The world is going electric, and whether or not you’ve jumped on the EV bandwagon yet, it’s looking increasingly likely that this will be the fuel of the future.
Electricity is a brilliant choice for the world because we, as humans, can generate much of it using clean sources – like solar.
But there’s no denying that an EV demands a lot of electricity. Most electric car batteries can hold up to around 60kWh. Considering an average home here in the Midlands only uses around 8kWh per day, is it reasonable to expect your solar panels to be able to charge your EV?
Absolutely. But perhaps not in quite the way you’re thinking. Here’s how to develop a personalised EV-charging solar system in your home using SigEnergy products.
Different ways solar can offset your EV charging
As we touched on in the introduction, an EV has a large battery. Even the largest residential solar array would struggle to charge it from 0% to 100%. Thankfully, though, you rarely use all your car’s battery all at once. That means solar can have a real impact.
Besides, as with any solar system, there’s no need to disconnect from the grid entirely. Solar can still make an effective difference to your EV charging and the associated bills, even if you still draw from the grid for some of your charging. The real value comes from reducing how much electricity you import and specifically choosing when that happens.
Here are a few different ways that households use solar to charge their EVs (directly or indirectly).
Charging your EV directly from solar during the day
Here’s the most basic setup. If you plug your EV in to charge while the sun is out, the solar-generated electricity feeds the charger straight away, along with all the other electrical appliances and loads in your home. Any solar that you don’t immediately use gets exported to the grid, and you receive a set rate per kWh in return, depending on your tariff.
If your setup includes SigEnergy monitoring and an EV charger that the system can see, mySigen can show your solar generation, your home demand, and what you export to the grid. In some cases, it can also show EV charging as a separate item.
It sounds like a great option, and it is. Especially for people who work or stay at home during the day, have flexible schedules or work night shifts. Even a few hours of daytime charging can offset a large chunk of your weekly EV mileage.
Unfortunately though, most of us are out during the day, and only get home at night. While you’ll still receive some money back via the Smart Export Guarantee scheme, there are better ways to use solar to charge your EV.
Using a battery system to charge your EV later
Because most of us charge our EVs in the evening or overnight, a battery system changes the game completely.
Instead of exporting your unused solar during the day, the battery stores it. Later, when you get home, you plug your car in, and the charger draws from the battery. Depending on how much charging your car requires, your battery won’t usually cover a full charge on its own, but it can significantly reduce how much power you pull from the grid.
SigEnergy’s SigenStor is designed for just this kind of setup. You get the battery storage, the inverter, and the energy management system all in one platform, which makes it easier to control. Plus, it’s modular, so you can add up to six separate ‘individual battery modules’ to increase the capacity over time.
Installing a solar battery storage device is usually a much more effective cost-saver than solar alone. But, as we touched on, don’t expect it to fully charge your car’s battery. Most residential setups simply don’t have the capacity (or enough solar generation). So, there are a few more things you should consider.
Combining solar with EV and time-of-use tariffs
Lots of EV owners already take advantage of time-of-use or EV-specific tariffs. These allow you to charge your car at much cheaper rates during off-peak times (usually at night or during the middle of the day). Combining these tariffs with a solar-and-battery system makes them go further.
Here’s a common approach to this setup:
- Rooftop solar covers part of daytime charging
- Solar battery storage stores any excess solar your house didn’t use
- Your car charges overnight, drawing from the grid at low, off-peak rates
- The energy from the battery powers your home during peak-rate periods; if there’s any left over, it too can supply a small charge to your car
With a SigenStor system, you can use the mySigen app to choose the time-based control mode. This allows you to set the battery’s behaviour based on the time of day. You can also see how many kilowatt-hours are imported or exported at each tariff rate, and use that to calculate your real-life cost savings.
Now, this approach doesn’t technically use solar to charge your EV, but it does use solar to cut the cost of charging your EV, even if indirectly.
How much money can you expect to save from using solar to charge your EV?
It’s very difficult to give you any exact figures, because savings can vary wildly depending on people’s setups. It’s also sometimes rather challenging to isolate how much you save in EV charging, as opposed to how much your entire home saves overall on its total energy bills.
We can’t give any guarantees at all, but £300 to £400 is a reasonable ballpark for how much you could save by using a well-designed solar system to charge your EV.
However, every kilowatt-hour of solar that you use for EV charging, or use to offset your energy bills in other ways, saves importing electricity from the grid at peak rates. Over a year and beyond, that really adds up, especially for drivers covering regular mileage.
In the mySigen app, you can actually track how much energy goes into your car, and how much of that likely comes directly from the solar panels or the battery. This can allow you to calculate a personalised savings figure for your setup.
Is solar EV charging right for every home?
In most cases, yes. But not always.
The complication here really arises from separating the idea of EV charging from the rest of your home’s electrical usage. In reality, it’s all the same, all drawing from your provider at the same rates. Instead of thinking of solar as only charging your EV, consider the overall benefits and cost savings you’ll bring your home. This is right for almost every home, even those without south-facing roofs or in tree-heavy areas.
Just remember, the goal here isn’t free driving, although, in a few limited cases, that may be possible. It’s about offsetting those charging costs as much as realistically possible, using energy that you’re already generating anyway.
So, if you already have solar, are planning an EV, or want to understand how a battery system like SigEnergy’s SigenStor could support your electric car charging habits more effectively, Electrical Innovations can help.
Based in Derby, our friendly team of experts examines your home, your usage, and your available tariffs, and helps you build a system that maximises the impact of your solar and its cost savings. Get in touch today to learn more about how we could apply this setup to your property.
