SOC-LCD-Meter "LeafCAN" with 2x16 Display by lincomatic

[SierraQ]

Who in their right mind would still be on the freeway at turtle?

Ya, I just used that as an example to make a point. I was actually moving about 35-40mph and was close to a charge station. If someone did reach turtle on the freeway, they would have to coast to a close exit and reach a station within a half mile.

I was on a freeway at turtle! And I was in my right mind! Or should I say my right brain? Had I been in my left brain logic would have told me not to leave the house on such a low charge. In any case the regen from coasting off the freeway was enough to allow me to travel 1.2 miles to home on turtle.

I do not recommend the experience. :mrgreen:

 

[TonyWilliams]

How do you use SOC % to quickly estimate range? I personally find it kind of useless, and usually just use raw SOC to estimate my "comfort factor."

Unlike the useless fuel bars on the GOM, mine are directly tied to SOC, and also are 10x less granular....

I gave an example in my post. But generally, I keep in my head the 60mph figures. I can go 84 miles, 50% means I better be well within 42 miles to get home (obviously, a totally different ballgame with 20-30% reduced batteries). Anyway, that what I prefer, or a really simple mutliplier that I could put in X.X miles per kWh and get a range readout.

As such, I want VLB as my zero point, since I can just use the raw SOC after it hits zero.

Ya, I don't want more adjustments to the data. I'm comfortable with real data.

My wife actually uses it now, and I she no longer incessantly asks me why she sometimes has only 20mi range left w/ 3 fuel bars displayed, though she usually has 34 driving the same way on the same route, because the fuel bar display on the GOM was so %#$ inconsistent.

I don't use the GoM. Solves that problem. Mine is (usually) covered.

Anyway, as I've been saying over and over, the display is customizable, so anyone is free to change it to suit their tastes and strong opinions.

Thanks for all the hard work. Hopefully, I'll be able to figure out how to customize it !!!

:mrgreen:

 

[lincomatic]

Thanks for all the hard work. Hopefully, I'll be able to figure out how to customize it !!!

:mrgreen:

The older versions are available from the download link on github, including hex files, so you can flash them in w/o Arduino.

https://github.com/lincomatic/LeafCAN/downloads" onclick="window.open(this.href);return false;

In addition, I'd be happy to make a custom firmware to suit your tastes, since you're such a great contributor here.

It's frustrating that I don't have access to the odometer, or I'd do something fancier. Does anyone know how to get the miles/KWh off the CAN bus?

I'm not sure how convenient it would be while driving, but another method would be to allow input of miles/KWh with a rotary encoder, and then calc range from the remaning pack KWh.

 

[Deleted member 1622]

Hi --
I love all the work Lincomatic has done to make this happen, thank you for the innovation. Excuse the ignorance if this has been covered before, but how do the rest of us "non-engineer" types install your creation? If you have a step-by-step like Gary has for his SOC meter, or if you can offer assembly, please let us non-techies know.

Thanks,
Josh

 

[TonyWilliams]

In addition, I'd be happy to make a custom firmware to suit your tastes, since you're such a great contributor here.

I really liked the unit that I used on BC2BC. Give me a call, 858-245-eight217, and we can chat about the details. Or give me a good time to call you.

 

[TomT]

So, I've had a LeafCAN for a few days (thanks, Glenn) and have a few of observations...

I am going to see about adding a dimmer circuit for night since it is pretty bright... A photo transistor and a couple resistors should do it.

I have noted a couple of oddities in the displayed data. I have version 1.3 of the firmware. The percent Gids seems to be about right at higher Gids (an 80% charge with 202 Gids shows 79% Gids which seems correct - though with my battery loss this percentage may be high as well) but as the Gids drop, the Gid percentage seems to be increasingly higher than it should be. 60 Gids, for example, shows about 36% which is well above what the GID percentage should be for that charge level...

Another oddity - though perhaps just I don't comletely understand how it is supposed to work - is the extended fuel bars. At 100% charge it only shows about 10.2 bars rather than closer to 12 or 13... As the SOC drops, it becomes closer and closer to tracking the actual dash fuel bars and is dead on at the point the last bar goes away. Perhaps my battery is more degraded than I thought...

