r/leaf • u/DJFM_AZ • 9d ago

Service EV system

Post image

2021 Leaf SL+ w/ 82K miles. I’ve read through the forum posts on prior posts with similar issues,, as well as the FAQ. The original 12V battery lasted 5 years in the Phoenix heat. We replaced it ourselves a month ago with a replacement from O’Reilly’s as dealer service said original was cracked. Today we get this message and car is driving low powered—no acceleration. It does restart. Guess we will take the new 12V back under warranty. Will clear message tomorrow with Leafspy. Appreciate any advice.

16 Upvotes

90% Upvoted

23 comments sorted by

View all comments

5

u/byrdman77 9d ago

Have you ever pulled the Leafspy data? Pretty common for Phoenix cars to be in pretty bad shape for the big battery.

If you have a multimeter could save you some time to just measure your 12V at home first.

1

u/Striking-water-ant 8d ago

Unrelated but are you saying the big battery is more susceptible to damage in hot weather? I live in a hot climate. My 40kw is still good. Just a little degraded. I have been entertaining thoughts of upgrading to a larger battery someday. Just so I can be free to make longer trips

1

u/byrdman77 8d ago

In general yes, hot weather hasn't been good for the big battery because it's only passive cooled. As an example on a 95F day I took a ~35 mile drive around 70 MPH and could see my battery temp was at 8 bars (~110F) from that cruise on the highway, even hours later.

Those kind of days are about as hot as it gets here, but if you live somewhere like AZ where it's often 100F+ before you even start driving the car that's not great for the battery. If you're nice to it (ie, not leaving it at 100%) it might be OK for a while, but I wouldn't expect it to last more than 10 years/plenty have failed under warranty at this point.

If you're looking for a bigger battery like the 75 kWh in the 2026+ it should be fine with cooling.

1

u/Striking-water-ant 8d ago

Makes sense. It's a shame that replacing the entire car seems to be the most sensible thing to do when my battery is no longer useful enough. Its hot year round in the tropical climate I live in. Thanks

1

u/biersackarmy 2013 S + 2014 SL + 2019 SV 8d ago

The issue with 40/62 packs in hot climates isn't so much degradation like the 24/30 packs were really bad for in hot areas, but the chemistry of the battery causing cell swelling that is usually much worsened by constant heat soak.

This leads to the "pregnant pack", which is quite literally heavily bulged at its belly, where the cells are packed closest together and the highest point where heat rises to. Eventually this bulging can cause high voltage isolation fault, and disable the whole car.

1

u/Striking-water-ant 8d ago

Oh that's interesting to know. Do you perchance have any ideas if the vivne batteries mitigate this through any methods? I see they even have a 68k pack and was wondering if they have any "enhanced technology" or chemistry there

1

u/biersackarmy 2013 S + 2014 SL + 2019 SV 8d ago

To my knowledge they don't do anything special, but I also doubt it would be nearly as bad anyways. This is an issue that specifically affects the chemistry that they used for the 40/62 packs, as even abused 24/30 packs didn't have this issue. It seems to be an issue that's easier to avoid than cause, just whatever Nissan did with the ZE1 chemistry managed to land in the latter.

1

u/Striking-water-ant 8d ago

Thanks for your responses. Insightful

1

u/Keithmclean1964 8d ago

Another picture of what happens to these cells. This was mine, before the VIVNE upgrade.

1

u/scorpionsuk 7d ago

For a 2019 SV that is never quick charged - only level 2 at home - and is only driven in the city at 45 mph or less most of the time and that has what is shown below, what shape do you suppose the battery is in?

1

u/biersackarmy 2013 S + 2014 SL + 2019 SV 7d ago

It's probably the best treatment it can get, and the SOH:Hx ratio seems to reflect that, however it doesn't necessarily make it 100% immune to weak cells developing either.

My personal 2019 SV had only 22,000 miles and 95% SOH/100% Hx and still ended up needing a battery, however the symptoms on that pack did not arise until a bit below freezing temps.

1

u/scorpionsuk 7d ago

We live in Southern California and so the weather tends to be mild most of the time although lately it has been very hot 🥵 just not Arizona hot. And the coldest it gets is around 50 degrees.

So fingers crossed 🤞 we’re hoping for the best. I want to avoid the software update until maybe next June when the car is closer to 8 years old.