Saturday, November 21, 2020

LEAF Spy, Batteries, Charging and Degradation; One Year Review Part 2

 I am currently collecting data from other Gen...uh...4? LEAFers with 40 and 62 kwh packs for a more balanced analysis of what we can expect to see long term.  Before 2018, I didn't have much interest since it wasn't till then that I wanted to keep any LEAF long term.  Even the bullet proof 30 kwh pack I had was only a considered cheap transportation purchase to use later to trade up. But despite the fact the 40 kwh had the range I would need,  it didn't have the buffer to allow better charge management which is why I am driving the Plus now. 


Starting with the 40 kwh packs, we started seeing large adjustments in pack  numbers via LEAF Spy every 3 months.  I still don't have enough data to tell you where we will be in 5 years but the early patterns are quite consistent among drivers with various needs, living in vastly different climates experiencing various driving conditions.  The "climate" factor so well published including a Gen One degradation prediction chart based on one's city (quite accurate actually) simply didn't work. We have people in VERY hot areas performing very well comparatively with others in mild climates that normally favor batteries by a large margin. 

Adjustments; Phase One

Although there seems to be outliers, the vast majority of us are seeing rapid drops in numbers lasting 9-15 months.  7 to 10% loss during this time is normal and covers over 90% of people who bothered to submit their battery stats.  My pack was no different. Not only was I losing chunks on my adjustment, I was also seeing a decline of .01 or .02% 4-7 times a  week. "That" alone can add up to over 2% annually. Hx is almost always skyrocketing here. There have been a handful of people whose Hx has remained "reasonable" lower than 110% and all of them (keep in mind my "all" is a very small list due to people not posting their stats when ASKED!) were slightly above the curve. 

Adjustments; Phase Two

But the  big chunks don't last. A new pattern emerges where the chunks lost in many cases, become chunks gained. Now we need to understand that realistically, this isn't possible but the circumstances of how these increases happen doesn't really allow us to blame instrumentation like the 24/30 kwh  packs which bounced up  and down on a near daily basis. So a huge number saw their numbers go up, others saw their adjustments get MUCH smaller or simply stop happening.  My guess is the adjustments are still  there but have nothing to report.  I also have daily records kept; something few others do. 

Adjustments; Phase Three?? 

Now, my Plus has only been in Phase 3 (I call  it  and...pretty much only I do) for just over a month.  In Phase 3, the downward trickle slows considerably.  Instead of seeing the .01 or .02% adjustments almost daily, they drop to almost once a week. In the chart below, to reduce the noise I only recorded ahr/SOH when the value changed.  Notice the Hx is also on the slow decline?  My adjustment happened during this period with a loss of .37% 

Notes; I have been on a SOC control kick.  Since I don't have NCTC any more, I have all but avoided DC charging for the most part and "maybe" that is contributing to the very slow numbers decline. I am running between 20-45% mostly with a few bumps to 65%.  Although it doesn't show here, the  longest day during the slow decline was 118 miles.  Another thing to consider is I am simply not driving all that much. With the new restrictions put in this week, it will be even less. I am  guessing neither the miles driven or lack of DC charging is a "significant" factor.  Below is my 40 kwh @ 15 months

Notes; Full on Summer here and all the public charging is DC since I had NCTC at this time which is why I didn't break out separate columns for DC and AC.  Unlike my Plus, I BAKED the 40 several times. Free charging does that to me and it was also during a time when Central WA was blowing up with new stations so trips to Ellensburg and Yakima were a must. Yakima was during Summer and it was HOT! Leaving there, I took White Pass back to Centralia Webasto; a 162 mile trip which is quite the challenge on flat ground. This meant charging on DC (it was free for the opening!) until it stopped at 98% and topping off at an L2 in town; all done at near 100º heat. Fun times!

Point of comparison; One year

2018 LEAF; 16,134.5 miles SOH 92.99%

Plus; 14,669.5 miles SOH; 93.13%

Factor in the mileage difference and its all but a dead heat. This is shocking to me. The charging/driving habits were as different as different can be. In the first year, my 2018 had a diet of 87% DC, My Plus only 55% DC with  nothing since August 24th.  The smaller pack charged to a higher level. I had 30 mins free so frequently charged until it stopped. So my SOC was higher, my pack a LOT hotter. 

