Does using only trickle charger degrade battery life?

[RonDawg]

When we first leased our LEAF back in July I spent a lot of time fretting over whether or not to install a L2 charger at home. Now that we are entering our third month of usage, I can say with 100% confidence that the included L1 charger is completely adequate for our needs and we'll never bother with the hassle and expense of installing a L2 charger at home. We only average about 20 miles per day so YMMV.

My daily commute is similar in distance to yours, and I have been living with just L1 since I got my car, but I've decided to go ahead and have an L2 station installed. There have been a few times where I've had to choose between an evening trip that would use up most of the car's charge, and being able to use the car the next morning.

There is also a 30% Federal credit (up to $1000) for EVSE installation, and this credit may not be extended after the end of the year, so that also influenced my decision.

 

[planet4ever]

I am another one of the L1-only people. Just hit 10,700 miles and last week had my first annual battery test, got 5 stars on everything.

A bit off-topic, but what does the battery test...test? Capacity, obviously, but what else?

The star rating is there essentially as an educational tool and a measure of owner behavior. The capacity indicated equals the capacity bars on the dash, so no real revelation there either. Ingineer has looked behind the curtain to see what might be transmitted to Nissan, and that data

appears to be a lot more interesting.

But note that even that data is not really a test of the battery. It is instead a dump of statistics the battery controller has been maintaining. To its credit, Nissan doesn't call this a battery test. They call it an "EV Battery Usage Report". That is exactly what it is.

Ray

 

[surfingslovak]

But note that even that data is not really a test of the battery. It is instead a dump of statistics the battery controller has been maintaining. To its credit, Nissan doesn't call this a battery test. They call it an "EV Battery Usage Report". That is exactly what it is.

Yes, indeed, and to use the 5-star rating to indicate anything other than the level of compliance with Nissan-monitored charging, driving and storage practices would be incorrect.

 

[LeftieBiker]

Thanks for posting the chart. I suspected it might be something like that, although the 'high use of electricity while driving' wasn't expected. The one I'm concerned about is the one about topping off while at a "high" state of charge. I charge to 80%, and then usually start charging again about three hours before I leave for work, to get to 90-95%. Is that going to count against me, even though I don't actually "recharge" when it's higher than 50%? Also, the way the charge timer is set (always on), if I leave the car plugged in but don't use it for a few days, it will charge briefly, from 79% to 80%, once a day. Will that count against me? I want a great battery report, because I have some ideas about end of lease negotiating...

 

[DaveEV]

Is that going to count against me, even though I don't actually "recharge" when it's higher than 50%?

Personally, I wouldn't worry about either.

 

[TomT]

It won't make any difference at the end of the lease. Plus, the battery report is more or less worthless in terms of the actual state of health of your battery...

I want a great battery report, because I have some ideas about end of lease negotiating...

 

[TimLee]

Thanks for posting the chart. I suspected it might be something like that, although the 'high use of electricity while driving' wasn't expected. The one I'm concerned about is the one about topping off while at a "high" state of charge. I charge to 80%, and then usually start charging again about three hours before I leave for work, to get to 90-95%. Is that going to count against me, even though I don't actually "recharge" when it's higher than 50%? Also, the way the charge timer is set (always on), if I leave the car plugged in but don't use it for a few days, it will charge briefly, from 79% to 80%, once a day. Will that count against me? I want a great battery report, because I have some ideas about end of lease negotiating...

I don't think battery report will have any impact on end of lease negotiating.
The one thing that can get you four stars on "Frequent charging when battery state of charge is already high" is use of the climate control timer to pre-heat the vehicle at a certain time prior to leaving for work. Only four star I ever got was on the first year battery report, and it had to be because of the use of the climate control timer. Vehicle was finishing charge to 80% with an end timer only setting, and the 2011 LEAF is very bad to finish very early, as much as an hour or hour and a half early.
So when the charging would start again for the the pre-heating, the data was showing "charging when battery state of charge is already high", even though doing that is an advantage of the LEAF for driver convenience, since the 2011 / 2012 and 2013 S heater is so slow to heat up. And also helps minimize range loss in the winter.
Your practice of charging to 80% early, and then charging to 90% or 95% 3 hours before work probably will also have a good chance to get you four stars in that category.
And leaving the vehicle plugged in for lengthy period with it brief daily charging could also do the same.
Leaving the vehicle plugged in when not charging is a VERY BAD IDEA. Doing that a lot will eventually get you stranded with a dead 12V battery, at least on the 2011 and 2012 LEAF. May have corrected that on 2013, but I doubt it.
On the 'high use of electricity while driving', I don't know how bad your m/kWh has to be to trigger that. Mine was pretty poor around 3.3 on the first battery test, and 3.4 on the second battery test, due to using the vehicle a lot while parked and not moving (listening to radio in garden, AC or heat use while waiting in the car). I got five stars in that category both years.

