Dumb**s alert: am I the first to drain it??

[evnow]

My EV, (a home conversion), starts cutting back power gradually and progressively as you near empty, so you get early warning.

You do get early warnings. If anyone gets a turtle, they have already pushed too far. You get Battery Low and Battery Very Low before turtle.

This is not to say 100 yard is fine with turtle.

 

[JRP3]

But I assume those warnings don't come with a reduction in power. If they did it would do two things, give visceral feedback that your range is near the end while also extending your range. If people see the warnings but continue to drive the same way the end will come sooner.

 

[klapauzius]

Nissan told me that the 24 kWH battery actually uses just 20 kWH for driving. The rest is buffer to keep the Li-Ion healthy.

Doesn't that contradict what others have found, and what Nissan has claimed? I thought 27kwh actual had been confirmed.
Regarding range information and turtle mode, I think a SOC numerical display should be mandatory, and I think turtle mode should be progressive, and start sooner than it seems to. My EV, (a home conversion), starts cutting back power gradually and progressively as you near empty, so you get early warning. I had one low SOC event and was able to drive about 3 miles as the performance gradually dropped till I was doing about 20 mph. Could have gone a little further but that got me home.

Apparently there is some degree of uncertainty, but this is what someone from Nissan told me - 24 kWH total, but the mid 20 kWh are used for driving. This is consistent with the SOC measure, actual miles driven and the trip average miles/kwh. However I would love to get some confirmation form others on this.

A factor playing into this is of course temperature. Is it possible that the battery at cold temperatures has less charge capacity? The manual says so. The people at Nissan told me, that it would not amount to much, but is it possible to have 27 kWh at say 68 F and 24 kWh at 42 F and less at 32F ?

 

[scottsim]

Grin,

Still happy I have a Prius conversion here...seems that you guys would benefit from what a ScanGuageII (OBDII) adds to the Prius, monitoring many internals, such as SOC and temperatures. Lately, I have been made more aware that the engine (ICE) needs to run at least occasionally to keep the lubricating fluids circulating properly.

Scott
www.smilingdogsranch.com/priusblog

 

[JRP3]

Nissan told me that the 24 kWH battery actually uses just 20 kWH for driving. The rest is buffer to keep the Li-Ion healthy.

Doesn't that contradict what others have found, and what Nissan has claimed? I thought 27kwh actual had been confirmed.
Regarding range information and turtle mode, I think a SOC numerical display should be mandatory, and I think turtle mode should be progressive, and start sooner than it seems to. My EV, (a home conversion), starts cutting back power gradually and progressively as you near empty, so you get early warning. I had one low SOC event and was able to drive about 3 miles as the performance gradually dropped till I was doing about 20 mph. Could have gone a little further but that got me home.

Apparently there is some degree of uncertainty, but this is what someone from Nissan told me - 24 kWH total, but the mid 20 kWh are used for driving. This is consistent with the SOC measure, actual miles driven and the trip average miles/kwh. However I would love to get some confirmation form others on this.

http://www.mynissanleaf.com/viewtopic.php?f=4&t=2823

A factor playing into this is of course temperature. Is it possible that the battery at cold temperatures has less charge capacity? The manual says so. The people at Nissan told me, that it would not amount to much, but is it possible to have 27 kWh at say 68 F and 24 kWh at 42 F and less at 32F ?

I don't think it would drop by that much.

 

[AndyH]

We have 24kWh available for us to use. 20kWh from full to the 'red bars'.

The battery will 'grow' extra capacity in warm weather, and will lose some capacity when cold.

The SoC gauge will give us feedback on the battery, but it doesn't give info on range. If we charge to 100% in our 70°F garage, and then take a short drive and park in a 80°F greenhouse for a couple of hours (98% SoC when we arrive, 101% when we leave) we might think we've still got 100 miles range. But a cold front passed thru while we were inside and now it's 48°F. As we drive, we use energy faster than average due to the colder more dense air, but we also lose SoC due to the cooling battery pack.

SoC is a moving target, and miles per kWh is as well. Throw in driving style and an extra passenger and any self respecting range-estimating computer will be in a fetal position under a back seat.

At the end of the day, the computers in the car are there to protect the battery, not ensure we get where we're going.

We have to explore the corners of the operation envelope at different temperatures, terrain, and loads to learn our cars. Once we do that, we'll know what to expect.

 

[SanDust]

We have 24kWh available for us to use. 20kWh from full to the 'red bars'.

That would seem to be contradicted by three different but converging pieces of information. One is that Nissan told klapauzius that you have 20 kWh available. Two is that if you take the EPA test numbers and evnow's 80% charging efficiency then a full charge uses 19.85 kWh (34 X .8 X .73). Third is that the known Volt numbers indicate a full discharge cycle uses 19.997 kWh (10.2 / 35 X 73 X .94). Put differently, if the Leaf is using 24 kWh per full charge-discharge cycle then it's not getting 99 MPGe and it's considerably less efficient than a Volt, which seems highly unlikely given the mass difference between the two cars.

