GregH
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Leaf Number: 26967
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LeafDD - Dash Display for Leaf

Fri Apr 26, 2013 4:54 pm

Thank you to the 140+ folks who over the last year have purchased the LeafDD (Dash Display). This has always been more of a hobby than a business and once the 150 PCBs originally ordered were consumed I decided to put the project to rest. It's been a blast and I hope the LeafDDs out there continue to provide useful information.
What follows is the rest of the original post:

The Dash Display is a small 3.9" x 1.9" x 0.6" blue OLED display (128x32) that connects to the OBD2 port on the Leaf under the dashboard.

The primary page shows Gids (of course) or a precise SOC (xx.xx%) or Gid% (xx.xx% Gid*0.356) or Ah (xx.xx Ah_CAP * SOC).
The primary page also displays real time current in or out of the pack graphically at the top of the display and battery pack voltage as a horizontal marker indicating 332-394V.
The primary page also displays the warmest of the 4 battery pack temperatures in tenths of a degree C or F. A small graph to the right of the battery temperature shows the relative temperatures of all 4 sensors just to give a feel for the relative distribution.

Pressing the button on the right of the OLED display toggles to other pages. A long press of the button brings up configuration stuff like SOC or Gids as primary display and Celsius or Fahrenheit for the temperatures. The LeafDD talks to the EV-CAN bus.

I should also be clear that the LeafDD includes a 5 sided 3D printed enclosure as pictured. The back of the main PCB is exposed although there are no components on it. The top left corner gets toasty due to the 3.3V regulator on the other side of the board. Double sided foam tape should work well to mount it just about anywhere.

Contact me directly at dashdisplay at gmail.com if you have any questions.

-Greg

front view without enclosure
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side view without enclosure
Image

This is the production gray enclosure
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Here's my first draft of a user manual for the Leaf DD.. I'll try to get a quick video going over this up in the next week or so.

The OBD2 connector is right by the drivers knees under the Leaf dashboard. The LeafDD comes with a 6ft right angle cable that points away from the driver. There's enough cable to wrap around the steering column, out of sight, to keep it out of the way. From this point, where and how you mount the LeafDD is up to you. As you can see in the photo I've got mine covering the "Eco tree" which also unfortunately covers the left turn indicator and warning symbols. There is plenty of cable for a variety of other mounting options. The enclosure has tabs on the top so in the future we may make snap on mounts or "shades" for the DD.

Image

The main page defaults to raw Gids and max battery temperature in celsius, but these can be changed.
To the right of the max temperature is a small graph that shows the relative temp of the other (colder) 3 or 4 temperatures. Each dot is -0.2C (or -0.35F)
Above the max temperature is a large dot that indicates the battery voltage. The tick marks indicate 390V, 380V, 370V, 360V, 350V and 340V. When you get down into the 340s you're pretty close to done! At full it should be 394V and at 80% it should be 388V.
Above all of this is the instantaneous current draw (or charge) to the battery. Discharge grows from the left side, charge grows from the right. The photo shows my 2012 charging at 3.3kW.
The raw Gids are usually 275-285 on a full charge with a car in good/new health. The Low battery warning comes on when Gids drops below 50 and Very low battery warning when it drops below 25. At this point you probably want to pay closer attention to the battery voltage..

On the main page pressing the button moves to page 2, or a long press (1 second) puts the LeafDD in setup mode where you can select the format of the "energy" reading as well as select Celsius or Fahrenheit for max temperature.

Press the button for more than 1 second and the Gids number starts to blink. Pressing the button again (short press) cycles to the following:

Image
Precise SOC from the car. This will go up to about 95% on full and down to a few percent on empty, regardless of your battery capacity. Fun to watch and it gives responsive feedback for regen (unlike Gids). Press again for:

Image
Gid%.. This is just the raw Gids multiplied by .356 (99.99 max) for the convenience of those accustomed to the older Gid-meters. New customers are probably better off using raw Gids. Press again for:

Image
Ah.. or rather Amp hour capacity * SOC. This is similar to the SOC but scaled to your battery capacity in Ah so it reacts like SOC but the units are more constant. An Amp hour near the top of charge means a tad more than one near empty because you're at a higher voltage (thus more kW per Amp drawn), but unlike kWh, Ah in and out of the pack are more constant and of course how you drive determines how many kWhs you get for your Ahs. Note this is not a true Ah counter, it's the SOC * Ah Capacity. Press again for Gids.

