How should Nissan respond to dropping capacity?

[padamson1]

Until recently, I didn't know about the just setting the END timer trick so I was starting my charge at midnight and it was sitting fully charged for a couple of hours each morning. I also, until recently, usually charged to 80% - only going to 100% if I knew I had an extra errand. Recently, however, I spent a few weeks charging to 100% on the recommendation of two different Nissan employees to see if that helped the car recover some of the lost capacity. It didn't. I'm going back to 80%.

I assume that the Nissan folks were advising 100% charge to try and force a re-balance of the battery cells in hope that that would get you some capacity back.

As I understand it to force a re-balance, you need to go to 100% without using the timer (manual charge with the timer disabled) and leave the car connected at least 3 extra hours (past the time the charge stopped at 100%), but maybe I'm wrong. GaryGid or Ingineer could probably confirm this.

 

[GaslessInSeattle]

Regardless of what Nissan should do, I think the question should be what should prospective buyers do? After reading all posts on this issue, in particular the one below from another thread, I cannot recommend that anyone buy a Leaf in an area like Pheonix. lease only until more is known, there is just too much liability and even then be very careful not to violate any of Nissan's recommendations so as not to be liable for a new battery when the lease is up! Loosing 1 bar a year would make the Leaf an unwise purchase by almost any calculation and it's hard to believe that Nissan would knowingly sell the Leaf in an area that they know will cause such accelerated decline. Also it's clear to me that we have access to much more of the batteries capacity than was originally thought and that even those of us in cooler climates should take the limits of the batteries seriously, limiting time at high or low SOC, even consider cycling the battery closer to 50% if one's commute is short/just a few bars and watch the temp when QCing multiple times. for those needing daily 80-100% charging, as has been said, certainly using an end timer is prudent. I'm sorry to say that it appears that the battery is not as robust as I had been lead to believe, though I'm am still confident that the car will meet my needs for many years to come.

I talked to one of the ECO techs today while QCing, and you owners in Phoenix aren't going to be too happy about what he told me. He talked to someone that had tested these packs, and was told that in AZ, they are expected to lose a capacity bar every 15,000 miles. So that would be only about 78% left in just two years. Even his LEAF lost one recently and then a few minutes later it came back. He tested his pack after an L2 100% charge, and he said he only has 17.6kW h capacity left. He also said he drove a LEAF in TN and tested that one after a 100% L2 charge and it said there was 23.6kW h in that pack available.

from:
http://www.mynissanleaf.com/viewtopic.php?f=31&t=8331&start=380

 

[abasile]

I'm sorry to say that it appears that the battery is not as robust as I had been lead to believe, though I'm am still confident that the car will meet my needs for many years to come.

Overall the battery appears to be quite robust in a variety of conditions; it's working out quite well for most of us. The big exception appears to be the battery's ability to tolerate extreme heat. If you're in Phoenix and have summers off, find a pleasant place up in Flagstaff or Show Low, and take your LEAF! As I write this, our LEAF is cooling off in the ambient temperature of 45 degrees in our driveway...

 

[phxsmiley]

If you're in Phoenix and have summers off, find a pleasant place up in Flagstaff or Show Low, and take your LEAF! As I write this, our LEAF is cooling off in the ambient temperature of 45 degrees in our driveway...

That sounds good. Let's see, it's 170 miles to Flagstaff from Chandler, then it's a climb from 1000' to 7500', with no charging stations past 30 miles from Phoenix. Sounds like an adventure!

 

[TonyWilliams]

Also it's clear to me that we have access to much more of the batteries capacity than was originally thought

I talked to one of the ECO techs ....said there was 23.6kW h in that pack available.

If you're basing the available capacity based on what an Ecotality guy told somebody else, let me just point out that this same reporter also said that he was told that the battery holds 28.8kWh last year.

Here's a few other comments from the same reporter, repeated many times on this forum:

http://www.mynissanleaf.com/viewtopic.php?p=142453#p142453" onclick="window.open(this.href);return false;

"I believe [battery capacity loss from sitting in the heat] is of no concern unless you have your LEAF in 120*F for 24 hours or more. The highest temp our garage was in the 'heat' was 110, but that was only for a few hours. Most of the summer it was between 100 and 109."

http://www.mynissanleaf.com/viewtopic.php?p=131736#p131736" onclick="window.open(this.href);return false;

"6-8%? That is in no way a gradual loss and I'll bet my bottom dollar that if you take your car in after one year and it has this kind of loss, they will replace the modules that are defective, no doubt about it. The consensus is that after ten years/100,000m, the battery will have a loss of 20-30% depending on its care. So that is a 2-3% yearly loss of capacity which wouldn't be covered and would be gradual/normal."

