Granny Charger vs Wallbox: Which Do You Need?

A granny charger is a slow 3-pin portable unit for occasional or backup charging at around 2.3kW, while a wallbox is a fixed home charger that delivers up to 7.4kW for daily use. Most EV owners are best served by having both: a wallbox as the everyday workhorse and a granny charger in the boot for when you park somewhere without one. If you drive high miles, a wallbox is close to essential; if you drive little and can charge over long stays, a granny charger alone may be enough. Compare your options with a proper portable EV charger or a dedicated Type 2 lead for your wallbox.

At a glance: granny charger vs wallbox

What is a granny charger?

A granny charger is a portable EV cable that plugs into a normal 3-pin domestic socket at one end and into your car at the other. It draws around 2.3kW, roughly 10A, which is why it is slow, adding only about 8 to 10 miles of range per hour. It needs no installation, so it works anywhere there is a suitable socket. The key safety rule is to plug it directly into a wall socket on its own circuit, never through an extension lead, multi-way adapter or smart plug.

What is a wallbox?

A wallbox is a dedicated EV charger fixed to a wall or post and wired into your home electrics by a qualified installer. Most home units deliver up to 7.4kW on a single-phase supply, adding around 25 to 30 miles of range per hour, so a typical car charges fully overnight with room to spare. Wallboxes often add smart features such as scheduling, tariff integration and app control, which make it easy to charge in a cheap off-peak window.

Which is faster and by how much?

A wallbox is roughly three times faster than a granny charger. At 7.4kW a wallbox adds about 25 to 30 miles per hour, while a 2.3kW granny charger adds only 8 to 10. For a large battery, that is the difference between a full charge overnight and one that spills well into the next day. The gap matters most for high-mileage drivers who need to replace a lot of range each night. For a light user topping up a few miles, the slower speed is often fine.

Do you actually need both?

For most people, yes, and it is the sensible setup. A wallbox handles daily charging quickly and cheaply at home, while a granny charger lives in the boot as a backup for holidays, visiting family or parking somewhere without a charge point. The granny charger is your safety net rather than your main tool. If you cannot install a wallbox, for example in rented or flatted accommodation, a granny charger may be your only option, so plan your charging around longer parked periods.

How do you choose for your situation?

Match the kit to your driving and your parking:

• High mileage with off-street parking: a wallbox is the priority, with a granny charger as backup.
• Low mileage or a plug-in hybrid: a granny charger may be enough on its own.
• No home charging: rely on public charging and keep a granny charger for occasional socket access.
• Frequent travel: keep a granny charger in the car regardless of your home setup.

Your parking situation usually decides more than your car does.

Frequently asked questions

Is a granny charger slower than a wallbox?

Yes, considerably. A granny charger draws around 2.3kW and adds roughly 8 to 10 miles of range per hour, while a 7.4kW wallbox adds around 25 to 30. For a large battery that means a granny charger can take a day or more for a full charge, whereas a wallbox usually finishes overnight.

Can I use a granny charger every day?

You can, provided you plug it directly into a good wall socket on its own circuit and it comfortably replaces your daily miles overnight. For low-mileage drivers this works well. High-mileage drivers may find it cannot keep up, in which case a wallbox is the better everyday choice with the granny charger kept as backup.

Do I need a wallbox if I have a granny charger?

Not always, but most drivers benefit from one. If your daily mileage is low and you can leave the car plugged in for long spells, a granny charger alone may suffice. If you drive a lot or need quick overnight top-ups, a wallbox makes charging faster, cheaper to schedule and less of a daily chore.

Does a wallbox charge cheaper than a granny charger?

The pence per kWh is the same, so the raw energy cost is identical. A wallbox can make charging cheaper in practice because its smart scheduling makes it easy to charge in a low off-peak window. You can also schedule via the car with a granny charger, but wallboxes tend to make it more reliable and automatic.

Can I install a wallbox myself?

No. A wallbox must be installed by a qualified electrician, as it wires into your home electrics and needs the right protection and, often, an isolator. A granny charger needs no installation because it simply plugs into an existing socket. Always use a competent installer for fixed equipment to keep your setup safe and compliant.

Which is better for a plug-in hybrid?

Plug-in hybrids have small batteries, so a granny charger is often perfectly adequate and can fully charge one overnight. A wallbox still adds convenience and speed, but the case for it is weaker than for a full EV with a large battery. Match the choice to how often you charge and how quickly you need the battery topped up.

Is it safe to leave a granny charger plugged in overnight?

Yes, when plugged directly into a sound wall socket on its own circuit and not through an extension lead or adapter. Overnight charging is exactly what these units are designed for. If the plug or socket feels hot, stop and have the socket checked by an electrician before charging again.

The bottom line: think of a wallbox as your daily driver and a granny charger as your reliable backup. To decide what to keep in the boot, read our guide to whether granny chargers are safe and our roundup of the best portable EV chargers in the UK.