Good news on range and battery health!

[surfingslovak]

I think that battery capacity is the most likely answer but it's not the only possible answer.

Of course, and nobody has said anything to the contrary. At the same time, if you believe that faulty sensors and software can cause up to 30% range loss, then run with that theory. It should be easy to prove.

The LEAF has electronics that is designed to provide an on board computer information about the battery pack's state of charge. If those electronics are giving erroneous information, that could effect the range. The LEAF is programmed to go into turtle mode and completely shut down to protect the battery pack if the state of charge falls too low. If the electronics (not the software) erroneously put low state of charge information onto the CAN bus the LEAF's on board computer may react and shut down the vehicle when in reality the battery still contains a significant amount of charge.

Thank you for explaining that, we wouldn't have known otherwise. As mentioned above, it's been suggested to collect voltage readings from the cars in addition to Gids and other parameters. This was done, and we can see that cars that hit turtle mode had pack voltages in the 300 to 320 V range. This is roughly in line with what owners unaffected by range loss were reporting from their vehicles. This is also something that Jack got wrong. While he might not have had the full picture, the test was certainly not based on "bars and turtles".

Voltages are measured through a separate sensor, and although a voltage reading can have an error, much like a temperature reading, there is no modification or interpretation that must be done through software. There were people suggesting that a voltage sensor error could cause variation in range, and while that's true, it won't explain something of the magnitude we observed.

Nissan is using voltages as a source of truth to correct any misestimates and errors that the software might cause, and if they are not able to measure something so fundamental correctly, then the Leaf has a big problem. Fortunately, it could be as simple as replacing a $20 sensor, which was a solution offered by another well-meaning unaffected owner who happens to live in a cold climate.

I'm glad that Nissan is taking some cars back. They may be doing so just to avoid bad PR or they may have reversed their position and agree with the battery capacity theory.

I'm glad too, whatever the reason, and wish that they would make it a priority to acquiesce the most affected and frustrated owners.

Personally I hope that they are right about it being faulty electronics rather than an overly heat sensitive battery pack.

You realize that Nissan measured battery performance in a bench test at Casa Grande and shared the results with some of the owners, don't you? Red500 (Azdre/opossum) tested at 85% by Nissan, and was at 82.5% capacity during the range test. White 626 (Ticktock) tested at 87% by Nissan, and 87.5% during the range test. This information is on the Wiki as well (thank you, Stoaty).

Sure, but then if this were the case, why hasn't Nissan come forward with this? Why did they buyback cars instead of fixing this problem or announcing that they would have a fix for this?

Exactly.

And then there are the statements by Nissan such as the Andy Palmer video at http://www.mynissanleaf.com/viewtopic.php?f=27&t=10257" onclick="window.open(this.href);return false;.

Nissan has pretty much confirmed that a large drop in pack capacity should be expected in the first year. What they offered as an explanation is that the loss should level off, and the battery will hold its capacity and meet the projected life cycle performance.

There was a number of people from colder climes that criticized the test, those associated with it, and the affected owners. While everyone is entitled to their opinion, I can guarantee you that the test was conducted thoughtfully and with a high degree of accuracy considering the circumstances. It should also not come as a surprise that owners experiencing 15% range loss or more after less than 1 1/2 of ownership feel uneasy about Nissan's projections of 80% original range after five years (76% for Phoenix).

 

[Stoaty]

It should also not come as a surprise that owners experiencing 15% range loss or more after less than 1 1/2 of ownership feel uneasy about Nissan's projections of 80% original range after five years (76% for Phoenix).

Especially true because the Battery Aging Model built from Nissan's own data predicts 76% remaining capacity for Phoenix owners driving 12500 miles per year at an average 4 miles/kwh efficiency after only 3.3 years. You can only reach 5 years with 76% remaining capacity if you limit your mileage to 7500 miles per year.

 

[Luft]

I think that battery capacity is the most likely answer but it's not the only possible answer.

Of course, and nobody has said anything to the contrary.

Really? My post that you are parsing was a direct response to exactly that...

How would you explain why one car went 59 miles, and another went 79 miles in controlled conditions? Answer: battery capacity.

At the same time, if you believe that faulty sensors and software can cause up to 30% range loss, then run with that theory. It should be easy to prove.

phil would be the person who could tell us just what it would take to determine the packs state of charge without using any of the on board electronics. I think it would require much more that I am able to do.

The LEAF has electronics that is designed to provide an on board computer information about the battery pack's state of charge. If those electronics are giving erroneous information, that could effect the range. The LEAF is programmed to go into turtle mode and completely shut down to protect the battery pack if the state of charge falls too low. If the electronics (not the software) erroneously put low state of charge information onto the CAN bus the LEAF's on board computer may react and shut down the vehicle when in reality the battery still contains a significant amount of charge.

