Kudos to the CANbus SOC meter team!

TonyWilliams said:

At 281 SOC data points, that's only 20 kWh of battery.

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Yes, absolutely. We don't have a large enough data sample to determine what the multiplier is. I would hope that it's 75Wh/SOC, but that's based entirely on nothing but speculation.

1. mike means miles/kWh, not kWh/mile

2. the multiplier is not constant over the SOC range, being lower (moderately predictably) at the high end and UNpredictably and significantly lower at the low end of the SOC scale.

3. Throughout the center range the multiplier might be meaningful, but it will depend upon temperature and it will decrease with "age/use".

garygid said:

1. mike means miles/kWh, not kWh/mile

2. the multiplier is not constant over the SOC range, being lower (moderately predictably) at the high end and UNpredictably and significantly lower at the low end of the SOC scale.

3. Throughout the center range the multiplier might be meaningful, but it will depend upon temperature and it will decrease with "age/use".

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Yes, thank you for catching that Gary! I corrected this mistake. If I understand you correctly, the SOC number likely correlates to a certain pack voltage. This in turn correlates to a certain amount of available energy, but exactly how much depends on several factors.

The reason why I'm looking to confirm the 75Wh/SOC multiplier is simple. If this number was correct, at least on paper, it would validate a few aspects of the following battery model: 21kWh of available energy, roughly 1.5kWh per bar, and 6% unavailable capacity on each end of the range. I apologize if this looked crude or otherwise inadequate, and I appreciate your comments.

Unfortunately, your WattHour per SOC-tick estimate will not tell you any of those THREE things, other than as approximate "averages", thus still just guesses.

My commute is almost identical to Mike's so, for comparison:
I received the SOC gauge on Wednesday night by UPS. I had driven 30.7 miles in the morning and 31.4 at night (slightly different, but faster route after 6:45PM). I used cruise control to keep speed at 60 MPH. After running the meter through its checks, I read 34.1% remaining and I always charge to 100%

Yesterday, pretty much a repeat of Wednesday with the exception of 1 slow patch coming home. Drive in 30.7 miles and using only 31% of charge, drive home for total RT of 62.1 miles left me with 36% charge remaining. Both days I was right at 4.8 m/kWh according to the energy meter on the dashboard.

The SOC meter might give me the confidence to try 80% charge for commute and/or Mike's approach, which is to go at 65 MPH (which does make the drive more bearable, believe it or not).

gascant said:

Both days I was right at 4.8 m/kWh according to the energy meter on the dashboard.

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Interesting - that's very good efficiency for 60 mph. You should be able to do 90+ miles easily on a full charge. Any AC usage?

Tony's Range-Speed-Bars table has 60 mph at 3.9 mi/kWh - how are you getting 20% better range?

gascant said:

The SOC meter might give me the confidence to try 80% charge for commute and/or Mike's approach, which is to go at 65 MPH (which does make the drive more bearable, believe it or not).

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65 mph should be no problem on a full charge - estimate about a 10% reduction in range going from 60 to 65 mph.

Does a 80% charge read 80% on the SOC meter?

surfingslovak said:

garygid said:

1. mike means miles/kWh, not kWh/mile

2. the multiplier is not constant over the SOC range, being lower (moderately predictably) at the high end and UNpredictably and significantly lower at the low end of the SOC scale.

3. Throughout the center range the multiplier might be meaningful, but it will depend upon temperature and it will decrease with "age/use".

Click to expand...

Yes, thank you for catching that Gary! I corrected this mistake. If I understand you correctly, the SOC number likely correlates to a certain pack voltage. This in turn correlates to a certain amount of available energy, but exactly how much depends on several factors.

The reason why I'm looking to confirm the 75Wh/SOC multiplier is simple. If this number was correct, at least on paper, it would validate a few aspects of the following battery model: 21kWh of available energy, roughly 1.5kWh per bar, and 6% unavailable capacity on each end of the range. I apologize if this looked crude or otherwise inadequate, and I appreciate your comments.

Click to expand...

this is very interesting... in your mind, what are your take-aways? The battery will hold up better than expected? They will be able to increase the car range via SW updates?

tks so much,

drees said:

Does an 80% charge read 80% on the SOC meter?

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On the SOC meter, 10 bars is actually 82.9% and in CarWings, it's 83%. I see that the bars that CarWings shows and their percentage are pretty close to the SOC meter (within 1% or so), at least at the 35%/4 bars and higher mark.

Just popping in to say that I came || close to hitting 100% / 281 on last night's charge - I was at 99.6%/280 this morning.

Now, how did I manage that last night, when my numbers before have been all over the map, but never that high? I have no clue, but one thing that was not typical from last night is that I was charging from just over 50% charged. Normally when I charge, I'm down to around 30% remaining. However, I did also noticed that my battery pack was cooler this morning (5 bars rather than 6). So maybe less heat is able to build up with the shorter charging time and, therefore, the pack is able to charge more? Just a theory.

