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Discussion Starter · #1 ·
with a Level 1 charger at 12 Amps over 2 days.

Now, I know that 8 Amps = .96 kWh/hr (min 3.6 mi/kWh) and 12 Amps = 1.44 kWh/hr (min 4.6 mi/kWh).

On Wed, I charged up my Bolt for 6 hours (07:00-1:00). And, on Thurs, I charged it up for 5.5 hours (weather caused a late start).

Now, on my previous 2, 12 Amps charging days, my mi/kWh was 4.6 (added 28 miles; up from 139 to 167) both times. But, on Thurs, with only 5.5 hours of Charging, I added 31 miles (which = 5.6363 mi/kWh).

But, since the electrical load was the same (same 20 Amp outlet, same load, as the outlet doesn't share any other electrical equipment), shouldn't the mi/kWh be the same? :unsure:

Though, I'm certainly not knocking the higher mi/kWh charging time. :)

And, jic you ask, I don't want to upgrade to a Level 2 Charger, as I'm only renting the place, and I expect to move within a year.
 

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Your predicted range is an estimate based on a lot of factors. As those factors change from day to day or week to week, your predicted range will change. I don't pay too much attention to the predicted range but instead watch miles/kWh and % charge.
 

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with a Level 1 charger at 12 Amps over 2 days.

Now, I know that 8 Amps = .96 kWh/hr (min 3.6 mi/kWh) and 12 Amps = 1.44 kWh/hr (min 4.6 mi/kWh).

On Wed, I charged up my Bolt for 6 hours (07:00-1:00). And, on Thurs, I charged it up for 5.5 hours (weather caused a late start).

Now, on my previous 2, 12 Amps charging days, my mi/kWh was 4.6 (added 28 miles; up from 139 to 167) both times. But, on Thurs, with only 5.5 hours of Charging, I added 31 miles (which = 5.6363 mi/kWh).

But, since the electrical load was the same (same 20 Amp outlet, same load, as the outlet doesn't share any other electrical equipment), shouldn't the mi/kWh be the same? :unsure:

Though, I'm certainly not knocking the higher mi/kWh charging time. :)

And, jic you ask, I don't want to upgrade to a Level 2 Charger, as I'm only renting the place, and I expect to move within a year.
Mathematically, the GoM takes the kWh added, then factors in your recent mi/kWh driving efficiency to get an expected miles of range. It is just a guess (thus the "Guess-o-Meter" label for the range estimate). The driving efficiency varies based on a number of factors.

In cold weather, two thing will impact your estimated miles. First, if it is cold enough, some pack heating will use some of the kWh you are adding, so you will add fewer kWh. Second, your driving efficiency will tend to be lower due to several factors relating to lower temps.

Extreme hot weather will also have a similar effect. Li Ion batteries prefer temps like humans, in the 70F range.

For example, 10 hours at 1.44 kWh = 14.4 kWh added. If your recent driving is 4 mi/kWh, that would mean 57.6 miles added to the GOM. If recent driving efficiency is 3 mi/kWh, it would mean 43.2 miles added to the GOM. And if conditioning (heating) the pack consumes some of the power and you only get 12 kWh added, well you see where this is going. Given the same amount of energy added to the pack, the GoM estimate will vary.

The efficiency factor is not pure either, it seems to be a weighted average of the EPA rated efficiency (3.9x mi/kWh) and last 1000 miles of so of actual efficiency.

Charging to a State of Charge (say 90%) consistently will rarely result in the same GoM estimated miles given the other variables. All of us who have lived through a few seasons with our Bolt, and who consistently charge to a specific SoC will tell you, the GoM will generally go up in summer, down in winter. The more extreme (hot or cold) the weather, the greater the variance.

So, it is never useful to use miles as a yardstick. Enjoy the higher estimates, they won't last.
 

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Discussion Starter · #5 ·
You're calculating the miles added by looking at the GOM? There's your problem.
So, what do you use?

Otherwise, how else is one to determine how many miles were added?

@ARob
Thanks. Though, I should have included in the first post, that I didn't drive anywhere after the first charging session. And, though the weather delayed me a bit on Thrusday, the air temp was pretty darn close to being the same (started out a few degrees cooler, but warmed up quickly to within a degree, or two of the day before).

Thanks.
 

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So, what do you use?

Otherwise, how else is one to determine how many miles were added?
So, with the caveat that I'm kind of a nerd, I use a bluetooth ODB2 reader, Torque Pro, and A Better Routeplanner (ABRP). I charge to a specific target charge level, integrate live data from Torque Pro into ABRP, and use ABRP to estimate the change in State of Charge to my destination.