Thank you for explaining that, we wouldn't have known otherwise.

I may be overly sensitive but that came off as unduly sarcastic. If that's how you meant it... Well I'll just let it pass because no good would come from what I would say in reply.

As mentioned above, it's been suggested to collect voltage readings from the cars in addition to Gids and other parameters. This was done, and we can see that cars that hit turtle mode had pack voltages in the 300 to 320 V range. This is roughly in line with what owners unaffected by range loss were reporting from their vehicles. This is also something that Jack got wrong. While he might not have had the full picture, the test was certainly not based on "bars and turtles".

I absolutely agree with you that Jacks verbal depiction of the testing was dismissive and disrespectful.

Voltages are measured through a separate sensor, and although a voltage reading can have an error, much like a temperature reading, there is no modification or interpretation that must be done through software. There were people suggesting that a voltage sensor error could cause variation in range, and while that's true, it won't explain something of the magnitude we observed.

I am not familiar with how the state of charge is determined. Is it determined through a single sensor or by a much more complex method? I do know that if whatever method is being used to determine the state of charge is failing then the car can be fooled into shutting down and I don't see why it couldn't explain something of the magnitude that you observed.

Sure, but then if this were the case, why hasn't Nissan come forward with this? Why did they buyback cars instead of fixing this problem or announcing that they would have a fix for this?

I would have to guess as to why. It could be that they know that the battery packs aren't handling the heat. I'm fearful myself that the loss of range is due to the battery pack. I'm just saying that we haven't proved it and before I would go out and replace a $15,000.00 battery pack or give up on the LEAF I think I would want to be sure.

It could be that they want some LEAFs that they know are failing to tear them apart and figure out what's going on. We just don't know.

 

[TonyWilliams]

At the same time, if you believe that faulty sensors and software can cause up to 30% range loss, then run with that theory. It should be easy to prove.

phil would be the person who could tell us just what it would take to determine the packs state of charge without using any of the on board electronics. I think it would require much more that I am able to do.

Actually, as was stated above, we have Nissan's Consult III data for at least two of the cars tested in Phoenix. Phil's capacity data with LEAFscan is nothing more than displaying the data from the car, just like the Gidmeters do nothing more than display the car's data.

None of these, including Consult III, are replacing measuring devices already on the car.

Now, if your talking about a more intrusive test, sure, Phil obviously can do that, and at least one government funded study has done that. I have no intention to ever do anything like that, because I know if it could be fixed with simple software changes or cheap measuring device changes, Nissan would be all over it.

It's unlikely that Phil will have access to a severely degraded battery to test, since his neighborhood doesn't hit over 100F for many months at a time.

I'm fearful myself that the loss of range is due to the battery pack. I'm just saying that we haven't proved it and before I would go out and replace a $15,000.00 battery pack or give up on the LEAF I think I would want to be sure.

Since the problem is accelerated degradation in severe heat, and you don't have that up there, there really isn't much for you personally to worry about. Your car will be fine, unless you drive 50,000 miles per year.

 

[Ingineer]

I have a very accurate coulomb counter that can be installed in a Leaf rather easily, and then a charge/discharge test cycle could be completed. This would bypass all instrumentation in the car. The problem is that the systems in the car determine when to stop charging and also when to enter turtle, etc. So even if I can tell you the exact energy in/out of a pack, and it was low, this doesn't necessarily mean the pack has less capacity if the on-board systems are stopping charge and/or discharge early.

Now it's also possible to bypass these systems and do a manual charge and discharge, but this is more complicated.

I'm willing to assist any way I can in getting to the bottom of all this, but my time and finances are rather limited right now unfortunately.

-Phil

 

[Luft]

I have a very accurate coulomb counter that can be installed in a Leaf rather easily, and then a charge/discharge test cycle could be completed. This would bypass all instrumentation in the car. The problem is that the systems in the car determine when to stop charging and also when to enter turtle, etc. So even if I can tell you the exact energy in/out of a pack, and it was low, this doesn't necessarily mean the pack has less capacity if the on-board systems are stopping charge and/or discharge early.

Now it's also possible to bypass these systems and do a manual charge and discharge, but this is more complicated.

I'm willing to assist any way I can in getting to the bottom of all this, but my time and finances are rather limited right now unfortunately.

-Phil

I think everyone here appreciates your wiliness to help and understands limited time and money. The sad thing is that Nissan is the one who really has a vested interest in this and they are the ones who need to step up to the plate, do the tests (or hire someone like yourself to do them) and be transparent about the whole thing.