Now the  Plus has not done the road trips I had planned. The real test was going to be a rafting trip in Central OR followed by a visit to Bend OR then swinging back up thru Central WA back to Olympia in the dead of Summer but COVID derailed those plans.  The additional range along with the fact the pack doesn't heat up enough on the first charge made hitting 110º quite the challenge. My only experience with Rapidgate was during a run when leaving home under 10% SOC. I stopped in Castle Rock charging only 20 mins which was more than enough to get me where I was going in time (barely) then grabbed another 23 minute charge and went back to EA Lacey and charged at 55 KW  when I normally would have seen about 73 KW.  A slowdown? Yes... drastic? You decide. 


Now we are in complete guess mode but based on the limited data submitted by other LEAFers over 2½ years on theirs, the trend is holding up. Below is two charts; the 2018 with 25,125 miles over 21 months then the Plus at just over a year. Data points taken every 1000 miles more or less (whatever the end of the day provided) and displays projected ahr/SOH @ 100,000 miles.  The 2018 has a wiggle in it due to a LEAF Spy recalibration of the SOH. 

To read the chart, you need to look at the drops and how they compare with the upward slopes between the drops. You can see over time, the drops become smaller and the upward slope becomes greater. This indicates the rate of degradation slowing. 

2018 40 kwh
Note; On the left side we see the drop being more than double the slow rises between adjustments. Then you see the slow rise with a jump up when I had my increase. After that you will notice just a slow rise. My last adjustment before the trade in was Zero. Its not like it didn't happen. It simply had nothing to say. If we extrapolate "part" of this chart taking the rate from my one year anniversary 2/16/19 to trade in 11/16/19. My projected SOH @ 100,000 miles would be 85.05%... A 12 bar LEAF. 

But what if the bump up didn't happen (although its quite common) what if it was a zero bump? Then my projected SOH @ 100,000 miles would be 78.97% SOH. Easy to see why Nissan maintained the warranty degradation. I literally have no chance.  It also reveals a possible motive why Nissan is now using the 40 kwh pack to warranty 30 kwh packs. 

2019 E Plus
When I talked about phases above, it was probably a bit of a head scratcher to you but after seeing this chart, it becomes clearer. Extrapolating this chart will be a lot less accurate since we have barely over half the data the 40 has and several projections using different points on the graph ranged from 60 to 74% SOH (July 1 and July 24)  So I took another view taking the degradation from the last adjustment to now and doubling it to get 81.57% which I have to think won't happen. Not doubling the rate puts me at 87.3% a more likely result.  Either way, you will know what I know when it happens. 

Piling On The Miles...Or Not

I got my 2018 when I was still doing the inventory job so my driving was extreme. My first two adjustments I had done nearly 4500 miles on each. Realize the first adjustment, I had only had the car less than two months. Needless to say, I DC'd a lot. Remember, it was 87% DC and that includes a few stretches of a few months when I did no home charging. 

2018 Adjustments; Apr/Jul/Oct/Jan
#1; -0.67% SOH on 4499.0 miles  total 1.30% drop
#2; -1.31% SOH on 4243.2 miles total 1.87% drop
#3; -1.20% SOH on 3254.8 miles total 1.71% drop
#4; -1.55% SOH on 3054.0 miles total 1.73% drop
#5; -0.92% SOH on 2637.8 miles total 1.07% drop
#6;+0.97% SOH on 2642.9 miles total 0.72% rise
#7; zero change  on 3532.7 miles total 0.40% drop 

The S Plus showed up 4 months before COVID hit and I still had NCTC  till February along with a $250 EVgo credit. 

2019 Plus adjustments; Jan/Apr/Jul/Oct
#1; -2.35% SOH on 3267.1 miles total 2.82% drop
#2; -1.29% SOH on 3265.1 miles total 1.61% drop
#3; -1.13% SOH on 4123.2 miles total 1.59% drop
#4; -0.37% SOH on 2898.0 miles total 0.49% drop

Notes; Adjustment 3 covered my labor share assignment when I was working at a different facility. It was just under 100 miles roundtrip 4 days a week for 6 weeks. It was "profitable" I banked $215 a week in untaxed travel pay all while using up my $250 EVgo credit. 