The last oddity - and I suspect this is related to the inherent inaccuracies in the Hall Effect sensor for the battery pack - is that the value shown for the pack Kw in/out always appears to be slightly negative at rest. In other words, when the car is on, but not moving, it shows a slight charge rather than a slight discharge... Anywhere from 0 to minus about 300 watts. The value is somewhat noisy and jumps around a lot but is almost always negative.

Has anyone else observed these phenomenon?

 

[garygid]

60/281 = 21.35 % so it would appear that something is "peculiar".

 

[TomT]

Yeah, I assume it is a math error in my version...

60/281 = 21.35 % so it would appear that something is "peculiar".

 

[GlennD]

After seeing the superb OLED display on the other SOC I purchased the Adafruit one. They say it is not compatible with their backpack and shield.

I instilled to this morning and it looks great! One problem that is really an annoyance is that the lines are reversed. I just have to get used to it I guess.

 

[lincomatic]

That's pretty nice. Is it easy to read in direct sunlight?

Maybe the lines won't be reversed if you use their library: https://github.com/ladyada/Adafruit_CharacterOLED" onclick="window.open(this.href);return false;

Also, I read that the RW pin needs to be hooked up to make it work right?

 

[Barbouri]

That's pretty nice. Is it easy to read in direct sunlight?

Maybe the lines won't be reversed if you use their library: https://github.com/ladyada/Adafruit_CharacterOLED" onclick="window.open(this.href);return false;

Also, I read that the RW pin needs to be hooked up to make it work right?

I designed a LeafCAN board several months ago specifically to interface with the AdaFruit oled display.
I put the build on the back shelve, because I was having problems with compiling the AdaFruit library.
If someone would like to compile a hex file for this board I would be happy to share one of the spare boards.
Greg C.

 

[lincomatic]

Sure, I could give it a go. Which firmware version is it currently running?
Send me a PM with your e-mail address.

 

[GlennD]

I used the display with no modification. The rw pin is grounded and it seems fine. Just for fun I tried it on an Adafruit shield and it put extra vertical bars into the display with my test OpenEVSE driving it. I did not have it hooked up long enough to notice if the lines were reversed there.

The display is quite readable except in direct sunlight. The yellow display would shift to reflective mode when exposed to bright light. In these conditions it is much better than the blue display but the yellow one wins.

The entire SOC draws about 35Ma so it could be left on. I put it into my original unit that had both switched and unswitched power. I would rather have the car dark when parked. There is no backlight to switch off.

 

[Barbouri]

Populated LeafCAN oled board ready for firmware load.

Greg C.

 

[lincomatic]

Nice, did you use hot skillet reflow?

 

[Barbouri]

Nice, did you use hot skillet reflow?

Thanks, Yes I did.
I have done a few of the OpenEVSE RTC display boards with just the surface mount IC's in the past.
This was my first full board using the Presto Liddle Griddle.
I have components arriving this Friday and should be able to finish the other two boards this weekend.

Greg C.

 

[Barbouri]

LeafCAN oled board programmed with updated oled hex file from lincomatic and connected to AdaFruit 2X16 oled display.

First power up with no OBDII cable or 12V supply, just 5v connected to the programming power header.

So far display is operating correctly, and will test with OBDII cable on 2012 Leaf this weekend.

Greg C.

 

[GlennD]

I spent some time playing to get a good compile this morning. I found that you must use ver 1.01. I tried 1.03 and 1.04 with no cigar.

Once I got the stock 1.3 to compile, I subbed Adafruit_CharacterOLED for liquid crystal and added a RW pin. It now compiled with no errors. The display now reads normally without the lines reversed.

 

[JeremyW]

Is there any update for the original leafCAN w/o OLED display? I'd like to simplify the screen to just percent gids (or the new soc value, whichever is more accurate), pack voltage, and (some day) pack temp. I also have the RGB version of the display, and would like to change the color vs the amount of power drawn (or regenerated). This adafuit fruit tutorial has some info on how to do PWM to make various colors: http://learn.adafruit.com/character-lcds/rgb-backlit-lcds

How would I go about uploading new firmware? What programmer do I need to buy?

I'm also going to design my own little case for this guy out of porcelain.

 

[Barbouri]

Connected the LeafCAN display with the oled hex file from lincomatic to the Leaf today. Everything is working great!
I will get it mounted a bit more securely and take it for a spin this afternoon.
Eagle CAD 6.2 files are available for those wanting to print your own boards.

Greg C.