Using Aclara SGM1416-B Smart Meter

Tenbob0

I am trying to check that my elecricity supplier is charging correctly for Economy 7. I have an Aclara SGM1416-B SMETS2 meter. I found the manual online on the smartme site. I can't post the link, but search "smartme SGM1400 manual".

The meter has four Time Of Use registers which I can cycle through by pressing button A. TOU Rate 1 and TOU Rate 2 have recorded units. The other two are zero.

(1) How do I know (rather than guess) which is Peak and Off-peak? And the on/off times?

(2) How do I know from the display which register is currently in use?

Unless I'm missing something, question (2) seems a glaring omission. The meter doesn't show which register it is currently using.

I could do a test, of course, by checking how the registers increment at various times of day. But this seems absurd if the information is already in the meter.

Any help gratefully received.

QrizB

Do you have a working in-home display? And a recent bill?

Tenbob0

Yes to both. But they may not help with my specific questions.

The IHD appears to show an incorrect tariff. It shows just one rate at the standard price, rather than the two rates for Economy 7. I wasn't unduly worried as many users have reported their IHD showing the wrong tariff. I assume the bill is based on the actual units recorded rather than some iffy calculation involving the tariff stored inside the meter.

I have the bills but this is the information I want to check against other sources. 

QrizB

I've got an Aclara meter from the same family. As far as I can tell there's no way to get the active register and the E7 timings directly from the meter.

• You can check the active register by seeing which one increments during the day. Cross-check with the readings on your bill ; eg. if the daytime register is reading 20xxx and the nighttime one 40xxx, the redings used for your bill should be similar.
  
• You can tell the E7 switching times by staying up to see when the ALCS icon in the bottom-right of the screen turns on, and getting up early to see it turn off seven hours later. If it runs for more than seven hours you might have split E7 timings, which mean there's a period in the middle of the night when you're on peak rate.

If you had an up-to-date IHD you'd be able to see the E7 switching times there. It's slightly (only slightly) worrying that you can't; the IHD gets its tariff and timing info from the smart meter, so if the meter knows its switching times so should the IHD. Have you tried unplugging/removing batteries from the IHD and restarting it?

If all else fails your supplier should be able to tell you your switching times, but the quality of answers from frontline CS staff seem to vary.

Ildhund

'E7 switching times' is a bit ambiguous, because there are two separate sets. One is the timings of the switch from one ToU register to the other, and the other is the timings of the ALCS. Ideally, they should be identical. They are both subject to the same randomized offset of up to 30 minutes delay on start times.

The tariff change will always (🤞) follow the DNO's diktat, so these graphics should help:
 

[Ignore the SSC - STD and E7 columns - they're supplier-specific]
  

  
To see the ALCS switching times (when the 'offpeak circuit' is active), QRizB's advice is sound as usual: watch the little icon in the bottom right-hand corner of the meter display to see when it changes soon after each end of the offpeak period. We did have a discussion here a few days ago about how to simplify this exercise by installing an indicator lamp indoors that would light up when the switched circuit was live, but I can't remember where 🤔

The Active Tariff Price is one of the items on the meter menu, and it should be replicated on the IHD. If it isn't right, get your supplier's customer service to Update Tariff Configuration. Note that prices are usually shown inclusive of VAT.  

Gerry1

Those times aren't correct for Area 19 (South East England, SeeBoard): the off-peak rate should be 2230 - 0030 and 0230 - 0730 GMT,

Ildhund

Thanks. The table only gives true E7 timings. I don't think split periods like the ones you quote count as true E7, but I'll look them up.

QrizB

Gerry1 said:

Those times aren't correct for Area 19 (South East England, SeeBoard): the off-peak rate should be 2230 - 0030 and 0230 - 0730 GMT,

And we've got a poster here who's in Cornwall (Area 22) but who's been told by Octopus that they've got split times too:
https://forums.moneysavingexpert.com/discussion/6580881/octopus-times-for-night-day-rate
Currently waiting for them to reply to that thread with more info.

Phones4Chris

Tenbob0 said:

Yes to both. But they may not help with my specific questions.

