Electric car owners in France advised to avoid charging batteries to 100%

France's ecological transition agency, ADEME, has advised motorists to not routinely charge their batteries to 100% when they do not need the extra charge. 

In a recent report on electric cars and charging, the government agency explored how motorists can get the most out of their vehicles while reducing both costs and environmental impact.

One reason to avoid charging to 100% is to help preserve battery health over time. Keeping a battery at a very high state of charge can contribute to its ageing, although the effect depends on the battery technology and the vehicle. 

Stopping at 80% can also save time as the final 20% takes considerably longer to charge than the earlier stages. 

According to the agency, charging to 80% takes around 30 minutes at a 100kW rapid charger and can provide approximately 180km to 200km of driving range, depending on the vehicle. A 200kW charger, again in around 30 minutes, can provide more than 350km.

When should you charge an electric car to 100%?

Drivers planning a long motorway journey may benefit from charging to 100% before departure, especially if their route includes stretches with fewer convenient charging points.

For most everyday journeys, however, the full capacity of the battery may not be needed. ADEME said that more than 90% of local car journeys during the week in France cover less than 30km.

When is the best time to charge?

ADEME recommended charging electric cars during the middle of the day whenever possible, as this is when solar power production is at its highest.

For drivers who have solar panels on their homes this can be especially useful since it allows them to make use of electricity already generated. This can have a positive impact on their utility bills as well as contributing to the wider use of low-carbon electricity.

Drivers without solar panels may also benefit from shifting charging away from peak-demand periods, especially in the morning and evening. Depending on their electricity contract, charging at other times may also mean lower tariffs.

Other tips to make the most of your electric car

ADEME also recommends a few simple ways to improve range and reduce energy consumption.

Driving smoothly and anticipating traffic is one way to recover energy through regenerative braking, which feeds electricity back into the battery as the car slows down.

Heating and air conditioning can also increase energy use so – where possible – pre-heating or cooling the car’s interior while it is still plugged in can reduce the energy drawn from the battery during the journey.

Planning routes and identifying charging points in advance can also help avoid unnecessary detours. 

Finally, driving more slowly on motorways can reduce consumption. For example, an average compact electric car needs around 50% more power to travel at 130km/h compared to 110km/h.