Octopus 12M fixed - Day and Night electricity rates

dosh37

Gerry1 said:

dosh37 said:

I just went outside and checked. The meter is labelled 'Radio Teleswitch'.

Hence, when the radio signal is eventually turned off, it will (I assume) just provide a single reading.

Don't assume !  It makes an a s s of u and me...😈

Without the RTS signal almost certainly everything would carry on as before, except that the clock might drift slightly and the ability to vary the precise switching times would be lost.  However, this feature is seldom used for domestic customers.

TL;DR — If Droitwitch et al had collapsed at the weekend you wouldn't even have noticed !

So what happens after the RTS signal is switched off and you get a power outage?

Unless the meter contains one of your magic everlasting batteries, the clock won't just drift.

It would stop completely until power is restored. It could end up way out by several hours and would never be corrected.

EssexHebridean

dosh37 said:

Now that Octopus have adjusted the tariff, my estimated total annual cost (electricity + gas) has gone down from £1120.10 to £1016.90.

A potential saving of £103.20, so It's just as well I questioned it.

Other customers need to be aware and do the same.

Most E7 customers will have good reason for being on E7 though, and being switched to single rate would cost them a fortune. When we were on E7 in our last home, our day/night split was something like 25%/75% - being on single rate would have cost us a fortune! We were using storage heaters though, and an immersion heater, and also load-shifting as much as possible in terms of general use to the off-peak period too to make the most of the lower off-peak rate. Now we are in a house with gas central heating and water, single rate electric is far cheaper. 

Certainly those on E7 should be keeping an eye on their split, maximising the off-peak hours and ensuring that it is still right for them, but it's certainly not a change that will suit many of those with dual rate meters. 

Scot_39

nologo said:

That would usually be known as"economy 7" type tariff & yes the lower nightime rate is offset by a more expensive daytime rate, to make this tariff viable about 60% usage needs to used at night IE heating, hot water, dishwasher, washing machine, battery charging ect, hth
regards.. nologo

Think you have the split in nominal 42:58 the wrong way round.

The threshold is more typically like 35-40 % - nowhere near  60% - to balance single rate pricing.  But it varies by quarter.

Think saw it as low as 30% in the past (late 22, when the difference between SR and MR cap prices had drifted apart - before moving abnormally dramatically iirc c2.3p closer in my region in Jan 23.  You might remember the e7 price rise complaints from heating charities at the time)

Take the top region in edf tables here as just one current example

https://www.edfenergy.com/sites/default/files/2024-09/DM1903-Standard-(Variable)-Deemed-and-Welcome-Credit-and-Smart-PAYG-Oct-24.pdf

29.23, 13.59p on e7 vs 23.77 single rate

Solve for fraction off peak to match total unit costs (will, ignore the tiny difference in standing charge to keep simple)


29.23 x (1-foffp) x total use + 13.59 x foffp x total use = 23.77 x total use
Foffp=0.349 or 34.9%

At your 60% off peak put 0.6 in above (dropping total use from both sides)
29.23×0.4+13.59x0.6=19.85p ave cost - nearly 4p below single rate.

My ave use is typically around 75% off peak as all electric.  Multirate a no brainer.

But many have moved away from conventional all electric best suited to e7 (nsh and hw immersion) but still have legacy metering - seen users who have posted numbers in low to mid teens so 10-20% off peak use post in past - paying several p more on average - before switching to flat rate.

Ofgem themselves still assume a 42% off peak use when calculating the average multirate price cap level still - which is why people think the nominal 42:58 split always applies.  Put 42% into the equation above - get ave 22.66p - 1p cheaper.
 


But the OP had clearly been switched from SR to E7 - and that suggests had already made the request to be billed at single rate in the past - based on their usage.

And changing tariff shouldn't in my opinion have changed that - although changing supplier often does.

Glad to hear that Octopus were able to switch the OP back again to their preference.

They (iirc for ex Shell customer in one post) and other suppliers have been less so in past posts here.

Gerry1

dosh37 said:

Gerry1 said:

dosh37 said:

I just went outside and checked. The meter is labelled 'Radio Teleswitch'.

Hence, when the radio signal is eventually turned off, it will (I assume) just provide a single reading.

