charger

Difference between level 1, 2 and 3 chargers

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A photo of my Nissan Leaf, with the car charging port open and a Type 2 cable plugged in.

This is one of those blog posts where I’d wondered something, looked it up, and am now sharing what I’ve found out. When it comes to charging your electric car, you may hear the terms ‘level 2’ or ‘level 3’ charger being used. They’re not common terms in the UK, but you may encounter them in other countries – especially the US.

Level 1 chargers

A level 1 charger is, essentially, just a standard 3 pin plug like you have at home. Your electric car will probably come with an adaptor cable, with a 3 pin plug on one end, and a Type 2 plug on the other end. There’s usually a chonky box on the cable, known as an EVSE (Electric Vehicle Supply Equipment), that regulates the power flow. Colloquially, these are known as granny chargers.

In the UK, our standard power supply is 240 volts and 13 amps. Going back to GCSE Science, we know that power is the product of voltage and current (amps), so the maximum output is 3.1 kW. An electrician may be able to fit a waterproof external plug socket for you which is rated at 16 amps, upping the maximum power output to 3.8 kW. One of our neighbours had this done for charging their plug-in hybrid as it was cheaper than a dedicated car charger (level 2, as we’ll encounter in a bit).

In the US, the voltage is lower (typically 120 volts) but the current can be as high as 20 amps, depending on how it’s been wired. However, even a 20 amp socket in the US can only output a maximum of 2.4 kW due to the lower voltage.

A level 1 charger is therefore going to charge your car quite slowly – especially if you have a big battery. I have also seen photos of plug sockets that have melted due to continual use for charging electric cars. And it’s (probably) the least efficient; some tests suggest that 25% of the electricity doesn’t make it into your car’s battery and is lost as heat.

Level 2 chargers

Level 2 chargers are the dedicated electric car chargers that you can get fitted at home. In our case, we have a Rolec EVO unit, and this will be fitted to the outside of your house. In the UK, it’ll have a Type 2 connector, and will be capable of much higher current – up to 32 amps. That equates to (almost) 7.7 kW, which is the maximum that you can get on a single-phase electrical supply that is standard in UK homes.

My Rolec charger lets me vary the current, so I can set it below 10 amps if I’m not in a hurry and want to make the most of my solar panels. Level 2 chargers also incorporate EVSE inside them, so the cables just tend to have a standard type 2 plug on each end.

Many public chargers are also level 2 – especially older ones. Some may be connected to a three-phase electrical supply, which triples the power output to 22 kW. You’ll generally find these at places where you can park your car all day.

I personally describe level 2 chargers as ‘medium’ speed, but a full charge at 7 kW will take a long time for larger vehicles. For our Nissan Leaf, a full charge (from 0 to 100%) would take 6 hours and 30 minutes, although that’s partly because it can only accept 6.6 kW from level 1 or 2 chargers.

Level 3 chargers

Level 3 chargers are the rapid and ultra-rapid chargers that can output 40 kW or more – some can do up to 150 kW. Unlike level 1 and 2, these chargers use DC (Direct Current) rather than the standard AC (Alternating Current) that you would get from a standard 3-pin plug. They also use different plugs – CCS2 is the most common, but some cars, like our Nissan Leaf, use a competing standard called CHAdeMO. You’ll also find that these are almost always ‘tethered’ chargers that include their own cable, so you won’t need to plug your own cable in.

I doubt you would be able to get a level 3 charger installed at home, as they’re expensive and would probably need planning permission and authorisation from the electricity distribution network operator (DNO). But increasing numbers of these rapid chargers are available when out and about, and especially at places like motorway service stations where you need to charge quickly whilst en-route somewhere.

How fast your car will charge will again depend on its maximum charging speed. Our Nissan Leaf, when using CHAdeMO, can only accept up to 46 kW. Still, that means a full charge in less than an hour.

DC chargers are also more efficient, in that you’re less likely to lose power as heat than AC chargers. As these chargers are generally the ones you pay a premium for, that’s a good thing as almost all the electricity you pay for will make it into your car’s battery. However, regular use of rapid chargers can degrade the battery more quickly.

Button battery charger

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A photo of a button battery charger with a LIR2450 battery inserted.

