Why slow charging is best for smart EV tarrifs

As a novice EV owner, I initially had reservations about solely relying on a travel charger for home charging. However, instead of following the crowd and shelling out over £1k for a 7.6kw charger installation, I opted for an EV-rated external socket (a prototype device, in fact) and charged at 2.4kw using the Intelligent Octopus tariff. While there are other options available now, Octopus was the pioneer in offering a cost-effective rate of 7.5p for the hours your car needs to charge, or every day from 11:30pm to 5:30AM.

This daily rate is particularly beneficial for me as I also have a solar battery system. It’s adequate for maintaining my Tesla Model Y at the recommended 80% charge, but it truly shines when I return after a weekend of extensive driving. For instance, I plugged in at 8:30pm last night and it provided a charging schedule from 8:30pm to 11am, which alone would restore over 50% of my battery. Upon checking the Octopus app this morning, I noticed it had updated the schedule to continue charging, adding slots from 11 to 12, 2:30 to 4pm, and again 11pm to 8am, aligning with my request for an 80% charge as suggested by Tesla.

Now, you might argue that this is over twice as long as it would have been with a 7.4kw charger. But that’s precisely the point. By slow charging at home, I’m also securing many more hours for the entire house at 7.5p, as opposed to the standard rate of 30p. With a faster charger, I would already be at 80% and no longer reaping the benefits of this excellent tariff.

While some have accused this approach of “gaming” the system on various online forums, it’s far from it. Providers like Octopus offering smart EV tariffs only extend the low rates if it’s advantageous for them, so slow charging not only benefits the customer, but also contributes to the overall energy balance in the country.

Lastly, I’m aware of many who “de-rate” their home charger from 7.4kw to a much lower capacity, either due to frequent electricity tripping (especially among those with only 40Amps to the house) or to enjoy the extra hours at a reduced rate, much like myself. I think they will be reluctant to buy a replacement “fast” charger in future :slight_smile:

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Interesting post, thanks! I have also had an excellent experience with Octopus Agile tariff - we also use home assistant to control at what price our EV starts and stops charging but I think you probably get a cheaper rate on balance (although we wre being paid £0.10 per kWh to use energy last weekend!).

Yes, Agile is great but when you also have solar and batteries you can go down to minimal from grid and pretty much anything you do need will be at the low 7.5p if on Inteligent Octopus :+1:

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