Yes, I even do this on my 8 mile commute.

So I don't think of my range in terms of miles, I think in terms of % of State of Charge (SOC). My commute uses 3% (6% round-trip). A drive to Trader Joe's uses 20%. A drive to my in-laws uses 61%.

The reason I prefer thinking in terms of SOC% instead of miles is because efficiency varies with speed. I can take city roads to work, so 4 miles / kWh is typical. Getting to my in-laws is almost all highway, with a significant stretch at a 75 mph speed limit, so efficiency is closer to 3.6 miles / kWh for the trip. Comparing by mileage, my in-laws live 17 times further than my workplace. But it will actually consume 20 times more of my battery SOC %.

That's one reason I use ABRP even though the navigation features aren't as good as Google Maps. Integrated with Torque Pro, it shows you the current SOC and the calculated SOC at your next waypoint. So it's very well suited to how I think about range in an EV.
 

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Your battery does not contain miles.

It's like imagining that your breakfast contains staircases climbed.
Exactly. Miles are not units of energy.

When you buy gasoline, do you buy miles or gallons of gasoline? One gallon of gasoline has about 33.7 kWh of energy content.
 

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Discussion Starter · #10 · (Edited)
@MichBolt
Thanks for the clarification, and explanation.

Though, I definitely prefer my way. ;) :LOL:

Your battery does not contain miles.

It's like imagining that your breakfast contains staircases climbed.
I never said it did. :rolleyes:

Based on my 2 days of charging, one day, the GOM indicated 29 miles added (or 4.5 mi/kWh) during the 6 hours of charging. And, on the 2nd day, the GOM indicated 31 miles added (or 5.6 kWh) during the 5.5 hours of charging.
 

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Based on my 2 days of charging, one day, the GOM indicated 29 miles added (or 4.5 mi/kWh) during the 6 hours of charging. And, on the 2nd day, the GOM indicated 31 miles added (or 5.6 kWh) during the 5.5 hours of charging.
If you want your GOM to vary wildly and throw off your calculations, leave auto defog on and use auto on the HVAC. Or, turn on/off the heater or AC.

The GOM is pretty wild. In a recent example, I was at 14 battery bars and a GOM of 189 miles. After driving 17 minutes for about 6 miles (odo only lists whole numbers), I was still at the same # of battery bars but the GOM was down to 156 miles.
 

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Discussion Starter · #12 ·
If you want your GOM to vary wildly and throw off your calculations, leave auto defog on and use auto on the HVAC. Or, turn on/off the heater or AC.

The GOM is pretty wild. In a recent example, I was at 14 battery bars and a GOM of 189 miles. After driving 17 minutes for about 6 miles (odo only lists whole numbers), I was still at the same # of battery bars but the GOM was down to 156 miles.
There was no change in the settings from one charging day, to the next, as I didn't drive either day.
 

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Discussion Starter · #14 ·

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Even if the car is off, and the controls haven't been touched? :unsure:

If so, :eek:
Don't know. But if auto-defog is on, who knows when that turns itself on/off? Same for the behavior of HVAC system in auto.

I'm not even sure how frequently the GOM decides to update itself. Auto-defog and/or HVAC auto could've changed state between updates.

Another problem is with determining actual state of charge. Leaf's 1% increment SoC display (on model year '13+ Leafs) can have some jumps (e.g. charging at 98%, unplug, jumps to 100% which I've witnessed myself). It's not like batteries have some output that says "this is my SoC". This might be why GM chose to only implement 5% increment battery bars.

When Leaf only had no 1% increment SoC display and only 12 battery bars + a GOM ('11 and '12), Leaf's Chief Vehicle Engineer Kadota-san in Dec 2011 put up a slide about "mysterious moves" on their gauge. I pointed to it at What could be the reason that a 100% charge would yield 98%? - My Nissan Leaf Forum. And, as I mentioned at The Anatomy of a Gid - Page 7 - My Nissan Leaf Forum, the slide said "Nissan strictly confidential" on it.

As I said at Why not use percent SOC as a range estimate? - Page 2 - My Nissan Leaf Forum, I ran by some of the above w/a friend who flies model airplanes and has some EE knowledge.

There weren't any NDA's presented but the media wasn't allowed and I'm pretty sure there was a request/order for no recording devices per Nissan Engineering Team Visit Dec. 3rd: Recap - Page 26 - My Nissan Leaf Forum.