About halfway between #3 and #4 is when I went to all level 2 charging and a lot less driving. The totals look ok but that is because school was out and my Son and I could take any day of the week for road trips so lot of "short" 200-300 miles trips were in there. Now that school is in, the only day we have to really do any traveling is Saturday which is just about my least convenient day.  

The 2018 bounced around quite a bit so hard to discern any real trends until the very end but the Plus is very predictable. The "total" you see in the last column is the adjustment plus the daily drops.  


Sorry... way too early to tell with any certainty which is why more data is important to the process.  This means several LEAF Spy data points spanning years.  Many 2018's will be hitting year 4 in the next few months and those data points are valuable but less so if we don't have your 2½ year data or your 2 year data.  I am guessing you figured out by now that this post was less a one year review and more a plea for more battery data. The MANY points mentioned briefly I will delve into more at a later date and that includes why charge management is more important than you think. I will also have more insights to my "keep it low" SOC experiment which will end around June. Hopefully by then the vaccine will be available and being rejected by millions (a sad and unavoidable fact I'm afraid) but traveling in relative safety will be an option for the more sensible people among us. 

Friday, November 20, 2020

One Year LEAF Plus Review

Just over a year ago, November 12, 2019 I received a call from Ray Raied Issak of Campbell Nissan of Everett WA  that was more than a bit unexpected. I was entering the 20th month of my 2018 LEAF S 40's 36 month lease when I was offered the chance to upgrade to a Plus at the same monthly cost.  Well, to say I thought there was a catch is a bit of an understatement but it was 50% more range, nearly double the DC charging speed so he definitely had my interest!

Now, I knew there would be a change on the backend because the Plus was simply more expensive so something had to change. My 40 kwh which I had thought about buying had a residual under $10,000 and its degradation had all but slowed to a crawl so my original 170 miles of range (Remember, YMMV) was down to around 158 to 160 miles. I could live with that. But the thought of a faster charger, the end of NCTC and the per minute billing of the day had me thinking that this was simply too good an opportunity to pass up so I resisted my knee jerk "Hell yeah" decision...and slept on it... Sleep didn't fix a thing so we set a time to swap cars. 

November 16th, I jumped in my car, set the NAV for traffic issues since this would be my 3rd car from Ray and I knew the way and off I went past a half dozen LEAF dealerships to THE best LEAF salesman in the Pacific Northwest. Ray was actually the best nationwide twice...or 3 times? Either way, he is VERY good at his job! 

The Pluses 


Ok, it VERY noticeably faster than my 40 kwh LEAF to the point of being a bit scary.  In a year, I have had it to the floor like 3 times and that is probably 2 times too many so if power is your thing, its got it but you probably need different tires. Ecopias simply spin too easily.


So I haven't really tested the range other than 3 times.  I did one trip during Winter and although not very cold with more than half the trip in the mid 40's with only the very end dipping into the 30's, it rained nearly the entire time including some pretty good downpours.  I was testing L2 chargers on the route so it was more than the normal in and out of the car which means running defrost more than usual was unavoidable but the car performed fine.  

Since I stopped to charge a bunch of times even if only briefly, I can only estimate the range to be just under the EPA rating of 226 miles. I was expecting over 200 miles of range so this was a pleasant surprise. As always, YMMV and this trip was the usual minimal climate control trip as much as could be done anyway. 

I did do over 272 miles with no charging stops with relative ease which is code for saying range anxiety did not play a part. The original route was about 265 but I had so much left I did some around town errands after my return with 275+ likely possible and yeah, traffic congestion played a part but that is everyday situation here with very few options to avoid it if going North. 

Note; All things are relative and I recently realized when I was putting this together that my perception has changed; what used to be a road trip isn't anymore. Any trip that requires less than 30 minutes of DC charging doesn't qualify in my mind and I did quite a few trips in the 300  mile range. 


