Charging – The technical version

So – you want the technical version – you’ve come to the right place.

As per the charging page, we’ll cover the various ways you can charge, but we’ll offer a little more technical information for those that want to know more.

There’s a less-technical version here.

Units – One for every season

Charge Rate: On the main page, I talked about all the chargers in terms of their output in kW.  There is a lot of confusion about charging rates, and Tesla don’t help a lot with this.

Firstly, If your car is set to display your charge in “Distance”, then your car will display your remaining range, rather than a percentage as well as show your charge rate in km/hr:

How many km it displays depends on whether you are set to display “rated” range or not.

In “rated” mode, it will display based on NEDC range of the car, which is mostly meaningless.  In “Typical” mode, it should display something close to your average use.  Either way, talking to other drivers about your charge-rate in km/hr is really ambiguous, and not, in my humble opinion, very useful. One other note – The charging screen also shows the average, rather than instantaneous rate, in “distance” mode while it’s charging.

If you have your settings on “Energy” instead of “Distance”, you will get your instantaneous charge rate in kW, which is much more concrete:

Here, my car is charging at 5kW and is at 80% charge on its way to 90% where I’ve set the charge limit for today.

BUT – it helpfully allows you to set a maximum charging rate in Amps – regardless of the mode you’re in!  So – what does that have do do with anything?  That’s a good question, and is mostly related to standards, and compliance.  Here, I have my charge rate set to 7A (out of a possible 16A as shown), I can convert that to Watts by multiplying it by the voltage – which it helpfully tells us is 248V, so:

7 x 248 = 1736W or 1.7kW

..except it’s not!  If I were on a single-phase charger, that would be true, but in this case, I’m on a 3-phase charger – it indicates 3-phase by putting a little “3” in a circle next to the charging Amps, so more correctly, you need to multiply the Amps by the Voltage and also by the number of phases, so:

7 x 248 x 3 = 5208W or 5.2kW

which is what it’s showing.  I tend to leave my car in “Energy” mode and use the Trip view to compute range for me.

What governs charge rate?

1) How charged your battery is – When you charge, your battery will charge faster when it has less stored charge and slower as it gets full.   This is physics – your battery is charged by applying a voltage higher than the batteries normal voltage causing current to flow into it.  As your battery charges, its voltage rises – as it rises, the difference between the charge voltage and the battery voltage gets smaller, and therefore less current flows.  So, while this starts out being limited by the charging hardware, it eventually is far more influenced by the state of charge.  This “tapering” is most noticable at DC chargers, but also happens on any charger.

2) AC – If you’re charging on AC, which is most places, your charging rate is limited by:

• The size of the onboard charger in your car – this sets a maximum rate-of-charge.  The battery is charged with DC voltage, as described above, so to charge from AC, you need to convert that into high-voltage DC. This is done by an onboard charger in your car – Tesla’s standard charger is a 11kW unit by default, but on older cars, this can be doubled to 22kW by adding a second physical charger, and on newer cars, this can be software updated to 17kW.  Tesla have more recently been including the higher rate at no additional cost.

There are also issues with single and three-phase maximum rate depending on which type of charger you have, but these are becoming less common.

on AC, the charge rate is also limited by

• What you’re plugged into – depending on what you’re plugged into. A domestic power point is 240V/10A, or about 2.4kW – this will take a long time to charge, and really only worth using for overnight stops.  A 3-phase socket (either via a tail or via Type-2 – see below) can supply up to 22kW at 32A, as described above, but you can only achieve this with an older Model S with dual chargers – most Model S’s and all Model X’s top out at 24A/3P, or about 17kW.  Also, as discussed below, the supplied mobile charger can only do 16A/11kW anyway.

3) DC – If you’re charging on DC, which means you’re using a Supercharger, or a ChaDeMo charger, the rate is governed by the charger. Superchargers max out at about 120kW and ChaDeMo chargers at about 50kW.

What cables do you need?

Your Australian Tesla (unless you have a first-generation roadster) has a chargeport with a “Type-2” connector which we share with much of the world – sometimes called a  “Mennekes” connector. This is not the same connector as used in America (or some other markets).

Depending on your car, your chargeport will have either a motorised flap or a manual one, and a single status light like this one, or a set of smaller lights.

Tesla-supplied cables have a button for both opening the flap, and unlocking the charger before removal.  Third-party cables don’t have this button, but you can just push on the flap to open the motorised ones once you’ve unlocked the car (or you can open it from the charging screen in the car).

This single connector is able to connect to single or 3-phase AC from standard sockets or various types of dedicated charger, to a Tesla Supercharger, or to a CHAdeMO standard DC charger with an adapter – see below for more detail.

If you only plan to charge at home, from household plugs and from Superchargers, you don’t need to buy anything, as you get cables for those with your Tesla.  If you plan to travel further afield, or would like to be able to use the full range of charging infrastructure, you may wish to buy some extras.

TOCWA has a set of loan cables if you are planning a trip and want the peace of mind without spending any extra money, or you’d just like to try them out.

Your Tesla comes with two cables:

1) A High-Power Wall Connector (HPWC) – sometimes also called a destination charger.

