Why would anyone buy a nissan leaf right now???

[cwerdna]

Bolt maxes out at 55 kW. Unfortunately, if the battery is too cold, it will be slow even at low SoC likely to prevent lithium plating.

Pages 10 and 11 (corner page numbers) of https://acep.uaf.edu/media/304144/Cold-Weather-Issues-for-EVs-in-Alaska.pdf discusses the subject.

 

[SageBrush]

Here is a 20-60% test based on dash SoC.

That was informative -- thanks

EVGo reports kWh "dispensed." I don't know if that is the energy counted by the utility meter or after the charger losses. They make it sound like the energy coming into the car but I'd like to know for sure. Your session dispensed 20.2 kWh in 20 minutes

If we go with the optimistic number, then average power was about 60 kW for what amounts to a pretty much best case DCFC stop.

The other calc you can do is to estimate your pack capacity. 20.2 kWh raised your SoC 40%, so full (0% - 100%) capacity is 20.2/0.4 = 50.5 kWh. Any usable capacity below "0%" SoC would be uncounted in this calc. I'm a big fan of using this charging data to calculate battery capacity since it is not distorted by BMS miscalibrations. The greater the SoC delta, the more accurate the result. For my car I plan to measure from 0% to 100% at home once a year in the spring when the pack is in the 60 - 70F range. My EVSE does not report kWh, but the OBD2 App I use will log charging over the session with enough granularity to easily and accurately calculate the kWh. LeafSpy can do the same.

I've learned more about the vagaries of battery capacity estimation. The example is my Bolt, but the ideas (if not the specifics) apply to all EVs so far as I know:
NOMINAL CAPACITY is measured from the manufacturer's set maximum charging voltage, down to the manufacturer's set minimum voltage. In the Bolt that results is 66 kWh, 188 Ahr, and a nominal voltage of 350.

The top 4% of the charging curve is not user accessible. "0%" SoC is set 4.2% above the minimum pack voltage, and the user can use 3.2% (meaning an OBD App will show -3.2% when the car shuts down. So a "0% to 100%" capacity of a new Bolt in Ahr is 188*0.918
= 172.584 Ahr
= 172.584*.35 kWh = 60.4044 kWh
The actual maximum usable capacity of a brand new battery is
188*0.95 Ahr = 178.6 Ahr
= 178.6*.35 = 62.51 kWh

 

[SageBrush]

Bolt maxes out at 55 kW. Unfortunately, if the battery is too cold, it will be slow even at low SoC likely to prevent lithium plating.

I think you meant to write 'fortunately' ...
But yes, the Bolt was 'cold-gating.'

 

[DougWantsALeaf]

You could do probably slightly better starting at 10% and charging for 20 min, but likely just another kWh in that time. A warmer battery start might have also modestly helped..but splitting hairs. When the car was new and EA was unconstrained, I once charged 22kWh (per EA) in 20 min. I would say that's as good as the Leaf gets.

The optic of a 32-35min 20-80% charge is still not bad by today's standards (not good either) as it ignores the distance achievable in that part of the charge.

I nearly forgot to mention that an Ionic 5 was in yet another stall. I peeked over and saw at 21% SoC it was charging at a blinding 68KW. Guessing it was coldgating a bit as well. If nothing else at that station at that moment, the Leaf was king in terms of charging speed.

 

[cxhansen]

TLDR: charge to 100% SOC with a timer set to departure time. SOC is State Of Charge


Charging to 100% causes faster "calendar loss", which is time driven. The longer at 100%, the more the loss. (Also high temperature)
So charge to 100% using a timer set for departure time, then drive the car. It will spend very little time at 100%. Especially true in winter, which is when likely more charge will be needed. Low temperatures slow calendar loss. As the LEAF doesn't allow for a lower target SOC, this is easier as well to implement.


Discharging to low SOC increases the rate of "cycling loss", which isn't time driven, at least until you go below 0% real SOC, which the car will not let you get to as the car shuts down at the lower margin (10%? 12% Something like that. I forget). Cycling loss goes up rapidly with lower SOCs.

Also the pilot's rule comes into play... you can never have too much runway in front of you or altitude above terrain or ... meaning for EVs more margin to get home, or more range left after getting home for some necessary trip.

A full answer would need to include exactly how low of SOC the car goes, as cycling loss increases rapidly with lower SOCs, how long and how hot it is at 100% SOC, and more. But it's very clear that battery life will be better with 90%-11% than with 80%-1%, and still better with 100%-21%, as long as you charge right before departure.

I wasn't going to clutter the thread for just a "thanks," but thanks for the detailed information!

It took Nissan two weeks to fix my account so I could use Nissan Connect EV. I was surprised that the car itself didn't have an option to charge to 80% SOC (what Tesla calls the "set limit" option). I'm even more surprised that the EV&Services app doesn't have that option. Nissan's design choices in-vehicle and in-app imply that you should just keep the vehicle plugged in and charge to 100% all the time. Does anyone know why Nissan doesn't provide a set limit option after 12 years of design revisions?

 

[LeftieBiker]

Either they REALLY carry grudges (see: EPA cuts Leaf's average range in 2014 because of the 80% charge option) or they have decided that the optics of being the only manufacturer who advises less than 100% charging in 2023 has the appearance of offering an inferior product.

 

[WetEV]

Does anyone know why Nissan doesn't provide a set limit option after 12 years of design revisions?

No. Nissan removed the 80% limit in 2013.

These are guesses.