It started out hot but didn't last and my relationship with Electrify America has soured considerably.  They expanded well moving into 4 of my 6 desired regions but the real goldmine was the ability to pull 200 amps while paying 18 cents a minute under their $4 a month subscription plan but then the veil was removed and Electrify America was revealed for who they are; NAZI's!!

Ok...maybe that was a bit over the top but they are thinly disguised Germans pretending to be an American company. First they throttled the Chademo down to 120 amps making Webasto and Blink faster. Then they went to a ridiculous 41 cents/kwh rate which means they now occupy the same brain space as Blink and its 49 cents/kwh rates for charging options. 

But it was awesome while it lasted. Getting a significant range boost in less time it took to leave some pee was totally cool! But as one fades, another emerges. Puget Sound Energy (PSE) has finally decided to get serious about providing public charging services. Yeah, they have had free level 2's for a few years now but few in anything remotely resembling convenient locations and...well its level 2. Great if there are amenities or near places where business needs to be conducted which these weren't.  Case in point; The free level 2 at the regional office in Olympia a few miles from my house existed for a few years before my first visit. This is a FREE station and you know me...can't leave them alone! 

So it was with HUGE gratitude I plugged into PSE's new complex  in Lacey and got over 200 amps! and it was at 25 cents/kwh...higher than the heyday of EA, but still quite reasonable! This was the first in a series they plan to build. We need to show some support here! Hopefully this will lead to many more locations! 

Safety and Convenience

Ok, some of this was there starting in 2018 but still worth mentioning because of the seemingly huge number of LEAFers who either don't know about this or doesn't use it.

One of the best features is the TPMS screen  which  shows individual tire pressures on each wheel AND they are self registering. When I rotate tires, it takes a few power cycles but the new positions are recognized. Pretty cool! 

Another cool perk is the steering wheel heater now has memory.  Before I had to turn it on every time I got in the car. Now, it remembers its last status and repeats it. So I turn it on in November, turn it off in May. Saving the button cycle count!  Keep in mind, its still on a timer so an occasional re energizing is needed. One thing I did test was letting it time out and it still came back on on the next trip!



Ok, I like Lemonade so I will start with what I like.  In WA, we are blessed with the ability to support our local charging infrastructure. Every year we pay $75 to fund that endeavour. Naturally the roads also need some love so an additional $150 goes to them. Like any tax, it works better for some than others. (A glance at trump's tax returns verifies this) To this date; the charging infrastructure has seen many new stations installed so its easy to see where that money is going.  So lets look at the cost of EVing Washington State. 


We pay one of the highest prices for gasoline in the country so its easy to see why EVs are so popular. Having just sprung for $300 for my tabs a few weeks ago (taken from the account that was supposed to pay the sales tax on the car. FYI; got enough in there for several more years of tabs) sometimes we need to remember how it used to be. 

WA bills us 51.9952 cents a gallon for gas. The feds tack on 18.4 cents which means 70.3952 cents for every gallon we buy supposedly goes to fix the roads or the same place our $150 EV tab fees supposedly goes. So why am I adding both the state and federal tax when the EV Tab is a WA thing?  Well, I challenged anyone to show me how to get gas w/o having to pay both and still waiting for an answer so until that happens, we will deal in reality, not semantics. 

Having a huge concern for my footprint decades before EVs started becoming mainstream, I naturally drove the car that came closest to my goals; The Prius. I got 3 of them and like my LEAFs, two of them were tax free.  Hypermiling was a new term probably invented by Prius drivers chasing the 50 MPG goal which we all soon found was rather easy to achieve.  Even with two highway trips to Disneyland, I had a lifetime average in my 2010 Prius just over 53 MPG. I thought it was super cheap transportation. Since I have gas receipts for the car, a "scenario" which is often tilted is not needed here. Again, reality wins. For this, we will  use the  last Prius owned; a 2010 Prius purchased May 13, 2009. 

