[geoffers]

This is another one for the app developers, but could have implications for billing too...

Having just joined the Next Drive EV tariff I’ve been analysing my usage to monitor the costs/savings I’m getting with this tariff.

I've been using the ½ hourly data from the Bright app (taken from the DCC) and comparing the measured kWh usage with my own usage recorded from my car-charger.

In an earlier thread I thought I had found an anomaly between the times reported by the DCC data, but realised that their data is based on Zulu time (ie UTC/GMT) and not BST.
https://community.eonnext.com/thread...iff-experience

I had also noticed a mismatch between my charger’s data and the daily “Usage” data being displayed in the EonNext app - I am now certain that the app is using the date/time from the DCC as it’s supplied (ie GMT) and not applying the correction for BST, so the daily totals are out by an hour during summertime.

For example, I’ve taken a couple of days’ usage and done the calculations for totals based on GMT, and totals based on BST.

I’m happy that the BST calculated data is correct as it matches my own recorded usage. However the GMT calculated data is what is being shown by the EonNext app, which will therefore be incorrect during the summer months.

I haven’t yet received a bill for the Next Drive tariff, but am concerned that there is the possibility of being charged at the daytime tariff rather than the EV night-time tariff for the first hour after midnight BST, as in the GMT data this is recorded as the last hour from 23:00 of the preceding day.

This image shows the data being displayed in the app



And these Excel extracts show the GMT calculation (in blue) on the left and BST calcs (in purple) on the right (rows 6 thru 46 hidden for clarity)

Consumption on the 27^th


Consumption on the 28^th

[retrotecchie]

@geoffers

The whole UK smart metering system is standardised on GMT all year round and doesn't apply any changes to or from BST. Because that's how the system works, and the DCC data will always be synchronised to GMT. Any other device or data interaction with the system should also use GMT, and that includes the E.on app as well as third party providers like Hugo and Bright.

If your charger is using BST, it's the charger that's not singing from the same songsheet.

[geoffers]

Originally Posted by retrotecchie

@geoffers

The whole UK smart metering system is standardised on GMT all year round and doesn't apply any changes to or from BST. Because that's how the system works, and the DCC data will always be synchronised to GMT. Any other device or data interaction with the system should also use GMT, and that includes the E.on app as well as third party providers like Hugo and Bright.

If your charger is using BST, it's the charger that's not singing from the same songsheet.

@retrotecchie

Hmmmm - with the greatest of respect I'm afraid I have to disagree. I accept that all the DCC data is based on GMT the whole year round but people on multiple rates tariffs changing at midnight will be expecting to switch their devices on at midnight BST.

So this explains why the EonNext app is showing the values which my spreadsheet calculations agree with when calculated using the GMT timings

My charger started at midnight BST, however the DCC data shows the charger starting at 2300 GMT on the previous day. Therefore that has data is included in the previous day"s total shown on the app, and would potentially be charged at the higher daytime rate.

Are you suggesting that to apply the next drive EV tariff, in the winter I will have to set my charger to start between midnight and 7 am, but in the summer I will have to set it to start between 1:00 a.m. and 8 am to get the correct overnight EV charging tariff.

I'm happy that if this is the case so be it, but I'm sure it will cause a lot of grief to other new users who aren't aware of this.

It's not really an issue for single a single rate tariffs, but clearly is an issue for tariffs starting with a cheap rate at midnight

[retrotecchie]

@geoffers

In many cases, people on multi rate tariffs such as Economy 7 or Economy 10 even without smart meters have the cheap rate tariff which moves an hour as the clocks change between GMT and BST. There are a few older meters which do apply the changes, but in most cases, the tariff period changes twice a year.

There are also significant variations around the country at which times the 'low rate' comes into effect. The 7 hour off peak rate is always 7 hours, but the start and end times vary depending on supplier and DNO. In some regions, there will even be a 'split' in the timings so it isn't one contiguous seven hour block, but maybe an hour, then an hour back on normal rate, then six hours of low rate again.

Anyway, your situation, and one which I assume more folk will encounter, is another reason why the pressure to abolish DST and to just stay on GMT/UTC is increasing. Life would be easier all round. As a wise man once said...you can cut six inches off your blanket and sew it on the other end, but you still have the same length blanket!

[Mailman]

@geoffers

Interesting issue but it has been raised on MSE Energy Forum

@retrotecchie is correct (as indeed you are) that DCC uses GMT data throughout the year. But other participants may/may not be 'helpful' in changing times automatically.

Looking at my Bright app, it 'helpfully' has time set at GMT+1 (if you look at the bright settings this is what it shows but is greyed out). Presumably Bright will be equally helpful in October when it should revert back to GMT. I don't know as never checked this before. I believe my IHD shows GMT+1 and will automatically change to GMT in October like Bright. I cannot comment on whether the Eon Next app is as equally helpful but would assume it would automatically change from BST to GMT is October as well.

