LEAF 12 Volt Battery Health

 Its that time of year when we are monitoring the weather report to see if road conditions warrant leaving for work 15 minutes earlier to make it on time. Its all about managing snow, sleet, ice and...your 12 volt battery. If you are a member of several LEAF groups like me, it will likely take you  less than 5 minutes to find one "car won't start" post and the culprit 95% of the time?  You guessed it.  So some ideas of keeping that battery reliable thru the Winter is something I think we all need to investigate.

Lead Acid Batteries 

12 volt battery issues during Winter didn't start with the Nissan LEAF.  I can't tell you how many times I cussed and bitched every time I couldn't get my $115 (yeah that is what I paid for it) Chevelle to start on a frigid January morning when living in Michigan. Being less than 5 miles from Lake Huron meant it wasn't a "dry" cold, it was a "feel every single degree of icy chill" cold along with that "nice" breeze. As a teen, I was lucky to have a car (although where we lived, you really didn't have much of a choice. Our town had no bus service that left town and we didn't live anywhere near town) but nowhere near the status of being able to park in the garage so it was all about my car not freezing over night while parked under the Elm tree in our yard. 

This meant at least half a dozen times a winter getting Mom's keys so I could jump my car with hers while hoping my fingers weren't permanently frostbitten during the process.  The reality is cold cars don't want to start first thing in the morning.  Now this was a 12 volt battery that was immediately topped off to a full charge right after starting. Right where lead acid wants to be; fully charged.  But if driving an EV (No, the LEAF is not the only EV with this issue) you are not afforded all the advantages you could have in the frigid fight of the Fahrenheit!

Nissan 12 Volt Management

Nissan's BMS charges the 12 volt battery on a regular basis triggered by several different events.  Starting the car is one, having the car sit for an extended period of time is another.  In none of these cases is the 12  volt battery fully charged. When 24 kwh packs were the norm, I could understand Nissan not wanting to spend a lot of electrons on topping off the 12 volt battery. So it was really all about creating an algorithm  that would boost the charge enough to keep it in the safe zone and for many of us, it works.  But the number of people who do have problems along with much larger packs suggests Nissan could be doing a better job. 

To be fair, they do warn you when the 12 volt battery is low (now why that warning doesn't trigger additional charging sessions is anyone's guess)  but like all "idiot" lights, by the time you see it, damage has already been done. According to Battery U, time under 50% SOC on a lead acid battery PERMANENTLY devalues the capacity. 

Symbol appears in upper left corner of the screen in red

 

The Test Part One

I park in a garage which means my 12 volt issues will be greatly mitigated simply because the battery won't get nearly as cold as one sitting outside. I also live in the Pacific Northwest 3 miles from the southern apex of Puget Sound which means pretty mild winters for the most part. 

Now because I have a Plus and a 28 mile roundtrip 4 day commute, I could easily gain enough range the night before my workweek began to cover me for the  week without any additional charging.  I did this for 4 weeks checking the battery voltage in the morning before taking off for the day.  The results were not encouraging. 

Day 1 range; 12.28 to 12.55 volts

Day 2 ranged from 12.15 to 12.41 volts

Day 3 ranged from 11.91 to 12.31 volts. 

Day 4 ranged from 11.99 to 12.21 volts

Now its obvious that the car is getting a boost from the battery during the night at least occasionally. This explains the high end voltage readings. Most of the readings were nearer to the low end of the range. Now I think with the newer LEAFs, the  12 volt gets boosted daily but was unable to capture it charging. Leaving LEAF Spy running all night is an option because it will only stay connected if the car is on which would have changed the algorithm  that controlled the 12 volt charging mechanism so I set up my Go Pro on the slowest frame rate to run all night to try to to catch charging sessions and it failed to capture anything in 4 days. When the 12 volt battery is being actively boosted and the car is not charging, the right charging light (facing the car) on the dash blinks. I will probably revisit this. 

NOTE; For anyone wondering how much power the car uses in the "on and parked" state. I split duty with my dryer plug to charge the car so am only running at 5.88 KW (240 volts, 24 amps)  LEAF Spy shows power in and out of the battery and here you see a .5 amp difference between car on, car off. Using the "PIE" formula (volts * current = power) You can see 5.22 KW of the 5.88 KW feed making it to the battery with car off.  With car on, its 5.04 KW. 

 

During this time, garage temps ranged from 48 to 58º and a few times, I was wondering if I should grab my boost box. 

Garage temp 51.9º 6:55 AM, car last driven 6:22 PM previous day

Luckily the car still started. I couldn't help but wonder if it would have started if parked outside when the previous overnight low was 39º?  After the car started, I decided to charge to see how long the 12 volt battery would boost.  

Lead acid needs over 14 volts to charge and LEAF Spy logs verified the 12 volt charging at 14.48 volts, just starting just 3 amps. (FYI; LEAF Spy not running the entire time so normally we would see a lot more entries in the drop to under 2 amps with each entry ~ 6 second intervals) 

But the battery only charged for 6 minutes.  FYI; I have a 12 volt battery charger that recommends 4 amp charging medium duty (cars) so 6 minutes? Yeah, barely qualifies as life support. 