During my Prius' 66,000+ mile journey, I consumed 1245.78 gallons of gas costing $4096.98 or  6.2 cents per mile. Granted some of time involved was during a much more expensive time than the prices we are seeing today. Those trips to California were EXPENSIVE! and included the highest price paid @ $4.319 a gallon!   A more recent example would be my Corolla that cost $1811.69 averaging 6.78 cents per mile. It did pay prices comparable to what we are seeing today including a lot of sub $2/gallon gas. Ahhh, those were the days! As long as you don't breathe too deeply... Its lifetime was 38.14 MPG. I gave it away 5 days after I picked up my 40 kwh. Yeah, it took that long to realize I didn't need it any more. 

Now my Prius was around well before the $75 Hybrid tab fee was a thing so the average tab renewal was probably $80ish but only because of my "DUALPWR" custom plates. The Corolla's last tab fee was $52.75 paid December 2017. 

Anyway, I felt that a per mile cost was the most equitable way of determining fuel costs. No maintenance costs are added. To make the Corolla a relatively cheap car (as cheap as you can get with a car over 230,000 miles that is) I had my Sister go thru the car and fix, update, etc. it before I gave it away and that included a badly needed new set of tires. The Prius also had a new set of tires as well. Other than a few "curb" incidences; none of my LEAFs had the burden of that expense.  So that is the gas option. Under 7 cents a mile is not all  that  bad a deal really. 

So lets look at the EV "scenario" since reality is waaaay too unfair in this analysis. For this scenario; we will toss in home rates at 2.5 cents/kwh (higher than I pay BTW)  The $225 tab fee (I know only the $150 is the "fuel" thing but people will whine so...)  and say $10 a month for that road trip over 300 miles.  That should allow us 2-3 trips out of town per month. 

So in 15,000 miles, my EV would cost

$225 for tabs

$120 for public charging

$345.75 for home charging (Public charging adjustment calculated using Electrify America's 41 cents/kwh averaging 4.0 miles/kwh) 

So that is $690.75 or 4.605 cents per mile.  

There you have!... "it?" Hmmm?? Ok, so EVs are cheaper but something seems "off" in this comparison... How many of you have done that radio promotion that goes something like "For the next two  hours KXXX 91 on your FM dial will be selling gas for 91 cents a gallon if you pull into XX station with us playing!" 

In reality, free EV charging is not uncommon and many EVers use it extensively to the  point where many have no home or public charging costs.  I used to be that way but the added range of the Plus has me not seeking out free charging unless its simply convenient to the day's agenda but I would feel amiss if I didn't mention it. Now, it will not be part of the "My tab fees are unfair" argument but it "is" reality...

After a year  and 14,726.1 miles,  my "real" cost is $141.39 cents and to be fair, that does include NCTC to Feb of this year, the $250 credit for the Plus lease and current price reduction thru EVgo to 20 cents/min until the end of the year.  Include in the total above is $60.53 in public charging fees paid mostly to Electrify America.  So my cost will go up on year 2. My guess; it will approach but not exceed the scenario above. Again, it won't be used as ammunition in the tab fee wars but just so you know what is possible. 


Like any computer, even one on wheels, glitches are a thing and my LEAF is no different. Like several versions before, this one also redirects airflow randomly. I also notice that occasionally, my steering wheel controls for the audio system don't work. So can't change channels or adjust the volume. But then again, up until 2004, couldn't do that with any previous car I had. Like driving a stick; once you learn, you never forget so a small thing, this audio bug. 

Another recurring issue is improper charge termination. This can be fixed by simply power cycling the car a few times or resetting the fault codes with LEAF Spy or disconnecting the 12 volt battery for a few seconds. Hard to blame this on the car considering the abuses public charging stations take both by EVers and outright vandalism but it happens so here it is. 



Recently I had the chance to drive the most iconic LEAF in the Pacific Northwest; Steve Marsh's 100,000 2011 SL.  Peppy with a new pack, I have to admit it was then that I realized two things; 

The power in my Plus is EXTREME and

The seats have taken a step back.  I did realize my hip issues were less the seats and more a drawback of one pedal driving. Using cruise control more (I never used it before as it is not the way for best efficiency) goes a long way towards fixing my issues but those 2011 seats were simply AWESOME!

