The heart of the matter

Altelium’s Alex Johns on how you can advise electric car owners to keep their battery in good health

Published:  01 December, 2021

The most valuable component part by far of an electric vehicle is its battery. Yet it is the one component that regular mechanics are not supposed to touch and due to lack of advice, it appears that few owners know how to keep the battery heart of their cars in good health.
Drivers tend to be primarily focused on short term-data that they can expect from their battery such as range or charge. EV manufacturers tend to give surprisingly little information about how to keep an EV battery in good shape on a day-to-day basis. What advice can be given to EV owners to help them look after their batteries for the long term?

If we look closer at the EV, the Li-ion battery and electric motor combination do the work of not just the engine, but also the gearbox and fuel tank you would find in an internal combustion engine (ICE) vehicle. With an ICE vehicle, mechanics and engineers at a car dealer or garage would be able to give tips and advice on how to maintain these parts in good working order. Few, however, know how best to look after an electric battery. In fact, EV owners are much more likely to be given advice and help in finding charging points or battery range, which is useful, but perhaps not as valuable long-term. By offering EV owners good advice on battery health, you are offering them a long-term benefit - and in turn, building a good reputation amongst that growing EV community.
Most of us are used to keeping an eye on the state of charge on our smart phones, making sure it is always charged as needed. You may even have discussed whether it is better to let it run down and then charge it overnight in one big charge or perhaps think it’s best to keep it topped up through the day and charge it little and often.
This is a great comparison to use when explaining battery health to customers. In practice, the same principal applies to the electric battery in your vehicle but obviously with vastly more energy involved. For example, one Tesla car battery can contain over 7,000 individual cells, whereas your phone might only have one small cell.
It was recently suggested by Tomas Ingenlath, Chief Executive of Polestar, the electric vehicle sister brand to Volvo, that people are “starting to feel a bit more relaxed about the EV question” – but what is the EV question?  
Is it how far your car will go when charged and if you’ll reach your destination? Is it how much it will cost to charge your EV?  Is it whether the battery can be recycled at the end of its life in a car? Or is it how to keep your battery healthy and make sure it lasts as long as possible? We think this is the key question for EV owners.
In some ways understanding battery State of Health (SoH) answers all these questions. Battery state of health is described as the current capacity of your battery as a percentage of its original capacity.
When I oversaw the trial of five Tesla electric taxis stationed at Gatwick Airport in 2019, before I joined Altelium, each vehicle had 300,000 miles on the clock when the trial concluded after three years, but the batteries were still at 82% state of health (SoH). They were still working really well with many years life left in them. There is no question over the quality of the batteries, but we were given clear guidelines on how to use them and charge them.

Battery health
How can this help to advice EVs drivers on how to best maintain battery heart health in their cars? First, fast charging on DC chargers should be no more than 30% of all charging. Charging has a large impact on battery health so try to charge at home wherever possible, using a household plug or A/C slow-medium rate charger.
Secondly, it is important to try not to let a battery run completely flat. It is best to keep it in the middle range as much as possible where the chemicals in the battery are held at optimal conditions. A car battery computer will be set to do this as far as possible, but drivers can certainly help by not running it down completely.
Additionally, if someone finds they are running a battery all the time, for example in a taxi role or delivery operation, then let it rest – not charging or driving – once a week at a moderate state of charge (30-50%). This allows the battery cells to rest. Although this is not the place to explain in full, information is available online from electro-chemists about what this allows a battery to do internally - and you could certainly suggest that as something EV drivers might want to read up on.
Another good tip is to keep electric cars in the shade on sunny days. The optimal temperature for a battery is at 21-21.5⁰C and extreme heat or cold will really impact the range of that electric car battery. While extreme cold will reduce battery performance, the effect of heat is more important from a health and longevity point of view. For more information, visit:

Related Articles


©DFA Aftermarket Media Ltd
Terms and Conditions