Don't assume !  It makes an a s s of u and me...😈

Without the RTS signal almost certainly everything would carry on as before, except that the clock might drift slightly and the ability to vary the precise switching times would be lost.  However, this feature is seldom used for domestic customers.

TL;DR — If Droitwitch et al had collapsed at the weekend you wouldn't even have noticed !

So what happens after the RTS signal is switched off and you get a power outage?

Unless the meter contains one of your magic everlasting batteries, the clock won't just drift.

It would stop completely until power is restored. It could end up way out by several hours and would never be corrected.

A capacitor could provide the minute current needed to keep the clock functioning for the few hours that the outage is likely to last.

Scot_39

dosh37 said:

Gerry1 said:

dosh37 said:

I gave two readings (Day & Night). As the rates were the same for each it made no diiference. I assume Octopus added the two together.

Don't make assumptions, just look at the statements.  It'll probably show the day and night kWh usage separately but charged at the same single rate.

dosh37 said:

Obviously the meter incorporates a radio teleswitch to allow it to distinguish between Day and Night. It does not have a built in realtime clock with battery backup or a user interface to set the time. There is no separate switch to automatically control appliances such as storage heaters etc.

Nope.  Some modern non-smart electronic meters DO have a built in clock preset to E7 times.  The E7 times are never user adjustable for obvious reasons.

A Radio Teleswitch is usually a bulky separate unit next to the meter and labelled as such, although there were some meters with an RTS built in.  Again, they were labelled e.g. Radio Telemeter.

Hmmm - how does that work?

How can you have a meter with a built in clock preset to E7 times with no way to set it?

What happens to the clock after a power outage? There is no battery backup.

It can only use the Radio Teleswitch signal to control it. (unless they somehow send control signals down the power line).

I switched from rts to digital and then digital to smart.

The digital completely stand alone - no time sync, no over tge air comms.

The off peak times were programmed in the factory into non volatile memory.  They remained fixed GMT times all year round  - as do many smart meter configurations for e7 off peak times today (though they don't have to).


Arguably they may even be programmed in a limitted fashion over optical serial link if firmware and hardware permitted - the second "led" next to the flashing imp light on some meters - in fact an IrDA serial comms port.

Not sure about meter timers in reality - id have to see a circuit diagram - but in other apps even a simple capacitor on a pcb will hold enough charge -  to run a crystal oscillator clock circuit / or integrated digital timer chip for days maybe weeks for instance as they draw only mW.

Not all memory is volatile.

Like your computer or your phone certain things can be stored temporarily in volatile memory  (ram) - your normal live working space - lost on power down - or non voltile memory (think eeprom for the motherboard bios on a pc or a solid state hard disk - your operating system files and saved user data).

And the motherboard - certainly on desktops where I have replaced them on my own Linux boxes -  some functioning after nearly 10 years - typically has a coin cell battery that lasts longer than many users keep their pcs.  When coin battery dies your prompted to set date and time every time you boot if powered off at mains.  I've not bothered doing it yet on one ancient laptop.

dosh37

The one I have looks like this:-

https://collection.sciencemuseumgroup.org.uk/objects/co8407354/gec-meters-radio-teleswitch-from-the-central-electricity-generating-board

It's in the science museum collection. That shows how old it is.

dosh37

It's hooked up to a multirate meter like the one in this photo:-

https://www.alamy.com/stock-photo-electricity-meter-close-up-sealed-domestic-home-multirate-single-phase-17989292.html?imageid=499D3576-8141-4C51-BC0D-1B47645850BA&p=89075&pn=1&searchId=36f0f64a0f5c45271cd4bb2daabdf5d5&searchtype=0

Gerry1

Your meter doesn't have a clock so it doesn't need battery backup.

The RTS tells the meter which register to use at any given time.

dosh37

Gerry1 said:

Your meter doesn't have a clock so it doesn't need battery backup.

The RTS tells the meter which register to use at any given time.

Yes - I know.

That is what I have been trying to explain right from the beginning.

I am a retired electronic / software engineer with 50 years experience.

dosh37

The meter does however need to retain the existing reading(s) following a power ouitage.