'13 Leaf (with the 1% increment SoC display in addition to GOM and 12 fuel bars) didn't ship in the US until a few months into 2013.

So imagine the determining SoC part which has difficulties/caveats coupled with another black box algorithm for the GOM.
 

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Discussion Starter · #16 ·
...Another problem is with determining actual state of charge. Leaf's 1% increment SoC display (on model year '13+ Leafs) can have some jumps (e.g. charging at 98%, unplug, jumps to 100% which I've witnessed myself)....
Yeah, my 2020 Bolt did this 2 times already. As soon as I dropped it into drive, the GoM/SoC dropped 10%. But, the next morning, it gained 10% So, for sure a bit, o_O

And, even though I charged once to 100% (according to the DCFC station, and they charged me 1 minute of idle time), my GoM read only 255. And, the Energy Efficiency didn't reset itself, as I read, that it's suppose to.

Oh, well. So long as the car is working, and I don't have to worry about range issues, c'est la vie
 

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Even if the car is off, and the controls haven't been touched? :unsure:

If so, :eek:
It's not changing the setting (well, auto-defog does).

If you set your home thermostat to 70 F and it's 100 F outside, I hope you expect a bigger electricity bill (assuming you have A/C). If you set it to 70 F and it's 65 F outside, you wouldn't expect a big bill, right? Same settings, different results.

So if you get home and your auto setting is 70 F and it's 100 F outside, the A/C has to run and the GoM is adjusted accordingly. You get in the next morning and it's 65 F in the car the A/C is not coming on and the GoM is adjusted up.

Now... there is a hiccup where even with A/C on and Heat off, if the temp in the car is close to the auto setting temp it will turn the heat on (secretly, no indicator light) to try to balance the A/C. It's stupid but it is what it is.
 

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I’ll add my two cents worth here. Charging the battery heats it up. Without going into details that would require an electrical engineering degree (as well as some physics and chemistry), this is related to current running through the internal impedance of the battery cells. This impedance changes with temperature and state of charge of the battery cells. As the cells heat up, the battery cooling system is activated to cool them. This requires using some energy that would otherwise be used to charge the battery cells.

As for the GOM, the only way to use this is as a dynamic value in conjunction with the trend bars. If you are able to operate the vehicle such that the trend bars never extend below or above the the GOM estimate, you will achieve exactly that estimate. Note that operating the vehicle includes more than just how you drive, but also your use of the heat, AC, and defrost, as well as things you don’t have control over such as battery temperature management.
 

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And, even though I charged once to 100% (according to the DCFC station, and they charged me 1 minute of idle time), my GoM read only 255. And, the Energy Efficiency didn't reset itself, as I read, that it's suppose to.
As you may be aware, you are not guaranteed a certain drivable range (like the EPA estimate of 259 miles for newer Bolts) when charged to 100%.

Also, consumption data stats on the big screen is reset only if you let the car terminate the charging session after it thinks it's full. DCFC usually cuts off the power when it reads that the car's apparent SoC reached 100%, before the car thinks it's really full. So if you want that stat reset, you should use an AC charger (e.g. Level 2).

Efficiency stat on the dashboard is reset only when you manually reset the trip meter.
 

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Discussion Starter · #20 ·
As you may be aware, you are not guaranteed a certain drivable range (like the EPA estimate of 259 miles for newer Bolts) when charged to 100%.

Also, consumption data stats on the big screen is reset only if you let the car terminate the charging session after it thinks it's full. DCFC usually cuts off the power when it reads that the car's apparent SoC reached 100%, before the car thinks it's really full. So if you want that stat reset, you should use an AC charger (e.g. Level 2).

Efficiency stat on the dashboard is reset only when you manually reset the trip meter.
Yes, I'm aware of that.

Unfortunately, I don't have access to a Level 2 charger at this time. Nor, do I see it for the foreseeable future.

And, yes. I know that, too.
...So if you get home and your auto setting is 70 F and it's 100 F outside, the A/C has to run and the GoM is adjusted accordingly. You get in the next morning and it's 65 F in the car the A/C is not coming on and the GoM is adjusted up.

Now... there is a hiccup where even with A/C on and Heat off, if the temp in the car is close to the auto setting temp it will turn the heat on (secretly, no indicator light) to try to balance the A/C. It's stupid but it is what it is.
You mean,even with the car turned OFF, the a/c and/or heat will still come on?
 
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