If You Have Battery Degradation, Read This!

Every day, I read posts from people who have lost a capacity bar on their LEAF and seeking information on why it happened or if their car is normal or not.  EVERY ONE of these posts do not provide the information that is needed to make a decent evaluation of that person's situation.

The reality is we as a society don't have the faintest clue as to what to do to maintain our battery packs. What I see is "I babied my pack and still lost a bar" which would imply they knew exactly what to do and guess what?? They were wrong.

What we need is a reference guide as to what we need to consider and more importantly a checklist as to what we need to report when looking for advice online!

Now this chart represents general guidelines on what affects the general rate of degradation. It is not a chart in reality. Only a visual representation only. What does "not a chart mean?" What it means is that X,Y points are not observed data points so should not be referenced.  The important takeaway here is the meaning of each color and its relationship to other colors on the chart. Despite SOC and temperatures being the most important aspect of the chart, they are for relational reference only (hotter/colder,  High SOC/ Low SOC)    

Now, we all know Nissan put the fear of God into us when charging to 100% and letting it sit. They even went so far as to put in an 80% charge option for a few years. Thankfully, they quickly realized that the wrong message was received and removed the 80% charge.   So lets look at the 100% SOC area.  First thing we see is that there is some Red when the temperature gets hot enough but we have to be on "Broil" (or live in Phoenix) to see Black.  Luckily, even Nissan knows this so they restricted the charge to 97% so the downside of charging to full overnight is pretty minimal. What Nissan did do is allow you to manipulate the charge so it finishes near the time you would be leaving so again, no real downside to charging to full!  Now this chart does not input any time parameters in here so that is on us to guess but in Winter, there is little reason to not charge to full every day.

So the next question becomes "Why are you not recommending I stay in the Yellow ALL THE TIME?"  Well, I am recommending that you do... IF you can. Realize staying in the yellow means your already limited EV range is now cut by MORE than half.   Another reason and much more important is look at the cushion you have between the Yellow and the Red at the bottom verses the cushion at the top?   Not a lot of forgiveness is there?

Thanks to the GOM's subliminal hypnotic suggestion, we tend to think we have more range than we really do. We also underestimate the impact of our habits like heat, taking the wrong route to work, etc.  After all, at the end of the day, how many times to do say "Wow, look at all that extra range!"
So, lets pretend "Yellow" doesn't exist.  For those of you that are retired, work at home or simply have nowhere to go, good for you! Your LEAF will last you a lifetime but then again you don't post online about losing bars anyway so the next time someone asks why Nissan removed the 80% option, now you know.

Now, I do have one recommendation; In Summer, if your ONE WAY commute does not drop your SOC below 80%, then probably shouldn't charge to full unless you are in an underground parking thingy, middle of the forest  or some place with a lot of shade.

Another thing to look at is the huge number of people who charge at work. The chart above shows Red in the mid 80's for SOCs at 80% (remember X,Y points are not valid so its important to understand the hotter the worse)  so if you are going to do this make sure you have shade and you don't start charging until after lunch. Remember, your packs can see radiant heat well over 100º on the mildest of Sunny days (People who live in San Diego or any other Sunny coastal area, please take notice. Your weather is FAR from perfect) So 80% would have been perfect for this right?  No, not really.  What it would do is give people the false impression that 80% would be ok even if done by lunch. In a perfect World, we would hit 80% 5 mins before 5.  The reality is half of you probably charge in the morning while your co-workers charge in the afternoon. Who is going to volunteer to be a "Red" EV?

Ok, so the full charge question is out of the way, lets look at the MUCH more familiar low SOC.

One of the things Nissan has not removed is the low state of charge warnings and for good reason. Look at the chart; other than extreme heat, low SOC is BY FAR THE NUMBER ONE reason for degradation. Remember this because this is THE MOST CRITICAL PART of the survey.  Low SOC is not affected in anyway by temperature which means this applies to everyone no matter where you live.  Simply another reason why you should charge more than you think you need. Its simply a good idea.

But I constantly read how people made it home with 8 GIDs and were proud of themselves and I ask them if they plugged in the car and they say, "I am fine, its on a timer"  or they say "I only charge when the rates aren't 30 cents per kwh"  and I think "Why do they want to screw themselves over like that??"  Is saving 50 cents really that important to you that you would sacrifice a $5500 battery pack? What is wrong with you!!

Either way; My recommendation on this is if you get home with ANY battery warning on, plug in ASAP. This is what I do and its only for 60-90 mins. Sometimes 2 hours if  I spaced it off.   How important is this recommendation?  It is the MOST important thing this blog is relaying to anyone.  Couple things to consider; The LBW (low battery warning) comes on first and it comes on at 16% more or less. Well, look at the chart. The Red starts at 25ish % SOC. So by the time you see that warning, you are already beating up on the pack...

Ok so the basics of charging are out of the way, so now we need to get into the checklist for info you want to provide us online to get insight into your degradation issues.

**Location. This is important to evaluate your climate

**Build date (located on driver door jamb) Purchase date and any info about time spent on the lot.  Dates are also important because there is a huge difference between spending ONE month on the lot in Summer verses Winter.

**Driving habits. How far you drive,  how fast (be specific. "keeping up with traffic" is not an answer)   mostly freeway? Cold blooded (run heat at 80º on a 65º day?... Don't laugh, I know a lot of people who do EXACTLY this!) Hypermiler or constantly late?

**Efficiency. What is your miles per kwh average? Its on your display and can be reset as often as you deem necessary and I highly recommend you do it often. At least on every season change. I reset mine DAILY.

**Charging habits.  Do you plug in ASAP at low SOC? (anything under 25 miles on the GOM)  What is charging type and speed?  Charge to full every day or only a few times a week? Charge at work?  Fast charge?  There is no such thing as too much info here.

**Parking habits. Garage or driveway.  At work; Garage? Park in shade whenever possible and is it possible? Get to work with less than 80% SOC and more than 30% SOC

Finally the thing to keep in mind is the above info is the MINIMUM you should provide and when if you forget something, no worries but adding that info in the middle of a 100 post thread... well you might as well not add it at all. Any question answered in the thread should be updated on the your original post.  Your original post, nearly everyone will get 75% of the info contained in it. As for additional info added in the thread of the post? You lucky if 10% see it.

Remember that this battery babysitting thing is still a bit new to all of us and we are still learning just like you but the quality of what we know is solely dependent on the quality of the information we receive and the thing to remember, we are all doing this to learn how to keep those 12 bars as long as possible so everything we learn from you will benefit everyone!