The IHD appears to show an incorrect tariff. It shows just one rate at the standard price, rather than the two rates for Economy 7. I wasn't unduly worried as many users have reported their IHD showing the wrong tariff. I assume the bill is based on the actual units recorded rather than some iffy calculation involving the tariff stored inside the meter.

I have the bills but this is the information I want to check against other sources. 

@Tenbob0 The IHD only displays the rate for the tariff currently being charged, so it'll show the Day rate during the times that it is Day rate, and the Night rate when Night rate is being charged. I've not seen any cases where the rate is different from that on the meter itself.
It also only shows you the TOTAL (Day+Night) number of units used, which you can also see on the meter when cycling through using the "A" button.

The IHD does not directly show the E7 times, but it can display a countdown bar upto 60 minutes in 10 minute chunks to when the tariff is going to change. The Display shows "Tariff Rate will change" with the countdown bar on the RHS of the display.

That picture was taken during BST so the E7 times (normally set in GMT) are an hour later.
(Note - that countdown may not be 100% accurate - it depends on how the meter has been programmed - I haven't checked it lately - actual E7 times can have a delay from the nominal times which will vary from area to area, the nominal should be shown on your bill and can be what the countdown display shows).
In my case, mine switches to Night rate at 0038 GMT at the same time as the ALCS switches on the off-peak loads. My nominal times are 0030-0730 GMT.

The Meter should display the current rate as "Active Tariff Price" when cycling through using Button "A". 
Also on the bottom RHS of the meter display, there are two switch symbols above each other labelled in roman numerals "I" and "II" above the symbols. "I" should be closed, "II" will be open during Day rate. When Night rate is operating the symbol could change to LC1 LC2.

You say you have the bills, so they will answer part of your question, it would have been helpful if you'd commented on what they say.

Do your bills show you are being charged two rates ie. a Day Rate and a Night Rate?
Are those rates what you expected them to be?
When you look at the IHD during the day, is it showing the Day Rate tariff?

Are the meter readings actual smart meter readings - the bill may say "OUR READ" or "Smart meter reading" next to the reading (depends on supplier). IF they show "Estimated" there could be a Comms problem.
If you are in the south of the country your comms unit (above the meter) will have 5 Green LEDs, first, second and fourth should flash together every five seconds. In the north, the Comms has only two LEDs.

What region are you in - On your bill you should see a big box labelled Supply Number, what are the first two digits of the long number in the bottom of the box - this tells us the region?
Who is your supplier?
Please note, do not post any copies of bills without obliterating personal information, eg. name/address/MPAN/meter serial number/account number/bill number or reference/any bar code.

Phones4Chris

Ildhund said:

Thanks. The table only gives true E7 timings. I don't think split periods like the ones you quote count as true E7, but I'll look them up.

I don't believe that's correct, just because they are "split times" doesn't mean it's not a "true" E7 tariff. We've seen several posts on these boards where people from several areas have split times.
In a previous thread, @Gerry1 posted that same information and i also posted that in part of Region 22 (South-West) nominal times can be 0030-0730 GMT.

Gerry1

@Phones4Chris Despite having GCH, I've had E7 and an RTS since the very late 80s.  Originally it was seven contiguous hours but I soon opted for 2230 - 0030 and 0230 - 0730 GMT to 'double dip' at the beginning and end of the day.

Can't remember how I found out that was possible in those pre-internet days, probably read it in New Scientist or somewhere.  E7 could be cheaper even with night usage as low as 15% - 20%.

More recently the 'split shift' timings became the default for Area 19 (Seeboard), but for some strange reason it's now almost impossible to find out what the regional DNO E7 timings are.

My switching times have never varied even when Droitwich has been off the air, so I'm firmly convinced that the only effect of ceasing the long wave transmissions would be that domestic RTSs might drift a few minutes per year.

BTW, does anyone know why the 'split shift' timings were introduced?  My guess would be that it was to make the switch from the old White Meter 8-hour tariff to E7 more tolerable for people with plain 'Box of Bricks' NSHs, the earlier start and later finish would have made late evenings a bit less chilly.