/  Petrus Holm

Smart charging of electric vehicles: all you need to know


Smart charging of electric vehicles is more common than ever. However, common doesn’t mean that everyone understands how smart charging services work in detail. In Synergi’s instance, we have been approached by customers who are genuinely curious about how it all works: how are their savings generated, who controls their vehicle, and most importantly, what does this all require from each of them?

In this blog post, we engineers at Synergi want to give you the scoop on how we built our smart charging service and approached the user experience. We also share some of the math essentials behind smart charging.

If you are a smart charging veteran, we know this is familiar. However, at Synergi, we want to make smart charging so effortless and intuitive that it’s easily approachable for every EV driver – so that blog posts like this will soon become history.

What is EV smart charging?

Smart charging is about charging your vehicle when the electricity is relatively cheap, usually at night. Some car manufacturers, such as BMW, offer the possibility to control car charging on a scheduled basis: quite a good amount of savings can be achieved by simply setting the charging to happen between 1 AM and 7 AM. But, for most of us, this is not possible.

The solution instead is to use a dedicated application, such as Synergi’s own or others, to control the charging. And, when you take that route, why not go all in and use smart charging? From the driver’s perspective, the effort is the same: set up once and enjoy the benefits.

These services only need to know when you will leave in the morning to control the vehicle’s charging or the so-called “smart charging deadline.”

We use this input to allocate the charging between when you plug your vehicle in and when you leave in the morning.


Smart charging in the Synergi smart electric platform
Smart charging plans can be reviewed in smart charging services.

How much time will it take to smart charge my EV?

After determining the available time and upcoming prices, we almost have the smart-charging puzzle completed. The final step is to determine how fast the vehicle can charge to the wanted level, say 80%. To do this accurately, the charging has to be “tried out”: the vehicle is programmed to charge for a couple of minutes while monitoring the charging power and battery metrics. With this information, we can simplify the equation into four variables:

  1. The amount of energy needed (kW)
  2. The time available (h)
  3. The electricity prices (€/kWh)
  4. The charging speed, affected by both the vehicle and the charger (kW/h)

As the logic here is relatively simple, most smart charging services are able to reach a similar level of efficiency. What makes the difference from the user’s viewpoint is the reliability: in the end, you want your vehicle to be topped up in the morning.

Where should I smart charge my EV?

To avoid unwanted behavior and large invoices, one should not use smart charging in public chargers, which often charge you at a minute rate.

Some providers have also made efforts to remove this hassle by developing a geolocation-based smart charging, which automatically enables and disables the controlling based on your vehicle’s latest location.

With Synergi, you can add locations based on your vehicle’s current location, so there is no need to learn the coordinate system. Some providers also allow you to enter a location manually, either by exact location or street address. Both are sufficient.

What personal information does EV smart charging gather?

All smart charging services collect and store some customer data. For you, it’s super important to read the fine print in every smart charging service privacy policy. At Synergi, we have a stringent privacy policy that details what data we collect from each user and how we use it to deliver an excellent service. In principle:

  • We do not collect data on individual use unless necessary
  • We encrypt all personal data collected
  • We never save or store vehicle login information

We have an in-depth blog post about data privacy in smart charging services which you can read to get a clearer view of what you should pay attention to.


Smart charging is a simple way to reduce emissions and save on charging fully automatically. Using a robust provider lets you leave the calculations to the algorithm.

See our smart charging calculator to find out how much you could save with Smart charging.

Synergi’s app allows you to optimize your electricity consumption when it’s cheapest and produced from sustainable energy sources without additional hardware. Getting started with Synergi happens in three easy steps: 

  1. Log in and link: Start with Synergi by linking your devices (EVs, heat pumps, or solar panels). No extra hardware is needed* – it’s as easy as it gets! 
  2. Set up your preferences: With Synergi, you’re in control. Set your preferences for smart charging, set usage limits for home heating & cooling systems, and others!
  3. Enjoy the savings: With Synergi, you can reduce your energy bills without lifting a finger. Sit back and enjoy the savings while our platform optimizes your electricity consumption to happen when it makes sense.

*Some heating & cooling units might require an additional air conditioning controller.

Join us today!

Petrus Holm