EV, Solar panels and finding the best tariff

Redlib

we recently bought our first EV and expect to do about 7500 miles per year mainly charging at home. We both wfh so the car spends most of its time in the drive or doing local runs apart from the odd trip to visit parents or collect kids at uni or go on holiday. It will cost a minimum of £1k to install a charging point. So first question is it worth installing one?

We also have solar panels producing about 5000 kWh per year. our annual electricity use is 2500 kWh. We export to Octopus. So Is it worth swapping to an EV tariff? My understanding is that although we will get the cheaper night time charging rate, our daily rate will go up. We might also have to pay to have a charging point installed. Or is it better to just charge the car on a sunny day and use the electricity being generated by the panels??

Many thanks

Peter999_2

My parents got a Soul EV in 2020. They had a granny charger for the first 4 years without any problems. They only do about 10,000 miles a year and like you the car is mostly sat on the drive. They get about 10% charge every 4 hours which is enough for about 30 miles of range.

Personally I'd just make sure that the plug socket is of good quality and only use the official granny chargers.

Have you got a battery? If not, then it does depend on whether the amount you get for exporting is less than what you pay to import for the grid. If it is then I would plug the car in to charge when it is sunny.

Qyburn

Octopus Go doesn't require you to have an EV charger, just to have an EV that you charge at home.

QrizB

Welcome back to the forum!

we recently bought our first EV and expect to do about 7500 miles per year mainly charging at home.

I'm going to guess that you'll need 2500kWh of electricity to drive your EV that far.

our annual electricity use is 2500 kWh.

That's 2500kWh of imported electricity per year, at present? So your electricity use is going to roughly double.

So Is it worth swapping to an EV tariff? My understanding is that although we will get the cheaper night time charging rate, our daily rate will go up.

The current electricity supply offer from Octopus is, roughly (varies by region):

• Flexible Octopus, the SVT: 25p/kWh
• April 2026 v1 10m fix: 26p/kWh
• Octopus Go, 12m fix: 9.5p/kWh off-peak, 34p/kWh peak

Lets assume you can do all your car charging off-peak but all your domestic electricity remains peak rate.

Your annual electricity supply costs will be:

• Flexible: £1250 (expected to increase in July and October)
• Fix: £1300 (fixed for 10 months)
• Go: £1088 (fixed for 12 months)

Switching to Go looks like it could save you £200+ a year.

Reed_Richards

I bought an EV in 2023 and have been managing well with just a granny charger. I'm on a 6 hour EV tariff and I can use about 14 kW in that time with around 90% efficiency of charge added to the car battery. I won't get an EV charger until I get get a bidirectional one, even though that wouldn't work with my current EV. At the moment only a few bidirectional chargers are available; I am waiting until there is more choice and they are a bit better established. With a suitable EV I could then use the car battery to power the house (when the car is parked at home). This would enable me to shift more of my electricity consumption to the cheap overnight rate and I calculate that could save me about £500 per year (I'm a heavy user of electricity because I have a heat pump).

Qyburn

Lets assume you can do all your car charging off-peak but all your domestic electricity remains peak rate.

Redlib doesn't say if his solar has a battery. If he does then he should be able to get a lot of his import at cheap rate.

Or is it better to just charge the car on a sunny day and use the electricity being generated by the panels??

You'd be cheaper charging on an EV tariff at say 9.5p and earning 12p by exporting the solar.

born_again

6K miles a year here. That £1K charger paid for itself in 9 months over the cost of fuel in old car compared to the cost of electricity to charge car.

You have solar, IOG & export solar at 12p kWh, charge car at 5p kWh.

Don't make the mistake many make by thinking that charging car from solar & saying it free charging.. When you can make 7p exporting it 😶‍🌫️ This is MSE after all.

johnbhoy70

https://forums.moneysavingexpert.com/discussion/comment/81951911#Comment_81951911

That's the way i looked at it re charger. We started leasing an EV for my wife in November 24 and going by rough calcs and a couple of youtube vids we reckoned break even was very roughly about 8k miles for a £1k charger at that time. She's sitting at very approx 10k mileage now and funnily enough the lease was over 8k miles a year too for 2 years. If the figures are right we'll hopefully just do similar come November

ps- i scoured for grants etc for the charger but absolutely nothing doing.

Reed_Richards

I think you are doing the wrong calculation. You should be comparing the cost of charging with a granny charger (2.3 kW) costing £100 with an EV charger (7 kW) costing £1000. You can charge your car about 3 times faster with the 7 kW charger but how often do you need to do that? In my case I only make two long journeys within a day or two of each other every couple of months so when that happens I have to add extra charge at the day rate but if I have to spend an extra £50 a year doing that it will still be 18 years until a 7 kW charge will have paid for itself. And I'm not sure if they even live that long.

johnbhoy70

https://forums.moneysavingexpert.com/discussion/comment/81952119#Comment_81952119

Fairly regularly and often at quite short notice tbh as my wife is with NHS and can have in person meetings just crop up. She can work from home on occasion but can't really plan well ahead. Therefore, we couldn't really maximise any cheap day savings elsewhere ( it's why I didn't move to octopus recently) . Also, and people can say this is unfounded, but I didn't really fancy the safety aspect of it and we had no real plugs close to driveway and didn't fancy extensions out the window. Different strokes for different folks I suppose.

born_again

https://forums.moneysavingexpert.com/discussion/comment/81952119#Comment_81952119

You compare cost of petrol to cost of electric used to charge car. Difference is how quick you pay the charger off.

But if you want to go the route of Granny V Charger. Decent granny a couple of hundred, cost of a proper sparky install of a external BS 1363-2 socket & wiring into a suitable consumer unit, another couple of hundred. So nearly 50% of a charger cost there.

Then limited to slower charging & more expensive tariff, making a longer payback time.

Yes granny chargers can have their place. But why limit yourself.

Example on IOG today. Set my car to charge overnight around & plugged in 12:00. Start time was shown at 02:30 when plugged in, as expected. As it's a greener night tonight & tomorrow night. So set for 35% tonight & will do the same tomorrow (bonus points/money back for doing this)

Now comes the bonus of a charger. Octopus have then decided that they have excess supply & means that car is now charging 12:30 to 16:14 (so whole house is at 5p kWh. Even bigger bonus is roast chicken for tea, so a big saving) Still get the greener night bonus as well 👍So that's a 25p saving per kWh over the 4 hours. So at least 20kWh going into car.

You would not get that with a granny charger.