The HPWC is designed to be permanently installed in your house or workplace. It’s installed by an electrician and depending on your supply, it can deliver up to the maximum rate that your onboard charger can take.  Often, this is limted to around 7-11kW by building wiring as you may only be able to wire up to 32A single-phase, or 16A 3phase.  This is by far the most common way you’re likely to charge.  The one pictured above is installed in an outdoor carport, and they are happy in just about any environment. The HPWC has an internal setting that governs its maximum current draw, and these are often mis-set my installers, so check with your electrician that he has set it to the current that the supply wiring is capable of.  You can install mutiple HPWCs on the same cable, and they can communicate to each other and share the available charge current between multiple vehicles.  The communications protocol has been reverse engineered, and some people are experimenting using it to remotely control the charge rate, for example, to match solar generation output.

Tesla also give these chargers to “destinations” such as hotels and restaurants and these show up on your car’s charging map automatically.  If you would like an additional HPWC for your workplace, they are also available for purchase for $700 from Tesla.

There are a number of options to the HPWC, which have extra features like automatically tracking available power generation.

2) A Universal Mobile Connector (UMC)

This cable is actually a chargepoint that you can carry around.  It allows you to connect to pretty much any power socket and will deliver up to 11kW.  It comes with a standard 10A, 240V plug in Australia, and this will give you 2kW – it’s great for overnight stays where there is no other infrastructure, and will roughly give you 1/3 of your battery back overnight.

The UMC can be fitted with different “ends” – the 10A “tail” is removable and can be replaced with a 3-phase adapter:

Becuase we share our Tesla specifications with Europe, the connector is a standard European 3-Phase one – if you’re in Europe, you can just plug this into the wall, but Australia has a different plug standard, so you need an additional piece or two:

These adapters are simply cables that convert a European 3-phase connector to the two types of common Australian plugs – one will do up to 20A and is a little smaller, one will do up to 32A and is larger.  Remember, though, that your UMC can only do 11kW, so that is a maximum of 16A draw on 3-phase anyway – the two connectors just allow you to plug in to the common sockets you’ll find out there.  AEVA have installed many 32A, 3-phase sockets in regional areas around Australia, as part of their “round-Australia route”, so if you’re touring, these are a must.

This is what it looks like all plugged together. It is also possible to attach a single-phase, 15A plug to one phase of the european 3-phase connector and allow for 16A single-phase charging – it’s a good idea to manually lower your car’s charge rate to below 15A, though.

TOCWA has a set of 3-phase tails that members can borrow.

You can also replace the standard mobile charger with third-party ones that can do more than 11kW.  The JuiceBooster is a common replacement, as it is compact and indestructable, but expensive.

There are other “EVSE”s available commercially, and also some kits that can be built quite cheaply like the OpenEVSE if you have the skills.

There are three other cables you might come across:

CHAdeMO

CHAdeMO is a clever French/Japanese portmanteau that means both “Charge de move” and “(o)cha de mo ikaga desuka” (do you want some tea).  it is also an international standard for DC charging of electric vehicles.  Tesla sell an adapter:

This adapter allows the bulky CHAdeMO connector to interface with the Tesla connector and supports high-speed charging at up to 50kW from dedicated chargers, like the RAC chargers in various locations in the south-west and in Perth and also the charger at the UWA Club.

Tesla sell this adapter for $690. TOCWA has a Tesla-CHAdeMO adapter that members can borrow free of charge.

Type-2

Many chargers, such as the Tesla HPWC and the RAC chargers have a tethered cable with a Type-2 connector that you can use without needing anything else, but in many locations, such as at the Synergy chargers at Home Base, Subiaco, there are chargers with a Type-2 socket.

At these locations, you need a Type-2 to Type-2 cable with you:

TOCWA has two Type-2 to Type-2 cables that members can borrow and we soon hope to have a supply for sale.  You can also buy one from Tesla for $305.

Type-1

In some locations, such as some City of Perth car parks like the Exhibition Centre and Pier St, you will also find older “Type-1” connectors.  These are electrically compatible with “Type-2”, but they only supply single-phase.  You can get an adapter:

The adapter takes the Type-1 tethered plug and adapts it to the Type-2 chargeport.

 

So – What cables do you need?

It really depends on your use.  For most owners, the standard cables from Tesla will be all you ever need – especially once Tesla add more Superchargers.  With the standard cables, you can charge:

• at home
• at Superchargers
• at chargers with tethered Type-2 connectors (such as the RAC ones)
• at any location with a household power socket

If you plan to charge at car parks around Perth, you may well want to get a Type-2 to Type-2 cable, as these are slowly becoming more common, especially as most new EVs coming onto the market also use Type-2 connectors.

There are few sites that still have Type-1 connectors, and they are aften quite slow, so unless you routinely park at the convention centre or Pier St, for example, it’s unlikely you’ll need a Type-1 to Type-2.

If you want to be able to charge at high-speed from the RAC and UWA chargers, you may want to get a CHAdeMO adapter, or you can choose to borrow TOCWA’s one when you go on trips.

If you plan to travel longer distances further out of town, then a set of 3-phase tails are worth investing in – there are many locations that have avalable 3-phase connectors, and the AEVA round-Australia route is mostly made up of these sockets – again, you are welcome to borrow TOCWA’s set when you go on trips.

Please feel free to ask questions via email for more information.