@marvinator80 these are 2 different things. By way of example... I have GivEnergy kit.

Inverter is Gen1 Hybrid 5kw

Batteries are 3 x 8.2kwh = 24.6kwh capacity

My inverter can convert DC to AC up to 6.5kw

With Nominal AC Output Power 5kw

BUT the max it will charge/discharge from batteries is at 2.5kwh

So if my batteries are fully discharged it will take 10 hours to charge them! Meaning I can only fill them at say 10% per hour ... a 3 hour cheap slot filling 30%.

Not ideal - but not worth upgrading. So I just have to work with that to maximise the way I use Agile 

Hope that clarifies... and helps

@jamespa thanks James. I’d be installing a Zappi (already have an Eddi) as it seems to be compatible with both Octopus and the car (BMW i4). 

And the battery seemingly does allow storage from the grid in its settings. So 6 hours at night I can charge the car, power the ASHP and charge the battery for 10 kWh of electricity for the pump and general house use at the 7p rate and then any other grid use is 25p. 

think this could be excellent in winter particularly and seriously impact my ASHP costs. 

@tim441 got you now. Thank you. 

I have 10kW batteries and they charge at about 2.1kWh, so the 6 hours overnight 7p rate should be just about ok for me, I think.

Posted by: @marvinator80

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I have 10kW batteries and they charge at about 2.1kWh, so the 6 hours overnight 7p rate should be just about ok for me, I think.

The conclusion is right but just to correct the units - you have a 10kWh battery and it charges at about 2.1kW.

Think of kW like speed and kWh like distance.   Alternatively remember that kWh is exactly what it says ie killowat(s) times hour(s).  So 1kWh is 1kW for an hour, or 0.5kW for 2hrs, or 2 kW for half an hour etc.  

Thus 2.1kW for 6 hrs is 12.6kWh, more than you need to fully charge the battery, so in fact it will stop charging after a bit less than 5 hours.

@jamespa yep, that’s my understanding. It might discharge for a bit when full and top up a little and with DoD of 90% I will prob get 10ish from a 6 hour overnight charging stretch, costing circa 70p.

I hope this is an appropriate thread to sort of re-start a topic questioning the average that those readers on OE’s Agile tariff find themselves paying per kW/h at present (or in the last few months at least). I swapped to Cosy on 1st. July and as best I can make out, this has ben consistently cheaper during the lowest rate in the tariff than any daily offerings from Agile.

I would appreciate it if any readers on Agile who select their HH’s to run their household needs and charge their storage (battery or heat store) at the most economic rates would like to say what their average unit costs are using this method.

I have been observing the daily findings for Agile as published by Agile Rates and they express the lowest rates as ‘average off-peak’ rate; this hovers around the 20-22 pence per kWh and has been in this ball park for the last few months on all but perhaps 8-10 days when there has been plunge pricing. Please, if any Agile user has the time to check their consumption and average price, I would be delighted to know.

I am keeping tabs on the published ‘average off-peak’ rates but wonder if the more savvy user (admittedly, those with time on their hands or an automation procedure to carry out the task for them) has been able to ‘better’ that average. My Cosy tariff lowest rate is still under 13 pence per kWh and I have not seen anything to approach this according to Agile Prices daily listings. Regards, Scroogely, Toodles.

@toodles I have been monitoring on a monthly basis since switching to Agile in March. I have solar & batteries.... so endeavour to import when cheap using WonderWatt as app to help. spreadsheet dates slightly wrong due to split monthly bills but totals are correct. I've now got Octopus to send invoices for calendar month

Ignoring solar ... so just Agile imports: total 4026kwh @ 10.23p

since 1st July to 31st Oct 2287kwh @9.25p

obviously last 2 or 3 weeks have not been so good due to lack of wind but even now its around 18p on the short term. so I think i will be able to get under 15p average in the next month and maybe nearer 12p if the wind blows nicely!

July was high due to hot tub! grrrrr!

@tim441 Thank you Tim, which means that July - October (The area of greatest interest at present) averaged 10.472 pence per kWh - this appears to suggest that Agile Prices algorithms use different parameters! Perhaps they use a wider time range than is actually required to fill / charge your set-up each day. Regards, Toodles.

@toodles well ... 10.472 is the simple ave of the 4 months ave prices divided by 4... but i think its more accurate to take the actual kwh and prices... which is:

1st July to 31st Oct 2287kwh @ 9.25p

i imagine Agile own averages uses a simple average through the day. But I fill batteries at night (sometimes very cheaply) and use almost nothing at peak rates

it makes all the comparisons very hard! different usage, battery sizes, charge/discharge rates etc all in the mix!

@tim441 I should have been an accountant - I know how to cook the books!😉 Toodles.

@toodles we probably need to swap notes again at year end....and every couple of months 

I see Octopus are stopping Fixed Export as an annual contract and changing to variable. For now continuing at 15p but with no term. Sadly my contract expires next March so will be interesting to see if they cut summer export rates.

I have not heard how much notice they will give of a change in export price.

During period from Oct to about end April I use everything my solar produces - so not an issue for now.

Posted by: @toodles

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@tim441 I should have been an accountant - I know how to cook the books!😉 Toodles.

...although taking them with a pinch of salt will do nothing good for your blood pressure. 😉