Am I taking care of my batteries?

I've spent quite a bit of time reading this forum, and it's great. Thank you in advance to anyone who replies. I've seen a lot of discussion about battery degradation in Phoenix, but I was wondering if someone could outline Do's and Don'ts of charging. What is it that really causes the degradation, and how can it be prevented? I looked for a thread like that in Tips and Tricks section, and hopefully I didn't miss it.

Some info about our situation... We're in San Antonio, TX, so it gets quite hot during the summer. However, my wife and I are both teachers, so the Leaf didn't see much action this summer. In four months of ownership, we've only driven 4k miles. During the school year, the Leaf was/will be our only commuter. I drop off the wife, then the kids, then park at work, then pick everyone up on my way home for a round trip of around 50-60 miles depending on any stops or errands along the way. We just use the cable that came with it, and we always just plug it in when we get home. It needs over 11 hours to charge, and it ends up parked for about 13. I don't manage the charging at all with Carwings or timers.

Based on what I've read in various threads, I'm planning to paint my garage door a lighter shade of tan instead of the current dark brown, insulate it, and perhaps cut vents near the ceiling of the garage. Currently only vented at the bottom. I'm also planning to figure out Carwings and start charging the car to only 80%, which I've seen numerous people mention on here. I thought rechargeable batteries liked being fully charged, but I guess cars are different? And is it correct that the car shouldn't sit fully charged for long? So I should time it to reach 80% right before we want to leave? Any other tips, or perhaps some reassurances that I'm not killing my car? We bought the car, plan to have it for the long haul, expect to replace/upgrade the batteries at 8 or so years, and don't want to be doing anything stupid this early in our ownership.

Different battery chemistries require different treatment. Li based cells should not be kept at elevated charge states for extended periods, and especially not at higher temperatures.

Will 80% charge meet your daily needs? I think so, but check it out. You will be better off using the timer to charge to 80%. Carwings not required.

I habitually charge to 80%, and if I anticipate needing more, hit the override button shortly before departure. Works for me.

Consider getting your EVSE upgraded so that if you do need to quickly charge to 100%, you can.
evseupgrade.com

Bill

WilsonSATX said:

I drop off the wife, then the kids, then park at work, then pick everyone up on my way home for a round trip of around 50-60 miles depending on any stops or errands along the way.

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Not what you asked, but I suspect you may need more than L1 at home this coming winter. I remember spending some very chilly days in San Antonio one January, days on which you would assuredly want a heated car for the kids. When you add heating I doubt if you will get much more than 3.5 m/kWh, and that would mean something closer to 17 hours of L1 to charge for a 60 mile trip.

Ray

I appreciate the replies. My wife just got home with the Leaf, and I already set up the timer to stop at 80%. And I saw quite a bit of discussion about the EVSE upgrade to L2, and I checked out their website. I'll be doing that shortly, I believe. I'm also eligible for a "free" L2 charger from the ChargePoint program, but I need to read their terms and conditions again -- seemed fishy last time. I've seen some online discussion of the fact that these government-subsidized "free" charger programs end up being pricey, because they've got a monopoly on the installation labor costs. The upgraded EVSE seems like a good option, especially since I can get it with the 120 v adapter and keep it in the trunk if I'm nervous about range.

:ugeek: Hello San Antonio! Bob here.. an Austin refugee now living in Hot Springs, AR.
just got my Leaf SL yesterday. I'm a retired engineer from UT Austin. I have a lot of experience
with Lithium Ion batteries. Here is what to know:

These batteries love to operate between 55F and 90F. They will freeze in extremely low temps...
the kind you never get in SA. If stored in ideal conditions for a length of time, that would be at 45F
and half charged. They don't like to be charged or used in really hot weather. What is that weather?
Well, that depends on how they can cool themselves...as they heat up while charging and discharging.
The faster you put energy into them -or pull it out of them, the more they heat up. They can fail easily
if you push them beyond their ability to dissipate the heat. Industrial-quality lithiums like in our cars can take
more abuse than garden-variety ones like in your cell phone. Lithiums have no memory nor need to be charged and drained to the limits to keep their capacity. In fact, they prefer to go between 20% and 80% for longest life.

