Alex Johns, business development manager at Altelium, talks about protecting EV battery health and residual values to Fleet World, and how to avoid an electric shock when you come to sell your electric fleet.

Alex Johns, business development manager at Altelium

Fleet managers may be shocked to discover that the wrong charging and usage pattern can make up to up to 400% difference to the life expectancy of a battery.

Alex Johns was one of the first people in the UK to operate a fleet of electric vehicles, managing the Tesla fleet at Gatwick airport. He now works for Altelium, the EV battery data, health and warranty specialists, and was recently invited to present to the Residual Value and Remarketing (RVR) forum of the BVRLA.

“Most fleet managers are well aware of the impact of different driving styles on fuel consumption in a traditional ICE vehicle. Many have invested significantly in training or software to keep costs down; now it’s time to invest in understanding and ensuring the correct charging patterns are used in their electric fleet,” Alex says.

Much of the resale value of an electric vehicle is based on the condition of the battery, and the most basic measure of battery health is a calculation of the range of the battery when fully charged, compared to its range when it was brand new.

The Teslas that Alex managed for Gatwick had driven 300,000 miles each when the three-year trial was complete and yet the batteries were still at 82% state of health (SoH).

“There are a range of behaviours you can adopt to protect and maintain the health of your vehicle’s battery, and their cumulative impact is significant. The same vehicle after 40,000 miles could have a battery at 86% or 96% SoH.”

In terms of resale value this will make a huge difference. Batteries are improving in quality all the time, so range is increasing all the time, but for a domestic vehicle the point at which they are considered no longer fit for life in a vehicle is 70% SOH, while for commercial vehicles – where range is critical – it’s 80%.

Batteries do not have to be discarded when they reach the 70-80% SoH level, however. They still have significant charge capacity, and therefore some residual value, and can be used in battery energy storage systems (BESS) until the battery reaches 50% SoH. This could mean a life of up to 15 years for a battery – a massive impact on carbon savings compared with recycling the battery immediately after its life in a vehicle is over.

Giving batteries a second life after they have been used in a vehicle is absolutely crucial, not only for their resale value but also for the planet. The precious resources in a battery must be maximised and the embedded carbon not lost, an extremely important point for any organisation with meaningful Environmental, Social and Governance (ESG) targets.

However, batteries can only be given that second life, and assigned a resale value, if their health is known.

This is where data and oversight is essential. Altelium has a vast database of knowledge to draw on to forecast the future health of a battery and, therefore, its risk profile. This knowledge is gained through enhancing real-life battery data with AI, and testing battery twins in laboratory conditions.

A video of the testing at Lancaster University illustrates how the process works. Up to 150 battery cells can be simultaneously tested, ageing batches of batteries under different, well defined conditions of current, voltage and temperature. This speeds up a process that normally takes a year to complete to a matter of weeks.

This testing at Lancaster University has proved that one of the main factors affecting battery health is cyclic aging. Depending on the battery chemistry, fast-charging can age batteries prematurely, yet for fleet managers it might be an essential practice to ensure the vehicles are ready for use in the right time and place.

The most common battery cell chemistries are lithium nickel cobalt aluminium oxide (NCA), lithium nickel manganese cobalt oxide (NMC) and lithium iron phosphate (LFP).

NMC batteries in particular shouldn’t be fast-charged too often, and batteries of all chemistries need to be rested once a week, if they are used commercially.

LFP batteries, used most often in heavy-duty vehicles, also need to be fully charged once a week. This allows the battery cells to be balanced out. Loss of balance is where even one cell at 3% less charge than another, in a pack which might include 1000 cells, can cause the entire battery system to fail because the battery management system (BMS) is confused, can’t process this single anomaly and has to shut the whole battery down.

Depending on the chemistry, the key steps to increasing the life and residual of your battery for high mileage fleet vehicles are:

• Avoid fast charging too often – not more than 30% of charging over the long term, although fast charging may be necessary if on a long journey;
• “Rest” the battery once a week – at least four continuous hours’ neither driving nor charging, at a moderate state of charge (SoC);
• Ensure the battery is fully charged once a week (only for LFP batteries);
• Avoid using the top 10% or bottom 10% of SoC (except when doing the weekly charge to 100% for LFP);
• Always drive in ‘eco’ or ‘chill’ mode.

Alex believes monitoring battery chemistry and charging patterns is the most important way a fleet manager can protect the resale value of their fleet.

“A fleet review which takes into account driver shift patterns and charging point type, location and usage could pay dividends from a business and environmental point of view.”

Alex also suggests looking into extended warranties to complement the original manufacturer’s warranty. While commonplace for traditional vehicles, these products have only come on to the market very recently for electric batteries, and reduce the risk for fleet managers considerably. For example, warranty mileage coverage could be increased from perhaps 100,000 miles over eight years to 200,000 over the same period. Selling the vehicle with this warranty in place will help considerably with the resale price as it offers such peace of mind.

In addition to the support it provides at the point of resale, an insured warranty is of course a help with day-to-day operational risk. A failed battery is more expensive to deal with than even the most significant mechanical failure in a combustion engine, so a few hundred pounds more on a warranty, spread over three or four years on the cost of the vehicle, could save over ten thousand pounds per vehicle if something goes wrong.