Battery chargers are just for AA and AAA batteries, right? Nope – it turns out you can buy rechargeable button batteries (also known as coin batteries) and a charger for them. Today, I’m reviewing this starter kit that I bought from Amazon (sponsored link) which includes a charger and four LIR2450 batteries.

The battery charger can charge two button batteries at a time. A red light shows that the battery is charging; it shows a green light when there’s no battery inserted, or the battery is fully charged. It’s not an intelligent charger, so it won’t tell you if the battery is dead, or give you an idea of progress.

As well as the provided LIR2450 batteries, this battery charger can also charge LIR2032 and LIR2025 batteries if you have these. These batteries should be compatible with any devices that take CR2450, CR2032 and CR2025 batteries, which aren’t rechargeable. It’s quite small, and gets its power via a USB-C cable, which is included. Batteries seem to take around two hours to fully charge.

I’ve got a Zigbee motion sensor that uses a CR2450 battery, and whilst it’s not needed its battery replacing yet, I can ensure that its new batteries are rechargeable. Disposing of batteries properly can be a pain, as they’re not supposed to go in household waste.

The starter pack, that includes the battery charger and four batteries, currently costs £16. Extra packs of four batteries seem to cost around £8 (sponsored link), so the equivalent of £2 each. That’s more expensive than buying the equivalent disposable CR2450 batteries, which can be had for about 50p each, but they should last longer and are better for the environment.

Cohhee Intelligent Battery Charger

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A photo of a Cohhee intelligent battery charger

Today I’m reviewing this Cohhee Intelligent Battery Charger (sponsored link) that I recently bought from Amazon, to recharge my AA and AAA batteries.

This isn’t the first ‘intelligent’ battery charger that I’ve bought – I have an older one, but it could only charge pairs of batteries (not single batteries) and didn’t detect batteries that could no longer charge. This Cohhee battery charger doesn’t have these faults; you can charge single batteries if needed, and mix and match between AA and AAA batteries. And, it’ll tell you if a battery is unable to be charged anymore.

Charging is quite fast – about 5 hours for AA batteries, and two hours for AAA. There’s a screen along the top that shows the charging progress of each battery. It’s relatively compact, and doesn’t need to plugged into a wall socket. Instead, it’s powered by a USB-C cable. It claims to have over-charging and over-heating protection too.

Having used it for a couple of months, I’ve found that the batteries I’ve charged up in it last longer than before. That’s probably because it charges the batteries individually, rather than as pairs, and identified the dud batteries that I could then get rid of.

Its normal retail price is only £9, but it’s on sale for £8 at the time of writing. Batteries not included.

Our journey towards an electric car – part IV

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A photo of a Rolec EVO electric car charger mounted on a Yorkshire stone wall

Time for the fourth post about our journey towards an electric car. Part one, in May, introduced the series, and part two last month answered the questions ‘why’ and ‘why now’. Meanwhile, part three talked about choosing a home electric car charger. Today, I’m going to talk about the charger that we had fitted.

We decided to buy our car charger first, before buying an electric car, so that we would be able to charge it at home from day one. So, back in May, we had a new Rolec EVO charger installed on the outside of our house, by a local electrical firm.

It’s an untethered charger, as the charger is located in quite an exposed place. That means that we can put the cable away when not in use, and it’s at less risk of being stolen. It connects over Wi-Fi and Bluetooth; we chose a Wi-Fi model as it’s (just) in signal range of our router.

Around the charger socket is a ring light, which changes colour based on its status. As there’s no car plugged in, but it’s ready to charge, it’s flashing blue. It’ll turn green once a car is plugged in and charging.

The Rolec EVO app and OCPP

A screenshot of the Rolec Evo charging app on iOS

By default, the Rolec EVO uses its own app, which is fine. Within the app, you can start and stop charging sessions, and select the level of current to charge slower or faster. There are also the ‘Eco’ charging modes, which I’ll explain further down.

You can manage the Wi-Fi network that the charger is connected to (whilst connected via Bluetooth of course) and perform firmware updates – since we had this installed in May, there’s been a couple of updates released.

The Rolec EVO also supports OCPP, and so I could switch it over to a different platform. For older Rolec devices, the default platform is Monta (there’s a guide here) but others are available.