I'm developing a series of guidelines for car use and charging in OUR kind of weather. As you've noticed, the big red blob of HUGE
heat has moved north to Dallas, Little Rock and Oklahoma. We are actually consistently hotter than you'all -570 miles north.
Global warming... it's not happening.. I heard that on WOAI 1200 AM.

So, to be safe... I would set the #1 charge timer for from 11PM to whenever you leave in the morning. This will insure that it drops
under 90F before you charge. You will have to put a small fan in the garage window to equalize in/out temps... put it on a timer to start at 9PM. Let it run all night (light timer)

I'm not going to use my Leaf when it is over 98F. I have a friend who does, and his seems fine. If you have to drive in around 100F temps, be light on the acceleration. Oh yeah, charge to 80% too... if this will get you to work and back.
The L1 115V provided charger produces the least heat in the batteries. That's a good thing. Our battery packs are rated for 2000 charge cycles. That's a lot.

If you get the charger modified for L2 (I am), only use that once the outside temps go below about 80F at night. These are very conservative rules... you most likely would not have a problem if you don;t so this stuff. Me? I have a Prius for the other days... I'm going to baby "EV".

Take care!

Bob-Hot Springs

Great stuff! Enjoyed reading your post, Bob. You might want to review an article another forum member wrote last year. Hopefully, we can refine these rules and come up with new ones in the future.

http://www.plugincars.com/eight-tips-extend-battery-life-your-electric-car-107938.html" onclick="window.open(this.href);return false;

GreenPowerVideos said:

I'm not going to use my Leaf when it is over 98F. I have a friend who does, and his seems fine. If you have to drive in around 100F temps, be light on the acceleration. Oh yeah, charge to 80% too... if this will get you to work and back.
The L1 115V provided charger produces the least heat in the batteries. That's a good thing. Our battery packs are rated for 2000 charge cycles. That's a lot.

If you get the charger modified for L2 (I am), only use that once the outside temps go below about 80F at night. These are very conservative rules... you most likely would not have a problem if you don't so this stuff. Me? I have a Prius for the other days... I'm going to baby "EV".

Click to expand...

For all the guidelines posted on all the threads I read, I agree with most everything you say with a couple of exceptions:
1) not driving above 98F seems a bit extreme (not CHARGING at these temps is another case)
2) not charging above 80F is definitely not practical in Texas (my garage hovers around 90F after 100+F days)

I appreciate the fact that you state these aren't "hard and fast" rules, but I think these 2 in particular give the impression that the Leaf can NOT be used as a mainstream car and might scare off EV candidates.

FWIW, I use the temperature bars as a guideline for additional/opportunity charging: I try not to charge at >6TB, (the 7th TB is right around your 98 degree cutoff). While I do own other ICE cars, my goal is to treat my Leaf like I DON'T have other cars (except in the case where distance is a factor).

i recommend you get the EVSE mod ASAP and charge to 100%

50-60 miles can be done on 80% but you are cutting it close and if busing all those people around, this gives you ZERO options during the day. I highly doubt it will work. too many people, too many variables.

as far as charging to 100%, its fine as long as you minimize situations where you are at 7 TBs (temperature bars, the gauge on the left) or higher. 5 or 6 TBs is where you want to be all the time 4 in winter is ok although you wont see it often.

the 240 volt EVSE is advantageous for a few reasons. its allows you to complete charging earlier. i recommend setting an END timer only for at least 2 hours before you estimated departure time but no later than 6 AM. this gives your pack time to cool a bit during the coolest part of the day.

setting an end timer also allows the pack to cool off from the hottest part of the day as much as possible because it starts as late as possible while still being able to give you the charge you need for the morning.

the other thing; speed kills. no one can give u a realistic evaluation without knowing the distances and speeds involved in your 50-60 miles. if its primarily 45 mph and less, then that makes 80% doable and probably a better option for most days. if its at least 30-40 miles of 65+ mph there is no way 80% will work