Single-Phase Or Three-Phase EV Charger - Which Is Better?

Is it better to charge an electric car from a regular wall socket, or should you splash out on a dedicated EV charger? And if the latter, is single-phase or 3-phase the better choice? Finn discusses the pros and cons of various electric vehicle charging options.

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[alecdietsch]

I am sorry to be Cassandra, but this is really misleading. It may be fine to suggest that a 32 amp 3 phase outlet will give 22 kW, but the cost of the 3 phase cable and outlet is the least of the costs. Most existing houses, are single phase with a 100 amp fuse limit. To upgrade an existing property, the supply cabling, the switchboard and perhaps the meters to 3 phase is quite expensive, perhaps $2, 000 to $5, 000. In addition, the solar system inverter will need to be 3 phase to balance the output loads. So, it sounds like reasonable advice, but it is likely to be uneconomic for owners of existing single phase houses, which is most of Australia. So, if you are building, or major renovating, and have not yet got an existing single phase inverter on a single phase house, then go 3 phase. For all of the other house/solar owners, 2 x single phase 32 amp outlets capable of 7 kW each will be a cheaper solution than upgrading the house supply and switchboard, and would achieve the same capability. You may even want to consider whether both cars will require concurrent charging at 7 kW rate all the time - otherwise one of the cars could be topped up using the 10 amp outlet, whilst the other is charging at 7 kW. In the odd circumstance when both cars need quick charging, and we are talking post 2028 before we are likely to have two electric cars, then topping up at a public fast charge station, of which there will be many, would work without having the extra higher capacity home outlet.

[campbellkennett]

Oh wow! Just reading the comments, most people seemed to have missed the point. Finn is merely suggesting that if you are going to run a new circuit to supply a 7kW wall box (great idea, btw) on your on your existing single phase supply, then future-proof yourself by running a 3 phase cable (4C+E) from the switchboard to your new installation rather than just a single phase wire (2C+E). IF you eventually have a requirement to charge more than 1 EV (and I strongly suggest that is a future likelihood) then you will likely want more than 1 x 7kW Wallbox or perhaps some other variant of a 3-phase Wallbox, be it 1x7kW, 2x7kW, 3x7kW, 1x22kW, 1x50kW, etc. In the latter case, you will definitely be upgrading your main supply lead-in cable to 3-phase and upgrading your main switchboard and metering. No need to do that just now to install a 7kW box on one phase but for the same installation cost plus a few extra dollars for heavier duty cable you are well advised to future-proof yourself. Nobody wants to wait 30hrs or more to half-charge a car on a 2A granny charger unless she only drives the car to church on a Sunday.

[kelsey_roy]

What about a retrofit to an already existing house? Does all the internal wiring cables behind the dry all need to be ripped out and replaced with 3 phase cables if I want to convert the entire house into 3 phase power?

[fishingphill]

No one has mentioned 2 phase? We have 2 phase here on our home in Australia. That gives us 2 X 80amp main fuses. The Tesla wall charger can be wired for single, two phase or 3 phase. The electrician has look at our set up and said no worries to wire it at 2 phase and doubles the power output 👍🇦🇺

[rockinrobstar]

So I guess the question starts to become - if I am putting solar on and thinking about going EV in future, should people start to consider getting 3 phase first (to remove the 5kW inv/6.6kW panel limits) and for EV 22kW charging in future?

[JustMeTalking]

100% agree. I retro fitted 3 Phase to our UK property and now have three wall chargers.

1 x 7 kW which uses Battery Storage & Solar Array
2 x 22 kW fast chargers which are Grid Tied

One thing you don't mention is charging home battery storage & load balancing during night time cheap rate electricity.

With 3 Phase you can have it all on, powering the house, 2 cars charging, battery storage charging... all at cheap rate

[diogoborges]

hello, what is better for the batteries?
charge 1 phase 7.2kw 32 amp or 3 phase 11 kw 16 amp?
Thanks

[AG-jtwq]

Thanks for that! it was a great HELP!!! Question, should I use a 3 phase pump motor (to pump rain water out of the basement) or should I use a single phase? Thanks in advance!

[jiamingtan]

Would a single-phase EV charger work on a three-phase supply? Specifically looking at the 7.4KW Wallbox's Pulsar Plus with Solar Optimization. TIA!

[Mladjasmilic]

In Serbia, 3 phase is the norm. But we use much less current. Main fuse for my house is 25A x 3, and all other fuses are 16A. My whole house is 17kW.
Yet, local electricians insist that all cable be at least 2 thick as norm:
6mm main 25A cable
2.5mm for sockets (16A)
1.5mm for lights (6A).

In most other countries they use 1.5mm for sockets and 0.75mm for lights.

[toli]

question, do u always need a higher power cable to plug into a wall box that says 22kw output? my car with the old wall box at work i am getting 7kw, now a newer box (seems higher output) same cable i am only getting 3.5kw?

[leehargreaves]

Useful info, thanks!
I have 9Kw of Solar feeding 3-Phase property. The solar inverter puts 33% into each phase, therefore a maximum of 3Kw per phase.
If I bought a 3-Phase car charger that means I could potentially use 9Kw on a sunny day BUT I also want to utilise the Solar for the rest of the property.
Can you "throttle back" the charger to, for example, 6Kw or less perhaps, to leave 3Kw or more to the house?
Despite having 9Kw potentially on tap, most days I'd only need a trickle charge, with the option of a faster charge occasionally.

Cheers for any help from South West France.

[fangitjoe]

Good vid. Needing to charge an EV from 0-100% in one hit at home would be an extremely rare thing. I've never been close to 0% for a start in 2 years of ownership. Also, I wouldn't necessarily go the extra expense of having 3 phase installed for an EV, even if you have 2 of them. As was said, most people will get by on a 10amp plug most of the time. Of course it depends on your individual circumstances, but IMO it would be extremely unlikely that 2 EVs in a household would NEED to charge at 7kW at the same time. With single phase you could have one charging at 7kW and the other on a 10 or 15amp (2.3 - 3.6kW) outlet. Don't forget if you are occasionally in real need of charging really fast you can drive to a nearby fast charger (ok, not always super convenient right now but will be exploding in numbers in the next year or two) and top up much faster - in 20-30 minutes.

[alfredlow]

Does going to 3 phase mean the whole house goes to 3 phase, or is it just the EV charger?

[fredflintstone]

You can't just run a three phase supply from your existing single phase supply can you? Surely you have to have at least a three phase coming from the street to your house, which would entail getting the network supplier involved.

[jtppdt]

There is no such thing as AC Charger. its AC Charging Supply Equipment

[robertnitschke]

You will probably not get 3 phase where you live. It is mostly in Industrial areas. "Solar Quotes" should mention this because you are giving people a false sense of security. Most street electricity is slow charging Single Phase and will cost $ Billions and many years to upgrade!