The AC charger cables have a resistor between protective earth (PE) and the proximity pin (PP) pin to indicate

  • that the plug is inserted
  • that the plug can therefore be locked (type 2 only)
  • the gauge of the cable, and thus the maximum current

Note that the PP pins are NOT wired through the cable. The most common resistor values and also those of your standard Renault cable are 220 ohms, corresponding to 6 mm2 and 32 amps continuous, and 680 ohm, corresponding to 2.5 mm2 and 20 amps continuous. These are per strand values and the power varies given the number of phases used.

These PP-PE resistors should be installed on both ends of the cable, which I had not realized before. Yesterday I helped a friend changing his home charger from a socket type to a fixed cable type, so that he didn’t have to get the cable from the trunk every evening. The cable came pre-wired with the resistor in the plug, but it didn’t work. Only when we installed a PP-PE resistor in the charger itself, indicating the cable was inserted on that end, the charger started the process. The other side effect is that if you measure the connectivity between the PP pins on your standard Renault cable, you’ll measure a confusing 440 ohms. That’s because both ends are wired to the ground lead with 220 ohm resistors.

1500 Ω resistor – 13A cable
680 Ω resistor – 20A cable
220 Ω resistor – 32A cable
100 Ω resistor – 63A cable

A (former?) Twizy and current Zoe driver in Austria called “AbRiNgOi” had a Twizplay laying around. This is an open source CANbus driven small display, based on Atmel micro controller. Anyone who has ever played with Arduinos knows what I am talking about. The specific controller used is an automotive version of an ATmega with a build in CAN controller.

He reprogrammed the Twizplay using the CANbus information that we gathered and that is available in the source code of CanZE on github. We are very pleased and proud that our hard work is spinning off toward other projects, in the true spirit of Open Source. Link here.

DSC02335

TwizPlay is originally programmed in BASCOM (a non-Free BASIC compiler for the Atmel and 8051 processors), but “AbRiNgOi” decided to do this the proper, but hard way and redo all using Atmel Studio 7 and C++, bringing it much, much closer to the Arduino community.

 

Our strong advice is not to leave the dongle active in the car while you’re away. In essence, it is a not-secure direct access device to the main CANbus of the car, with a default Bluetooth password. I have been able to wake up all the ECU’s from a sleeping Zoe using just the dongle. Things like opening doors are probably pretty hard to do but I wouldn’t consider it wise to believe it is impossible. That is one more reason we like the Konnwei – Maxiscans: they have this little on/off button on the top (unfortunately, they do not seem to go to sleep after half an hour of CANbus silence as the documentation suggests, but alas). At least it is easy to switch it off.

Another side of the question is power usage. I am bringing this up as my Zoe was completely and utterly dead this morning with a flat 12 volt battery. So, I decided to check how power hungry my dongle is: less than 1 mA when off, 40 mA when on with a sleeping CANbus, so that should drain the battery of not more than 1 Ah per day and should not be an issue.

Bottom line: be smart and switch it off. If not, and she’s still there where you left her, no harm done.

PS: It was really odd as the car was connected to the charger (had not charged for one reason or another), but the traction battery was still at least half full. My charging logging email from Renault suggested that she had her last charge in the night from December 30th to 31st. That could be right, as there was virtually no driving last week but last night definitely is strange. I have a suspicion about what happened but before I am sharing that I need to get rid of the error and ensure the 12 volt battery is not a dud.

Update: I had her up and running again after charging the 12 volt battery enough (a few hours on 3A) to wake her up and start charging. Never ever do this with the car connected. Remove the minus lead and, as the car can decide to try to charge the battery even with the contact off, make sure the lead is isolated. My suspicion is that the charger plug was not seated correctly and it tried locking it for a couple of hours with most of the ECU’s awakened by the dashboard computer. After charging there was a message to check the electrical system, but that went away by itself.