In other words, I'll believe hard data. So far, that suggests 281 * 80 = 22.5kWh available, which is about 93% of 24kWh. 2% is left unusable at the bottom, and 5% at the top. Those are fairly hard facts for a 100% fully functioning new battery. Just to be clear, that 22.5kWh isn't what you'll measure for range, because there are losses when the power is used, which brings us to 21kWh useable.

Neither 28.8 nor 23.6 is accurate. Having said that, yes, your points are well taken not to cycle the battery too far from 50%, and that works great for folks who can do that. As we've seen, there is one gentleman with almost 40,000 miles, charging to 100% twice per day, and he put a Gid meter on it, and it looked like a new battery with near 281 Gid performance.

So, the common denominator to these loses of capacity is HEAT.

 

[mwalsh]

So, the common denominator to these loses of capacity is HEAT.

With myself being the apparent exception, at least when it comes to extreme heat.

Edit: Actually I see from reading one of the other theads tha JPV's capacity seems to be tracking the same way as mine, and she lives in SoCal too (though her LEAF lives in the warmer inland during the day while mine lives near the coast).

 

[thankyouOB]

until this month, I hadnt paid attention to battery heat gauge.

Now, I see that when i charge at home overnight, the battery is typically five bars.
but it is typically six bars when I get in the car after work. I charge there in the AM for about 1.5 hours.

it is parked outside at home and in a large underground garage at work.
I think it is generally a bit warmer in the garage.

is this an ambient temperature phenomenon?

 

[mwalsh]

until this month, I hadnt paid attention to battery heat gauge.

Now, I see that when i charge at home overnight, the battery is typically five bars.
but it is typically six bars when I get in the car after work.

My gauge is tracking the same way as of now. Except on cooler mornings, like yesterday's, when I start with four bars. I doubt your inside vs. my outside is all that much of a factor, being as how the pack is pretty well sealed up. How is your Gid count holding up and what is your current mileage?

 

[thankyouOB]

i have 14k miles but no gidmeter.
i am holding out for the new ingineer toy, though all the chatter about capacity loss has me curious.

i dont have a good comparison with the first 6 months when I tracked bars left and GOM miles left carefully, as I have been able to charge at work since March. But my two-and-from bar usage remains at four bars to go 25 miles.
I guess I could skip it for a few days and see if the roundtrip is still 8 bars with GOM at 20-25.

 

[TNleaf]

i have 14k miles but no gidmeter.
i am holding out for the new ingineer toy, though all the chatter about capacity loss has me curious.

I'm in a similar boat. I have no gidmeter, but am now curious at how many "gids" my car has been reading. I've been about 50/50 on 80% and 100% charges... but just recently I've been noticing that I'll lose the 3rd bar (from a 80% charge) a lot sooner than I used to, and that's even with better economy figures that I was getting before. Only a slight indicator of something being changed, but it doesn't have me worried too much.

Again, just out of curiosity, I want to get a "gid" reading or an actual SoC reading from the LEAFSCAN when it becomes available.

 

[tzzhc4]

The issue isn't just in Arizona. My LEAF only has 11,800 miles on it and I only charge to 80% but I have lost capacity as well. 100% charge only gives me 247 gids now with 80% only going to 208 gids.

 

[GRA]

The issue isn't just in Arizona. My LEAF only has 11,800 miles on it and I only charge to 80% but I have lost capacity as well. 100% charge only gives me 247 gids now with 80% only going to 208 gids.

Given summer temps in parts of Texas (esp. last year), I'm not surprised. I'd expect to see similar losses at least in parts of Nevada, Oklahoma, and New Mexico, and maybe even Kansas/Nebraska.

 

[TonyWilliams]

The issue isn't just in Arizona. My LEAF only has 11,800 miles on it and I only charge to 80% but I have lost capacity as well. 100% charge only gives me 247 gids now with 80% only going to 208 gids.

Arizona or Texas are just political boundaries that heat doesn't recognize. My car is also well below 281 on average (at 24,000 miles) and it has never been exposed to Arizona / Texas style heat.

I know that my battery will has a greater degradation impact than the guy who has almost 40,000 miles in mild weather because I cycle my battery deeper, frequently. He is still knocking out solid full performance data, but it will eventually start falling. I don't expect my battery to degrade any more than the 2-3% per 10,000 miles that Nissan specifies.

