What is an EV smart charger

“Smart” EV charging is a term being bandied about a lot these days – but the three most common questions I get about it are actually more complicated to answer than they first appear. These three seemingly simple questions are:

The reason these questions are deceptively complicated is that EVSE retailers here are rather reluctant to admit that you can’t actually take advantage of the full features of a smart charger yet. Nor are their protocols -yet – that allow them to talk to the Australian grid to do their ‘smarts’.

So first-up, for the purposes of this article I am going to define a truly ‘smart’ charger as one that can talk to the grid/have the grid talk to it in ways that negotiate the best time to charge and at what kW (kilowatt hour) rate that best suits the power production available.

As can be seen in figure 1, smart charging will be of great benefit to minimise the building of additional power supplies as well as soak up excess capacity at windy and/or sunny times.

Figure 1: Benefits of smart EV charging for the grid. Image: Energy Atlas/IEA via Wikipedia

In order to make sense of the types of chargers currently available, I am also going to arbitrarily define two other types of Mode 3 charger here. (For more on Modes of charging, see article here).

1. ‘Dumb’ ones – These simply provided the set kW rate to the car when it is plugged in.

2. ‘Smart-ish’ ones – These are able to sense how much power is being used by the building and adjust the charge rate to keep within a set overall limit for the incoming supply. A variation of smart-ish are ones that can sense the amount of solar output and prioritise that over using grid power.

Some smart-ish ones, by the way, can do both – but they are still smart-ish. Effectively, a ‘smart-ish’ one operates to make changes to charging times and rates behind the meter and the grid has no capacity to influence its operation.

It is worth noting here that some also have either older or proprietary software that prevents them ever being fully ‘smart’ chargers. Others have a more recent, open source version of the charger software that is supposed to be compatible with these units becoming smart chargers down the track.

I have summarised my division of charger types in Table 2 below.

So the question arises: why not avoid all complications and buy ‘smart capable’ chargers now that have all the functionality in the last column and just enable the smart function when we can?

There are three reasons why this isn’t yet feasible (or perhaps not even possible):

Smart chargers are the new, really geeky kid on the block. As they offer premium features they are marketed (and priced) accordingly – at least until they are mandated as the minimum requirement for an installed Mode 3 charger, as is already done in some other markets.

In the case of future smart charger mandates, we may end up with some basic ‘not-so-smart’ smart chargers on the market that don’t offer ‘behind the meter’ local load or solar output sensing … but we’ll have to wait and see on that one!

Our Australian regulators have yet to agree a standard way to achieve this back and forth communication between a car charger and the grid, so even if you had a smart charger installed it wouldn’t do anything than act in a smart-ish way anyway. 2025 is the expected date for this to happen here.

The other detail is that whilst some chargers are sold as ‘smart capable’ (as in they have the right programming language built into their operating system) the way they will talk to the grid here isn’t fully sorted yet. As a result, you might be jumping the gun to buy a smart capable charger with the ‘right’ operating system as it might not include some other yet-to-be-thought-of additional feature when our supply authorities eventually roll out their requirements.

Vehicle to home (V2H) and vehicle to grid (V2G) are features that require either smart-ish or fully smart functionality. V2H requires a special sort of smart-ish unit as it does not require the grid to ‘talk’ to it, but it does need to sense the grid is there if it is do its work to switch-over to the car battery should the grid go off-line.

V2G on the other hand needs really high level smart-charger capability to talk and respond to grid commands as it can deliver power to the grid as well as take from it.

However, when it comes to the CCS2 charge plug fitted to virtually all new battery electric vehicles in Australia, the group that is looking after developing that CCS system is still developing how V2G will work. They are close to finalising this (trial units are already being tested overseas) and the first cars with V2H/G capability will be arriving here soon.

Unfortunately, you still won’t be able to connect a V2H/G charger in your home due to my previous point that the standards are not yet agreed.

Smart charging is a coming ‘thing’ and will shake-up the way we think about and interact with electrical retailers and the grid.

As seen in figure 1 – smart charging is a must to balance the competing demands of grid infrastructure costs, car charging and variable renewable supply. EVs will, in fact, become a net benefit to the evolving renewably supplied grid. However we are not there yet.

True smart charger functionality is not enabled here, nor is the penetration of EVs into the market so high yet as to make dumb chargers charging at ‘dumb’ times an issue. In addition, CCS2 socket V2H/G cars and chargers are not yet available (or allowed to be connected).

Therefore – if wanting to install a charger now, you need to weigh up your needs and whether you may want to upgrade to smart grid managed charging (or even V2G) in the future.

If according to my article on EV mode choice, a standard power outlet is all you need – do so now, but wire it for a future smart Mode 3 charger.

Adding the bigger cable and a couple of data lines now is not a large additional expense when the power cable is being installed. Same for assessing yourself as needing a smart-ish Mode 3 charger with household load and/or solar generation sensing.

Install it now, but at least check if it has the latest, open source operating system so it might only be a simple programming change and data connection to become ‘smart’ instead of buying a whole new unit.

If however you don’t need household load or PV sensing, really want V2H/G capacity in the future but need 3.6kW, 7kW or even 11kW charging now, perhaps chat to your electrician about installing a higher power outlet and buying a higher capacity portable charger that you can also use on holidays etc.

That way you can avoid installing a Mode 3 charger that will become redundant for your needs when fully functional smart chargers are available and approved to be installed here.

Going down that latter path does mean though you personally become the charging ‘smarts’. By this I mean you’ll need to either program the car’s charge timer according to ever-changing peak/off peak times and/or remember to get up late at night to turn it on and/or remember to adjust your charging rate to stay within your solar output on a hot summer afternoon.

(There is a reason why smart chargers with that flexible timing and sensing capacity built into them will eventually become the ‘norm’).

Notes:

Bryce Gaton is an expert on electric vehicles and contributor for The Driven and Renew Economy. He has been working in the EV sector since 2008 and is currently working as EV electrical safety trainer/supervisor for the University of Melbourne. He also provides support for the EV Transition to business, government and the public through his EV Transition consultancy EVchoice.