Author: Jeroen Meijer

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You will not find many obvious changes this week’s release. We’ve taken a small step back from the rather crazy development cycle and the rest of our efforts have been focussed on fixing issues.

It seems we’ve been pushing the ELM a bit too hard; CanZE appears to freeze now and then, though it is usually the communication between the CanZE and the ELM. Please know it has our full attention, but it’s a hard one to crack as it’s really a bit of a random issue. We believe we’ve made some improvements though. Keep us updated (through github please!) and send us your logs please as it helps is pinning down what’s going on.

We’ve split the “Experimental” section into “Experimental” and “Technical”. Technical contains screens that should work, but are for the users that want to dig a bit deeper. At the same time, we’re cleaning up the “Main” activities to only display the information that matters most.

The Cell Voltages Heatmap has a new function that you should actually never see: if a cell turns bright red, it means it has a serious problem. The algorithm used is borrowed from Nissan: If the delta between the mean and lowest cell voltage is greater than then 1.5 times the delta between the mean and the highest cell voltage, it is considered bad. This check is only valid (and will only be performed) if the pack’s SOC is roughly 25% or lower.

EDIT: I was not aware that the Leaf uses a different chemistry for the battery than the Zoe. The red cell algorithm used may, or may not be valid. Don’t rely on it.

Here is a (faked) example

Screenshot_2015-11-15-23-18-41 (1)

Have a great remainder of your weekend!

Last weeks release was not very stable with respect to the Bluetooth connection. A lot has been done to improve that, but if you have still have problems, please switch on “log to sdcard” in the new setting screen, so we might find some more remedies with the extra logs.

The Consumption screen has changed a lot and we hope you like it!

We removed a lot of overly technical information for the charging and braking screens based on feedback we got. Things are simpler now and more focussed on the things that matter. The old charging screen is still available in the experimental screen and we’re contemplating creating a third menu screen called “Technical” for the more detailed information.

As always, we appreciate your feedback. Enjoy!

This week we have above and under the hood developments for you.

We’ve added two heat-maps, giving a quick overview of your battery temperatures and voltages. Those will give you immediate insight in the overall stability of your battery pack: the colors indicate the deviation of the mean temperature / voltage.

Data for graphs is now retained much longer so your graphs will simply continue once you restart them.

Then there are some graphical updates, a bit better handling of different screen sizes. Also we’ve become a bit more aware of potential licensing issues so you might notice some different wording, removal of copyrighted graphics, stuff like that.

Of course there has been the usual bug fixing but we’ve also improved on the differences between the Zoe, Fluence and Kangoo.

Under the hood significant changes going are on. We’re constantly optimizing speed and memory usage and there are a lot of technical changes that you will notice above the hood too. One notable change is the ability to differentiate better between slow changing parameters, such as temperatures, and fast changing ones, such as speed. This way we can optimize display speed for the fast changing ones.

Also, there is now a setting to let CanZE continue to run in the background instead of closing or pausing. Note that this will use significantly more power on the device.

These enhancements create even more possibilities that we will announce and implement later.

DTC readout is already working for a few ECU’s, you can try in the experimental section (at your own risk!). It certainly works for the TCU (Telematics) and the CLUSTER (instrument panel).

We get a lot of questions about the braking system. Here is how it really works.

Zoe braking system

  • Coasting without braking is not a braking function and is performed entirely by the EVC (the motor management computer);
  • As the driver starts pushing the brake pedal, the requested torque is computed by the UBP (braking computer) based on main cylinder pressure and pedal position. This requested torque is passed to the ESC (the ABS computer that controls the oil valves to the friction brakes);
  • The EVC permanently sends messages to the UBP stating the maximum torque of the motor. This is determined by gear, SOC and temperature;
  • The UPB requests the EVC to apply braking torque. In principle this is the same as the driver requested torque, up until the maximum the motor can deliver;
  • The EVC sends the truly applied torque to the ESC. The ESC computes the difference and applies friction braking for any difference.

Note that if you put the car in N, no motor braking is possible and the ESC will command all braking through the friction brakes.