But you know what else I've noticed....is that it doesn't matter what I've got charge-wise when I leave home (and I've started out with only 92% before today), I seem to loose that first 10% or so with about the same speed no matter what.

Starting out with almost 100% also blows my first bar reduced mileage theory out of the water too, because I didn't do any better today that I would any other. But I haven't seen the restorative action of pre-conditioning the cabin of my car since winter. Maybe it takes pre-conditioning via heater to work, or maybe my pack isn't capable of being restored in this fashion anymore? Hard to say.

mwalsh said:

So maybe less heat is able to build up with the shorter charging time and, therefore, the pack is able to charge more? Just a theory.

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Or maybe the car will let the battery charge a bit more thanks to the lower temps - and in warmer temps it cuts off charging sooner to help preserve battery life also knowing that a warmer battery is also a bit more efficient than a colder battery.

I suspect that the top 2% of the SOC contains only 0.02% of the battery's energy. Thus, charging to 98% or 100% makes no noticable difference.

I really don't know where to put this. I know we've had discussion on the linearity of the discharge curve, but I'll be darned if I can find it again now I come to look.

Last night I had the opportunity to discharge further than I'd done before since I got Gary's meter - down to ~10% SOC, whereas previously I'd only discharged to ~20%. What I noticed is that the discharge curve remained pretty predicable down to around 13-14%, after which consumption appeared to near double. Now I've only done this once, and this is only my pack in it's current condition, but if further adventures reveal similar results, I would say that you could count on performance that is very predictable for the middle 75% of the pack.

And my further observations from this week are that I seem to get around 1 mile per % SOC in that more predictable part of the pack while cruising at highway speeds (between 65mph and 70mph), assuming relatively flat terrain and no climate control use.

mwalsh said:

And my further observations from this week are that I seem to get around 1 mile per % SOC in that more predictable part of the pack while cruising at highway speeds (between 65mph and 70mph), assuming relatively flat terrain and no climate control use.

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I'd say the same thing, especially since I'm about 5 MPH slower than you. I rarely use climate control and my commute is pretty darned flat.

Next steps, for those interested:

1. Download and use my evolving CAN-Do program with its Logs and Recipes.
See http://www.wwwsite.com/puzzles/cando/" onclick="window.open(this.href);return false;

2. Modify the SOC-Meter to do logging of YOUR OWN usage of the LEAF.

I should try this "mod" out here first, but have not yet had the energy.
See details in the thread:
"SOC-Meter for One-CAN Logging & Graphing".

garygid said:

2. Modify the SOC-Meter to do logging of YOUR OWN usage of the LEAF.

"SOC-Meter for One-CAN Logging & Graphing".

Click to expand...

Here's the link.
http://www.mynissanleaf.com/viewtopic.php?f=44&t=4929" onclick="window.open(this.href);return false;
I think all the parts should be available at your local Fry's, no?
Or, the kit idea is pretty good, too. I'm thinking it might be worth mounting the female connector into the case of the SOC meter?

GOOD Suggestion!

You are correct, mounting a 9-pin D female "Logging Port" on the box is better.

The slight difficulty is that this requires a person to add a "large" D-slot, ...
and two easy-to-drill small holes for the two mounting screws/bolts.

There is sufficient room inside the box near the front edge of the Right Side of the SOC-Meter.

Adding the D-slot might be a problem for many, particularly if the meter is already built. However, drilling 7 to 9 quarter-inch holes might allow one to finish the slot with an eXacto knife (or similar).

I will add the slot and 2 mounting holes to "Rev 2a" of my Hole Template, and post it.

I just wanted to add my further kudos to the list of the grateful SOC meter owners. Mine was put together at a build session with garygid and starry on Thursday. It already had the 1.08 version software and it is happily showing all of the five data types that mwalsh has mentioned.

I mounted mine the same way that mwalsh did, routing the 6 foot OBD cable over the steering wheel area and down to the front part of the center console. I have to get used to NOT looking down there too often while driving, for the sake of safety. The SOC numbers don't change too fast, but looking at the Power and Charge (regen) numbers rapidly changing can get distracting... :lol:

Thanks again to the master designer/builder/brain trust of MNL, Mr. gid, and to his small army of collaborators.

I just "flashed up" to V 1.08 this afternoon and it's great! And, I agree, watching it too much can get distracting. Might be good to find a way to mount it on top of the dashboard, just in front of the side pillar window.

Did I actually see 40 kW of regen power while braking downhill??

I have seen 34 kW Regen,
and 240 Amps Power-out current.

It sits well on the shelf right on top of the Nav system.

Glad you got the "flashing" working, and like the new F1.08 firmware.

garygid said:

I will add the slot and 2 mounting holes to "Rev 2a" of my Hole Template, and post it.

Click to expand...

If you have a template with space for a DB-9 for logging I'm more then willing to give it a try (I have yet to start on building my meter).

Besides cutting and filing to make the proper hole for the DB9 it looks as if one would need to gouge out the ribs from the inside of the box.

(and this after I told gascant it would be quite painful to mount the connector to the box)