As the original head lights are what we call “glowing nails”, I decided to replace the bulbs with HID (“xenon”) types last summer at the Zoe drivers meeting. It does entail some cutting in the rubber cap and a small metal clip, but all in all it was rather doable, about 10 minutes work per lamp. I must say it is something I would never want taken away anymore. Visibility is so much better. And the white-blue light fits the Zoe pretty good. Recommended.

Still it wouldn’t be fair not to state the drawbacks.

  • Sometimes one of the HIDs won’t start. It is a rather common problem. I always check the reflection. Switching off for 20 seconds usually solves the problem.
  • HIDs have a start-up time of roughly 30 seconds. As the Zoe has projector lamps with mechanical shutters, flashing during daytime is impossible.

Development of LEDs has been going at a crazy pace. Temperature management seems to have been the most serious issue. A few fellow drivers have installed these types of LEDs and are reporting good results. The fanned out copper mesh wire seems to cool the thing quite effectively. I am not 100% convinced of the longevity but the light is comparable to the HIDs and the two mentioned issues are non-existent.

Edit: Harm Otten posted his experience with two LED headlight systems in his ZOE here (in Dutch but google translate is your friend). Based on that, if I had to do it again, I’d use the ones he installed instead of the HIDs.

BTW, the tail lights are LEDs and integrated in the lamp holder. Braking and Turn-signal are colored traditional bulbs.

We will release a new version today. As usual, a lot of under-the-hood things, especially reducing the footprint of the application and small speed improvements. No major changes, but you can find a detailed change list here but these are the highlights.

  • Several improvements in the consumption graphs screen, including a low pass filter on the real consumption per 100 km line.
  • Small changes in the logging.
  • Added 12 volt reading (several drivers had flat batteries this winter) and the kilometers of the battery (if you had your battery changed) in the technical charging screen.
  • Added an experimental screen with parameters about the battery-clima interaction.

Enjoy!

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

In the Dutch Renault forum, the issue came up that the maximum regenerative power allowed is higher than what CanZE reports as the Max battery charge / regen kW power. Based on a few experiments of my own only, it seems the Zoe will allow double the reported power for regeneration, capped at 40 kW DC of course. After all, it is supposed to be a short burst and the amount of energy, by definition, has already been taken from the battery.

I would appreciate your findings. Just open CanZE on the driving screen and whenever the Max battery charge / regen kW is substantially below 20 kW, try to do a serious regenerative brake (from a high speed works best, i.e. a motorway exit) and see how far the DC Power kW (or if it refreshes too slow, the blue kW in the dash) shows please. Thank you!

Edit: based on my own testing it seems there is indeed a short over-power possible. The rough formula is max_charge_power * 1.65 + 3.5. More testing by Borut suggests this seems sustainable for either roughly 40 seconds, or until the total battery voltage reaches 390 volts (4.06 volts per cell), see the comments.

It should be possible to calculate the max regen power by taking the max_regen_torque (the blue bar in the driving and consumption screen) and multiply that by the wheel speed (in rad/sec). I might implement this in a test screen.

The Zoe has a crawling mode that cannot be disabled (which is unfortunate I think, but I know others differ). It needs a bit of braking to counter this crawling when at a traffic light. When the brake pedal is pressed only a bit, the motor will still push and you’re spoiling a couple of hundred watts in the motor. So, when at a red light, either press the brake a bit firm, or switch the gear to N.

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.