Time for part three of my series of posts about our journey towards buying an electric car. Part one, in May, introduced the series, and part two earlier this month answered the questions ‘why’ and ‘why now’.
Today, I’m going to focus more on point one from my ‘why’ post – being able to charge a car at home.
Granny chargers
When you buy an electric car, it’ll probably come with what is colloquially known as a ‘granny charger‘. This allows you to charge your car from a standard 3-pin socket, and gets its name for when you’re visiting your grandma’s house – the implication being that she doesn’t have a proper electric car charge at her house.
Granny chargers are okay to use occasionally when there’s no better option, but there are good reasons not to use them regularly:
- The maximum power output is about 2.3 kW, which means your car will charge very slowly.
- They must be plugged directly into a wall socket without using an extension lead, which may be awkward if you don’t have a plug within reach of your car. You may also need to have a window open to get the cable outside.
- I’ve seen photos of plug sockets that have melted due to continual use with a granny charger.
Waterproof outdoor 3 pin sockets
You can alleviate some of these issues by having a waterproof outdoor 3 pin plug socket installed, which you can also then use for powering lawnmowers, for example. If installed correctly, and in the right place, there shouldn’t be any risks of melting/fire or the cables not being long enough. Indeed, my neighbour has chosen to go down this route for their hybrid car. Make sure that you get the socket professionally installed, of course.
However, this solution doesn’t alleviate the first issue, which is the slow charging. If you’re going to regularly charge an electric car at home, then you should invest in a dedicated electric car charging socket.
Electric car chargers
If you want to be able to charge your car more quickly and safely, then you’ll need to get an electric car charger socket installed. This is a box fitted to the outside of your home, that has a cable that you can plug into your car to charge it. Where it differs to a 3 pin socket is that it will have its own fuse in your consumer unit (fusebox) and will be rated for much higher energy use – up to around 7 kW. That means your car will charge more than three times faster with a dedicated home charger, than using a 3 pin socket. It’ll still be slower than some of the fast public chargers, but it will be cheaper.
Getting an electric car charger fitted can be quite expensive. When I’ve looked, the cheapest prices have been around £800, with £1000 to £1300 being the typical cost. This includes the cost of the charger unit and installation.
What to look for in an electric car charger
There are a number of different chargers available, from companies like Rolec, Ohme, Myenergi and Hypervolt that you may not have previously heard of. I’m not going to recommend one particular manufacturer, but here are a few points that I considered when choosing one:
Tethered or untethered
Some chargers are ‘tethered’ – in other words, they come with a permanently connected charger cable that you can coil up out of the way when not in use. The advantage of this is that the cable is included in the cost of the charger, and you don’t need to store it somewhere.
Untethered chargers have a socket for you to plug in your own cable, which typically isn’t provided and needs to be purchased at an extra cost. However, this does mean that you can put the cable away securely when not in use – I’ve heard of a couple of instances where tethered cables have been cut and stolen. If your charger will be in a more exposed place, maybe consider an untethered charger.
Wi-Fi or mobile data
Just about all electric car chargers include an app to manage charging. This allows you to monitor the charging process, and authenticate cars that are plugged in. After all, you probably don’t want any random car charging using your electricity that you pay for.
This means that the charger needs to connect to the internet. If your charger will be located some way away from your house, then you may wish to consider one that includes a mobile data SIM to connect to a cloud service. Otherwise, you can have one that connects to your home Wi-Fi network – but make sure that it’ll have a good signal before it’s installed. Some also come with Ethernet, if you have this available and want a physical network connection.
Some chargers also work via Bluetooth, which is fine over a short range, but not the most convenient.
OCPP compliance
I would recommend buying a charger that supports the Open Charge Point Protocol (OCPP). This is a common protocol for communicating between your charger and the cloud API. It’s an open standard, and means that you can potentially connect to different back-end servers if the one provided by your charger’s manufacturer is no longer available. Considering that chargers typically cost a low four figure sum and need to be professionally installed, you don’t want to be in a position where you have to replace a perfectly good charger simply because its manufacturer has gone bust.
You can, if you wish, host your own OCPP server – Home Assistant users can install one from HACS. That way, you’re not at all reliant on a cloud service for managing your charger.
Variable rate charging
I know I bang on about having solar panels, but it’s a key reason why we’re considering an electric car, as it’ll essentially allow us to charge for free at home. However, the maximum output of our solar panels is 4.8 kW, which is less than the maximum output of a typical charger. So ideally, you want one where you can set it to charge more slowly, so that you only use your own solar energy and not additional electricity from the grid that you have to pay for.
Some chargers will also use a CT clamp to measure home energy use and vary the rate of charging to match. If there are lots of high load devices running, such as ovens or electric showers, then the car charger can automatically lower the power draw and charge more slowly.
Chargers for on-street parking
If your house has a drive, where you can park your car away from a public road, then you shouldn’t have any issues getting a charger installed at home. If you don’t, and you park your car on a public road, then you’ll need to check with your local authority regarding their rules. Some may insist on a groove being cut in the pavement to fit the cable in, so that it isn’t a trip hazard. Others will flat out refuse, and insist that you use public charging points.
Companies like Edion will sell you a cable protector for around £50 which should ensure that your cable isn’t a trip hazard, and there are also plenty available from Amazon (sponsored link) too. As someone who is quite passionate about accessibility, I would urge you to consider one of these if you have to lay a cable across a public right of way.
Really useful breakdown – I hadn’t considered the safety concerns around granny chargers or the benefits of OCPP compliance. Makes me realize there’s a lot more to think about than just plugging in. Looking forward to the next part!