Using clone ELM327 Bluetooth OBDII adapter with Leaf

[bradbissell]

Version 0.26j (-FS) is ready for testing.

Features
* Settings/DTE panel has an option to select "Alt DTE calc" which will use Tony Williams' formula for calculating DTE. It includes temperature compensation.

Thanks for including the temp compensation. This will really help this winter!

 

[JPWhite]

How would a technically disinterested person know to do that, or how much to "adjust" for? Heck, I wouldn't know how much to adjust for without some good number crunching, and I'd say that I'm pretty adept at this stuff. How much would you adjust the miles/kWh with a car cold soaked at -10F versus one at 70F?

Even more confusing would be that any adjustment would vary significantly from the readout on the dash. For the record, I do appreciate that you included a reference to DTE in the way I suggested it earlier. I'd just like it to be the best that it can be.

I'm all for automation where it is possible and makes sense. I'm glad Jim has been able to include the calculations. I'm not sure its as difficult to make seasonal adjustments as you indicate. Doing mental calculations/gymnastics from first principles isn't necessary, simply tracking efficiency on the dash is all that's needed to adjust the battery app to current driving conditions. The automation is welcome but not strictly necessary.

 

[LeafSwe]

I'm testing version 0.26j

I like the max/min/avg temp on screen 4
A suggestion is to add colours instead of always red mercury, same colours as on screen 3
And make the "mercury" a little bolder

 

[vrwl]

In version 0.26j, on screen 4, when displaying the Min/Max/Avg temps in nighttime mode, the average temp font color is the same as the black background color and you can't see the reading.

 

[TonyWilliams]

I'm all for automation where it is possible and makes sense. I'm glad Jim has been able to include the calculations. I'm not sure its as difficult to make seasonal adjustments as you indicate. Doing mental calculations/gymnastics from first principles isn't necessary, simply tracking efficiency on the dash is all that's needed to adjust the battery app to current driving conditions. The automation is welcome but not strictly necessary.

You're right... automation isn't necessary. My rule of thumb is simple... could my wife or daughter do it?

If you're tracking efficiency to make your "mental calculations/gymnastics", then you are not forecasting range, you are reacting to it. Big difference.

Would you like to ride in the back of my airplane on a trip from Dubai to Los Angeles? We'll go over the north pole, and I'll just track the efficiency to see if there's enough fuel to make it. Does that make sense? Or would you prefer we accurately forecast what should happen, and monitor to verify that is the case?

These kinds of issues are particularly frustrating when we have the data, and don't automate it.

 

[Stoaty]

Would you like to ride in the back of my airplane on a trip from Dubai to Los Angeles? We'll go over the north pole...

Sounds interesting. When do we leave?

 

[Turbo3]

After a night's rest I see Version 0.26j only implements Tony's formula for the "rsrv" setting.

I will correct that with the next version.

Also a question for Tony. I assumed that the temp was the temp of the battery. Is that correct? I currently only have that temp available.

Jim

 

[stjohnh]

How would a technically disinterested person know to do that, or how much to "adjust" for?

Jim,

This is an important question, and I wonder what you would think of having a "Basic" and "Advanced" mode for your app. I love all the detail, but my wife, who is using it also, really only wants DTE, and not really much else. What about a screen that has DTE in big font, a "Hiway" or "Min" value to the left in smaller font (corresponding to 3.5 mi/kwh) and a "city/careful" mileage to the right corresponding to 5.5 mi/kwh. Perhaps adding a "see advanced" warning light if temp/airpressure exceed safe limits. Seems to me that the cell pair voltages and voltage histogram are definitely "advanced" functions.

Also the screens are showing so much data that it may become a distraction to a user looking at the screens while driving.

Thanks for the incredible work !!!

 

[TonyWilliams]

After a night's rest I see Version 0.26j only implements Tony's formula for the "rsrv" setting.

I will correct that with the next version.

Also a question for Tony. I assumed that the temp was the temp of the battery. Is that correct? I currently only have that temp available.

Jim

Yes, only the battery temperature. We can calculate air density separately to compensate for aerodynamic drag.

1% loss per 4F below 70F

1% gain per 8F above 70F

This also compensates for the GID tendency to go up in the winter and down in the summer, completely counter to the actual useable stored energy in the battery. Cold batteries never hold more energy than they do when hot (before exploding!).

My suggestion for GID value is to default to 75 wattHours per unit, and allow adjustments from 75-80.

