Active EV-CAN sampling: cell voltages, pack temperatures...

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Turbo3 said:
LEAFfan said:
Turbo3 said:
Correct value is 4821

Actually, Greg said it was 8421 and we had the incorrect one.
I guess GregH and Gary Giddings need to talk ;-)

When everyone agrees on a single value then I can hardcode it. But it sounds like now is not that time.

Here are the shunts coming on after powering up the car about an hour (and 10 miles) after a "full" charge. This is with the 8421 bit ordering. Note as the shunts turn on the corresponding voltages sag a little.

[youtube]http://www.youtube.com/watch?v=ek98u2SBdzc[/youtube]
 
Thanks for that - having the video really helps especially if you pause it and step through it backwards (so you can see which CP to focus on when you step forward in time). It does appear to do as you say - I am no longer skeptical. :)
 
Turbo3 said:
Need help with ambient temperature decoding.

To get ambient temperature send:

797 8 03 22 11 5D

Get back:

79A 8 07 62 11 5D 7F 72 7F 00 (which is a reading of 73.4 degrees)

The task is to determine which of the last four data bytes are used for temp and their conversion factor.

Jim
Copying from the from the [passive] canbus decoding thread since this is an active (requested) message. I think this is an important value to decode if we want to temperature compensate the DTE computations since pack temp is usually quite different than ambient.
 
I'd like to do some more analysis on the parameter Greg discovered in the Group1 data called "perhaps health" by Greg and Hlth in the leafApp. While it does seem to be a good indicator, I don't think it is really what we are looking for based on my observations.
Below is some information I've previously reported along with additional data from 5b3:D2 which I believe is the true SOH as defined by Nissan:

  • Just before update:
    9 capacity bars
    62.4% Hlth
    68% SOH
    45.59 Ah

    Just after the update (measured in the parking lot):
    12 capacity bars
    100.0% Hlth
    100% SOH
    65.60 Ah

    Upon arriving home:
    12 capacity bars
    50.9% Hlth
    100% SOH
    65.60 Ah

    The next day:
    12 cap bars
    50.9% Hlth
    72% SOH
    46.92 Ah

    15 days later:
    12 cap bars
    51.7% Hlth
    73% SOH
    48.3 Ah

    Today:
    12 capacity bars
    51.7% Hlth
    72% SOH
    47.42Ah

    LEAFfan's 2013:
    12 capacity bars
    90.6% Hlth
    90% SOH
    59.37Ah

Based on this, it appears:
  • 1) SOH is pretty nearly Ah divided by 65.6. Probably exactly that post-sw-update (good news if you are not able to monitor canbus)
    2) Since Hlth was able to update mid drive home but SOH (5b3:d2) and Ah didn't get updated until after a full charge, it appears hlth is not a measure capacity (maybe resistance or something else that also degrades with age).
 
So it looks like you gained back a few Ah after a few weeks of being on the new s/w. Hope I get that much this Friday when I take mine in for the update. I'll be able to charge to 80% routinely again :)

TickTock said:
I'd like to do some more analysis on the parameter Greg discovered in the Group1 data called "perhaps health" by Greg and Hlth in the leafApp. While it does seem to be a good indicator, I don't think it is really what we are looking for based on my observations.
Below is some information I've previously reported along with additional data from 5b3:D2 which I believe is the true SOH as defined by Nissan:

  • Just before update:
    9 capacity bars
    62.4% Hlth
    68% SOH
    45.59 Ah

    Just after the update (measured in the parking lot):
    12 capacity bars
    100.0% Hlth
    100% SOH
    65.60 Ah

    Upon arriving home:
    12 capacity bars
    50.9% Hlth
    100% SOH
    65.60 Ah

    The next day:
    12 cap bars
    50.9% Hlth
    72% SOH
    46.92 Ah

    15 days later:
    12 cap bars
    51.7% Hlth
    73% SOH
    48.3 Ah

    Today:
    12 capacity bars
    51.7% Hlth
    72% SOH
    47.42Ah

    LEAFfan's 2013:
    12 capacity bars
    90.6% Hlth
    90% SOH
    59.37Ah

Based on this, it appears:
  • 1) SOH is pretty nearly Ah divided by 65.6. Probably exactly that post-sw-update (good news if you are not able to monitor canbus)
    2) Since Hlth was able to update mid drive home but SOH (5b3:d2) and Ah didn't get updated until after a full charge, it appears hlth is not a measure capacity (maybe resistance or something else that also degrades with age).
 
Yes... as reported, anyway. It is still too early to tell, though, if this is real and results in a 4% increase in range. After another month of data collection, I hope to have something more conclusive.
JPWhite said:
So it looks like you gained back a few Ah after a few weeks of being on the new s/w. Hope I get that much this Friday when I take mine in for the update. I'll be able to charge to 80% routinely again :)
 
TickTock said:
Turbo3 said:
Need help with ambient temperature decoding.

To get ambient temperature send:

797 8 03 22 11 5D

Get back:

79A 8 07 62 11 5D 7F 72 7F 00 (which is a reading of 73.4 degrees)

The task is to determine which of the last four data bytes are used for temp and their conversion factor.