Now this may come as a shock to some but there are misconceptions going around on social media including the fact that the normal voltage the LEAF 12 volt DC system runs on 13.04 volts; is enough to charge the battery. This is NOT true, not even a little tiny bit.  The battery is essentially electrically disconnected from the system. 

I then scoured my LEAF Spy logs and found the average to be around 4-5 minutes for a boost with some being as short as 2 minutes. I did see one event that went 7 minutes until LEAF Spy was shut down. Had I only known...

Test Part Two

This part of the test, I measured the voltage every morning when I got up like part one but this time, I plugged the car in immediately afterwards. I would only be charging for ~ 75 minutes so SOC was still quite low (under 50% most of the time)  Since I was charging every day, there was no sense in breaking out day one, day two, etc. so I took 8 measurements (2 weeks worth)

Range; 12.18-12.71 volts. (ok, the 12.71 volts probably should have been tossed out as 2nd highest was only 12.48 volts) 

Wow! so charging every day definitely helps but not nearly as much as I had hoped. I will say that the garage was colder as low as 46.8º and the highest during this time was only 53º. Unlikely significant...

NOTE: Although my car enjoys the pampered life at home, she is just another car at work braving the elements in an uncovered lot for 10½ hours a day.

Living On The Edge

All this made me wonder "Just how close am I to the flame?"  So I went out, checked the battery and it was its customary range at 12.12 volts with the garage at 57.4º. I disconnected the battery entirely from the car and it read 12.30 volts.  I knew that my trip computer would be reset when I disconnected the battery so I turned on the car just long enough to get my LEAF Spy readings for the day before doing all this.  But a .2 volt drop from the system was an interesting data point. 

NOTE; I don't have telematics (Nissan Connect, CARWINGS or whatever its called nowadays) but I do have Wi Fi. Its my guess that Wi Fi is not active when the car is off so shouldn't make a difference. 

So I hooked up the charger. Voltage went to 14.40 volts so a bit lower than the LEAF system. And...

Well, not looking super good (to say the least) 

It did move to 50% in less than 3 minutes. Another 13 minutes to 75%. The time to 100% will be of less value because when the charger senses the voltage starting to rise, it will cut back the current and I have no real way of knowing how much. Either way, I am charging 50-100% faster than the LEAF would be so its pretty obvious that most of the boosts are coming nowhere near bringing the battery as high as 50% charged. Now for Lithium, that would be awesome but Lead Acid? 50% ensures an early death. 

I let the charger run for 40 minutes disconnecting when the charge voltage hit 14.52 volts which was near when the current would likely start to drop. After reconnecting the battery, I waited 5 minutes and checked it. 12.33 volts.  Don't know how much good it did but I sure feel a lot better about it. 

FYI; Temps expected to be below freezing tonight 😉

EDIT

Naturally a few days after I publish this, Elon responded. He is usually pretty good about that ;) 

December 2020 Drive Report; Hope For The New Year!

2021 promises a reset of the challenges faced in 2020 but the progress is slow. WA is still locked down for all social activities so its take out only, no sporting events, concerts, movies or much of anything else.  Although retail locations are restricted to 25% capacity, other than small (easy to track) shops in the malls, there is very little policing going on.  Each store does have people out front going thru the motions but I have only encountered one line at Costco (didn't go in) but other places like Safeway was packed and pretty sure they were well over the 25% limit but so far, no infections

As you can see; as of Wednesday the 7th (when I took the test) I am free to roam...with a mask of course. Since the test, I have only had close interaction with my Son who sees no one other than immediate family as he is still doing CFH (classes from home)  and a few different people I picked up food from and yes, I and they were wearing masks.  

As far as when I will be able to take more advantage of my range, that remains to be seen. Restrictions were supposed to be "adjusted" on the 4th but were extended to the 11th and then an announcement by the governor is breaking up the state into regions where different levels of restrictions will apply. Due to paywall issues, I have no other information than that but its my hope by this time next week, I will be able to do something besides shuttling a few miles for food and groceries. 

I will be getting the vaccine when its available and due to age and occupation, I will likely be in the first 3rd or so in WA? But still looks to be not before early to mid Spring, so that is a long way off not to mention the 30 day 2 shot process and the several days of immunity building before I am "relatively" safe. 

The Numbers

December as expected saw me under 4 miles/kwh barely. I am actually surprised I came as close as I did due to my higher average speed on my commuting but guessing climate control experimentation played a small part but ended the month going 810.2 miles @ 3.96 miles/kwh costing $19.86 or 2.45 cents/mile. That is a slight drop from last month despite higher utility rates which I calculated at 12.21 cents/kwh. Due to the rate change in the middle of the month, a straightforward calculation would have been tedious so I split the taxes, etc. 50/50 although my tier one/ tier two usage was 600/450. All my EV charging was tier two.