 

[TonyWilliams]

Would you like to ride in the back of my airplane on a trip from Dubai to Los Angeles? We'll go over the north pole...

Sounds interesting. When do we leave?

Right after I determine the fuel required based on aircraft gross weight, flight level(s) expected, fuel flow at those altitudes, winds aloft, temperature aloft at all expected altitudes, alternate airports required (w/ ETOPs requirements), weather at destination and all alternates, plus 45 minutes of fuel after the last alternate, plus whatever company required contingency fuel, plus "pucker factor" fuel for ATC flow control, known delays, long taxis, significant APU use, any Minimum Equipment List items that affect range, fuel, altitudes, pressurization, etc.

We will calculate that all on the dispatch "release", as is legally required, before the power goes to TOGA. Amazingly, running out of fuel in a transport category aircraft is virtually unheard of.

 

[JPWhite]

This is an important question, and I wonder what you would think of having a "Basic" and "Advanced" mode for your app. I love all the detail, but my wife, who is using it also, really only wants DTE, and not really much else. What about a screen that has DTE in big font, a "Hiway" or "Min" value to the left in smaller font (corresponding to 3.5 mi/kwh) and a "city/careful" mileage to the right corresponding to 5.5 mi/kwh.

Good idea.

Screen 3 could become the basic mode and screen 4 the advanced mode. That isn't to far from reality as it stands

 

[vrwl]

How would a technically disinterested person know to do that, or how much to "adjust" for?

Jim,

This is an important question, and I wonder what you would think of having a "Basic" and "Advanced" mode for your app. I love all the detail, but my wife, who is using it also, really only wants DTE, and not really much else. What about a screen that has DTE in big font, a "Hiway" or "Min" value to the left in smaller font (corresponding to 3.5 mi/kwh) and a "city/careful" mileage to the right corresponding to 5.5 mi/kwh. Perhaps adding a "see advanced" warning light if temp/airpressure exceed safe limits. Seems to me that the cell pair voltages and voltage histogram are definitely "advanced" functions.

Also the screens are showing so much data that it may become a distraction to a user looking at the screens while driving.

Thanks for the incredible work !!!

I know there have been some folks who would like to see the demise of screen 3, maybe just the basic DTE info (bare bones minimum info) would be a good alternative for screen 3.

 

[vrwl]

This is an important question, and I wonder what you would think of having a "Basic" and "Advanced" mode for your app. I love all the detail, but my wife, who is using it also, really only wants DTE, and not really much else. What about a screen that has DTE in big font, a "Hiway" or "Min" value to the left in smaller font (corresponding to 3.5 mi/kwh) and a "city/careful" mileage to the right corresponding to 5.5 mi/kwh.

Good idea.

Screen 3 could become the basic mode and screen 4 the advanced mode. That isn't to far from reality as it stands

Great minds think alike

 

[JPWhite]

This is an important question, and I wonder what you would think of having a "Basic" and "Advanced" mode for your app. I love all the detail, but my wife, who is using it also, really only wants DTE, and not really much else. What about a screen that has DTE in big font, a "Hiway" or "Min" value to the left in smaller font (corresponding to 3.5 mi/kwh) and a "city/careful" mileage to the right corresponding to 5.5 mi/kwh.

Good idea.

Screen 3 could become the basic mode and screen 4 the advanced mode. That isn't to far from reality as it stands

Great minds think alike

Indeed. ;-)

Next on the list for Jim is voice activation :shock: :lol:

 

[TonyWilliams]

Making a singular screen with just DTE would certainly be awesome, since many user would use nothing else. But, please don't dumb it down for simplicity.

That means, not using arbitrary economy figures ONLY. Currently, you can select the miles per kWh, and I would keep that, just like in a gasoline car where you have to know basic mile per gallon info. The range of potential economies is just too large, with gigantic changes for heater use.

So, in addition to selecting the economy, you could have Highway 65mph which would equal 4 miles/kWh, Careful City at some value (5.0 maybe), and a heater button consumption with two or three levels (my Rav4 EV actually does this with three levels).

With a default of 4 miles per kWh / 250 wattHours per mile, that is exactly the EPA "rated" range of the car. I want to be able to adjust that number, also. Everything related to the actual battery useable energy remaining should be automated and transparent on this DTE page.

 

[Deleted member 9549]

Can someone list what data this app is retrieving from the car, vs what information is derived or calculated based on data from the car.

