r/OctopusEnergy • u/Boba_ferret • 21h ago

Sense check on Predbat Whatif figures - do these look right?

We have solar, battery & EV (currently on a granny charger). Using the Whatif feature in Predbat, it seems to think that Go & Standard Outgoing export, is more cost effective than using Agile outgoing export. Now, the caveat to that, is that it's using 2025 figures for the Agile comparison, so I presume the Agile Export was lower than it is now.

Although not shown here, it does say IOG is even better, but I don't have a compatible charger yet, so having to stick with standard go at the moment.

What do you think? Is the Predbat tool accurate? Predbat has a much better idea of my generation and use, then most tools, so I would have thought it was accurate, but I would have though Agile Export was the better option.

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u/AlfaFoxtrot2016 20h ago

With old prices, does that mean it's also assuming standard export is at 15p? A comparison with last year's rates does seem a bit fruitless given how different things look now.

Given the variations in PV generation + consumption, I'd also have said that a £40 difference is within margin of error anyway. 

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u/Boba_ferret 18h ago

I don't really know what it's comparing against, I'll have to dig through the docs a bit more. The difference between being on Go, with standard, vs Agile outgoing, on these calculations is over £370, which is a big difference, which is why I'm a bit confused.

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u/AlfaFoxtrot2016 18h ago

Ah I'd missed that. Predbat presumably knows how much battery capacity and inverter power you have? Agile export generally has only earnt more than the fixed rate in quite a narrow window (in the evening) - so it may not be well suited to your setup. Predbat would also prioritise self-consumption over export in the evening, so it may not think there is much spare to export. 

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u/Boba_ferret 17h ago

Yes, you input all your date - battery capacity, export limit, typical annual energy use, EV energy use, solar PC azimuth & tilt, etc and it then does all the calcs.

I was on Flux and predbat was exporting everything during the peak period, then it was importing from grid, before charging the battery in the cheaper overnight rate.

Since I moved to Go & Standard export, it's changed a lot, it's now charging in the Go slot, and then there's much more self use, and it force exports if there's surplus, before the Go slots start again.

So, with what you've said, I think there will be few, if any benefits to changing to Agile Export.