Average LEAF only Charges 2 hrs a day! INL

[SanDust]

1. The twelve bars do not represent all of the available battery energy. You probably still have about 15% of it left when the last bar disappears. So you can't calculate 5/12 X 20 = 8.333.
2. It seems very unlikely that all bars represent the same fraction of the available energy, again invalidating the above calculation as well as not allowing another term to account for the 15%.
3. Phil (Ingineer) has calculated the input power to the charger carefully, and it is capable of 3.84 kW, not 3.3 kW. The charger is presumably capable of sending 3.3 kW to the battery, so you can forget your 90% adjustment, at least in terms of charger efficiency. There will be some loss at the battery, however. 85% seems to be an accepted overall efficiency with 240v 16A charging, so 3.26 kW into the battery is probably about right.

I could believe that LEAFfan is getting 5.4 to 5.5 kWh into his battery in 100 minutes, and that might well translate to charging from 5+ bars to 10- bars. (9.6 bars - 5.4 bars would be a delta of 4.2 bars.)

You're just rationalizing.

1. Since the Leaf has something around 21 kWh of usable battery, I made allowance for a 1 kWh reserve when I said assume 20 kWh. That's realistic if perhaps a bit generous. Your idea that you have 3 kWh of the usable battery left when you have zero bars isn't. So yes, 5/12 X 20 is going to be a good number but I wouldn't argue with 5/12 X 20.5.

2. On balance each bar of the 12 bars will have about 1/12 of the energy. Postulating that there are a few magic bars that contain far less than others, and that they're all grouped together, and that those are the bars he's charging, does rationalize his claim but you don't have any evidence this is the case. It's just a rationalization.

3. This point I don't get at all. I conceded for the sake of argument that you'd end up with 3.3 kW at the battery. You say 3.26 kW. That makes it worse because now you've only getting 4.89 kWh after an hour and a half, leaving you far short of the 8.33 kWh that you need for five bars.

As a note on the conversion losses, I have no idea what you're saying. You suggest that a 90% efficiency number is totally wrong but then turn around and say that an 85% adjustment is "accepted". Huh? What do you think that 85% adjustment factor is? It's an efficiency factor. I just gave him the benefit of the doubt and used a higher number. (Maybe this is semantics. FYI when I say "charger" I mean the actual charger in the Leaf not the EVSE.)

Bottom line is that while you may believe it's possible, the numbers simply don't permit charging five bars in 100 minutes with a 3.3 kW charger. Not to beat a dead horse, but 1.667 X 3.3 = 5.5, and 5.5 isn't remotely close to 8.33. Even your idea that he's only charging 4+ bars doesn't wash because he can't even charge 4 bars in 100 minutes. This follows because four bars of charging would require 6.66 kWh at the battery and you admit that you're not going to end up with more than 5.43 kWh after 100 minutes.

On the right day when everything goes perfectly might one find that after an hour and a half of charging you had restored five bars? Possibly. Unlikely but do it enough times and lots of things can happen. But as a regular matter? No way.

 

[FairwoodRed]

This thread title is inaccurate. The INL report shows 2 hrs charge per EVENT, not per day. For a lot of people, event=day, but not for me. Almost every day, I plug in when I get home to grab what charge I can before I run errands after dinner. On Wednesdays, I have 5 charge events due to opportunity charging.

I know that I drive much more than average, but I think INL's reporting is missing some key relationships. Especially when they are going to take the per event data and translate that into a percentage of existing electricity generation per year. They did that by taking the average energy per charge event of 7.1 kWh and multiplying it by average charge events per day of .78 to get 5.5kWh average power per day. This approach totally ignores the max demand placed on the grid and assumes that cars will be charged at a time that is most benefitial for the power company - including charging a little bit everyday rather than overnight every couple of days.

 

[planet4ever]

2. On balance each bar of the 12 bars will have about 1/12 of the energy. Postulating that there are a few magic bars that contain far less than others, and that they're all grouped together, and that those are the bars he's charging, does rationalize his claim but you don't have any evidence this is the case. It's just a rationalization.

I certainly do have evidence for this claim. My evidence is Tony's chart, which he developed through extensive testing using Gary's State Of Charge meter. Perhaps you choose not to believe that chart, SanDust, but it has proven to be extremely accurate for a large number of owners. It says:

3.6% for half of bar 6
8.2% for bar 7
4.6% for bar 8
7.1% for bar 9
2.1% for the portion of bar 10 up to 80%
------
25.6% Minimum total usage for LEAFfan's scenario.

I used half of bar 6 because if the bar was less than half full it would not show at all after a power down and power back up.
The maximum would include all of bar 6 and half of bar 5, and would yield 32.8% usage.

Your 5/12 would be 41.7% of the capacity, almost 2/3 higher than the 25.6% that Tony's chart shows is possible!