Another long (1sec+) press of the button makes the max temperature blink. A short press toggles between Celsius and Fahrenheit.
Image
A long press from here gets you back to the normal (non blinking) main screen.

For software version 1.1.4 or newer (units shipped in July 2013) if you see two dots vertically near the bottom center of the main page that indicates an impedance test was done and results are waiting on page 2 (described below). The last line on Page 2 will be temporarily replaced with an impedance reading (mohms) as well as the pack SOC and temperature at the time of the test. This is basically an indication of how much the voltage sags under load (or rises on a DCQC or regen) and thus how much power you have. The Leaf battery has very low impedance with plenty of margin so this not so important as perhaps interesting. A new Leaf might be 50-60mohms whereas a degraded vehicle could be 2x that or more.

A short press takes you to page 2:
Image
This page has all 4 (or 3) temperatures on the left in Celsius.
S is the precise SOC from the car. None of the values on page 2 auto update, you need to hit the button 3 times to scan new data.
C is the cars estimate of your true Ah capacity. A new Leaf should be 66-67Ah.
H is a number in the group 1 data which looks like a Health % number but I'm not really sure. Expect about 100% on a new car. (I did see 111 on a new 2013 with 67.4Ah capacity, but under most other cases it seems to scale to the Ah capacity on most other cars)
Below the H is the voltage of the Leaf's 12V battery actually measured by the LeafDD (not from the CAN bus data)
To the right of the 12V voltage is a number representing the temperature of the Dash Display not really in C or F.. when it gets over 195 the Leaf DD will dim to save power.
In V1.1.x the two numbers on the bottom right are just bytes from the passive CAN data I was interested in.. The first from 0x5fe to tell drive from charge mode and the 2nd is byte 7 from 0x5bf from the 2011/12 on board charger showing power (used to control an additional Brusa charger for those playing with that).
The top right corner has dots showing the version number.. 1.1.1 shown here.

Note if there's a + or - next to one of the 4 temperatures it means my software has incorrectly calculated the exact temperature (at really high or low extremes).
Image
A long press of the button on this page toggles to the raw temperature data from the car.. both in degrees Celsius and the raw A/D readings. If you see a + or - on the regular screen, please forward me the raw info (after a long button press) so that I can make the software more accurate in the future!

Finally one more press of the button takes you to the cell voltages page (page 3)
Image
All 96 voltages are graphed relative to the average cell voltage. On the left side the max, avg and min voltage are displayed. Below that the ID number of the max and min.
In this example the max (3.923V) is cell number 91.. There's a small dot above 84 to highlight it.
In this example the min (3.901V) is cell number 70. A small dot above highlights it.
If there were any active cell balancing going on it would show up as dots on the bottom of the screen below the cells being drained. Sometimes these blink on and off and I don't know what, but other times (after a full charge) you'll see the same pattern come up every time you turn on the car for a while. This photo shows my 2012 at 54% SOC after a full charge and my morning commute. Note the cells being drained are usually the lowest relative voltage.

A long press on the voltages page will set the display (for all pages) to dim mode. The display will be dimmed (ie low power mode) only if A: you select it here, B: the DD gets too hot or C: while charging. When the Leaf is off and not charging, the display turns off. A button press while off will bring it up for a few seconds to see the last data or check the 12V battery.

One more button press to return to the main page. That's it!

Lastly here's a quick 4min intro to the Leaf Dash Display.. (prototype with white enclosure, production units are gray).

Sorry about the flicker in the video, that's an artifact of the iPhone camera, not the display.


New Brusa charger control on V1.2.x LeafDDs:
If the LeafDD detects a Brusa charger on the CAN bus it will ramp it up alongside the 2011/12 OBC and also cut power as soon as you touch the EVSE handle (as does the OBC). The LeafDD calculates additional EVSE ampacity based on the EVSE pilot and supports up to 16A more (via Brusa) from the line on 240V, 14A from the line on 208V or 4A from the line on 120V assuming the EVSE pilot reports sufficient ampacity. If the EVSE reports only 12A @ 120V or 16A @ 240V the LeafDD will not turn on the Brusa. If a Brusa is detected when you plug in the EVSE, the LeafDD switches to page 2 and the 2nd half of the last line (after 12V voltage) is replaced with information specific to the Brusa such as EVSE line voltage and ampacity, OBC DC charge current + Brusa DC charge current, Brusa temp (graphically) and Brusa on/off (as a big white block). If you wish to disable your Brusa, just press the LeafDD button to go back to page 3 or 1 and the Brusa will shut down.
Last edited by GregH on Tue May 06, 2014 5:57 pm, edited 16 times in total.
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Stoaty
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Re: *NEW* Dash Display for Leaf

Fri Apr 26, 2013 5:04 pm

I would like to see the 4 battery temperatures. Looks great, count me as a customer (have a Gid meter, but always like new Gadgets and the price is right).

