which added on KWs.

PeterZ_2

furndire wrote: »

At the moment I've been checking the meter more or less hourly - big discrepency while the sun was shining, but I also think there is a discrepency while its not! We will know more in a few days.
I have been reading the meters as soon as I get up - usually about 7.30 - the solar is producing a bit then, and I read it last thing at night. I've been doing this since 25th April.
We will be going for an export meter when this is sorted. I doubt if we will export much in the winter. but we will make up for it in summer.
I agree re can of worms - after talking to to the guys who came today the whole lot is a shambles - even the smart meters they are supposed to rolling out have problems. The technology has moved so quickly & they've all been caught napping.
The young man who fitted the meter said ours was the first one that he personally had come across which added on KWs.

Unfortunately it is the roll out of the smart meters that is causing some of the problems. We are in a transitional period where no one wants to spend money replacing meters only to change them again next year for the smart meters.

Last I read on the smart meters was that there have been problems getting the specification agreed. Is the target date still next year for the roll out?

furndire

I think 2012 is what they said.

Today is one of the days where it's diffiucult to see what's going on. Its dull producing under 1000, so meter Generation Meter & Old Meter are about par, because we will be more or less breaking even from the panels - , but even so, the check meter says we have used 0.17 kw from 8.10 am to 11.15 am - old meter 2 kw & the generation meter says we have produced 2 KW.

furndire

Right now got first 24 hours data

Check Meter used 6.15 KW Old Meter used 13 KW Generated 12 KW

Conclusive proof I think!!!!!!!!!

HalloweenJack

best get on the phone and ask them to come back sooner rather than later

Jon_Tiffany

Pleased to hear that you got such a conclusive result so quickly, you must be relieved!

Now I can't wait to find out what they make of it when they come back to check the readings on the check meter....

furndire

Thanks Jon - yes I am relieved to a certain extent - but also now the real nitty gritty is going to start. I also suspect that our meter is running fast - which, if I am correct has been going on for 10 years, ever since we built the house. The more we think about it, the more convinced I am. Until 5 years ago, there was no-one at home all day - we were all working!!
What a mess this is.
My son is here for a few hours, and he is trying to show me how to put my data into a graph.. He did a bit of it last night - but as usual this morning I've forgotten most of what he showed me - managed a bit. What was done last night clearly shows the Old Mains meter & the Generation Meter going up side by side, and shows when we are doing something to use the electric. (I had put a few little notes at the side of my data to show when we put the washer on etc)
I'm hoping that he will have time to do the rest today.

I'm going to ring them today.

I'm pleased that I have been reading my meter all through the day & most of the night, as the problem is worse than it appears. (Dunloadin hit the nail on the head) During the day, we are maybe only using a couple of KWs. but if you take off the total of one meter from another the difference averages out, so appears we are still using more than we are. Its really diffiucult to work out unless you have the figures. This is going to really by fun trying to explain again.

For an example yesterday, from 9.40 am to 4 pm, we didn't use any electric - generating was much more than we needed to tick over but the Old mains meter said we had used 7 KWs Generation meter showed we had generated 10 KWs. in that time, but check meter didn't move. How that translates I'm not sure, it needs someone far better than me to work it out.

I am just wondering if the local college can help me out.

I think that I want them to possibly leave the meter for a few weeks of me taking regular data, and then give someone all the figures to get a clearer picture - not just gung ho and dismiss what I have monitored.

Anybody seen the programme "The Mentalist" on TV - that's who I need!!!!!!!!!!



72 hours with check meter - used 25 KW of electric
72 hours Old meter ........ . - used 42 KW

Got everything on a lovely graph now.
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