Receptacle Roundup XI: Renault Caméléon

…and then, Renault snuck in its “Caméléon” system.  This one came in under the radar because 1) it uses existing plugs and sockets, and 2) Renault originally intended to extend EV range via battery swapping (Better Place™), but ended up with Caméléon instead.

Credit: Mennekes GmbH

Photo Credit: Mennekes GmbH

In Europe, EV groups settled on Mennekes Type 2 (IEC62196-2) with shutter.  It’s their equivalent of the SAE J1772 connector, and also SAE-backed.  It is intended for Level 1 and Level 2 charging (slow and medium), like ours.  The Mennekes has one more pin, for three-phase circuits, more common in Europe.  That lets Renault charge their ZOE at up to 43 kilowatts- i. e., in as little as half an hour.  Yup, one plug does trickle-charging from standard home outlets, medium-speed at dedicated wall boxes, and fast charging at road stops (Level 3).  Fast charging just happens to be AC, instead of other solutions’ DC.

If that sounds like the Tesla Model S connector, it’s no accident.  Both groups, tackling the EV question, came to some similar conclusions.  And yet, Caméléon is the opposite of Tesla’s solution in some ways.  Veeery interesting…

Three-phase AC power is an industrial specification, with higher voltages and currents.  It’s also closer to the output of power plants and the long-distance grid, in both Europe and North America.  For both reasons, industrial sites like to tap this power; homes and offices then downconvert this to the low voltages and currents of their specification.  The difference is that in Europe, the downconversion often happens further downstream, closer to the end users.  Thus, a person looking for high power in Europe is more likely to turn to 3-phase specs.

That’s the “server” end; on the client end, batteries are DC devices, and want DC power.  How do you convert AC, to feed them as quickly as possible, when higher and higher powers become more difficult to convert?  At low and medium speeds, all EV companies use the same solution: a purpose-built charger (mostly an AC-to-DC converter).  Level 1 and 2 are mild enough that the charger is still small and inexpensive, and can fit inside the vehicle- an onboard charger. (One exception is the Mission R motorcycle, which leaves its charger behind; however, you can’t actually buy a Mission yet.)

At Level 3 power, though, the DC converter grows large, and runs hot, needing a big cooling system.  Companies had decided that Level 3 AC/DC converters should be left on the curb, where they can be big and heavy.  However, now you need separate Level 3 boxes along the roads- a complete EV network of these big, heavy, expensive things.  This means a network rollout, and a major infrastructure cost.

In the case of CHAdeMO (the Japanese solution for Level 3), the compatible vehicles have ranges of 75-100 miles, requiring numerous 45-kilowatt AC-to-DC chargers and a massive network.  TEPCO (Tokyo Electric Power Company) simply bit the bullet, and installed well over a thousand in Japan alone.  Despite favorable terrain, climate, and traffic, even this might still be skimpy.  And yet, CHAdeMO has received pushback.  Vendors responded with 25-, 20-, and even 10-kW charger units, which lower the cost but, of course, the speed too.

In the case of Tesla’s Model-S solution, that design has ranges of about 200 miles, going up to 260.  Thus, the chargers (still AC-to-DC) can be much further apart, and far fewer in number- about an order of magnitude fewer sites, for a far larger country.  Tesla, despite being a startup, could tackle this deployment itself.  The guts of the AC/DC converters were also designed to be similar to the in-car Level 2 units, to make their deployment scalable and more economical.

Both Tesla and Renault took advantage of a development that CHAdeMO did not.  AC-to-DC conversion uses switches and coils to smooth out the ripples.  Electric vehicles, most of which use AC motor types, already have coils and switches to turn battery DC into AC thrust.  The largest coil, it turns out, is the motor itself.  Thus, a vehicle can feature a gigantic “charger” with little added cost and weight.  The drivetrain just needs to be skillfully designed so that it can also run backwards, charging the pack instead of draining it.  Siemens devised and patented many of the details of this process.

The Siemens technologies are used by Renault; their ZOE then accepts AC at a ferocious 43 kilowatts.  (Tesla changed just enough details to avoid paying Siemens; it’s still enough to build a 10 kW onboard AC charger, or optionally two parallel units inside.)  The fact that the power comes in three phases, over three lines, doesn’t hurt.  Once the car can accept grid AC at these levels, the curbside unit no longer needs complex, heavy converters.  A Caméléon unit, then, is closer to a simple plug and socket.

Renault claims the Caméléon will cost a fourth of its CHAdeMO equivalent.  With this lower cost, network rollout should be faster and easier.  Renault is cracking the chicken-and-egg problem by installing the first thousand itself, to include dozens in the UK.  Italy is convinced, and Caméléons will be on its highways.  (Of course, the unit itself is only part of the site cost.  Caméléons will still total less than CHAdeMOs, but not down to one fourth.)

A similar system will be used by Smart, for Euro (but not US) versions of their ForTwo EV.  However, as a smaller car with a smaller pack, 22 kW is plenty of juice.  The ForTwo will use the same plug, but an onboard charger from BRUSA instead of Siemens.  I presume a 43-kW Caméléon site will throttle down to also handle a Smart; Renault ZOEs will definitely accept 22-kW sites, which are already in deployment.

And away we go: a network with an attractive rollout plan, supported by some big names (Smart is owned by Mercedes).  Two cars from two manufacturers will immediately use these units, but that doesn’t matter.  Every European EV can handle the Mennekes plug in some way or another, so each Caméléon site also happens to be a Leaf, iMiEV/C-Zero/iOn, Volt/Ampera, etc. site- just at low levels.  That implies that CHAdeMO and, later, Tesla drivers will at various times find themselves supporting Caméléon, by patronizing the ZOE-enabling infrastructure and suppliers.  Delicious!  The name “Zoe” means “life” in Greek; this girl is not only alive and kicking, but veeery clever!

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4 thoughts on “Receptacle Roundup XI: Renault Caméléon

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