Also would like the option to display Gids as percentage of 281 rather than raw number.
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TomT
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Re: *NEW* Dash Display for Leaf

Fri Apr 26, 2013 5:45 pm

Does it dim at night?
Will the firmware be upgradeable by the end-user?
I'd like to be able to show at least Gids, battery current in/out, SOC, Kwh capacity, and summed bat temp on one page.
59,991 miles/12 bars/289 Gids/68.54 AHr/101% SOH/101.64% Hx 7May15 w/ new Lizard (barely made the warranty).
71,770 miles/12 bars/256 Gids/59.04 AHr/88% SOH/87.92% Hx 3Mar16 at lease return.

Now driving a 2017 Volt Premier. Model 3 reserved.

GregH
Posts: 851
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Re: *NEW* Dash Display for Leaf

Fri Apr 26, 2013 5:54 pm

TomT wrote:Does it dim at night?
Will the firmware be upgradeable by the end-user?


It's not overly bright at night, but I could add a dim option in SW. I'm not sure if I want to leave it on, dim or off when the car is off.. I've had my larger EDrive Dash display (128x64 amber OLED) on 24/7 and never had a problem with the 12V although I do unplug when I'm away on long trips..
The software will not be user upgradable.. :cry: You'd have to catch me at a Hometown buffet in SoCal or send it back for updating. Hopefully I can get a robust a feature set in place before the first units ship in a month or so. At $80 I'm not making anything on this, I just want to help facilitating getting access to the info out there.
'17 blue Volt Premier w/ACC
'12 SL black Leaf
'11 SL blue Leaf
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TomT
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Re: *NEW* Dash Display for Leaf

Fri Apr 26, 2013 6:02 pm

The only problem with leaving it on when the car is off is that it is something of a beacon for thieves... Dimming is not that big a deal but I would like to see the backlight go off when there is no EV CAN buss activity... I'm sensitive to this as my first Gid Meter (Garys) was stolen from the car. at night.

Firmware updating at HB works for me!

I do appreciate you doing this for the community!

Thanks,
Tom

GregH wrote:
TomT wrote:Does it dim at night?
Will the firmware be upgradeable by the end-user?


It's not overly bright at night, but I could add a dim option in SW. I'm not sure if I want to leave it on, dim or off when the car is off.. I've had my larger EDrive Dash display (128x64 amber OLED) on 24/7 and never had a problem with the 12V although I do unplug when I'm away on long trips..
The software will not be user upgradable.. :cry: You'd have to catch me at a Hometown buffet in SoCal or send it back for updating. Hopefully I can get a robust a feature set in place before the first units ship in a month or so. At $80 I'm not making anything on this, I just want to help facilitating getting access to the info out there.
Last edited by TomT on Fri Apr 26, 2013 8:56 pm, edited 1 time in total.
59,991 miles/12 bars/289 Gids/68.54 AHr/101% SOH/101.64% Hx 7May15 w/ new Lizard (barely made the warranty).
71,770 miles/12 bars/256 Gids/59.04 AHr/88% SOH/87.92% Hx 3Mar16 at lease return.

Now driving a 2017 Volt Premier. Model 3 reserved.

lincomatic
Posts: 312
Joined: Fri Jun 10, 2011 10:01 am
Delivery Date: 06 Apr 2011
Leaf Number: 3819

Re: *NEW* Dash Display for Leaf

Fri Apr 26, 2013 7:05 pm

Awesome work, Gregh!

Maybe you could have it turn off the display when the CAN bus is idle, and then automatically turn it back on when the CAN bus wakes up. When the CAN bus is idle, a button press could wake up the display for some preset time, before blanking again.

