DougSchwartze
Don't Worry... Be Hopi...
Completely normal and if the lowest you are seeing is 12.25 volts, your battery is in pretty good shape relatively speaking. I see much lower and have never had a starting issue. The weather is "finally" expected to turn (at least for a few days) at the end of this week which means 12 volt monitoring will be stepped up.
One likely load is the monitoring of the inverter. It heats up and once I heard the water pump run for about 2 mins after the car was unplugged (this only happens on AC charging) so naturally, had to load up LEAF Spy. It did appear the fan was running of system power and not the battery though.
https://daveinolywa.blogspot.com/2021/04/charge-your-leaf-every-day.html
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Thank You Dave. These are all good clues.
On the subject of the "Dead 12 volt battery" issue it is known that
Sulfation of lead acid batteries is a major cause of early life failures.
Sulfation is crystallization which slowly shorts out a cell and happens quicker when a battery is left sitting at a voltage
of 12.4 volts or below.
https://www.power-sonic.com/blog/what-is-a-sulfated-battery-and-how-do-you-prevent-it/
Leftiebiker notes that this 15 minute period happens during the traction batteries cell equalization process. I believe here should be no drain put on the 12 volt battery at this time. Software and hardware should stop any large load from being applied to the battery.
If I disrupt the equalization by removing the EVSE cord from the car just before, or just when the 3rd light comes on solid then I do not see a load put on the 12 volt battery and it rests nicely at 12.6 volts.
My contention is that this repeated discharging of the 12 volt lead acid battery leaving it sit below the required 12.4 volt limit may be causing sulfation of the cells. Leaving your car sit at 85 degrees F. will also increases the discharge rate by 50%. There are many possible other causes working against us as well.
I am focusing on this one deficiency (in my opinion). It appears that either my car is different than others (for example it has a bad anti-drainback diode in the DC/ DC convertor output), or there may be
room for an engineering improvement which could improve everyones' 12 volt battery charging function forever.
I believe that Nissan owes us Faithful Customers old and new, the best Service Support possible.
There is a lot of competition out there these days.
All the nerds I know appreciate good continued Engineering and Service support, and show it through their EV buying Dollars.
Nissan Leafs are great cars with awesome engineering. Many of us plan on keeping our old ones forever and hope to buy new ones as they improve as well. It would be a mistake to not give it all you've got with open support before you lose what you had to start with... Customers.
Peace, and Happy Charging !!!
-Doug...
One likely load is the monitoring of the inverter. It heats up and once I heard the water pump run for about 2 mins after the car was unplugged (this only happens on AC charging) so naturally, had to load up LEAF Spy. It did appear the fan was running of system power and not the battery though.
https://daveinolywa.blogspot.com/2021/04/charge-your-leaf-every-day.html
[/quote]
Thank You Dave. These are all good clues.
On the subject of the "Dead 12 volt battery" issue it is known that
Sulfation of lead acid batteries is a major cause of early life failures.
Sulfation is crystallization which slowly shorts out a cell and happens quicker when a battery is left sitting at a voltage
of 12.4 volts or below.
https://www.power-sonic.com/blog/what-is-a-sulfated-battery-and-how-do-you-prevent-it/
Leftiebiker notes that this 15 minute period happens during the traction batteries cell equalization process. I believe here should be no drain put on the 12 volt battery at this time. Software and hardware should stop any large load from being applied to the battery.
If I disrupt the equalization by removing the EVSE cord from the car just before, or just when the 3rd light comes on solid then I do not see a load put on the 12 volt battery and it rests nicely at 12.6 volts.
My contention is that this repeated discharging of the 12 volt lead acid battery leaving it sit below the required 12.4 volt limit may be causing sulfation of the cells. Leaving your car sit at 85 degrees F. will also increases the discharge rate by 50%. There are many possible other causes working against us as well.
I am focusing on this one deficiency (in my opinion). It appears that either my car is different than others (for example it has a bad anti-drainback diode in the DC/ DC convertor output), or there may be
room for an engineering improvement which could improve everyones' 12 volt battery charging function forever.
I believe that Nissan owes us Faithful Customers old and new, the best Service Support possible.
There is a lot of competition out there these days.
All the nerds I know appreciate good continued Engineering and Service support, and show it through their EV buying Dollars.
Nissan Leafs are great cars with awesome engineering. Many of us plan on keeping our old ones forever and hope to buy new ones as they improve as well. It would be a mistake to not give it all you've got with open support before you lose what you had to start with... Customers.
Peace, and Happy Charging !!!
-Doug...