While trying to figure out how not to get stranded coming back from the airport, the first rule would be to skip the 80% charging and charge to 100% whenever possible. Not only will you start trips with more energy in the battery, but while charging to 80% may slightly prolong battery life but it may also contribute to the car's overestimating both the range and the energy in the cells. The second rule would be that, in cold weather, take the range that you think you should get, or apparently what the Leaf suggests you will get, and half it. Then subtract another 10 miles for a buffer. This may limit your range and when you can use the car but it will also prevent you from getting stuck and having to call for a tow.

 

[mxp]

There are 2 ways you are supposed to be able to shut it off under normal circumstances- push the starter button 3 times in succession, or if that doesn't work hold the starter button down for 2-5 seconds. Neither worked. The dealer wasn't able to get it to turn off either as of the time I left.

I am realizing how specific I need to be when posting on the site or people misunderstand. While I mentioned I generally go 60-63 on the highway, this is San Diego at 3:45 in the afternoon. From the I-805 merge up past Encinitas I was doing between 18-35 on the highway. This is about 10-12 miles of the trip. I took it to 63 for about 8 miles before i saw it hit the 17 miles left and started slowing down just in case.

I was on city streets in San Diego for a good portion of the trip today. More than 1/2 of the trip this morning southbound was at 20 mph with traffic. I also didn't mention that I stopped at a Nissan Dealer in San Diego to charge for an hour before heading north.

My average is 4.1 - 4.3 on driving. So I don't typically drive 88 miles at 63 mph. I typically drive no more than 45 miles during the day on city streets.

I will be out of town for the next week, so I told the dealer to keep the car and put it through tests while I am gone. I will post if I hear anything. But have a sinking feeling the title of my post is correct... Dumb**s.

Hi Kelangst, I am interested in your update. Could you kindly update us as to what exactly happened after you came back to pick up your car? Did they replace your entire battery pack?

Do let us know what's the story so far.....

Thanks!

 

[Nekota]

I would think Level3 charging would be very helpful to get the car going for another 20 miles (10 min charge). Level 3 charging can give up to 80% charge in 30 minutes and would be done with a generator similar to the ones used for the Nissan Leaf test drives. This level of charge would require a 50KW alternator which doesn't seem to be all that difficult - e.g. a Leroy Somers M45 is 600 lbs and 30 x 24 x 20 inches and could be powered by the tow truck engine. A new meaning for Leeeeroy :!:

 

[AndyH]

We have 24kWh available for us to use. 20kWh from full to the 'red bars'.

That would seem to be contradicted by three different but converging pieces of information. One is that Nissan told klapauzius that you have 20 kWh available.

Who at Nissan?
- We have direct quotes from Mr. Perry that we have 24kWh available to the user with a total pack capacity that is 'proprietary.'
- Nissan reported to the EPA that the pack was 24kWh (Page 11 http://www.smidgeindustriesltd.com/leaf/EPA/FOI-BNSXV0000LLA.pdf)
- We have real-world drives from "100%" to "almost-time-to-get-out-and-push" that took more than 24kWh to fully charge
- We also have Ingineer's 'quality time' with the Nissan scan tool where he reports a total capacity in the 27kWh vicinity.

Two is that if <snip>

We no longer have to guess, fumble, or compare with other cars as we have all the proof we need that the capacity available to Leaf drivers is 24kWh.

 

[DeaneG]

- We have real-world drives from "100%" to "almost-time-to-get-out-and-push" that took more than 24kWh to fully charge

Shouldn't it take 24kWh/0.8 or about 30kWh from the wall to fully charge from flat?

 

[Ingineer]

... We also have Ingineer's 'quality time' with the Nissan scan tool where he reports a total capacity in the 27kWh vicinity. ...

Just to be clear: The battery ECU reports usable capacity in Amp-Hours not kWh! On the car I tested recently, it reported 67.568Ah. If the batteries are cold, then internal resistance increases, thus I2R losses go up resulting in voltage sag which means less kWh but still the same Ah. This is why battery capacity is measured in Ah!

 

[JRP3]

- We have real-world drives from "100%" to "almost-time-to-get-out-and-push" that took more than 24kWh to fully charge

Shouldn't it take 24kWh/0.8 or about 30kWh from the wall to fully charge from flat?

Depends on the charging efficiency, it should be much better than 80%, I'd think 90% or better.

 

[AndyH]

- We have real-world drives from "100%" to "almost-time-to-get-out-and-push" that took more than 24kWh to fully charge

Shouldn't it take 24kWh/0.8 or about 30kWh from the wall to fully charge from flat?

JimmyDreams reported 25.6kWh from the wall for a full charge from "consumer zero%" to "consumer 100%".
http://www.mynissanleaf.com/viewtopic.php?p=52709#p52709

80% efficiency for lead acid or NiMH, maybe. Welcome to the Wonderful World of Lithium.