 

[LeftieBiker]

Leaving the vehicle plugged in when not charging is a VERY BAD IDEA. Doing that a lot will eventually get you stranded with a dead 12V battery, at least on the 2011 and 2012 LEAF. May have corrected that on 2013, but I doubt it.
I'm aware of this issue, but battery voltage after 4 days (the longest it will ever sit plugged in) was still fine in my 2013. My driving patterns seem to keep the accessory battery adequately charged, at least in mild weather. I am going to modify that behavior, though, and sacrifice a little convenience (being able to restart charging for longer trips without going out to the car first) for maybe a better battery report, although that seems far from clear. I'm also going to use a battery tender Jr. In Winter if it looks like I'll be parking the car for longer periods. My reference to "negotiating" doesn't have to do with the dealer.

 

[da119]

Leaving the vehicle plugged in when not charging is a VERY BAD IDEA. Doing that a lot will eventually get you stranded with a dead 12V battery, at least on the 2011 and 2012 LEAF.

Hi Tim Lee, can you explain why?

Thanks!

 

[LeftieBiker]

Leaving the vehicle plugged in when not charging is a VERY BAD IDEA. Doing that a lot will eventually get you stranded with a dead 12V battery, at least on the 2011 and 2012 LEAF.

Hi Tim Lee, can you explain why?

Thanks!

I can answer that. There are two issues, really: when plugged in, the car will periodically "check" the status of the connection, using accessory battery power. Also, while the 12V battery is supposed to be recharged with the main pack, that process doesn't work as well as it should. So when my car turns on to go from 79% to 80% once a day, the 12 volt battery charge gets lower each time if it isn't driven afterwards. Checking the status via CarWings also slowly drains the 12 volt battery. I really am going to stop leaving it plugged in for longer than 12 hours after charging ends.

 

[TomT]

The real reason is that, when the car is plugged in, many of the processes that would normally go in to a quiescent low power state do not do so, so the 12 volt draw remains relatively high. This drains the 12v battery before the dc inverter can charge it.

Leaving the vehicle plugged in when not charging is a VERY BAD IDEA. Doing that a lot will eventually get you stranded with a dead 12V battery, at least on the 2011 and 2012 LEAF. May have corrected that on 2013, but I doubt it.

 

[TimLee]

Leaving the vehicle plugged in when not charging is a VERY BAD IDEA. Doing that a lot will eventually get you stranded with a dead 12V battery, at least on the 2011 and 2012 LEAF.

Hi Tim Lee, can you explain why?

Thanks!

I can answer that. There are two issues, really: when plugged in, the car will periodically "check" the status of the connection, using accessory battery power. Also, while the 12V battery is supposed to be recharged with the main pack, that process doesn't work as well as it should. So when my car turns on to go from 79% to 80% once a day, the 12 volt battery charge gets lower each time if it isn't driven afterwards. Checking the status via CarWings also slowly drains the 12 volt battery. I really am going to stop leaving it plugged in for longer than 12 hours after charging ends.

The real reason is that, when the car is plugged in, many of the processes that would normally go in to a quiescent low power state do not do so, so the 12 volt draw remains relatively high. This drains the 12v battery before the dc inverter can charge it.

+1, Both answers taken together are correct.
It does seem like the only mode in which the 12V battery voltage gets properly maintained is having the vehicle in Ready mode for a long enough period of time.
Some people speculated in other threads that even that may be marginal, as the highest voltage the DC to DC converter provides is relatively low compared to what some consider adequate for maintaining proper charge. But Phil indicated in another thread that he considered the Ready mode 12V battery charging acceptable.
When not plugged in, the LEAF will activate the DC to DC once every 7 days to maintain the 12V battery. But there is some uncertainty on whether it does the same as it does when in Ready mode.
Similarly if you put the LEAF into ON mode (two button pushes with foot NOT on the brake pedal), when the 12V battery voltage drops low enough the DC to DC will activate and will operate for a while indicated by flashing of center blue LED.
But that is apparently NOT properly maintaining the 12V battery like when the vehicle is in Ready mode. I did that a lot the first two years I had the LEAF, and 12V battery was replaced free of charge under the warranty at the two year maintenance.
But for some strange reason when the LEAF is plugged in to charge but isn't charging, it will never charge the 12V battery, and is sitting there with a significant drain on the 12V battery.
Many people did this the first year or two when going on vacation, and came back in 5 or 6 days and the 12V battery was completely dead.
Proper treatment of the 12V battery for an extended non use of the LEAF is to leave the LEAF main pack at ~50% status of charge. The 12V battery will probably be OK for a couple weeks, but it is best to disconnect the 12V battery to be sure, and ideally leave the 12V battery connected to a battery maintainer.

 

[youngr3]

Last winter/spring I stored the Leaf for 4.5 months. The 12 volt battery was fine for 4 months and one week before running short of power. I was charging main battery once a week for 10 mins. at 110 volts over this time period.
This year I will attach a battery tender to 12 volt battery.