Battery temp management for new leaf
- Thread starter Tony828
- Start date
Help Support My Nissan Leaf Forum:
Keep reading; eventually you might get a clue. Or not.Joe6pack said:
Hint: the RM range meter in a Tesla is not guessing anything.
Let me put it this way: the Tesla BMS is at least as accurate in monitoring cell voltage and current as the LEAF.
Again, since you didn't get it the first time. The BMS may be equivalent, but what is on the dash is an estimate of miles, not a direct reading of the remaining capacity. It is well established on these boards that AHrs is a measurement of remaining capacity. The miles at startup is not. Are we supposed to believe that the Tesla GOM is a direct measure of AHrs alone and does not involve some sort of algorithm that takes other factors into consideration?
Again, how do you explain the negative degradation?
Again, how do you explain the negative degradation?
As the originator of this thread, I feel obliged to bring my private and public findings to the group. 1) The new Nissan Leaf continues to use passive battery thermal management system; Nissan’s management claim that the new Leaf has more heat resistant battery chemistry that’ll do the job in hot areas like Florida, 2) in the last few weeks I heard from almost a dozen Florida Leaf owners that advise against it. One from Orlando lost a third battery capacity bar in his 2016 model year (same battery type as in the new model). Despite all the vigorous defense of the current system (that may work well in cooler climate), I wish all the best but’ll move on in a different direction .........
WetEV
Well-known member
Tony828 said:
I would agree if you live in a hot place. In a moderate climate, the passive and the active thermal management is more of a personal choice than a simple technical decision.
In cool places, better battery life, cheaper and simpler look all like a clear gains for passive, other than for the few drivers that do a lot of long distance trips with many DCQCs.
I'm sure that passive vs active cooling will be discussed endlessly. The last word will not come until long after the technology gets mature.
My Leaf has been through 4 summers, has 35k miles, and is at about 90% battery capacity or 10% loss. SOH has bounced up to 92%, but a linear projection shows that the battery should be at about 10% loss. If loss is linear, then I'd be looking a replacement battery in 12 years or 2026 or so. The battery has only rarely gotten hot enough that an active cooling system would have even turned on. Some local 2011 Leafs lost the first bar this summer at 90+k miles. There is one 2011 Leaf I know of just below 90k miles that has a fair shot of passing 100k miles before loss of first bar. I'm not going to do that well, I average 2 QCs per week.
I suspect however, I'll buy a 60kWh car after they become more available. The Bolt's seat doesn't fit my rear end, so the Bolt is probably out the running unless GM fixes this. The Teslas are more excitement and dollars than I want. Eh, still looking.
Wait, Nissan is on record as saying that they are using the EXACT SAME cells in the new model as in the 2016, unchanged in any way by the manufacturer since 2016? Or just that the new battery is using an NMC type (lithium-nickle-manganese-cobalt) cell? Because those are VERY different statements.Tony828 said:
DaveinOlyWA
Well-known member
BuckMkII said:
Considering one pack is 33% larger in nearly the same volume, how can anyone think there is no change?
DaveinOlyWA
Well-known member
WetEV said:
Lot of debate over what, if any progress Nissan has made in battery robustness but I am seeing a definitely improvement over the 3 models I have driven. I questioned the degradation of the 30 kwh packs suggesting another "2013" issue where the quality of the pack was vastly different based on when it came out of the factory and was pretty lambasted over that statement. I think time will prove me right.
But I do agree that paying for something "I" don't need is not something I would be happy about so an option to have TMS is applicable to some, not to me.
As far as your statement I bolded above.... I submit a few pix. LEAF Spy reading and my mileage log showing two columns that should be clear enough. One shows date, the other shows miles driven that day. Keep in mind; I have dozens of periods that look pretty much the same. Sept 2017 I drove 2900+ miles and it only ranks as 3rd busiest month in my LEAF's "almost" 11 month history.
You forgot the third possibility -- that the 30 kWh packs are *less* robust than lizard packs. I personally think it is at least as likely if not more so than the other choices, because I expect that Nissan's loss of interest (and now sale) in the battery manufacturing plant will have QC side-effects.DaveinOlyWA said:
Battery tech requires ongoing investment to not only stay competitive but to maintain the status quo. I'm skeptical of Nissan's willingness to pour more money into a money losing venture they are exiting.
That was my implicit point: The capacity of the pack is doubled. The new pack is not twice the size of the old pack. This shows that the cells must be a different design. Therefore, we can make no assumptions about the degradation characteristics of the new pack. It could be better, worse, or the same as the preceding pack.DaveinOlyWA said:
Nissan's history of not getting it right the first time is not reassuring, but it doesn't prove anything.
Hopefully, this time they had a couple hundred cells of several different cell prototypes made up, charged them to 4.1 V and stuffed a pile of them in a 125 °F oven. Pull out a set of 5 or 10 every month and test them for degradation. DID they do this? They're not going to tell us.
DaveinOlyWA
Well-known member
SageBrush said:
higher voltage? oh cmon!
Cells are supposedly 40% more energy dense. despite additional space added between cells that overall pack size remains nearly the same with a slight weight gain. So we supposedly will have more passive air cooling due to greater air space but guessing without active venting (like exhaust or inlet fans) temperature control will only improve due to larger packs, shallower cycling, etc.
I think what we are losing sight of is the 2018 LEAF is NOT LEAF II. Its LEAF 1½ and the 40 kwh was chosen because that is all the battery that could be crammed into the existing space. IOW; it would be crazy to think the batteries are the same because they are not.
Actually a better name for the 2018 would be LEAF PP because THAT is the main reason the car has changed.
But it does signal that the EV is no longer a "special" car. Its moving to the mainstream. So minus the VERY vocal group of "EV Nomads" what we have is a car that will have a very health niche of its own.
Dooglas
Well-known member
There, fixed it for you.SageBrush said:
My own experience (and that is all I have to go on) is that both my 2013 24 kwh battery and my 2016 30 kwh battery have been as "robust" as I would wish them to be. They both performed well in the situations in which they were, and are, being used.
DaveinOlyWA
Well-known member
SageBrush said:
dk. not the source. ask Nissan but you must realize by now that the dimensions of the 2018 have not changed so its simply not possible to have a drastic change in the physical dimensions