For the year; entire fuel cost was $194 and change which included $42.10 in public charging fees, most of which happened when I was homeless. At 13,985 miles that works out to 1.39 cents per mile. I can live with that. Unfortunately the loss of NCTC likely means an estimated 240% increase in cost.

Degradation Predictions

"Probably" should have waited another 2 weeks for my adjustment but as you can see (the black arrows) in the chart, the last one was hardly a thing and I am expecting more of the same. What the chart portrays is projected ahr/SOH @ 100,000 miles using current degradation trends from day one. Although I have date lines, this data points are logged every 1000 miles.

Now if we were to use only the trends of the recent past; .03% SOH the last 1k miles or .04% the previous 1K miles, I would hit 6 figures around 90% SOH. Unrealistic? Well, there are already 4 LEAFers over 100,000 miles and two of them are still over 90% SOH so yeah, its possible. Obviously they have a much lower level of time based degradation.

Here is the latest entry @ 16,003 miles and I guess we can say things are looking up 

By Date

By miles

Notes; There are now 4 LEAFers (40 and 62 kwh) over 100,000 miles with no capacity bar loss including at least one still over 90% SOH.  Granted their timed based degradation will be less than mine, but so far things are looking good.  We are still searching for the first lost capacity bar. If you know of one, grab some pix and comment below! 

Climate Controls

Recently I discovered my Plus has gained a lot more climate control options.  Not sure my 40 kwh could do some of the stuff but I know my older LEAFs couldn't. 

As we know, heat is the big range killer so using it sparingly is the easiest way to boost range on those longer drives. Here in the Pacific Northwest, the challenge is even greater due to the high humidity that comes hand in hand with lots of rain. So anyway, I am buzzing over to grab dinner and have defrost on and as usual, I am toggling the heat button on and off based on how much comfort I need and got stuck behind a smelly at the light. I immediately closed the vent but since it was pouring rain, I knew fogging would quickly become an issue so I left the A/C on. 

The light turned green, I proceeded to my destination and sat in the car waiting for my food to arrive. (carside delivery) The food came out after a 3 minute wait and off I went and that is when I realized the vent was still closed and until hot food was introduced,  the windshield stayed clear!  This was a shock!

So I decided that I would investigate further so the next day. I drove around this time with LEAF Spy running and results were pretty cool 

 

The phone covers it but I drove around all 

day w/o heat. The day was mild so not an

issue! 

Here there is no power draw but I did see power occasionally, so had to access LEAF Spy logs and saw power ranging from 200 to 350 watts briefly but mostly zeros.  On the chart below, the number you see is the power used in 50 watt increments. So 1 = 50 watts, 2 = 100 watts, etc.  Each reading happens roughly every 6 seconds

Now the weather was a lot drier than it was the previous night so unable to know how bad fogging would be but there would definitely some fogging normally as only the driest, sunniest days are fog free when the vents are closed. I did have light rain in the morning but it was mostly dry with sunbreaks in the afternoon. 

Now there are caveats to this method. Although the A/C is not "technically" cooling the air, removing moisture will lower the temp of the air somewhat. I much prefer the closed vent option especially around town and found that blowing cold air on my feet was easier to tolerate than the face or windshield. It did irk me a bit as the front left vent on the dash leaks but I simply pointed it to the driver's window and that fixed it. 

On milder days in the 50's, it was easy to never turn on the heat. I did toggle heat on/off on a roughly 30/70% cycle in colder weather in the 40's down to the upper 30's when the heat was on most of the time. I will be playing with much more but so far, very impressive results. 

Electrify America

I can't even tell you how much it irritates me that my most hated public charging option is becoming so useful! As mentioned, the Olympic Peninsula Scenic Highway is a major challenge even for long range (200 mile plus) EVs due to no DC charging! Tesla has it covered but that is all.  Well, things have changed as EA has sited and will soon break ground on key locations in Aberdeen, (first convenient CCS/Chademo plug in Grays Harbor county!) Port Angeles, and Poulsbo, WA.  This makes the longest distance between DC chargers at no more than 164 miles which literally takes all the challenge away for me.  Even 40 kwh LEAFers can make it with a few short pit stops at one of free level 2's along the route and there is a LOT of places worthy of a visit!  

All will be located at Walmart.  To be fair, I should mention that Leavenworth, WA (our Bavarian mountainous, Christmasy town) another popular destination will also have an EA location but that area has several DC stations already but as we all know; on busy holidays, there is never enough plugs so the more the merrier!  

We also have a state sponsored public charging rollout(most notably Highway 12 over White Pass) that EA is partially involved in (not sure how much the state has involved in these new EA locations) which means more stations coming.  I have requests for Forks and Shelton which will be very helpful as well. 

But the convenience is "nearly" overridden by the crazy per kwh rates EA started last year. I suggest we all send our thoughts to EA about this. We live in one of the hottest EV adoption areas and we are paying THE highest rates for a charge. Something is not right here!