SOC-Meter Kit Hardware, Display, and Issues

[lincomatic]

I have one of those 2-line HD44780 displays that I bought on eBay for about $8. Unfortunately, it was a while ago, and I can't find a link, but they're easy to find. It has a white backlight with a blue background. When I first got it, the characters had terrible contrast, but with some adjustment via a potentiometer, it looks great. I'm don't think the characters are big enough for your tastes, though. These guys have cooked up a way to display bigger characters:

http://www.arduino.cc/cgi-bin/yabb2/YaBB.pl?num=1245352653

or

http://opengauge.org/mpguino/

I agree, they're not very nice with green background.

 

[waidy]

SOC-Meter Options:
...
...
8. what else ??

What about display of voltage and impedance of each battery; programmable % charge; programmable of when turtle mode should come on; display of # of DC kWh fed in each session (the charger tells you AC kWh); charge time in each session; It would bonus to "automatically" store the number of miles between each charge session (I know I am dreaming, but it's a good dream

 

[TonyWilliams]

Regarding what "range" to show, I've seen several posts asking for what seems to me to just be additional variations of the built-in guess-o-meter. That doesn't seem very useful to me....
What I think would be nice is a min/max range display. Not guestimates.

What I proposed earlier is much like what I'm familiar with in aviation; data based on KNOWN conditions to predict the range.

For a typical drive, you can predict what those conditions might be, and a very basic formula can be developed to predict range. For example:

A 75 mile trip might be:

25 miles of level freeway at XX mph equals AA units of electrical power consumed.

25 miles of city at YY.....

25 miles of snow covered gravel road uphill at ZZ ....

Any prediction that is based on what has previously transpired is only valid if those same conditions prevail.

We have a fancy GPS navigation system that can calculate how many miles, and basic formulas to predict the electrical consumption are already developed. Further refining data like uphill/downhill grade, wind, road conditions (snow, rain, etc), etc, can be added.

We can land a vehicle on the moon, or fly it around the world, and predict the total energy consumed to an amazingly small error. It's not rocket science any more !

 

[garygid]

We can do a lot when we find (out how to get) the necessary data.

You can use our CAN-Do programs and logs today to help LOOK FOR useful data in the CAN messages. (New Logs coming soon.)

 

[tomsax]

Regarding what "range" to show, I've seen several posts asking for what seems to me to just be additional variations of the built-in guess-o-meter. That doesn't seem very useful to me, as I drive mostly in the city, and sometimes on the highway, at varying "burn" rates. How I've been driving the past few minutes, miles, days, or weeks will often have little correlation with how and where I may be driving next.

I really like what the Roadster tells me: miles left assuming the combined EPA drive cycle. I don't particularly care about the EPA drive cycle, but that number just happens to be the energy use I get driving about 57 mph on level freeway in moderate temperatures and clear weather. This number is called "Ideal Range Miles" or just "ideal miles".

I don't use this number to tell me how far I can go, I use it to tell me if I have to think about range at all, and if so how I need to drive to get to my next charging location. If I have 40 ideal miles and 20 miles to go, it doesn't matter how I drive, I'll get there and don't have to watch the meter. If I have 10 ideal miles, I need to find closer charging. If I have 20-25 miles, I need to do whatever is necessary to beat the 57 mph energy use.

This number also makes it possible to have sensible conversations with other Roadster owners. On two trips to Ellensburg, it took me 113 ideal miles to travel from Sammamish over Snoqualmie Pass to Ellensburg at 60 mph or 119 ideal miles at 70-75 mph. Climbing hills cost about 7 ideal miles per 1,000-foot elevation gain, and descending gives about half of that back. Using these simple rules, I can plan a trip and usually hit within a few ideal miles of my estimate.

I never want to get to zero, so I generally plan trips to stay out of the bottom 10% of the battery pack.

If the LEAF community can pick a similar standard mile-based energy unit, then we can tell how to drive, plan charging for long trips, and have sensible conversations about energy use for specific trips with other owners.

 

[TonyWilliams]

Tom,

Thanks for that insight.

Tony

 

[TEG]

Suggestion / something I would like to see:

The ability to see the ampacity signal (pilot signal duty cycle) coming from the EVSE when plugged in and charging.
Also the voltage.

I see that the Leaf charger diagnostic probes do provide this data.

From the service manual:

EVSE SIGNAL PULSE WIDTH [?s] : Displays the pulse width of the PWM signal being sent from the EVSE.
AC INPUT VOLTAGE [V] Displays AC input power voltage.