Jim
Copying from the from the [passive] canbus decoding thread since this is an active (requested) message. I think this is an important value to decode if we want to temperature compensate the DTE computations since pack temp is usually quite different than ambient.

Since the car uses Celsius you're looking for 23, not 73.4... Maybe the 0x5d?... -70? Hmmm.. Need more data points. Oops. No, that's the request Id.. Sorry
 
Ambient temp seems to be the 6th byte. In this example that would be 0x72= 114 subtract the magic number 41 gives 73. The other two bytes seem to be interior temps.

Two other samples are 0x6f = 111 -41 = 70 which was the dash reading and
0x6D = 109 -41 = 68 again the dash reading.

Ok, one more 0x6c dash reads 67 degrees.

Just left the garage door open to cool the car down and modified the battery app to display the four bytes.

This was much easier than I thought it would be.
 
Turbo3 said:
Ambient temp seems to be the 6th byte. In this example that would be 0x72= 114 subtract the magic number 41 gives 73. The other two bytes seem to be interior temps.

Two other samples are 0x6f = 111 -41 = 70 which was the dash reading and
0x6D = 109 -41 = 68 again the dash reading.

Ok, one more 0x6c dash reads 67 degrees.

Just left the garage door open to cool the car down and modified the battery app to display the four bytes.

This was much easier than I thought it would be.

Awesome!! Looking forward to this being included in a future build :)
 
So now that I have implemented displaying ambient temp in the app it was 1 degree off on my first test sitting in the garage. So I have changed to -42 for now and will see how it compares to the dash number when I get to take the Leaf out.

Perhaps there is some delay between what I read and what gets displayed. Time will tell.
 
I was reviewing my daily logs and it appears that the 24th and 25th entry in the first group of 79b/7bb data is equal to the accessory battery voltage times 1024. 24th entry would be 4th line, 3rd byte.

7bb:
group:1 line:4 ((D3<<8)+D4)/1024
 
The Ambient temperature displayed in the eyebrow of the
original 2011 LEAF is substantially delayed and "processed"
from the actual sensor readings... enough to make it almost
unusable, IMO.

Has this changed in the 2013 model?
 
Great, the 12v "battery" (really the 12v bus) voltage times 4 in
the high order byte, with additional precision in the next byte.

Another great find, an example of what even a few people
can accomplish when they are collaborating and sharing
information, as opposed to keeping discoveries proprietary
and plotting to bankrupt competing efforts.

Imagine how splendid the world could be if people
were able to cooperate worldwide. With that, we would
probably have food replicators instead of 20 competing
oil companies, and clean water to drink worldwide,
and maybe even really exciting, rapid mass transit, instead
of packing people into flying sausages.

Keep up the splendid cooperation... doesn't it feel good?

I am very pleased to have been a small part of this
really great community, and (I hope) revolution.
Ahoy Mates!
 
garygid said:
The Ambient temperature displayed in the eyebrow of the
original 2011 LEAF is substantially delayed and "processed"
from the actual sensor readings... enough to make it almost
unusable, IMO.

Has this changed in the 2013 model?

Can't answer about the 2013, but the associated passive carcan and evcan messages do not appear to suffer from this on my 2011:

http://www.mynissanleaf.com/viewtopic.php?f=44&t=4131&start=275
 
Trying to figure out how to obtain GIDs and kWh as I start writing an iPhone app. Where is it? First post is great at describing most data. Lots of threads to pursue.

Thanks
 
dm33 said:
Trying to figure out how to obtain GIDs and kWh as I start writing an iPhone app. Where is it? First post is great at describing most data. Lots of threads to pursue.

Thanks

I've been keeping a document of all the known messages here. There are four canbus', two of which are the most useful (EVCAN and CARCAN). If you discover something new, either post here (if it is a query/reply) or here if it is available just by passive snooping.
 
TickTock said:
dm33 said:
Trying to figure out how to obtain GIDs and kWh as I start writing an iPhone app. Where is it? First post is great at describing most data. Lots of threads to pursue.

Thanks

I've been keeping a document of all the known messages here. There are four canbus', two of which are the most useful (EVCAN and CARCAN). If you discover something new, either post here (if it is a query/reply) or here if it is available just by passive snooping.
I found a reference in your doc to GIDs, haven't tried it yet. But I find no reference to kWh. How is that obtained?
 
Depends on the app. I integrate V*I*delta_T to compute the kWh during driving for efficiency computations. For remaining energy in the battery, gids remains the best indicator. Multiply by .075 to get kWh.
 
TickTock said:
Depends on the app. I integrate V*I*delta_T to compute the kWh during driving for efficiency computations. For remaining energy in the battery, gids remains the best indicator. Multiply by .075 to get kWh.
Thanks. That doesn't seem to be what the Android Leaf app is doing. For my car it shows 260 GIDs and 20.8kwh at a recent 100% charge.
260*.075 = 19.5 kwh.
I had seen a GID described as 80 watt hours. That if I use 0.08 then it does work out,
260*.080 = 20.8 kwh.
Which value is correct?
 
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