Is a 3-phase electric vehicle charger at home really necessary? | The Driven
three phase charging evse
Source: AEVA/Christopher Walkden

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I hope you can help with this. It follows on from a comment you made to another reader re his new build. In that case he was in the country and was intending to install three phase power.

You made a reference to three phase power probably not being needed in the city, given that fast charging stations would be around (if I read you correctly). I am doing a new build at Shoreham on the Westernport Bay side of the Mornington Peninsula. It is not way out in the country but it is not in the city either. No charging stations are nearby (to my knowledge).

We will almost certainly get an EV in the next year or two, so we want to make sure we are ready for charging facility. Should we make sure that the house is ready with three phase power to the property? Or will we be OK with single phase power, as our electrician is suggesting? Do you have a view about the relative costs of installing 3 phase now compared to single phase and 3 phase at a later stage?


Hi Mark – it is an interesting question as to whether 3 phase power is really needed for charging EVs as EVs (and EV charging systems) are evolving rapidly towards longer ranges and flexible, simplified charge management. I’ll therefore do an update on my last answer based on these changes.

As an example of the evolution of the EVs themselves, my new Hyundai Kona electric (a full battery electric vehicle, or ‘BEV’) on a single phase 32A (7kW) EVSE (Electric Vehicle Supply Equipment: <see FAQs here>) will be fully charged and ready to go in around 9 hours.

And I charge it only once every week or two, based on doing 200 – 400km a week.

On the other hand, my old Leaf took 4.5hrs at 3.6kW (its fastest possible charge rate) and needed charging 3 – 4 times a week. Plus, because of its short range, I needed to find time to charge it during the day between trips occasionally. (As well as take my ICE car for trips over 90km return L ).

And I should point out, the Kona electric (like many EV models currently on the market) does not have a three phase charging system, so it simply cannot get a faster AC charge on three phase.

A few EVs do charge using three phase (notably the Renault Zoe that does up to 22kW AC charging and is capable of a full charge in under three hours), but currently the Kona is typical of most EV brands in not charging above 7kW single phase. (See table 1 below).

Table 1: List of new BEVs in Australia and their charging rates

Approximate AC EVSE charging rate, in hours
  1 phase 3 phase  
EV model Battery size 7kW 11kW 22kW EV range in km (Real-world1)
Hyundai Ioniq 28 4.5 N/A N/A 200
Renault Kangoo ZE 33 6 N/A N/A 2002
Nissan Leaf 40 7.5 N/A N/A 240
Renault Zoe 41 7.5 4 2.75 3002
BMW i3 120Ah 42 9.75 4 N/A 246
Tesla M3 Std. Range 50 8.5 5.5 N/A 354
Hyundai Kona electric 64 9 N/A N/A 420
Tesla M3 Long Range 75 12 8 N/A 523
Jaguar I-Pace 90 13 N/A N/A 375
Tesla Models S and X 100 14.5 9 N/A S: 540; X: 460

Notes to table:

1: Real-world figures given are US EPA range ratings (give closest to achievable ranges in Australian conditions).

2: Manufacturer ‘real-world’ range ratings used as Renault do not sell into the US market.

As you can see, all but the Jaguar I-Pace and the Tesla Models S and X will fully charge overnight on single phase 7kW charging, but the Jag does not do more than 7kW AC charging to be able to do any better. Even for the Tesla S and X, on single phase both will still be close to a full charge on overnight charging at 7kW.

Therefore, unless you fully flatten the battery every day in these last three, all BEVs currently on the Australian market will be fully charged by the time you are finished breakfast and unplug/take-off in the morning.

So for a single EV household, you would have to be an extreme outlier on the vehicle usage curve to justify installing 3 phase power to charge it, even if it could take advantage of it. Installing it as ‘future proofing’ for vehicles coming later that can utilise 11 or 22kW charging would still not be justifiable for the average vehicle user.

HOWEVER: EVs will eventually replace all ICE vehicles, so what happens when households replace the second (or even third) ICE car with electric if only one can get a full-charge overnight? Will homes need to plan ahead and set up EV charging rosters? Or will EV owners have to set alarms to get out of bed at 2am to swap the lead over???

There are already multiple answers to those questions that will not need three phase power connected to run multiple EVSEs. One option is to get a multi-lead EVSE that shares the 7kW if two EVs are charging, so if one was close to charged and finishes early, the full 7kW goes to the second EV once the first finishes.

In addition, most new EVs offer a ‘maximum charge level’ setting – so the household EVs can be set to say 60% or 80% for most usage and if one person wants 100% – their car can be set to that.

You can also buy EVSEs that are able to be programmed to share information between them and be monitored and adjusted from apps – so all charging can be controlled from inside the home. (No midnight runs outside in slippers required J).

Even if your car does not get a full charge by the time you set off in the morning, with the longer ranges offered by modern EVs there is little likelihood of running out for the standard work commute or local runs for shopping and kid shuttling.

Even then, there are increasing options for AC workplace and destination charging. (Destination charging being a grab-all name for AC charging at a destination other than the workplace or home. For example: shopping centres, motels, BnBs etc, etc). All these are the current options.

In the future, there will also be the ability to DC fast-charge along your route if you really want to pay the convenience charge of a high electricity rate for doing so. This last (as yet) is still limited to some of the major intercity routes – but DC chargers are now rolling out at an increasing rate.

The point I am trying to make is that a lack of three phase power is not a barrier to EV ownership – in fact for most people installing it would be an unnecessary expense.

On the plus side for installing three phase power, in a new build it does not cost a lot extra to install over single phase: you might be looking at $1000 – $2000 over the cost of single phase wiring and equipment. (It would be a lot more costly if retrofitting it afterwards).

Also the ongoing metering and supply charges are generally only slightly more than a single phase installation. (By the way: these charges can vary wildly between supply authorities.

You will need to do your homework and check out your local area electricity connection and tariff charges before making the decision to install it).

Also, if you have reasons other than EV charging for wanting 3 phase power (like to run a three phase machine in a workshop, run a large air conditioner or to install a larger, balanced solar PV system), then installing a three phase EVSE is a minimal cost ‘extra’.

To sum up:

  1. For the vast majority of single EV households, installing three phase only for EV charging is not necessary.
  2. Given the larger batteries going into EVs now, even for the majority of future multi-EV households the new crop of load sharing EVSEs, car apps and EVSE phone apps will enable hassle free EV charging without the need to install three phase power. This means installing three phase power as a ‘future proofing’ measure is still unnecessary for most multi-EV household scenarios;
  3. Three phase power IS worth installing where:
  • there are uses for three phase power in the household beyond just EVs,
  • and/or where there are multiple long-range EVs needing full-charges from near empty on a regular basis AND there are no DC fast-chargers within a reasonable driving range or on a regular driving route.

I am sure there are other scenarios where installing a three phase power at home for EV charging is justifiable – what I am saying is it is well worth thinking through the options beforehand as there are getting to be fewer and fewer reasons to do it as vehicle battery sizes increase, home EV charging systems evolve and AC destination charger (as well as DC fast-charger) networks roll out.

If you are still uncertain about what to do – you can also call on an experienced EVSE supply and installation business to do a personalised EV and EVSE assessment and make recommendations based on your needs.

As a final note – if you have three phase power, you do have the (deep pocket) option of installing an 11 or maybe even a 22kW DC fast charger. However 11kW is only 1.5 times 7kW, so the extra cost of the EVSE may not be worth it, and 22kW would likely need an upgrade to your supply cable – so extra cost again!

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