awhile wrote: ↑Sun Oct 02, 2022 12:56 pm
GaleHawkins wrote: ↑Sat Oct 01, 2022 9:36 pm
5% annual is within normal limits Since Feb 2020 when we got the 40 kWh pack we have added 16K miles on our 2016 Nissan Leaf SL that is now showing 41K miles total and SOH is 94.95% Typically we loose 0.01% SOH daily when the 12 volt battery is connected which is around 3.65% annually.
SOH held at 94.96% for 30 days but today I closed the 12v cutoff switch and drove down 82% SOC to 55% and SOH dropped from 94.96 to 94.95%.
Our car sets outside but in the shade until 3-4 PM. Seldom does SOC go below 30% and 98% of time i charge to 100%. Fully charged our mV reading drops to the 2mV-4mV range showing good ability to discharge and recharge or flexibility. High battery temperature noted this summer 107F. Air temperature this summer hit 98-103F for about 30 days.
So is the connection to 12 volt battery the most significant contributor to battery SOH degradation/decay? More than time spent at "high temperature + fully charged"
I am still racking my brain on the WHY.
Someone mentioned that provides a path to ground for the traction battery.
After it got totaled we had it in our shop working with it for about 18 months this was during COVID-19 and everything else.
For safety reasons especially with an EV you do not want the 12v battery connected while it's sitting inside your shop that reduces fire risk.
Every time that I went out to mess with the car I would run Leaf spy Pro and I was noticing there was no battery degradation from the last time where it been a day or a month. The times that I forgot to disconnect the battery cable and I came back there would be degradation of about 0.01% per day. In 18 months SOH dropped from 96.08 to like 95.72% which was like the number of days that it was at other shops that I farmed it out to for body and airbag work.
I drove the Leaf the first time in a month yesterday to go to town to get some diesel fuel for the tractor and I plan to drive it tomorrow. We recently picked up a 2015 Prius C and I have been playing with it and trying to figure it out and so I've just left the Leaf parked with the battery disconnected because I actually put a blade cutoff switch on the negative post cable.
Hopefully someone else with Leaf spy Pro and a Leaf that gets parked for a few days at a time can see if they can duplicate the results that Leaf Spy Pro is reporting in our case.
I have always wondered why Nissan had such a bad issue in some cars with degradation and maybe this is a factor? If one had the schematic and could sit down and work through a possible discharge maybe they could come up with an answer. It would seem that Nissan knows this fact or should.
As a side note I also discovered that the car would not move out of the intersection and I have figured out that a relay is held open until the 12 volt battery discharges so that and that would be a safety feature. The 12 volt battery was dead when I went back to the tow yard and so I removed it and fully charged it and then brought it back and put it on the car and the car moved just fine and I actually drove the car around and we loaded it on our tilt trailer.