 

[EdmondLeaf]

The issue isn't just in Arizona. My LEAF only has 11,800 miles on it and I only charge to 80% but I have lost capacity as well. 100% charge only gives me 247 gids now with 80% only going to 208 gids.

Given summer temps in parts of Texas (esp. last year), I'm not surprised. I'd expect to see similar losses at least in parts of Nevada, Oklahoma, and New Mexico, and maybe even Kansas/Nebraska.

Any suggestions how to lower the loss, temp in low 90 now(which is not different than PHX today)?

 

[surfingslovak]

Arizona or Texas are just political boundaries that heat doesn't recognize. My car is also well below 281 on average (at 24,000 miles) and it has never been exposed to Arizona / Texas style heat.

I know that my battery will has a greater degradation impact than the guy who has almost 40,000 miles in mild weather because I cycle my battery deeper, frequently. He is still knocking out solid full performance data, but it will eventually start falling. I don't expect my battery to degrade any more than the 2-3% per 10,000 miles that Nissan specifies.

Is your Leaf around 270 Gids, Tony? Given the temperate weather in San Diego, have you seen any seasonal drop-off correlating to higher temps?

 

[GRA]

The issue isn't just in Arizona. My LEAF only has 11,800 miles on it and I only charge to 80% but I have lost capacity as well. 100% charge only gives me 247 gids now with 80% only going to 208 gids.

Given summer temps in parts of Texas (esp. last year), I'm not surprised. I'd expect to see similar losses at least in parts of Nevada, Oklahoma, and New Mexico, and maybe even Kansas/Nebraska.

Any suggestions how to lower the loss, temp in low 90 now(which is not different than PHX today)?

Just follow the same recommendations as have been made for Leafers in Arizona. Better yet, if you haven't bought one yet, opt for a car with a TMS.

 

[TonyWilliams]

Is your Leaf around 270 Gids, Tony? Given the temperate weather in San Diego, have you seen any seasonal drop-off correlating to higher temps?

About 260-ish.

 

[TickTock]

i have 14k miles but no gidmeter.
i am holding out for the new ingineer toy, though all the chatter about capacity loss has me curious.

I'm in a similar boat. I have no gidmeter, but am now curious at how many "gids" my car has been reading. I've been about 50/50 on 80% and 100% charges... but just recently I've been noticing that I'll lose the 3rd bar (from a 80% charge) a lot sooner than I used to, and that's even with better economy figures that I was getting before. Only a slight indicator of something being changed, but it doesn't have me worried too much.

Again, just out of curiosity, I want to get a "gid" reading or an actual SoC reading from the LEAFSCAN when it becomes available.

Since I think it is important for us to gather as much information as possible and for everyone to have a baseline for future comparison, I will also (Leaffan already made this offer) offer to provide access to a gid-o-meter for anyone who wishes to check their status in the east valley (within reasonable distance to Queen Creek). PM me and we can arrange a time for me to come by when you are at 100% charge.

 

[LEAFfan]

I talked to one of the ECO techs ....said there was 23.6kW h in that pack available.

Neither 28.8 nor 23.6 is accurate.

Tony, the tech that drove the car in TN isn't the same one that told me that Nissan told him it was a 28.8KW h pack. After he drove the car, he used his 'laptop tools' and read 23.6kW h available in the pack. His own LEAF reads 17.6kW h. Since you're not a 'tech', I find it strange how you can dismiss his readings. You need to stick to what you know instead of dismissing things that you obviously don't have the knowledge or facts.
Speaking of accurate, you should redo all your charts and make them realistic instead of using just set speeds. When someone takes a 'trip' somewhere, they just don't start out at your set speed nor do they end it at your set speed. More accuracy with the m/kW h would be realized by making the 'whole' trip with those set speeds included. I drove mostly freeway speeds today, with a little before and after and exceeded your chart numbers by quite a bit even though almost all of it was freeway speeds.

 

[surfingslovak]

Any suggestions how to lower the loss, temp in low 90 now(which is not different than PHX today)?

Just follow the same recommendations as have been made for Leafers in Arizona. Better yet, if you haven't bought one yet, opt for a car with a TMS.

I would keep a low SOC during the hottest portion of the day. If 3 or 4 bars can get you home, then aim to arrive with that SOC at work. Preconditioning will help a bit as well. This means that if you had an airconditioned garage or a cooler parking spot at work, this will benefit you, and help carry the car through the hottest portion of the day. The core chassis temperature won't rise as quickly as the interior of the car.