Particularly related to battery capacity. Which of the following fields are directly reported by the Leaf and which are calculated by the app.

- Ahr
- capacity %
- kWh that the battery is currently charged to
- SOC%. How does this relate if at all to the soc% reported on the 2013 console?
- GIDs

Thanks
What is the expected max kWh charge that should be reported?

Only DTE miles/km and Wh used are calculated numbers. Everything else comes from the Leaf. So everything on your list comes from the Leaf.

If when you charge your 2013 to 80% and 100% the console display shows 80% and 95% then the SOCs are the same. Max charge on a new battery is reported to be 281 GIDs which would be 22.48 kWh.

Ok. The reason I asked about SOC is that the value reported by the app almost never matches the SOC reported by the 2013 console. Often its not even close. Like now, the car console says 50%, the app reports SOC:53.9%, GIDs 47.3% . I think I may have seen them briefly match at 75%, but then they diverged again as it continued charging.

What about 'health'? Is that another value from the car? I'm in the camp of those with a new 2013 reporting low capacity (93%) and trying to understand the various numbers. All other percentages top out higher than capacity, ie kWh, GIDs (96%), SOC, health (95%)

 

[surfingslovak]

The reason I asked about SOC is that the value reported by the app almost never matches the SOC reported by the 2013 console. Often its not even close. Like now, the car console says 50%, the app reports SOC:53.9%, GIDs 47.3% . I think I may have seen them briefly match at 75%, but then they diverged again as it continued charging.

The dash SOC hides the fact that the car charges to less than 100% when full and still has something left when reaching VLB. As a result, the SOC follows a different slope with diverging end points. As confusing as it might sound, these two SOC indicators won't be the same. Gids are an indicator of stored energy, and not SOC. They provide a measure of available energy, not fullness. Although using percentages does not make much sense in this context, some of the early drivers got used to Gid percent as a measure of range (about one Gid percent per mile). I think the app is versatile enough to offer something for everyone, even though it might be hard to interpret all the available data correctly.

 

[stjohnh]

Programming question: I am pretty sure Nissan has changed some of the data sent to the OBD2 connector for my 2013 Leaf, and likely most of those with 2013 Leafs that are showing 60-62 AHr capacity.

The specific problem I notice with the app is that the DTE is very inaccurate below LBW (ver 026 general release). I had been worried about my low capacity (60.5) reported in my new Leaf. Today I ran down to turtle. Here is the info I posted on the thread specifically addressing 2013 Leafs with low capacity.

I ran my car to turtle (first time ever) AND Ta Da!! 28 miles from LBW to turtle, much more than predicted, which gives me total range from 100% to turtle of 90 miles at 4.0 mi/kwh.

Other VERY curious observations: as I got down around 10 gids, the energy effic meter suddenly jumped from 4.0 mi/kwh to 4.7 mi/kwh, without any change in my driving. Also, as I got below 10 gids I noticed that the miles/gid seemed a lot more than it should be. By the time I started measuring, I got 4 miles on one gid, going from 7->6 gids. Got turtle at 5 gids. The Leaf Battery app (v026) predicted 15 miles from LBW to .6kwh (expected turtle) but I got 28 miles. Clearly Nissan has changed something in the programming. And I can go a lot farther per gid when gids are below 10 on my 2013 Leaf. My WattsLeft gave the same readings as the Leaf Battery App.

Also, as expected LBW came at 49gids, 18% SOC on the Leaf Dash.

Puzzling, but reassuring that I have a normal range even though the capacity is only 60.5 AHr.

 

[TickTock]

I have some evidence that, post-sw-update, battery capacity is considered to be 100% when AHr is equal to (or greater than) 65.6 according to Nissans formula for SOH computation. Furthermore, the Hlth does not appear to be directly related to capacity (although there does appear to be correlation). Following post has more details on what led me to this conclusion:

http://www.mynissanleaf.com/viewtopic.php?f=44&t=11676&start=83

 

[TonyWilliams]

I ran my car to turtle (first time ever) AND Ta Da!! 28 miles from LBW to turtle, much more than predicted, which gives me total range from 100% to turtle of 90 miles at 4.0 mi/kwh.

Other VERY curious observations: as I got down around 10 gids, the energy effic meter suddenly jumped from 4.0 mi/kwh to 4.7 mi/kwh, without any change in my driving.

There is a thread for these issues.