For EV owners on this new EV Eon Next Drive tariff, clarity around the BST/GMT issue is needed clearly stating what happens during BST. My gut instinct (don't know for sure) suggests that the EV hours of 12am-7am are applied to GMT hour periods rather than BST during the summer months.

Are you suggesting that to apply the next drive EV tariff, in the winter I will have to set my charger to start between midnight and 7 am, but in the summer I will have to set it to start between 1:00 a.m. and 8 am to get the correct overnight EV charging tariff.

Possibly correct ....

[geoffers]

Originally Posted by Mailman

@geoffers

Looking at my Bright app, it 'helpfully' has time set at GMT+1 (if you look at the bright settings this is what it shows but is greyed out).
...
For EV owners on this new EV Eon Next Drive tariff, clarity around the BST/GMT issue is needed clearly stating what happens during BST. My gut instinct (don't know for sure) suggests that the EV hours of 12am-7am are applied to GMT hour periods rather than BST during the summer months.

Possibly correct ....

I hadn't spotted that GMT+1 setting an the app, but presumably it just allows the app's GUI to adjust the displayed figures to BST

If you go into the website to download the actual data from the DCC (in CSV format) it just has the date in Zulu time (ie UTC/GMT) format "ccyy-mm-ddThh:mm:ss.sssZ

epochTimestamp,kWh,dateTime
1656540000,0,2022-06-29T22:00:00.000Z
1656541800,0,2022-06-29T22:30:00.000Z
1656543600,0.039,2022-06-29T23:00:00.000Z

[geoffers]

Originally Posted by Mailman

@geoffers
...I cannot comment on whether the Eon Next app is as equally helpful but would assume it would automatically change from BST to GMT is October as well...

@retrotecchie ; @Mailman
I think this confirms the discrepancy with how the data is processed…

1. We all agree that the raw DCC data as is supplied in UTC forma

epochTimestamp,kWh,dateTime
1690498800,0.861,2023-07-27T23:00:00.000Z
1690500600,1.018,2023-07-27T23:30:00.000Z
1690502400,0.986,2023-07-28T00:00:00.000Z
1690504200,0.979,2023-07-28T00:30:00.000Z

1. The Bright app applies the GMT+1 adjustment, so its interpretation of the ½ hourly data agrees with my spreadsheet calculations for BST

1. The EonNext app uses the GMT data as supplied with no BST correction, so the daily totals agree with my spreadsheet calculations for GMT

1. Who knows what interpretation Eon Next’s billing system uses, which is why we need clarification from Eon

[Mailman]

Originally Posted by geoffers

I hadn't spotted that GMT+1 setting an the app, but presumably it just allows the app's GUI to adjust the displayed figures to BST

If you go into the website to download the actual data from the DCC (in CSV format) it just has the date in Zulu time (ie UTC/GMT) format "ccyy-mm-ddThh:mm:ss.sssZ

epochTimestamp,kWh,dateTime
1656540000,0,2022-06-29T22:00:00.000Z
1656541800,0,2022-06-29T22:30:00.000Z
1656543600,0.039,2022-06-29T23:00:00.000Z

The Bright GUI is just trying to be 'helpful' but complications can and do arise for customers on special TOU tariffs such as Eon Next's



Yes indeed, I am used to changing csv files into more manageable spreadsheet format. I know some suppliers (such as Shell) lets you do this this for your consumption down to whatever the period is and the other 3rd party players out there such as n3rgy (which I have also used in the past for the 'Demand Flexibility Service' events ran last winter). There was no confusion for DFS as we were on good old Zulu time anyway for most/if not all of the period of DFS. As a former reservist in the RN many years ago this quote seems highly applicable.

'We always reference Zulu Time as it is common to all and means regardless of where you are in the world, you can work out what time people mean and do things at the same time if you need to.'

Lt Cdr Thompson (Royal Navy)

DCC are clearly in line with the RN 👍

So to Eon Next, 2 things:

1. A clear communication to all on TOU tariffs as to what happens to the UTC/GMT/Zulu time periods during BST.
2. How about giving customers a easily downloadable CSV file of consumption, not only via the app (which I cannot seem to use on my tablet) but also via the online account website for those on smart meters (in line with some other energy suppliers and some other energy players)?

[WizzyWigg]

Everyone seems to have gone app and internet data crazy. 😵 From experience and looking across the board, nothing compares with the good old fashioned way of keeping a regular manual record of readings direct from the meters, and doing a little bit of simple arithmetic. 🤔To date I've not found anything more accurate. 😊👴

[retrotecchie]

@WizzyWigg

With you there, mate. Can't beat a stub of pencil, the back of an envelope and a few grey cells.