Ray

 

[SanDust]

This thread title is inaccurate. The INL report shows 2 hrs charge per EVENT, not per day. For a lot of people, event=day, but not for me. Almost every day, I plug in when I get home to grab what charge I can before I run errands after dinner.

Nice. Yes this would explain why the numbers seem off.

Your 5/12 would be 41.7% of the capacity, almost 2/3 higher than the 25.6% that Tony's chart shows is possible!

It's not that I don't believe the chart, though I suspect the numbers vary slightly battery to battery. My problem with the approach is that since there is 50% of the charge in the upper six bars and 50% in the lower six bars, you're relying on a set of recurring coincidences (aka cherry picking specific bars) that seems most unlikely.

But really that's not an issue for me because that wasn't my interest, and you're actually making my point while directly contradicting his claims. My point was that, on average, I didn't understand how you could get 30 miles or 37 miles of range by charging for two hours using a 3.3 kW charger. He said the numbers were perfectly fine because he got far more range than that. To buttress this claim, he said that he routinely got 5 bars of charge in 100 minutes, the clear implication being that 5 bars was far more than necessary to go 30 or 37 miles.

What you're saying is that those five bars he is getting are misleading because they represent far less energy than you might expect from 5 bars. That's OK but if he's only getting 5.12 kWh of charge he's not getting sufficient charge to go 30 miles much less 37 miles, so his assertion about getting 30 miles of range was wrong in the first instance. In essence you're agreeing with me that he's not getting the range he was claiming to get.

 

[planet4ever]

My problem with the approach is that since there is 50% of the charge in the upper six bars and 50% in the lower six bars, you're relying on a set of recurring coincidences (aka cherry picking specific bars) that seems most unlikely.

Well, I don't charge every day, and my normal policy is to charge to 80% any night that the car has dropped to 5 or fewer bars, so your claimed "cherry pick" is quite likely for me, and it may be for LEAFfan as well.

if he's only getting 5.12 kWh of charge he's not getting sufficient charge to go 30 miles much less 37 miles, so his assertion about getting 30 miles of range was wrong

My highest efficiency so far has been 5.6 m/kWh, so I agree that I wouldn't expect to be able to go 30, let alone 37, miles on 5+ kWh. But LEAFfan consistently claims to be able to get 7 or more m/kWh, so I tend to believe his assertion -- for his hypermiling driving style.

Ray

 

[garygid]

Average length of a charging-event?

So, 7 hours at home, and three 20-minute L2's is ...
4 events, 8 hours total, so 2 hours per event.

Very misleading indeed.

 

[EricH]

I'm just wondering if a headline like "Average ICE Fill-up Only 4 Gallons!!" would attract attention.

A 2-hour charge session on a Leaf is about 25 miles of range, or maybe 1/4 of the total capacity. It doesn't shock me that people who are early-adopters of the Leaf either: 1) drive about 25 miles/day, or 2) have access to mid-day charging, which results in 2 (or more) daily charge sessions that might be only a few hours.

If refueling an ICE were easier (I could do it in my garage) and hauling the extra fuel didn't add vehicle weight, I might well top that car off every night too, irrespective of the range...

 

[TonyWilliams]

My problem with the approach is that since there is 50% of the charge in the upper six bars and 50% in the lower six bars

I disagree. Half the useable battery capacity is in the top 7 bars and the lower 5 bars, plus the two battery warnings.

 

[SanDust]

I disagree. Half the useable battery capacity is in the top 7 bars and the lower 5 bars, plus the two battery warnings.

Yes I see what happens when you trust clever labeling where you have 14 divisions and the last one is number 12. LOL

In any event not relevant. He said he was charging in the upper half: "If it's at 5 bars left (48% actual), mine will charge 5 bars in about 100 minutes."

 

[thankyouOB]

as pointed out to some degree above, the average charge per charge event is misleading.
I have during the week, usually on the weekends, a few short charging events, where I plug in and then unplug but charge for less than 10 minutes. Perhaps, I am testing the timer, or need to get around the cord, or want to move the car a few feet to get past it with a box, then I plug back in.
so I charge for 3.5 hours but plug in three times.
it really is one plug-in event that is interrupted.

this happens all the time.

 

[Stoaty]

A 2-hour charge session on a Leaf is about 25 miles of range, or maybe 1/4 of the total capacity.

I charge for 2 hours 25 minutes and get 45 miles out of that charge (including 1,000 foot elevation gain). Depends how you drive.

 

[smkettner]

This is what happens when the experts and statiticians do not actually drive a Leaf :roll:

 

[LEAFfan]

A 2-hour charge session on a Leaf is about 25 miles of range, or maybe 1/4 of the total capacity.

I charge for 2 hours 25 minutes and get 45 miles out of that charge (including 1,000 foot elevation gain). Depends how you drive.

+1! I can get almost 6 bars with a 2 hour charge and go at least 50 miles! I can easily get 100 miles from an 80% charge. Eric, it's all about how you drive.