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

[lincomatic]

Thank you all for the wealth of info here and elsewhere. I'm about to pull the trigger and order parts to build my own.

One thing I'm not getting a good handle on is what all information is available from each of the CAN busses? I've seen Gary's VarParmList.csv posted on his site, but, it is not entirely obvious what many of the fields are.

Is there a comprehensive list being maintained anywhere that verbosely describes all of the known canbus data variables/registers available?

Thanks!

~john

Use CAN-Do to decode Gary's recipe file. Just click the See Filters button. You can also use it to enter new recipes and test them out on log files.

 

[lincomatic]

I bought a couple of the black on yellow LCD's on eBay that GlennD is using. They're dirt cheap at $3.58 including shipping, and look pretty good.

Photos and indoor/outdoor comparison here: http://blog.lincomatic.com/?p=809

The black on yellow is a clear winner in direct sunlight. (Photos are of OpenEVSE instead of LeafCAN, because it was easier to set up)

 

[lincomatic]

For those who find the characters hard to read, it's not hard to modify the LeafCAN code to display large digits, instead. Here is an example library: http://www.instructables.com/id/Custom-Large-Font-For-16x2-LCDs/

 

[LEAFfan]

I prefer knowing what I actually have to work with so I prefer 0 equal turtle level which I believe is 4 Gids...

Out of the three warnings, Turtle is the only one that varies. If you are driving slowly, then it's 1.4% (4 Gids), but if you are moving on the freeway, Turtle will come on at 2.4% (6.7 Gids) instead of 1.4%. The others make no difference how fast you are going.

 

[pchilds]

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

 

[GlennD]

To me a large single line display too much. The Hong Kong yellow greenish display is clearly adequate, It goes into reflective mode when the sun is directly behind it. I am pleased with the performance and the price is more than right.

I am considering replacing the display om my portable EVSE.

By the way, the display has an internal 100 ohm current limiting resistor so eliminating yours makes the display much brighter.

My last unit draws 62 MA using its internal dropping resistor and the complete logic assy.

 

[GlennD]

I just uploaded your latest EVSE file using Adafruits Liquid crystal. Now LeafCAN errors on compile. Are you going to make it compatible or do I have to replace the file every time?

 

[lincomatic]

I just uploaded your latest EVSE file using Adafruits Liquid crystal. Now LeafCAN errors on compile. Are you going to make it compatible or do I have to replace the file every time?

Yeah, it's very irritating. I changed the name of Adafruit's library to AdaLiquidDisplay so it doesn't clash anymore.
The problem is that the AT90CAN files don't have a Wire.h.
I'll update OpenEVSE + my modified library soon to fix that.

 

[lincomatic]

ChrisH made a V2 rev of the circuit and built some prototypes. Very nice work. He sent me a board this week (Thanks, Chris!). The components are now all on one side of the board, and the backlight is software-controllable. By leaving the header pins out, we now have a very thin circuit:

Here's a comparison of the cases for V2 and V1:

I've modified the firmware to automatically turn off the backlight 5 seconds after CAN bus activity ceases, and turn it back on when activity resumes.

 

[lincomatic]

I just uploaded your latest EVSE file using Adafruits Liquid crystal. Now LeafCAN errors on compile. Are you going to make it compatible or do I have to replace the file every time?

Yeah, it's very irritating. I changed the name of Adafruit's library to AdaLiquidDisplay so it doesn't clash anymore.
The problem is that the AT90CAN files don't have a Wire.h.
I'll update OpenEVSE + my modified library soon to fix that.

OK, I pushed the OpenEVSE fix to github. restore your original <arduino>/libraries/LiquidCrystal library so that you can compile LeafCAN.
For OpenEVSE compilation, extract my AdaLiquidCrystal.zip to <sketchbook>/libraries/AdaLiquidCrystal.

 

[garygid]

Looks like you are using your Solid Printer to make the case?
Very nice results, indeed.

 

[lincomatic]

Looks like you are using your Solid Printer to make the case?
Very nice results, indeed.

Yes, I designed the case with OpenSCAD, and printed on my DIY printer using 3mm natural ABS filament.

 

[lincomatic]

The new display is much more readable during the day

(note: it's a lot easier to read than appears in the photo) and still nice at night

I'm using a phone cable now, which is thinner, so I can jam it into the crack between the dash & door.
Notice that SOC % is now missing from the display. In its place is fuel level 13 = 281 SOC, 0 = VLB (24).
The single decimal point gives it more resolution than the 12 fuel bars on the dash display - basically shows you how "full" the current bar is.

