Background

In the UK, mainland Europe and the USA, Tesla supplies the model S with a “Universal Mobile Connector” (UMC). This plugs into the car at one end, has a lump in the middle with some electronic smarts inside, and can accept a variety of different clip-on adaptors at the other end in order to allow it to connect to all manner of different electrical outlets ranging from 1 to 11kW.

Tesla UMC

The Tesla UMC is supplied with the Model S and is a smart looking, Tesla-branded unit which matches the look of the car.

It’s a universal cable with 4 different adaptors available:

  • UK 3 pin (included)
  • Schuko (European) plug [actually available in both “European” and “French” variants covering both polarities of socket]
  • 32A blue single-phase commando (included)
  • 16A red three-phase commando.

The UMC auto-detects which adaptor is connected and sets the current limit appropriately (10A for the UK 3 pin, 13A for EU Shuko, 16 and 32A for the commando adaptors).

It’s 7.5m long, Tesla branded, and has a charge port door opener button built into the Type2 connector.

The UMC can charge a Model S at up to 11kW (from a three phase source), which makes it very capable if you expect to charge at sites where three phase power is available.

Note that while the Tesla UMC appears to be a “standard” Type2 charge cable, when used with the 32A blue commando adaptor it is actually wired in an unconventional way which makes it unsuitable for use with any electric vehicle except a Tesla Model S. If you have multiple electric cars you may find this limitation annoying.

Cost is around £80 for each additional adaptor.

Why might I need another charging cable?

As EV adoption grows the number of professionally installed, purpose-built, EV charging points available at hotels, restaurants, shopping centres etc. is increasing, and the Type2 connector is now the clear winner (at least in Europe). The Model S can accept a Type2 cable directly if you purchase a Type2-Type2 charging cable for use at untethered charge points. For many owners, this will meet all their charging needs, both at home and on the road.

However, many owners want to have a charging cable that gives them the ability to connect to “regular mains outlets” as well as to purpose-built vehicle charging points, so that they can travel further “off the beaten track” and, in particular, so that they can charge overnight and avoid ever having to stop to charge en route, even on long-distance trips.  In the UK this means charging from 3 pin 13A (BS1363) sockets in the homes and garages of friends, relatives, hotels, etc, and possibly also using both single and three phase Commando (IEC 60309) sockets. Even if you don’t ever plan to charge this way, it’s useful to have something in the car in case you find yourself caught short.

A charging cable that allows an EV to be connected to a general-purpose mains outlet is properly called a Portable EVSE (Electric Vehicle Supply Equipment) but also goes by other common names such as “mobile charge cable” and “granny lead”.

Are there other options?

The UMC bundled with the Tesla, coupled with a Type 2 cable will cover the vast majority of cases. However there are a few other options on the market. The most interesting of these is the Juice Booster 1 which enables the use of more sockets than the UMC supports including the ability to draw 22kW from 3-phase 32A red commando sockets.

There are also a couple of alternative 3-pin 10A connectors that may suit particular needs but were of more interest to owners in the UK prior to Tesla starting to bundle the UMC with every new car – these are included here for completeness, however these days there’s little reason why you’d want these in addition to the Tesla UMC.

Juice Booster 1

The Juice Booster 1 is a German third party EVSE, built to provide the ultimate flexibility to EV owners who want to be able to plug in and charge anywhere in Europe, at the fastest speed possible.

It’s the only mobile EVSE on the market that can charge at 22kW if a three phase supply is available and your car is equipped with Dual Chargers.

There are two variants: the first has adaptors for all the common European mains plug standards, and the second has additional adaptors so that even the rare and unusual varieties are covered.

Physically, it is not as elegant as other chargers (it is more bulky). It comes with a 5m cable attached but can be ordered with extension leads.

When you use the Juice Booster you have to configure the appropriate current limit using buttons on the device, before you connect it to the car.  This makes it flexible (for example you can choose to draw 13A through a UK 3 pin plug if you are confident that it is safe to do so) but, on the other hand, if you are not confident in your abilities it’s possible to choose an inappropriate current level and blow fuses and trip breakers, or even to melt cables.

It costs around €1000 with the basic adaptor set (which is already very comprehensive) and around €1400 for the full deluxe set (which adds some really obscure European connectors, and extension leads to help you reach sockets further away).

Mennekes 10A Portable EVSE

Mennekes manufacture a 10A EVSE with a 3 pin UK plug on one end, and a Type2 socket on the other.

It’s 8m long, simple, robust and waterproof, but limited to only 10A maximum charge rate (for safety reasons). There’s a thermal sensor in the 3 pin plug to spot issues before they become dangerous, which makes it basically foolproof.

A high quality product and a great choice if you only want something for emergencies, or to charge at friends’ houses where a 3 pin socket is the best you can expect.

Tesla used to sell this for £370 in the UK but may now have stopped stocking it since the UMC now has a 3 pin adaptor and is bundled with the car.

EVConnectors 10A Portable EVSE

The EVConnectors 10A EVSE is another simple charging cable with a 3 pin UK plug on one end, and a Type2 socket on the other.

It comes in 5 and 8m lengths and is simple, robust and IP44 rated (which makes it splashproof but not something you’d want to leave lying in a puddle of water). Like the Mennekes cable, it has a thermal sensor in the 13A plug.

It’s also limited to a maximum of 10A so is only useful for slow charging at a 3pin plug. A few owners bought these before Tesla started supplying the Mennekes-branded cable: Now that Tesla are supplying this it’s not clear why you’d choose the EVConnectors one (except for the fact that it comes with a nice bag, which the Mennekes one doesn’t!).

Cost is £395 for 5m and £410 for 8m at the time of writing (early 2015).

Conclusions

Everyone is different, and people should think about their own needs/requirements before choosing. You may find you don’t need a mobile charging cable at all.

But in terms of broad guidance:

  • if you only ever want an emergency cable for occasional charging from a 13A UK socket, the Tesla-supplied UMC will have you covered.
  • if you want ultimate flexibility and know that you will have access to 3-phase 32A red commando sockets (and your car has the optional upgraded on-board charger) then the Juice Booster is the most capable