 

[DaveinOlyWA]

- We have real-world drives from "100%" to "almost-time-to-get-out-and-push" that took more than 24kWh to fully charge

Shouldn't it take 24kWh/0.8 or about 30kWh from the wall to fully charge from flat?

a bit less than that i think. hard to pinpoint since i cant fully recharge from that low of a pack, but i am guessing it would take more like 28 Kwh give or take. my efficiency appears to be around the 85% range.

now, i have run down to turtle mode once, 2nd battery warning about half a dozen times. problem is with 120, an overnight charge only gets me to around 60% SOC. which is about 14-16 kwh. then i drive my commute of just over 18 miles come home, plug in again and do another 14-15 kwh.

am working on getting a better picture and now feel i have collected enough data to do so, will take a bit to crunch #'s as soon as i figure out what to crunch

 

[DarkStar]

80% efficiency for lead acid or NiMH, maybe. Welcome to the Wonderful World of Lithium.

My experience has generally been 90-95% efficiency when charging LiPo batteries so this matches up well!

 

[Kelangst]

Hey guys - sorry I took so long to get back to you. Was out of town. Sounds like the experience klapauzius had was almost exactly like mine. So here's the feedback from Nissan:

They brought in a specialist from Los Angeles, and TWO engineers from Japan. They put my car through extensive testing over the course of almost a week. Charging, discharging, driving, etc. Bottom line: nothing is wrong with batteries, nothing is wrong with systems, nothing is wrong with car. I drove it until it had no power.

Their feedback was that Nissan knows they have an issue with calculations of available distance and Human Interface issues under 2 bars of charge. So my problem was that I first charged the car to only 80%, then without driving it I thought I might need more so I charged for another 45 minutes, then I drove it, then I charged for 70 minutes, then I drove it.... bottom line is that it had trouble given all of that and the mixed driving of both highway and city street. It just wasn't able to provide me the feedback that I needed. They have a software update that has been tested and partially deployed in Japan that they believe will assist with this problem, and which should be pushed to the cars in the US soon.

So this is a root cause of human error, with the contributing factor that one needs to be aware that when you hit the last 2 bars, the calculation gets a little dicier.

And just to respond to one of other question: I was at 2 bars at 17 miles left. The last 2 bars disappeared very quickly.

I feel like they responded to this issue well. My experience with the roadside assistance was just as laughable by the way. But I intentionally had mine towed to the dealer just in case something was wrong.

 

[wsbca]

Shouldn't it take 24kWh/0.8 or about 30kWh from the wall to fully charge from flat?

Depends on the charging efficiency, it should be much better than 80%, I'd think 90% or better.

In a perverse way I'm now actually hoping that charging efficiency IS lower - we're pretty consistently getting 3.2 miles/kWh from the wall, as are other folks. So if we can only shove 24kW (or 25 or 26) into a truly empty car as measured from the wall, the ultimate range of the car in our environment (by which I mostly mean terrain) is only going to be 75-85 miles. Although higher efficiency in terms of $/mile would be nice, I'd rather have more range at the expense of a bit of $. Especially as the public infrastructure starts to appear, making trips other than our normal commute plus errands more feasible. Longer-legged trips I mean. For example a day trip to a location where we could get a full L2 charge while we were there, or an overnight trip combined with an L1 charge. I want that range to be further (setting aside for the moment the inclusion of L3 charging en-route).

What I mean is, I'd rather have to put 30kWh from the wall into the car and be able to go 96 miles, than be able to fill the car using just 25kWh but then be constrained to 80 miles. And based on the empirical fact that I'm going to get 3.2m/kWh (again, in our terrain), reality is somewhere along that continuum.

 

[leafme]

I was at 2 bars at 17 miles left. The last 2 bars disappeared very quickly.
My experience with the roadside assistance was just as laughable by the way. But I intentionally had mine towed to the dealer just in case something was wrong.

Thanks Kelangst

Questions

1. Last two bars disappeared quickly... How many miles would you estimate you drove during those last two bars and was it at freeway speeds or city street speeds?
2. Laughable roadside assist... Can you elaborate a bit on this? Were they incompetent and did not know what they were doing? or?

Thanks

malcolm

 

[Kelangst]

In response to questions: I was at 17 miles and 2 bars at Tamrack exit. By Carlsbad exit (1.5 miles away going probably 60-63) I dropped a bar and was --. Less than a mile away I was turtle. Less than a mile I was dead and drifting through a left hand turn on a coast to try to get to a parking space. So clearly when I looked down at 17, I probably had very little left in the second-to-last bar. I had the trip planning screen up ensuring that my house was still in the white zone. I mean I was paying attention. But given the explanation and all of the things I put the car through that day, and the complexity of calculating the available driving distance.... it is understandable.

The roadside assistance:

1. Almost 2 hours before tow truck showed up
2. Guy on the phone kept asking me the model of the car. "Nissan Leaf"... "a what? I'm sorry, I meant what is the model of your car."
3. I also got the "do you need a jump start" question.

Roadside assistance isn't a Nissan company, it is a third-party company. My guess is that they had not updated the call center scripts yet.