Why is my EV Taking So Long to Charge?

If your EV is taking more time to charge than it used to, then a common question to ask is why is my EV taking so long to charge? In this article, we will investigate common problems that can cause an EV to charge slower than normal.  

We will also look into the factors that contribute to EV charging times, including battery size, charging station power output, and the vehicle’s onboard charging system settings. 

By the end of this article, you’ll have an insight into how to fix common EV charging problems and how to optimise your EV charging.

Tesla model S charging at a public supermarket charger

Why is my EV taking so long to charge?

Here’s a quick look at the most common reasons your EV is taking so long to charge:

  • Large battery capacity
    Larger batteries take longer to charge

  • Low charging power
    Low-power chargers increase charging time

  • State of charge
    Near-empty batteries take longer to charge

  • Battery temperature
    Extreme temperatures affect charging efficiency

  • Damaged charging cables
    this could interrupt the connection

  • The wrong charging settings
    Are you restricting the charging power via the settings?

  • Turn off other devices
    Air-con and entertainment systems drain the same battery you are attempting to charge

Let’s explore each of these charging problems in more detail and run through some solutions that might help.

Battery capacity problems when charging EVs

Larger batteries take longer to charge because they have a higher energy storage capacity. As a result, it takes more time to fill them up compared to smaller batteries.

What’s the solution to battery capacity charging problems?

Your EV battery is fixed so there’s little you can do to help the capacity, although you can think about charging your EV more often instead of waiting for the battery to be nearly empty. This way, you can take advantage of faster charging speeds when the battery is at a medium state of charge, reducing how long it takes to charge overall.

Charging power problems when charging EVs

How fast an EV is charged is determined by the power output of the charging station and your EV’s onboard charging system. Slower chargers will take longer to charge a car.

What’s the solution to charging power problems?

You can consider upgrading your home charger to a more powerful unit, you may need to upgrade your electricity supply from single phase to 3 phase in order to facilitate an upgrade. If you are using public chargers try and find fast-charging stations that offer much higher charging speeds, allowing you to recharge your EV more quickly.

Battery temperature problems when charging EVs

Extreme temperatures, particularly cold weather, can negatively impact charging times.

Batteries don’t work so well when they are too cold or too hot. Your electric car may need to spend extra energy warming or cooling the battery before it can be charged efficiently.

EV chargers in a car park in England on a winters day
A cold winters day in the UK will mean an EV uses energy to warm up

What’s the solution to battery temperature problems?

There are a few solutions to consider here:

Precondition the battery
Many EVs offer a battery preconditioning feature, which warms or cools the battery to the right temperature before charging.

Park in a garage
Whenever possible, park your EV in a garage to protect the battery from extreme temperatures. 

Charge during warmer parts of the day
In cold weather, try to charge your EV during the warmer parts of the day, as batteries tend to be more efficient at accepting a charge when they are not extremely cold. You can set this schedule up with your EVs smart charger.

State of charge problems when charging EVs

If a battery is nearly empty it will take longer to charge because most EVs are designed to charge slowly when the state of charge is low and faster when the battery’s state of charge is medium (above 20%) and slow down again as the battery gets closer to being fully charged.

This charging curve helps protect the battery and extend its lifespan but can lead to longer charging times if the battery is almost empty.

What’s the solution to state of charge problems?

Don’t let your EV get below 20% before you start charging it. Top up charge whenever you have an opportunity to take advantage of the faster charging rates when the battery is above 20%. It’s a good habit to get into!

Incorrect charging settings when charging EVs

Most vehicles will have customisable charging settings, which let you adjust the charging rate or set charging timers. If you do not have the EV charging settings set up correctly then your EV might charge slowly. You may be accidentally limiting the charging rate that the vehicle can accept!

What’s the solution to incorrect charging settings problems?

Go back to the car owner’s manual and double-check the available charging settings and options. Ensure that the charging rate is set to the maximum allowed by your vehicle and charging station. Do the same thing for your Smart charger settings.

Also, be sure to check your vehicle’s software is up to date, as manufacturers may release updates that improve charging performance or fix issues related to charging settings.

Damaged charging cable problems when charging EVs

Damaged charging cables can cause an EV to charge slowly as the connections may drop out when charging or the electricity will flow will be reduced due to resistance. Both of these issues will result in the power transfer being disrupted and therefore it will take longer to charge. Also, damaged cables can be a risk to the EVs safety as the risk of fire increases.

What’s the solution to damaged charging cable problems?

Be sure to inspect your cables regularly to look for any signs of fraying or damage.

You can also try and clean the connectors occasionally to make sure there is no dirt or debris that might affect the connection. When you store your cables don’t twist them or bend them more than you need to. If you do notice any sign of a damaged cable then look to replace the cable immediately.

charging cable running over a gravel driveway
Check charging cables regularly and try not to wrap them up too tight when stored

Turn off other devices when charging EVs

Using other electrical systems that draw power from the battery will cause your car to charge slower.

Common systems that should be switched off when charging include:

  • Air conditioning
  • Heating
  • Radio
  • Sat nav

Turn these all off when you are charging your EV to stop energy flowing out of the battery as it charges and speed up the charging time.

Why is my Tesla taking so long to charge?

The reasons for slow charging listed above apply to every electric vehicle, including Teslas.
There are a few Tesla-specific factors that could result in longer charging times:

  1. Long waits at Superchargers 
    Ok, so not really a car-specific issue per say but something to consider if you are thinking about buying a Tesla. Tesla Superchargers can get very busy leading to longer wait times or reduced charging speeds if multiple vehicles are charging simultaneously.

    Tesla may limit the charging power at busy Supercharger stations to accommodate more vehicles and ensure everyone gets a chance to charge.

  2. Tesla software updates
    Sometimes, software updates can affect the charging performance of your Tesla. Make sure that your Tesla software is up to date, as Tesla may release updates that improve charging performance or fix issues related to charging.

  3. Charging settings
    Review your Tesla’s charging settings in the infotainment system to ensure they are set to the maximum allowed by your charging station, or to an appropriate level based on your charging needs.

  4. Tesla preconditioning
    Teslas have a battery preconditioning feature that helps maintain the battery at an optimal temperature for charging. If this feature is not turned on or set up correctly then you might experience slower charging times, especially on a very hot or cold day!

The final word on why your EV might be taking so long to charge

There are a number of reasons why your electric car might be taking a long time to charge:

  • Battery capacity
  • Charging power
  • State of charge
  • Battery temperature
  • Charging cable condition
  • Incorrect charging settings
  • Concurrent use of other high-energy devices

It’s vital to understand these factors and keep on top of them, many of the issues on this list are a quick fix! Regular maintenance and proper charging habits can definitely speed up your EV charging times.

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