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Is A Granny Charger Type 2 All You Need? Home Charging Times & Savings

This article breaks down the charging speeds of granny chargers versus wallboxes, explores electricity costs, and analyses overnight charging capacity. We’ll also explore what constitutes the best granny charger for different user needs, including insights from UK EV drivers who use granny chargers as their primary solution. By the end, you’ll know if a granny charger fits your lifestyle or if an upgrade is worth considering.

What Is a Granny Charger and How Does It Work?

A “granny charger” is the nickname for the standard 3-pin plug cable often included with electric vehicles. Many new electric cars come with a granny charger, often referred to as an ‘in cable control box’ (ICCB). You simply plug it into a domestic socket, much like you would with any household appliance, making it a convenient starting point for EV charging.

Key specs of a granny charger:

  • Power Output: Typically delivers up to 2.3kW.
  • Compatibility: Works with any standard UK 3-pin socket.
  • Ease of Use: No additional hardware installation required.

The Benefits of Using a Granny Charger

  • Cost-effective: No additional investment beyond what’s already included with your EV.
  • Great for light users: Ideal for people with lower mileage needs who can manage slower charging speeds overnight.
  • Portable: The portable charging cable can be easily carried and used wherever there’s a standard wall socket—perfect for trips to visit family or friends.

However, the 2.3kW power output significantly impacts charging times, which brings us to the main question of whether granny chargers are practical for most EV owners.

Granny Chargers vs. Wallboxes: A Speed Comparison

Charging Speeds Explained

The charging speed of your EV depends on several factors:

  1. The charger’s power output (in kW).
  2. The capacity of your EV’s battery (measured in kWh).
  3. The car’s onboard charging system, which determines how quickly it can accept power.

Some chargers offer a delayed charging feature, allowing users to set the charger to start charging in a few hours, providing flexibility in managing charging times.

Using these factors, here’s how long it would take to charge various popular EVs on a granny charger compared to a home wallbox with a 7kW output.

VehicleBattery Size (kWh)Granny Charger (2.3kW)Wallbox (7kW)
Nissan Leaf40 kWh~17 hours~6 hours
Tesla Model 3 Standard54 kWh~24 hours~8 hours
Kia EV677 kWh~33 hours~11 hours
Volkswagen ID.358 kWh~25 hours~9 hours

Takeaway: A granny charger’s slow speed works for light users who can plug their car in overnight, but for frequent drivers or those with larger battery EVs, charging through a wallbox is significantly faster.

Impact of Charging Electric Cars Overnight

Most households have access to cheaper electricity rates for off-peak hours, usually between midnight and 4 am (depending on your energy tariff). Even on a granny charger, these hours are often sufficient to top up enough miles for daily use.

Some chargers come with a delayed charging feature, allowing users to schedule charging to start during off-peak hours, optimizing energy costs.

Example for a Granny Charger User:

Off-peak energy rate (Economy 7): £0.15/kWh.

Miles added overnight (~6.5 hours): ~45 miles for a Nissan Leaf.

Cost per charge: ~£1.80.

For moderate daily commutes or errands, relying on a granny cable can meet daily demand without breaking the bank.

Electricity Costs Per Charge

When comparing charges between a granny charger and a wallbox, it’s essential to consider not just the speed, but also the energy cost. Both deliver the same cost-effectiveness per 

kWh of electricity; however, the difference comes in the amount of electricity delivered within a certain timeframe.

Different types of charging cables can impact the efficiency and cost of charging, with some offering adjustable charging capacity and user-friendly designs.

To simplify this, let’s assume a Tesla Model 3:

  • Granny Charger (2.3kW): Adding ~10% charge in 4.5 hours costs ~£1.20 at off-peak rates.
  • Wallbox (7kW): Adding ~30% charge in the same 4.5-hour time window costs ~£3.60 at off-peak rates.

While it sounds like a granny charger offers cheaper bills, the key difference is the reduced flexibility of being limited to such slow speeds. If you need a quick top-up for a longer trip, a granny charger might leave you waiting all day.