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Boomer23
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Re: *NEW* Dash Display for Leaf

Fri Apr 26, 2013 8:13 pm

Very nice, Greg! I'll vote for a GID % display as being very important to lots of folks. It makes it easier to do quick mental calcs of remaining miles at an assumed driving efficiency.
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GregH
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Re: *NEW* Dash Display for Leaf

Fri Apr 26, 2013 9:24 pm

Yeah, I'll probably turn off the display when the CAN bus is idle although I do like glancing at the display in the morning before going to work to see the Gids before powering up.. I guess I can live without that... Maybe just make it so a button tap when the screen is off brings up the last data for a few seconds..
I suppose I could add Gids/2.81 if there is high demand for that although as you may have guessed from some of my other posts I'm somewhat opposed to the whole concept. As an absolute number, Gids by itself works pretty well and there are other, newer indications of relative battery health/capacity in the Group 1 data now so the old practice of comparing Gids on a full charge to 281 is somewhat passe.. But I understand for those who've lived with the early Gid-meters and are accustomed to seeing Gids/2.81.

Here's a rather bad video of the DD in action at night. (Clearly I need a cameraman rather than trying to drive and hold an iphone simultaneously)
You can see the instantaneous current graph as well as the voltage marker move with power and regen.. The little tick marks are (from left to right) 390V, 380V, 370V, 360V, 350V and 340V.

'17 blue Volt Premier w/ACC
'12 SL black Leaf
'11 SL blue Leaf
RAV4-EV 2002-2005
Gen1 & Gen2 EV1 1997-2003
PV 2.4Kw, 10kWh lithium battery SCE TOU-DA

Stoaty
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Posts: 4428
Joined: Fri Jun 18, 2010 9:50 pm
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Re: *NEW* Dash Display for Leaf

Sat Apr 27, 2013 6:46 am

GregH wrote:I suppose I could add Gids/2.81 if there is high demand for that although as you may have guessed from some of my other posts I'm somewhat opposed to the whole concept. As an absolute number, Gids by itself works pretty well and there are other, newer indications of relative battery health/capacity in the Group 1 data now so the old practice of comparing Gids on a full charge to 281 is somewhat passe.. But I understand for those who've lived with the early Gid-meters and are accustomed to seeing Gids/2.81.

The reason to have Gids/2.81 is to scale Gids so they go from 1-100. It's a lot easier to keep track of, especially since with very careful driving (and not too fast) you can drive one mile with 1% Gids. This makes estimating distance to empty pretty easy, and lets you know how much you have to slow down to reach your destination with a certain Gid Percentage remaining. If kwh remaining is displayed, I have to multiply by 5.7 (my miles per kwh average) in my head to get the number of miles I have left on a flat road at a somewhat slower speed.
Lifetime 5.5 m/kWh (Dash) over 57,200 miles / 67 months
Capacity Loss Predicted - 27.4% Actual - 30.1%
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GregH
Posts: 851
Joined: Fri Jul 01, 2011 4:16 pm
Delivery Date: 13 Jun 2011
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Re: *NEW* Dash Display for Leaf

Sat Apr 27, 2013 2:17 pm

Stoaty wrote:
GregH wrote:I suppose I could add Gids/2.81 if there is high demand for that although as you may have guessed from some of my other posts I'm somewhat opposed to the whole concept. As an absolute number, Gids by itself works pretty well and there are other, newer indications of relative battery health/capacity in the Group 1 data now so the old practice of comparing Gids on a full charge to 281 is somewhat passe.. But I understand for those who've lived with the early Gid-meters and are accustomed to seeing Gids/2.81.

The reason to have Gids/2.81 is to scale Gids so they go from 1-100. It's a lot easier to keep track of, especially since with very careful driving (and not too fast) you can drive one mile with 1% Gids. This makes estimating distance to empty pretty easy, and lets you know how much you have to slow down to reach your destination with a certain Gid Percentage remaining. If kwh remaining is displayed, I have to multiply by 5.7 (my miles per kwh average) in my head to get the number of miles I have left on a flat road at a somewhat slower speed.


I understand.. although it's not really 1-100.. for some it's 1-101 and for many it's 1-90 or 1-95... YMMV
All dividing by 2.81 does is provide synthetic precision taking what was a number from 1 to 2xx to a number from 1 to 9xx, but it's not real precision. If you're used to seeing the synthetically (and somewhat arbitrarily) inflated number that's cool.. but having two ways to represent the SAME information causes confusion when some are talking about Gids and others Gid%. It seems to me this could have been avoided long ago...
'17 blue Volt Premier w/ACC
'12 SL black Leaf
'11 SL blue Leaf
RAV4-EV 2002-2005
Gen1 & Gen2 EV1 1997-2003
PV 2.4Kw, 10kWh lithium battery SCE TOU-DA

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