Editor's choice
10 juin 21

Why you shouldn’t go for the biggest battery available

Many BEVs come with two or even three battery sizes to choose from. You might be tempted – budget permitting – to go for the highest number of kWh, but that is not per se the best choice.

Let’s take VW's electric ID.3 as a starting point for this discussion. The popular fleet car’s line-up comprises three battery packs: 45 kWh, 58 kWh and 77 kWh, resulting in a range of minimum 350 and maximum 547 kilometres. The big-battery model (Pro S) is roughly €4,500 more expensive than the medium-battery version (Pro), which in its turn costs some €3,000 more than the entry-level ID3 (Pure).

At nearly €36,000 excluding VAT (Germany), the ID.3 Pro S fits in many company car drivers’ budget. It may convince e-sceptic ICE drivers because it combines nippy accelerations with a very comfortable range of between 400 and 500 kilometres realistically. It does raise a few eyebrows, though.

Weight: enemy number one

For starters, it puts nearly 2 tonnes on the scale – which is 160kg more than the 45kWh Pure version This heavy weight compromises both performance and efficiency. The numbers speak for themselves: equally powered (150 kW) the 58kWh model is faster than the 77kWh one wile consuming 15.4kWh/100 km rather than 15.9kWh/100 km (WLTP).

Even though the conditions were not entirely similar, we averaged 18.4kWh with the 77kWh ID.3 and 16.0kWh with the 58kWh model. Even if you start from a difference of 2kWh/100km, 100,000 km driven will result in a electricity cost disadvantage of between €500 and €1,000, depending on the price of the kWh you charge.

And there is another cost factor: tyres and brake pads. The heavier the vehicle, the faster they wear. Especially the front wheels are put under more pressure – literally – because the vehicle weight is shifted forward every time you brake. It might mean the difference between having to provide an extra pair of tyres and brake pads and saving these costs.

Charging time

Another thing to consider is the charging time, which increases with the number of kWh in your battery. If you go for the big-battery model, you will have to wait longer for a top-up than with the medium or small battery. It might be a matter of just a few minutes at a DC fast charger, but a matter of many hours if you use single-phase AC.

This drawback could be offset by the fact that you have to charge less frequently with the big battery. It is something every driver should work out for themselves, considering charging access and personal driving profile. In any case, if you are a motorway driver covers 300 to 400 kilometres per day, the question is whether a BEV is the best option to start with.

BEVs are very thirsty on motorways – in the case of the ID3 Pro S, you will find it hard to consume less than 22 kWh/100 with the cruise control set at 120 km/h. Arguably, long-distance drivers are better of with a diesel plug-in hybrid, which enables them to travel efficiently on the motorway while entering the city centre emission-free.

Raw materials

Last but not least, the bigger the battery, the greater the amount of critical earth materials, such as lithium, nickel, manganese and cobalt. Mining these materials has an impact on the environment and possibly on the health of those working in the extraction industry.

The question we should ask ourselves, is whether we want to put an extra strain on the planet and people’s health for the sake of our own driving comfort. Also, the more material goes in one battery, the less will be available for others, putting a brake on the electrification momentum.

Top tips

If range is an issue, there are still ways to make BEV driving work even with a 250-300km range in real life – which most medium-sized battery models will give you. Here are our top tips:

  1. Plan your trips and decide beforehand where you want/need to charge.
  2. If you do need to travel long distance, consider public transport or renting an ICE vehicle.
  3. Make sure you have a DC fast charging subscription with preferential rates to keep fast charging affordable.
  4. Always use the sat nav of the vehicle. It increases range by proactively recovering energy.
  5. Always pre-climatise your BEV while it is charging. This way, you don’t waste energy from your battery to cool or heat your car.

Finally, it is highly recommendable to profile your drivers before ordering a BEV. You will find that in most cases, the small or medium-sized battery model provides sufficient range. There are tools out there to make life easier for you, such as telematics. Connectivity can also help you determine where to provide charging infrastructure for your vehicles – and which type.

Picture copyright: VW, 2021

 

   

Authored by: Dieter Quartier