Safety Considerations for EV Granny Chargers

When using an EV granny charger, safety should always be a top priority. Here are some essential safety tips to ensure a secure and efficient charging experience:

  • Check Compatibility: Always verify that your granny charger is compatible with your electric vehicle before plugging it in.
  • Inspect the Socket: Ensure the charger is connected to a suitable and well-maintained socket. Avoid using sockets that appear damaged or worn out.
  • Avoid Extensions: Refrain from using extension leads or adapters, as they can increase the risk of electrical shock or fire.
  • Keep Dry: Make sure the charger and cable are kept away from water and moisture to prevent electrical hazards.
  • Monitor Charging: Never leave the charger unattended while in use. Regularly check the charging process to ensure everything is functioning correctly.
  • Know Your Limits: Be aware of the maximum power output of your granny charger and the capacity of your vehicle’s battery to avoid overcharging.
  • Regular Inspections: Frequently inspect the charger and cable for any signs of damage or wear. Replace them immediately if any issues are found.

By following these safety considerations, you can minimize risks and ensure a safe and efficient charging experience with your EV granny charger.

What Are the Flexibility Benefits?

Flexibility is where wallboxes truly shine. Fast charging means you aren’t reliant on overnight parking to stay charged. For instance, if you unexpectedly need to drive 100 miles after work, a wallbox can provide the additional power required in as little as an hour or two.

Having a portable charger, like a granny charger, provides flexibility for EV owners who may not have immediate access to dedicated charging stations.

To illustrate flexibility in real-world terms, here’s what UK EV drivers using granny chargers have to say:

Testimonial – Josh H., Bristol

“I’ve been using a granny charger since I bought my Kia e-Niro last year. For my 20-mile round-trip commute, it works great. I charge overnight twice a week and haven’t needed a wallbox yet.”

Testimonial – Sarah D., London

“The granny charger worked fine initially when I wasn’t travelling much. But as soon as I started doing weekend trips, it became clear I needed faster charging. Switching to a 7kW wallbox was a game-changer!”

Using a Granny Charger Abroad

Planning to take your electric vehicle on an international adventure? Here’s what you need to know about using your EV granny charger abroad:

  • Check Compatibility: Ensure your granny charger is compatible with the local power outlets and voltage requirements of your destination.
  • Use the Right Adapter: Invest in a travel adapter specifically designed for EV charging. Avoid using standard travel adapters, as they may not handle the power requirements safely.
  • Understand Local Standards: Familiarize yourself with the local electrical safety standards and regulations. Make sure your charger complies with these standards to avoid any legal or safety issues.
  • Research Charging Options: Look into the availability of public charging points and networks in the country you’re visiting. Sometimes, using a dedicated home charger or public charging station might be more convenient.
  • Follow Manufacturer Instructions: Always adhere to the manufacturer’s guidelines for using your charger abroad. Take necessary precautions to prevent electrical shock or damage.

By considering these factors, you can safely and efficiently use your EV granny charger abroad, ensuring a smooth and reliable charging experience wherever your travels take you.

Is a Granny Charger Right for You?

To decide if a granny charger type 2 is sufficient for your charging needs, consider the following scenarios:

Most electric vehicles come with a portable domestic charger, colloquially known as a ‘granny charger.’ This type of charger is essential for EV owners, particularly when access to a dedicated charging point is unavailable, as it allows for charging using a standard household outlet.

  • Yes, it’s enough if…
  • You drive fewer miles daily (e.g., under 30 miles).
  • You have regular access to overnight off-peak charging.
  • You do not regularly rely on fast top-ups for trips.
  • No, you’ll likely need a wallbox if…
  • You drive significant daily mileage (>50-100 miles).
  • You want the convenience of faster charging.
  • You own an EV with a long-range battery (60kWh+).

Alternatives to Consider

Other than wallboxes and granny chargers, public and workplace charging facilities are worth exploring. These can complement your setup by offering fast, on-the-go charging for those occasional long trips or busier-than-usual weeks.

Dedicated home EV chargers offer faster, safer, and more efficient charging options compared to granny chargers.

The Verdict

Granny chargers are a practical and cost-effective solution for light EV users, particularly for charging small to mid-sized batteries overnight. However, for heavy EV drivers or those looking for flexibility and faster charging times, a 7kW wallbox offers clear advantages.

Having a reliable charging solution is crucial for electric cars, especially for those with larger batteries or higher daily mileage.

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