So when the car is charging the display could switch to show something like:

Vehicle SOC: 57%
Pilot signal ampacity: 30amp
EVSE voltage: 208V
Current being drawn: 3.27kW

 

[garygid]

We just need to locate the data and determine the scale factors.

So many bits, so little time!

 

[TonyWilliams]

We just need to locate the data and determine the scale factors.

So many bits, so little time!

Take a deep breath, brother! There's all the time in the world (well, until that last breath;-)

 

[evnow]

What is "pEEf" using here ?

It uses a very bright LED backlit LCD with more resolution than the ScanGauge and is easier to see in all light levels, even with sunglasses on. It automatically detects when you turn the lights on and dims the display for night use (as shown).

 

[evnow]

Here is one more LCD that seems to be a cheap favorite ... 84x48 Nokia.

http://www.sparkfun.com/products/10168

Also available on ebay for $8 shipped.

 

[91040]

What is "pEEf" using here ?

Reportedly, it is Ingineer's name on another forum.

 

[evnow]

What is "pEEf" using here ?

Reportedly, it is Ingineer's name on another forum.

Right - I was wondering which LCD he was using.

 

[evnow]

My LED has again gone off. I had to redo the soldering to be able to put it in the project box properly - now AVR no longer talks to the LED. I tried the pressing BUT routine to set the baud rate - but couldn't get it to work. Wonder whether I've killed the LED with excess soldering heat.

 

[garygid]

Just 2 wires, to Gnd and +5v, should light up "0000"
on the SparkFun "serial" LED 7-segment Display.
Are you getting that?

 

[mwalsh]

I've not been keeping up very well on these threads, Gary, so I'm a bit confused as to where this is at and where it's heading. Are you still going to be building units or doing kits instead? Or are we sourcing the kit parts ourselves based on your recommendations?

 

[TomT]

Me too! I can't keep track of it all anymore...

I've not been keeping up very well on these threads, Gary, so I'm a bit confused as to where this is at and where it's heading. Are you still going to be building units or doing kits instead? Or are we sourcing the kit parts ourselves based on your recommendations?

 

[garygid]

Sorry for the confusion, but things here are in flux (*).

I intend to:
1. "Finalize" my SOC-Meter hardware configuration in the next few working days.
2. Get Part and Source info accurate,
3. Get the Assembly instructions accurate,
4. Make a physical-hole template to aid is cutting the box,
5. Post some picures
6. Post a zip file of all the Project info files.

I do this so that I/we/others could buy parts and:
A. build-their-own
B. Provide Kits to others
C. Have Build-your-Meter Workshops,
D. Build and "distribute" finished SOC-Meters.
E. Program extensions and improvements as we discover more CAN-info.

I have tried to make the hardware easy to obtain and assemble,
not too expensive, yet flexible enough to support many added functions.

------------
(*) As an alien visiting this planet that you call Earth, I can say that it has been confusing, interesting, and at times overwhelming. Some of you have the arrogance to think that you "own" the "blue ball", but it is really just a short-term lease. The original paperwork was on file in the Library at Alexandria, but then, as now, most do not "grok" "backup" (or "disaster"). Apparently the Mayans had a copy of it all written down, but some overwhelmingly stupid humanoid(s) decided that their books and knowledge would make a good bonfire. Since a recent biological test of my host body seems to suggest that a radical prostatectomy is most likely in its near future, I am unsure what roll(s) we (my body and I) will be able to play in your drastically uncertain future. Some were sure the world was flat, and others, more recently, that there was no "climate" change. With "wisdom" like that from your "leaders", we wonder why you follow (or even tolerate) them. I am still hoping that this "condition" (strange cell shapes) was discovered in time so that we will still be able to put a lot of gas-free miles on the "Maple" (LEAF) creature that currently lives with us.

Yes, your faith-prayers are welcome, and any faith-mechanism is accepted.

 

[mwalsh]

Yes, your faith-prayers are welcome, and any faith-mechanism is accepted.

Our faith-mechanism will be working full-time on your behalf. Be assured.

 

[evnow]

Just 2 wires, to Gnd and +5v, should light up "0000"
on the SparkFun "serial" LED 7-segment Display.
Are you getting that?

Yes - essentially the LED is behaving as if the baud rates are not synced (like you described earlier - with random charatcers showing up after a while). I'll check today whether avr studio 4 lets me run the code in debug mode.