There might be a technical reason why. Some battery chemistries can only be balanced at high SOC, so charging to 100% is necessary. LiFePO is this way, used by Tesla and (I think) others for the "standard" range or smaller battery.

Nissan might have found good enough chemistry to make calendar loss not important enough to bother with an 80% limit. Or just developed battery chemistry good enough so that life > warranty period. So no business reason for Nissan.

Sales. Nissan was somewhat burned by the USA EPA over an 80% limit in the early days. EPA reduced the stated range of the car due to having an 80% limit. The 2011-2013 had an 80% limit. The simpler story you can tell the easier it is to sell the car. The larger the stated range the easier it is to sell the car.

 

[SageBrush]

Does anyone know why Nissan doesn't provide a set limit option after 12 years of design revisions?

Only speculation.

Mine is that (as always) there are more than one reason. I'd say the most important argument inside Nissan is that the LEAF is a money loser and on the way out for a company on the brink of BK. The money and resources available to feed the customer 'want' machine are close to nil. Nissan spends some money to occasionally bump up the battery pack capacity, and they did re-skin the LEAF for 2018+ but in just about every other way the LEAF has been +/- stagnant for 10 years.

Does the Ariya have a charging limit provision ? My blind guess is yes, consistent with the idea that R&D resources have gone to that project.

Addendum: A short time googling says no charge limit in the Ariya. Is Nissan recycling LEAF s/w ?

 

[cxhansen]

https://drive.google.com/file/d/1Qf17N2lFM3F4pBFSqKfvguxr_ac_3d_-/

Let me know if the link does not work.
This is the article I have been posting graphs from

The Google drive link worked for me. Thanks for sharing it! It's also online here https://www.mdpi.com/2313-0105/8/11/234.

I'm trying to distill these articles and recommendations into something that's quantitative and accurate, but also simple for my spouse and driving-age offspring to understand and follow. I came up with this table https://docs.google.com/spreadsheets/d/1ne3rcXFScakFjS2r5lPceZh4mF3nw4IF_8rnCO0kzYk/edit?usp=sharing. If you're a newbie like me, you may find it helpful. For those who know more about battery health and chemistry, please let me know if you see anything that's wrong or missing (in the doc, or here).

Some of the big takeaways for me (largely based on the Gao et al article above, but also posts on this forum) are

• Battery temperature has a way bigger impact on SOH than charging above 80%, so I'm not going to fret about charging to 90 or 100% as needed

• Occasional L3 charging has a low impact, unless the battery is <55ºF

• The Leaf's lack of thermal management system has jumped to the top of my long-term concerns, above the lack of CHAdeMO stations

• Apparently, I need to run a 30K BTU propane heater in my uninsulated garage so that I don't charge my battery cold (only half joking)

 

[LeftieBiker]

As someone who partially heats an unheated garage (to about 40F at this time of year) I'm suggest instead that you try to use L-1 charging when possible, to try to time it so that the car is charging during the coldest nights. I have about 6 lithium-powered vehicles and devices in my garage, and the car no longer fits. :|

 

[SageBrush]

As someone who partially heats an unheated garage (to about 40F at this time of year) I'm suggest instead that you try to use L-1 charging when possible, to try to time it so that the car is charging during the coldest nights. I have about 6 lithium-powered vehicles and devices in my garage, and the car no longer fits. :|

I'm surprised that works. What pack temps do you start and end at ?

Arithmetic:
Say 1200 watts to the pack at 360 volts, so 3.3 Amps
By I^2*R, that is negligible heat into the battery

 

[LeftieBiker]

Since the car is outside, it does indeed no longer work for it. As for the bikes, I need the packs above freezing to safely charge them. If the garage never falls below 30F or so (those excursions are for a couple of hours only) and is usually 40F or warmer, then the bicycle packs never get close to freezing. The Vectrix, which uses a Leaf pack, stays even more above freezing because of the mass of its battery.

 

[SageBrush]

Since the car is outside, it does indeed no longer work for it

That makes sense to me. In the garage the the total waste heat was 'captured ' by the garage, about 20% of 1,400 watts. Similar to placing a ~ 280 watt resistance heater in the garage.

 

[Rebecca]

I recently purchased a 2023 S from CarMax to replace my 2012 SV. The 2012 was barely making it home to San Jose from Watsonville over highway 17 during these cold spells. My 2012 LEAF had absolutely no mechanical problems during my 10 years of ownership. My son-in-law now commutes in it on flat land about 30 miles round trip twice a week. Who could ask for more. I am hoping my 2023 gives me 15 years of continual driving pleasure. I bought another LEAF because I am a totally satisfied customer.

 

[Marktm]

I recently purchased a 2023 S from CarMax to replace my 2012 SV. The 2012 was barely making it home to San Jose from Watsonville over highway 17 during these cold spells. My 2012 LEAF had absolutely no mechanical problems during my 10 years of ownership. My son-in-law now commutes in it on flat land about 30 miles round trip twice a week. Who could ask for more. I am hoping my 2023 gives me 15 years of continual driving pleasure. I bought another LEAF because I am a totally satisfied customer.

I've had a similar experience with a 2012 Leaf that served me very well for over 5 years (especially after the battery was replaced under warranty). My 2021 SV+ does exactly what I expected - at a very competitive price. I will replace it with the first V2X capable EV, but not sure when/if that will happen :mrgreen: .

 

[DougWantsALeaf]

Somehow Leaf is 4th in sales in November in Norway...beating Ariya.

https://elbilstatistikk.no/

Leaf has had incredible staying power there.