I hope that's not too much to ask.

 

[surfingslovak]

I think everyone here appreciates your wiliness to help and understands limited time and money. The sad thing is that Nissan is the one who really has a vested interest in this and they are the ones who need to step up to the plate, do the tests (or hire someone like yourself to do them) and be transparent about the whole thing.

I hope that's not too much to ask.

That's exactly right. Nissan has conducted the bench test you are looking for, and shared the results with some of the owners. From what I've gathered, it was a 5 kW steady-load discharge test. I don't believe that all the owners were informed, and it's unclear if Nissan will publish the results or not.

That said, given all the problems with dash gauges and other related software (e.g. CarWings) we have observed over the past year, I'm sure that instrument error played some role this summer. This won't explain 25 or 30% range loss however. Not unless these failures were incredibly severe, and nearly catastrophic in nature. It's far more likely that battery capacity losses are responsible for bulk of the problems, and sensors and software pick up the slack. This would explain why the measured range loss for two of the Casa Grande cars we had results for came in very close to the battery capacity loss Nissan reported to owners.

If you continue to be concerned about your battery and the Phoenix range test, ask Nissan to release actual numbers from Casa Grande for the vehicles they repurchased from owners. Ask a local dealer to determine battery capacity loss of your vehicle. I know of at least one person who was successful with such a request.

 

[Luft]

If you continue to be concerned about your battery and the Phoenix range test, ask Nissan to release actual numbers from Casa Grande for the vehicles they repurchased from owners. Ask a local dealer to determine battery capacity loss of your vehicle. I know of at least one person who was successful with such a request.

I'm not overly concerned at this point. My LEAF is holding up. However, I have been hearing mixed messages as to the cause of the problem and would like to have some answers because this problem may effect me at some point. If it is caused by high temperatures for extended periods do I need to pray for crummy summer weather for the next five to ten years?

But the fact is that we don't have enough information to determine much of anything other than some cars are having problems. I'm not even 100% sure that heat is the problem. If it is a problem with the electronics then I would like to know if the cars being effected all contain a batch of electronics produced by bad run. Sometimes this can happen. There can be an entire batch of electronic parts that are defective. Is it just a coincidence that cars in the Phoenix area have had problems or are there cars in more temperate climates that have also experienced the same problem. If cars from other areas have been affected do they have electronics from the same run? Are there cars in the phoenix area not having problems that also contain electronics produced by the same run?

As early adopters we are Nissan's EV base. We are the ones who will sell the EV movement to an ever growing customer base by using the vehicles, by talking about the vehicles and by innovating. It will be in the best interest of everyone if Nissan would give all of us complete information as to what tests were done and listen to what we have to say. Personally I would be interested to know if in the test that they did perform did they charge and discharge the packs without using any of the on board electronics? Without complete information how can we possibly come to any meaningful conclusions?

Nissan would be well served by approaching a competent expert like Phil to do testing. Phil is someone that our community trusts to run meaningful tests and provide pertinent information. It wouldn't be cheap but having a person that we trust give us information that we are sure hasn't been massaged by a corporate PR team would have great value.

 

[TonyWilliams]

I have a very accurate coulomb counter that can be installed in a Leaf rather easily, and then a charge/discharge test cycle could be completed. This would bypass all instrumentation in the car. The problem is that the systems in the car determine when to stop charging and also when to enter turtle, etc.

This problem isn't going away, and Nissan clearly isn't going to fix anything (or even acknowledge an issue), so I'll just suggest that we could do a follow-on range test next summer with "laboratory standards". Here's a tidbit; only one of the cars we tested Sept 15 had reached 95% SOC; every other car was significantly below that.

I'm willing to assist any way I can in getting to the bottom of all this, but my time and finances are rather limited right now unfortunately.

-Phil

Thanks. I suspect that we can get the finances covered, and hopefully next summer, you can make some time. I'm suggesting next summer, because that's when heat related issues will once again explode, only this time, it won't be "just" 140 cars affected... Maybe 1140.

 

[Herm]

I have a very accurate coulomb counter that can be installed in a Leaf rather easily, and then a charge/discharge test cycle could be completed. The problem is that the systems in the car determine when to stop charging and also when to enter turtle, etc.

But you can get a good guess about the SOC by measuring the voltage (and cell temp), so your coulomb counter would still give you a good consistent capacity number.

 

[surfingslovak]

OK, now we are in trouble ;-)

 

[EnergyNovice]

The Leaf battery in AZ is not that functional.