Steering Wheel Heater

Another thing I would love to see is a high/low switch on the steering wheel heater. A lot of people didn't like it when the 2013's came out with them because they would cycle from very warm to cold. I loved the very warm part. Some thought it was hot but then again, some don't like coffee. Shocker, isn't it!!   Now my steering wheel heater gets warm and stays that way...warm. So give me the "very" switch! 

Drive modes

E Pedal has memory. In settings, we can set it so its on all the time or controlled by the switch next to the Eco button which also has memory.  So why doesn't B mode have memory?  I don't do D. Its too caffeinated for my tastes. I want the caffeine in  me, not driving me. 


I don't know what I am doing but lately it seems like I am a "distracted driver" magnet. Experiencing two very close incidents in less than a week made me realize my horn isn't cutting it.  One incident had me moving over TWO lanes to avoid someone redesigning the side of my car and I had the horn "bleeping" the  entire time. I began to wonder if they could even hear the horn? Expect a blog on addressing that concern. 

LEAF Spy, Batteries and Degradation

Finally the BIG thing and as I frequently do, this post has rambled on way too long which means many of you won't make it this far so looks like I will have to make this a two parter. 

Although I won't likely post it until tomorrow, I can tell you it is the deepest dive into LEAF Spy data I have done so if you are into that, you might like part two better. 

Thursday, November 5, 2020

To Pump Or Not To Pump?

 A Facebook post on one of the LEAF groups asking about the low tire pressure symbol on the dash. More than a dozen chimed in that they also saw it as well and its Winter which is a bit concerning. Like all dash warnings, they come on when the situation is quite dire. Since Nissan already low balls the tire pressure recommendation is it imperative to check those pressures EVERY time you drive the car. 

The new LEAFs makes it easy. Starting in 2018, Nissan started listing individual pressures on each wheel and these are self registering so no need to keep track of the changes in position when rotating tires.  Like all TPMS systems, it takes a few seconds for the tires to measure the pressure but this is something you should do before traveling too far. 

To access this menu option, use the steering wheel buttons to scroll horizontally thru the options. The one you are looking for is the one just left of the options menu or the "Information" screen.  Notice the vertical dots on the left side of the display? Those represent how many subcategories are contained within that menu. 

The information button has 4 subcategories and two of them should be used frequently. The Trip computer is my default screen which makes checking tire pressures that much easier since its just a single click up to see the TPMS screen

Notice we are now on subcategory "3" 

Why is it important to check pressures right away? Tire pressures should be set during the coldest part of the day. That is hardly convenient but the general idea is to check them before driving too far because tires heat up unevenly.  The heating of the tires is directly due to flex. The more the tires flex, the more energy is robbed from the motive force used to get you down the road so your efficiency drops. Well, that energy has to go somewhere and it goes two places; degrading the tire and heating up the air inside it. Obviously, the goal here is less flex. This means longer tire wear and better range but there are caveats.  A less flexible tire has less traction. In most cases, you will be fine unless you are a tailgater or speeder, or...something. 

So balance is the key. Many choose the Nissan recommendation of 36 PSI and this is the least efficient option. You will have less tire life and lower range.  Others choose the maximum tire pressure listed on the sidewall; typically 44 PSI and this gives you the best tire life, the best range, and the least traction. 

So what's the best option?  That is for you to choose. But this is also why I am writing this.  The #1 cause of tire failure is low pressure. The ideology that a tire will "pop" if inflated too much is actually quite laughable. Those days all but ended when steel belted radials came along.  

So the real danger happens when you stray outside the range set above; below 36 PSI or over 44 PSI. Since we are talking "cold" pressure, seeing 46 or even 47 PSI on your tires after an hour of timing laps on a roundabout is not only normal but expected. Its all about the law of reality AKA Physics. 

So we need to be not too low or not too high.  So are we looking at the lazy way or the smart, diligent and much harder way? 

Well, the easy way is to set it and forget it. We really only need to adjust when the temperature changes so if you haven't already, now is the time.  We really only need to do this twice a year. The pressure inside the tires changes roughly one PSI for every 10ºF.  In the northern tier, maybe 3X a year. 