I've been driving around with it for a couple of days, and it's easier for me to use than the SOC %. Based on my current driving scenario, the miles/bar is anywhere from 5-11. It's easy to just multiply the bars remaining * miles/bar to get a quick estimate of range.

 

[LEAFfan]

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.

 

[garygid]

You should not depend upon Turtle giving you any more
than immediately getting off to the side of the road.

Yes, Turtle MIGHT give you more distance, when driving
slowly on a flat road (or going downhill), but Turtle Mode
does not have a guaranteed amount of usable energy remaining.

 

[TomT]

I have to say that I am not a fan of this change. I much prefer a percentage as that makes it much easier for me to visualize or do math in my head...

Notice that SOC % is now missing from the display. In its place is fuel level 13 = 281 SOC, 0 = VLB (24).

 

[lincomatic]

I have to say that I am not a fan of this change. I much prefer a percentage as that makes it much easier for me to visualize or do math in my head...

Notice that SOC % is now missing from the display. In its place is fuel level 13 = 281 SOC, 0 = VLB (24).

The beauty of Open Source is that you aren't stuck with what I like.
You can just download an old version or change a compile flag or change the code to your tastes.

 

[TonyWilliams]

Ingineer says that 80*GIDs = KWh, and I think TonyW likes 75. Your scale factor is even more conservative. How are you guys calculating "usable" KWh?
Right now, I'm just using Ingineer's number. For the purpose of the SOC meter, accuracy really doesn't matter; the only thing we really need is something that's consistent.

Actually, it does matter for a simple reason. Using 80 units per Gid will provide 22.5 kWh at 281 Gid, but there is NO WAY that you will drive at 4 miles per kWh (from the dash display) multiplied by 22.5 kWh "stored" and travel 90 miles.

You will, however drive 84 miles, or 75 wH per Gid. Using 80 just gives us another exception to compensate for. We get plenty of that from Nissan. I would like somebody to give me a single reason why 80 makes any sense for us as end users? Yes, Nissan publishes that data, and Ingineer disclosed it, and it's nifty neato to know, but I don't find the 80 number very useful.

I also do not wish to imitate dumb information, like trying to display fuel bars. Please make a percentage and Gid count, as previous. When I drove 100.7 miles along the Big Sur coast, I knew when I had 50 miles traveled and showed 50.8% with your previous meter setup, there was a chance I would make it, as opposed to returning.

There is not ANY electricity at all along much of this drive, and I drove it from 9pm to about 3am. Telling me that I had some useless amount of arbitrary bars (13?) probably wouldn't be very intuitive. I can look at the current fuel bars and GoM to get useless info. By the way, the halfway point on the current fuel bars is 5 of 12. Not very intuitive with that either.

 

[GlennD]

While I prefer the old style display, Lincomatic is very accommodating. I just comment out the line I do not want.

I think as an engineer he is making the display too busy but hey, its his program and he can do what he wants! He has made it possible for me and others who prefer the old display to use it.

I have found after using both options The top one is not for me but I like the second line energy use.

 

[lincomatic]

I also do not wish to imitate dumb information, like trying to display fuel bars. Please make a percentage and Gid count, as previous. When I drove 100.7 miles along the Big Sur coast, I knew when I had 50 miles traveled and showed 50.8% with your previous meter setup, there was a chance I would make it, as opposed to returning.

There is not ANY electricity at all along much of this drive, and I drove it from 9pm to about 3am. Telling me that I had some useless amount of arbitrary bars (13?) probably wouldn't be very intuitive. I can look at the current fuel bars and GoM to get useless info. By the way, the halfway point on the current fuel bars is 5 of 12. Not very intuitive with that either.

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, since I display 1 decimal place. I find it to be a very useful quickly estimating range while driving. Say it currently displays 8.1. I just count the mileage for it to hit 7.1, and if it was 10mi, and I know I have 20mi to go on the current road w/ similar terrain, I know I'll burn about 2 bars before I exit. It's easy for me to decide length that I want to use for averaging. I can just count down for .5 bar drop if I want something shorter.

I know that worst case on the freeways that I drive is about 5mi/bar, so if the meter says 7 bars left, I comfortably have ~35mi before VLB at worst case. If it says 7.9, I'll estimate ~40mi for the worst case.

I'm not interested in driving until the battery dies. I just want to feel comfortable that I'll be able to make it home w/o feeling anxious. As such, I want VLB as my zero point, since I can just use the raw SOC after it hits zero. 130 steps is plenty of resolution, and it's a lot easier to do the simple arithmetic in my head using my fixed bars than dealing with SOC %, which also doesn't help at all with calculating my current fuel burn rate.

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.

Maybe you should try it out before dismissing it as imitating dumb information.

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.