I may well consider switching to Monta, as there’s a Monta integration in HACS for Home Assistant. As yet, the backend for the Rolec EVO app doesn’t appear to have a public API. That means it’s not currently possible to add it to Home Assistant, other smart home platforms, or other electric car charging apps, unless you change to Monta.

Eco modes and schedules

As well as the big chonky electric cable that runs from your charger to your consumer unit (what most people call a fusebox), there’s a smaller cable attached. This connects to a CT clamp, that monitors your household electricity usage. If you put the charger in ‘Eco’ mode, then it’ll adjust the charging rate depending on how much power is being used elsewhere in the home. For example, if your oven is on, it might lower the current.

Eco+ mode is there for solar panel users, and so ensures that charging takes place when the sun is shining. That should save you money over using grid energy.

You can also set a charging schedule. This is helpful if you have an EV electricity tariff, which offers lower energy prices at set times of the day. That way, you can plug your car in, and then it’ll wait until the cheaper times kick in before it starts charging. We’re with Octopus (here’s my referral link), and they have two dedicated EV tariffs. One, ‘Intelligent Octopus Go’ requires you to have a certain model of car and a certain charger. It supports a lot of chargers, including other, older Rolec chargers, but not the newer EVO model that we have. The other, Octopus Go, simply offers cheaper electricity in the early hours of the morning. We’ll need to look into these once our smart meter is working again – you’ll need a working smart meter for both tariffs.

Future-proofing

I’ve mentioned that the Rolec EVO charger supports OCPP, so I can change to a different back-end system or run my own OCPP server. But it looks like it uses an Espressif ESP chip for Wi-Fi and Bluetooth, based on how it presents itself to my router. So it might be possible to put custom firmware on it in future. Having spent a four figure sum getting installed, I don’t think I’ll be looking at this anytime soon, but it should mean I’m in a good place if Rolec were ever to go out of business.

We just need a car now

So that’s the charger that we’ve had installed. Now we just need a car to plug into it. The good news is that we put a deposit down on a new electric car on Saturday, and will be picking it up at the end of the week. I’ll conclude the series once we’ve got it.

Our journey towards an electric car – part III

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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.

Six port car charger review

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A photo of a six port car charger in my car

With us having guests in the car for a long journey, I’ve recently bought a new USB car charger to go in the back of our car. Unlike others that I’ve bought in the past, which offer 2 or 3 USB ports, this offers six.

It’s currently on sale on Amazon for £13 (sponsored link), but I picked mine up cheaper elsewhere. There are two USB-C ports with Power Delivery, and then four USB-A ports. Of these four, there are two standard ports which offer 3 amps, and then a green one and an orange one, which support various proprietary quick charge specifications. I’m already using one of the USB-C ports for my CarPlay unit in the front, on a long cable.

Above the ports is a three digit display, which shows the current voltage coming in to the charger. This should nominally be 12 volts, but as you can see in my photo it’s higher at 14.4 volts. Should it go higher than 14.8, or below 11.6, that would be a cause for concern. The whole thing also glows blue when the engine is on and it has power.

Apparently you can’t use all six ports at once – the maximum is five. However, it’s apparently capable of quite high wattages. Whilst I’ve always known it as a ‘cigarette lighter socket’, the official name is the Automobile auxiliary power outlet, and the maximum current can be as high as 10 Amps. As such, 120 Watts is possible, assuming a 12 volt supply (see, I remember what I learned in GCSE Science). In practice, the maximum power from any one port will be around 60 Watts, but that’s still enough to charge a laptop.

For what it’s worth, I haven’t found any chargers offering more than six ports, so this seems to be the maximum. In the front of our car, we have a much smaller two port USB car charger, with one USB-A and one USB-C port. The location of the auxiliary power outlet, which is right next to the gear stick on the driver’s side, means that I prefer a smaller, low profile charger that doesn’t get in the way. Still, this means we have 3 USB-C and five USB-A ports available in the car.

Our car dates from 2012 and so it only came with one USB-A port built-in – I haven’t included it as it’s a 0.5A port and therefore a bit useless for charging. Also, if I plug my iPhone into it, the car stereo instantly starts playing the first song in my iTunes library, which is ‘Nothing’ by A. More modern cars presumably have many more USB ports, and I can see the cigarette lighter sockets becoming less common. Not least because it’s illegal to smoke cigarettes in a car with children in it in the UK, and barely anyone smokes nowadays anyway.