The battery. The core part of any electric car, and the biggest differentiator from a combustion engine vehicle.
It’s not something you should be scared of, though, or something that’s particularly new.
The battery in your EV, is the same as you’ll find in your laptop or smartphone – just considerably bigger. Lithium-ion batteries power the modern world.
And just like any technology it needs to be looked after correctly so that it performs at its optimum for as long as possible.
To do that, it’s helpful to understand some basics around battery health. Don’t worry, you won’t need a periodic table.
Let’s start with a few basics.
Battery capacity is measured in kilowatt hours (kWh). The bigger the battery, the more miles you’ll get. Of course, if you’ve got an SUV and city car with the same size battery, it’s the lighter car that’ll go further.
As you drive, the battery will deplete and just like your phone, how much you have left is displayed as a percentage. This is known as State of Charge (SoC).
Still with us? Ok, strap yourselves in.
When 100% is not 100%
Within a battery, there are lot of variants that impact performance.
That means that sometimes, even if the battery is charged to 100%, you might not see the range you would expect. One reason could be the State of Health (SoH).
SoH relates to the age of the battery. Just like the battery in your phone, your EV battery will degrade a little over time. It’s a slow process, though. Studies by fleet management companies and experts at GRIDSERVE Technologies, show that after five years, SoH is on average still almost 90%.
That means if you’re leasing an EV, it’s not something you’ll ever need to worry about.
But my electric car is only a few months old so why is my range reduced?
The State of Balance (SoB) could also be another reason that your estimated range is below what you’d expect.
To explain this, we’ll need to delve a little deeper into battery construction. We’ll be brief.
The battery in your electric car is made up of a number of modules. Within each modules are the battery cells – these can total into the thousands.
Think of these like the AA batteries you put in your remote control. As the battery is charged, discharged and recharged, these cells don’t do so equally.
Over time, this means that although you’ll charge to 100%, some cells fill up faster because they have less capacity, while others remain emptier. The knock-on effect is reduced range. It may also occur if the car is left unused for an unusually long time.
Good news is you can rebalance the cells. The best course of action is to keep the car plugged into a Low Power charger (at home or work) for up to 24 hours – even once you hit 100%. This slow, trickle charge will allow the cells to rebalance and boost the range back to the true figure.
Ok, but why is the range and charging power inconsistent day to day?
As we’ve mentioned, battery performance fluctuates based on a number of factors. It’s nothing to worry about.
The current ability of the battery to either receive or deliver power at any given moment is known as State of Power (SoP).
Both the State of Charge and State of Health impact this – for example, if your car is nearly full (i.e. a high SoC), the battery will throttle back charging power to avoid ‘overfilling’ batteries. That’s part of what’s known as the charging curve.
Temperature can also play a part. In colder climates, your battery won’t perform to its maximum. Engineering whizzes work hard on complex battery management systems to minimise the impact of this, so you’ll only really notice in extreme conditions.
Which electric cars have the best batteries?
Battery technology is constantly evolving and two cars of the same make and model may not actually have the same battery pack, which means it’s hard to pinpoint which ones are better or worse.
If you’re leasing a new EV, you’ll never really need to worry anyway, as it’s very unlikely you’ll notice any variations in performance.
As time passes, though, the used electric car market will grow. And it’s at this point you’ll want to understand the health of the battery before you purchase it – the same way you ask for an MOT or service history.
Our experts at GRIDSERVE Technologies are working on exactly this kind of battery history to give you complete confidence when you make the switch.
