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How long can a battery charge a bank of EVs?

With fleet electrication on the rise, how do you affordably introduce sufficient charging points and the energy needed at peak times?


With fleet electrification becoming not just commonplace, but essential, for many organisations, there’s an equally common challenge as a result – how to affordably introduce sufficient charge points and the energy to power these, especially at peak times.

Battery energy storage is an increasingly common consideration for many because of these issues, but a question that often arises is how long can a battery installation like our E-STOR system charge EVs?

Of course, there are a range of variables to the answer: how many vehicles will be charging at any one time; which vehicles with what battery size; how much charge is required, etc. But E-STOR isn’t a hypothetical solution, it’s a real-life commercial solution, so let’s take a look at some examples of our latest battery energy storage projects implemented to solve EV challenges.

Volvo Truck & Bus UK: Charging HGVs and buses

Two UK service workshops for Volvo Truck & Bus have turned to us to help supply the necessary power to charge its all-electric trucks. Neither site had the import capacity needed from the grid to power its truck chargers – which can be up to 50x more powerful than car fast chargers.

Our 300kW E-STOR systems will provide enough power to ensure both service workshops can run high-capacity charging points – 350kW and five 22kW electric car chargers for courtesy cars and vans for Enfield, while at Carlisle E-STOR will support a 150kW truck charge point and two 22kW electric car chargers for courtesy cars and vans.

Is your site eligible for battery energy storage? Use our online calculator to work out how your systems could be used.

Dundee City Council & SWARCO

We have provided two E-STOR 300kW/360kWh systems for the Council’s Clepington Road depot. The systems will be used to support two charging hubs and will work with solar PV arrays to power a range of fast, rapid and ultra-rapid chargers.

There are 22 7kW chargers, two 50kW chargers and a 100kW charge point, totalling 25 charge points that are supported with our E-STOR system.

So how long can a battery charge a bank of EVs?

High powered charging

In the case of Volvo UK, our 300kW/360kWh system could power a 350kW charger for just under an hour depending on the requirements of the vehicle. In Volvo’s example, the vehicle will most likely be receiving a top-up rather than a full charge, meaning a much shorter charging time is required.

Rapid charging

At Dundee, the two 50kW rapid chargers would equate to power demands of 100kW and so E-STOR could power both chargers continuously for over three hours.

The same result stands if the E-STOR was running the 100kW charge point alone, or it could run all three chargers for almost two hours.

Fast charging

The 22 public fast chargers, at 7kW each, would equal 154kW of total power demands if they were all in use at the same time. The E-STOR could power all of these simultaneously for 2 hours before the batteries would need recharging.

Speak to Connected Energy about your options

Connected Energy is a world leader in battery energy storage. For over ten years, we have designed and developed our innovative storage systems which are being used by businesses across the UK and Europe. Our systems store energy – either from renewables or direct from the grid – for use at a time when it’s needed most. This gives businesses greater control over their energy use. By repurposing electric vehicle batteries, we have created a solution that solves many of the power challenges businesses are facing, helping towards a more sustainably powered world.

If you’re looking to potentially utilise battery energy storage to support your business needs, whether that’s in relation to EV charging, or otherwise, please get in touch with the team.

Those interested in using BESS specifically for an EV charging installation may want to use our calculator and download our brand-new whitepaper.

Download our whitepaper

Discover the role of battery energy storage in powering the next generation of high-powered EV charging in Connected Energy’s latest whitepaper…