Lowballing It

If 36 is your lucky number, you can make it work but it is a lot more work.  The problem with living on the edge is you have to be diligent...half the time....and you picked the edge that should get 100% of the attention.  Tires work by creating pressure inside that holds the tire to the wheel by its bead. That tire pressure maintains the bead and only a minimal amount of air escapes and can take several days if not weeks before we notice it but it WILL leak.... PERIOD.  So checking the pressures EVERY time you drive the car is very important and luckily we now have a process that takes 2 seconds (if you are slow) to check them.  Of course, the lower the tire pressure, the lower the integrity of the bead and the faster air leaks out.  The #1 cause of tire failure (as mentioned above) is...well, the #1 "avoidable" cause of tire failure is low tire pressure resulting in a bead that loses its integrity easier over bumps, etc. 

Bottom line; expect to boost the pressure frequently. 


44 PSI may seem like living on the edge but its not. Again, driving will push the pressure above 44 PSI but that is ok. Tire engineers already accounted for that. Now, just because tires don't have the "this is not a toy, do not place over mouth and nose or suffocation might result" warning doesn't mean they have the same BS legal ramifications to contend with. They do so the "maximum" tire pressure listing is a very very VERY safe thing to do.

as mentioned above, tires leak. Some leak slowly, some leak faster but they all leak. Now everyone here will contend that theirs don't leak because they have had a set of tires where they set the pressure one time and never went beyond the "look to see if one is lower than the other" method for the rest of that tire's life. FYI; most of these people also complained how bad their tire life was as well. Coincidence? Who knows...

Ok so just because there has never been a recorded incidence or air sneaking "IN" to an inflated tire doesn't necessarily mean it couldn't happen but as I understand it; the circumstances that would be needed is quite rare here on Earth. This means "one" car might have an issue but the rest of us should be fine. 

So yeah, even if in the "44" crowd, occasional airing up on the tires is needed. I wish I could say that I have added air less than a half dozen times since the early 90's (when tire pressure became important to me) but I didn't actually start tracking it until 2004 but discounting major intrusions of the screw variety, I have only added air "off schedule"  13 times and all 13 of those times was before I got my 40 kwh in February 2018.  But that was when I had my under 100 mile LEAF and my "trigger" point was 43 PSI.  Nowadays, I don't adjust until it gets to 40 PSI which is one reason why I haven't. I do adjust twice a year to account for Summer and Winter temperature changes but that is all. I guess my range concerns have "diminished"  😎

Spread The Work!

Ever wonder why birds fly in formation?  Its all about efficiency. If you had to flap your arms for weeks at a time, you would understand.  The lead bird faces the most resistance due to air currents.  When breaking that resistance, the bird creates a wake of lower air pressure where birds following are able to work much less to follow along.  Each bird takes its turn leading so no one isover fatigued and the entire group benefits.

Your tires also see this imbalance. Your front tires guides your car. This means all the inertia your car has is applied to the tire every time you change direction (which in the case of the typical WA freeway driver is every .4 seconds!) which means they wear out faster. They are also the drive wheels and as we know, the new LEAF will spin them tires like crazy. So I would be amiss if rotation was not mentioned.  To get the best tire life, you should rotate your tires regularly. 

So the only real question is how often? The answer is "often enough to maximize tire wear but not often enough to be an inconvenience"  Now what this doesn't mean is rotate them when its convenient. It means setting a schedule based on something.  The easiest way is by mileage interval. The LEAF even has a maintenance setting where you can set reminders to rotate when a certain mileage is obtained. 

Since I average 15,000 miles a year, I rotate every... 4, 5, or 6,000 miles.  Why so inconsistent? 

Miles are only equal in length. The wear on the tires is not. Freeway driving provides a lot less wear on the tires.  A good example would be Steve Marsh; the "100,000 Mile LEAFer" whose OEM tires lasted him over 70,000 miles! And he kept his tire pressures between 38 and 39 PSI so not even an "extremer" 

So based on that; in Summer, I rotate every 6,000 miles due to a MUCH greater portion of freeway driving due to road tripping. In Winter, its more around town driving which wears out tires faster so it 4,000 miles so it averages to 5,000 miles a year.  How you do it is up to you but do it!