Battery seems to be degrading fast
- Thread starter Todd1561
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DaveinOlyWA
Well-known member
Your pack seems to be rather "normal" compared to other 40 kwh packs.
You will eventually notice your big drops happen every 90 days (great way to know when your car was actually built) and that will likely last 12-15 months. After that, most are seeing a rather significant decrease in the rate of loss.
I don't see any benefit to charging to 100% to top end balance cells. They balance all the time and yours are pretty close.
The real question is what happens after that 12-15 month break in period. Only a few have continued the rate of degradation. Some have seen their numbers go up (mine did) while others have seen the rate drop below .2% per month w/o the large 90 day adjustments.
You will eventually notice your big drops happen every 90 days (great way to know when your car was actually built) and that will likely last 12-15 months. After that, most are seeing a rather significant decrease in the rate of loss.
I don't see any benefit to charging to 100% to top end balance cells. They balance all the time and yours are pretty close.
The real question is what happens after that 12-15 month break in period. Only a few have continued the rate of degradation. Some have seen their numbers go up (mine did) while others have seen the rate drop below .2% per month w/o the large 90 day adjustments.
DaveinOlyWA
Well-known member
Todd1561 said:
This has been bounced around for nearly a decade and Nissan has not seen it necessary to make it clearer. There are TWO warranties involved. A workmanship warranty (which is what the above was written) that is 8 years/100,000 miles and addresses ONLY cell failure, etc. So a 10 bar LEAF with a failed cell will have that cell replaced and it will still be a 10 bar LEAF.
Later a degradation warranty was added that only stated mileage/age terms. There was no other clarification other than when the car lost its 4th bar it was "eligible" to be inspected by Nissan to determine if the pack qualified for a warranty EXCHANGE. IOW, a wholesale pack swap.
Ok, now we can think that Nissan "might" give us a 9 bar replacement pack and we do this 3-4 times a year until the 8 year 100,000 mile mark is reached...or not.
Or we can simply realize that when Nissan added the degradation warranty, they failed to clearly clarify what would happen.
lorenfb said:
Furthermore, many express concern about the ambient temperature reaching 85-90F and the effect it'll have on battery degradation,
but few seem to have concern while driving at some speeds where the Leaf's battery temperature can far exceed an ambient of 85-90F.
DougWantsALeaf
Well-known member
Its hard to tell with the newer chemistry if the battery sitting at 90 continuously is that bad or not. I have driven for many hours with the car at 11 bars with no loss of performance, and no...immediate effect on SOH. Long term is yet to be known.
It does feel like the 18-20 batteries have their leveling off in the low 90s which is ok, but not great.
It does feel like the 18-20 batteries have their leveling off in the low 90s which is ok, but not great.
Todd1561
Active member
Can someone explain the battery temp. gauge? I have a blue bar at about the 15% mark this morning and a grey bar about 45%. I assume the blue bar is the current reading. Is the grey bar the lifetime maximum? The manual only says that anything under the 2 red ticks is "normal." Also, what reading on the temp gauge do people consider "too hot?" It seems to me getting all the way to the red ticks would be too hot, even though the manual states this is "normal."
Today was just a short drive (10 minutes) and cold out for NC (40F). I'll take a look on my next long drive.
Today was just a short drive (10 minutes) and cold out for NC (40F). I'll take a look on my next long drive.
HerdingElectrons
Well-known member
Todd1561 said:
The grey bar is your actual temp of the pack. Refer to LS for the actual values & there's three different sensors so that also gives you a better idea of what you're looking at.
The blue bar represents the pack being cold or too cold if I'm understanding your question however I have an '18 SL 40kWh so they may have changed the UI graphic
danrjones
Well-known member
Leaf Spy gives you at least three separate temp readings, even in the free version. As data that would be more useful.
Todd1561
Active member
Here's a picture of my gauge if that helps. I'll check out the temp info in LS, although I'd rather not have to fumble with my phone while driving. I just checked LS now with the stale data it still had on screen from this morning and it was reporting 67.6/67.6/65.3 F. What is considered too hot?
danrjones
Well-known member
lorenfb said:
I'm not a battery expert, but its not just how hot you get your battery, but how LONG its hot. That's why in an area like mine where the battery last summer was basically above 100f for several months, I expect more pack degradation.
Also, again, get leafspy, even the free version, and and OBII dongle, and look at the actual temps not the nebulous "bar".
Todd1561
Active member
danrjones said:
Yep already have the paid pro version and am currently using it (that's where all this SOH data is coming from). But I'll start using it for temp readings as well.
WetEV
Well-known member
lorenfb said:
Tesla TMS limits temperatures to about 45C. That's 113 F. So go look in my LeafSpy logs. The hottest I've ever gotten my 2014 Leaf is 38.4 C. With multiple QCs on a hot summer day, peak ambient 33C... Latest SOH is ~90% at 58k miles.
DaveinOlyWA
Well-known member
Todd1561 said:
That is a loaded question and really based on need and circumstance. Its all about "death by a million tiny cuts" with the goal being restricting your "cut count" to a few hundred grand...
The new gauge when centered is the 6th bar. On the lower half of the temperature spectrum of that bar is the optimum temperature for DC charging. The upper half is the beginning of Rapidgate. Now just because that is where Rapidgate starts does not mean or should it imply that this is where the real danger starts. This is probably the reason why it also has the largest temperature spread.
But heat alone is not the factor you should be worried about. Its high SOC. Now is that a problem? Well no...if you got your car to use it, that is. DC charging does generate heat but for most of us, its during a road trip so that SOC is reduced almost immediately lessening the effect heat has on the pack. So the heat is only really a catalyst. It does not create a bad situation but it does make a bad situation worse.
FYI; the E Plus packs have been completely redone including how they handle heat during a DC charge. I will post some stats when the heat of Summer comes along so we will have a more complete picture of the changes unless of course we get a bit of... "Indian Spring?"
Todd1561
Active member
Something of an off topic question, but related to the overall question of SOH degradation. When the SOH drops does the battery consequently use less energy to charge and charge faster? Or am I still dumping the same kWH into the pack just getting less power out of it? Hopefully it's the former!
DaveinOlyWA
Well-known member
Todd1561 said:
It will lose less energy but will actually charge slower in a miles per hour scenario. Smaller capacity means charging to a higher SOC to get what you need. As the SOC goes up, the rate of charge will slow dramatically on DC. On AC, the effect will be less unless you need most of your capacity.
goldbrick
Well-known member
Todd1561 said:
When the SOH drops the battery's capacity to store charge is decreased. So it will take less energy to reach 100% SOC. Eg, instead of a 40kWh pack, you might have a 37kWh pack so it will only accept 37kWh of energy rather than 40kWh of energy. I don't really know if that means it will charge in less time or if the charge rate is also reduced by the same %.
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