In normal operation this means braking is almost entirely regenerative, with the following exceptions:

  • very fast braking: the hydraulic system is faster than the electrical system (see below for some more details);
  • very powerful braking: the hydraulic brakes are more capable than the electrical system;
  • related to the above: if fast, powerful braking is applied, it’s hydraulics all the way as the car might want to apply any form of EPS which requires individual control of all 4 wheels;
  • when the electrical system cannot apply the requested torque (max charging power reached, you can see this in the driving and braking screen);
  • at very low speeds, when the motor simply cannot brake.

Here is a revealing graph: yellow (hard to see, hidden under purple and red) lineĀ  is the driver requested torque. The blue line is the regenerative torque and you can see the hydraulic system (red line) compensating for any difference. Note that the final cut over is at a very low energy state (roughly last half second before full stop, 10% of the time, 1% of the energy).

brake

*) Other than this graph shows, when serious braking is applied very fast (3rd bullet above), and therefore, the hydraulics kick in immediately and substantially, they are not released anymore and replaced by motor torque. So, for economical, max regen braking, it is better to not only push the braking pedal not too deep, but do do it gently too.

ps: look here for a description of the computers in the Zoe.

pps: there is a ton of information in this document on scribd.

ppps: Here is some more info on braking.

We have some exciting news this week.

CanZE is now available in the Google Play Store. Once installed that way, updates will come to you a tiny bit slower, but fully automated. We will maintain a weekly release schedule as long as features are changed or added as frequently as they are now. When we’re confident that the updates in the Play Store come through fast enough, we might close the download page here.

We were able to shed a lot of code that was no longer necessary, meaning easier to maintain, and less error prone. We hope to have added again a bit of stability.

Also, we have gained a lot of information about the Zoe this week, straight from Renault. Consequently, we also now know that a few things in CanZE are simply wrong. Friction braking is far smarter in the car than we anticipated, and that code needs to be rewritten. The information came in too late to make to this weeks release, just know that the friction braking bars are not correct for now JUST made it in time for today’s release.

Also, the firmware screen was unfortunately picking up a wrong field. This has been corrected, but of course we need to work on reference versions again based on your input. Please do report newer versions if you see them in your car.

Today I have spoken with a Renault specialist and to make a long story short: my definition of friction braking is WRONG. In normal operation, the brake system is entirely “fly by wire” and does not perform friction braking as CanZE reports. I will fix this, but I doubt it will make this weekend-release. Long story short, Zoe uses far more motor braking than anticipated. To be continued.

The weekly build we have coming up for you is mostly one of serious un-cluttering. We have moved allĀ  experimental and playground stuff out of the way and to a new screen. This can be accessed through the “three dots” menu, just next to the settings. Developers now have each have their own playground. Go there at your own risk!

A very nice enhancement is that time-plots are now saved, so their data is not lost when switching screens.

The driving screen now displays a real time kWh/km. I’ve been running this for a few drives and I’d say it is more pressing than the raw kW in the dash. Quite the eye opener!

For the UK drivers, there is now a “Miles” tick in the settings screen, and it already works for the text based screens.

Maybe somewhat boring but still worthy news is that we have significantly stabilized and speed up ELM again. And as we’re getting more confident about CanZE restoring order when things go wrong, there is now an option in the setting screen to change the log level, enabling you to get rid of those blasted warnings popping up. For the daring, builder people, the Due based hardware is getting more integrated too and is VERY responsive. See Bob’s blog post below this one.

We discovered that Firmware versions can be dependant on the hardware version of certain components. We’re not ready to take up that challenge for several reasons. Just know that the dealer might be right if he tells you that really no, there is no update for your car while CanZE says there is.

Enjoy and stay tuned!

We have exciting features in this weekly release. Most are a bit under the hood, but you will notice them anyway.

ELM327 stability has improved a bit and it is a little bit faster too. As I mentioned last week, we’re shaving and modifying there in tiny steps. It might be a tad more talkative when things go wrong.

Behaviour when CanZE goes out of focus has improved a lot we believe. In essence, CanZE is paused and communication with the ELM or other device is stopped.

A few timed graphs have been added on request, i.e. state of charge over time.

The driving screen now has a function where you can add the distance to destination, and CanZE will update you on the expected distance available in the battery on arrival. You can also choose to double the distance to destination when planning for a round trip. Just tap the “distance to destination” line to get a pop-up.

A feature that we really like is that the last values that were requested from the car are now retained so you can open all the screens even when not connected and they are showing real information.

Stay tuned and don’t forget to report issues, or requests on gitub.

Stay tuned

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