LEAF's 12V battery behaviors - and why they go bad

[arnis]

Bought a CTEK charger as a result of that understanding, as it runs a pulse cycle to reduce sulfating. Seems to work; but time will tell.

You've been misinformed about desulfation due to normal market competition. It is not really possible to revive thick sulfation as no current will flow through it. It is only possible to do with lighly or mildly sulfated battery with high charging voltage and higher temperatures. Any charger that charges the battery is providing somewhat raised voltage. Therefore any charger desulfates. Going above 14.4V speeds the process but also hurts the battery in other ways.

LeftieBiker, before fixing something a fault should not only be identified but also a solution should be found that not only fixes this specific problem but also avoids making another. As we can clearly see, many have left their Leaf for extended periods with positive outcomes. These few positive experiences already determine, that problem is not occurring on every Leaf.


Nubo - we have already concluded, that if battery has been somehow discharged, as soon as Leaf has been turned on (or is connected to grid) it will rapidly charge 12V battery. If harm is already done (discharged for many days) then it only charges as much as battery absorbs. It is most likely true that Leaf is not programmed to deal with damaged batteries and doesn't even tell the user to do something with that. But it is Nissan and not BMW. Totally different companies with different values.

powersurge - voltage is only one indicator and we can't even agree on that. This voltage is the biggest disagreement of them all. Some of us think that 12.5V is too low for lead acid battery. And those who disagree also disagree to justify their conception.

It is in human nature to accept the first way of notion, not the second or third. I bet JimSouCal understands and agrees with that.

 

[macnut]

Haven't been able to follow the heated discussion as it's a bit above my head,

but aside from the issue of how the Leaf charges the 12V battery, I would appreciate thoughts on the following:

- newly installed Nissan Series 6000 12V battery installed late May 2016

- didn't check resting voltage when it was new, but hard wired a CTEK charger as a precaution to keep the battery healthy

- have charged it with the CTEK every few weeks, usually requiring about 12hrs. for it to show (float) charging complete

- now taking a bit longer to fully charge and I measure the resting voltage at only 12.51V when CTEK says it has finished

Should I be surprised that I can't get a higher resting voltage than 12.51V in a battery that is less than 6 months old?

Have confirmed voltmeter is accurate as a 10 year old O.E. battery in a 2007 Sentra still registers 12.68V when fully charged.

The 6000 Series battery has small covers over each cell that look like a manufacturing convenience rather than for end user maintenance.
Could be pried off I suppose but as they are so small it looks only useful for adding distilled water and not viewing the plates for sulfation.
Might be just big enough diam. though for taking a S.G. reading of each cell.

 

[LeftieBiker]

12.5 volts is about what we typically see in situations where the car is driven in ways that don't match perfectly with the charging pattern, but isn't killing the battery. IOW the charge is chronically but not critically low. If you didn't use the charger/maintainer regularly, you might have problems. Having to do this is why there are complaints.

 

[RegGuheert]

Should I be surprised that I can't get a higher resting voltage than 12.51V in a battery that is less than 6 months old?

Please ensure the following when you make this measurement:
1) ELM327 is not plugged in.
2) You do not open any doors following the charging cycle. In other words, open the hood before you start charging so that you can measure the voltage without waking up the car electronics.

If you opened a door just prior to taking the measurement, I would say you likely have a healthy battery.

Otherwise, by way of comparison, my over-five-year-old LEAF OEM battery has been thoroughly desulfated using a BatteryMinder 1500. Recent tests following a full charge and letting the battery rest for 12 hours (in the car overnight, so no sun on PV) resulted in a voltage of 12.71V.

The 6000 Series battery has small covers over each cell that look like a manufacturing convenience rather than for end user maintenance. Could be pried off I suppose but as they are so small it looks only useful for adding distilled water and not viewing the plates for sulfation. Might be just big enough diam. though for taking a S.G. reading of each cell.

One thing I love about the OEM battery is that the case is translucent, thus allowing me to check the electrolyte level by simply holding up a flashlight behind it. It doesn't tell me specific gravity, but I can know for sure the battery is not using water.

 

[arnis]

12.5V is the same voltage I see on all other vehicles I've worked on (I diagnose electric problems with BMW's).
And I just tested one random battery that is not connected to anything. It pretty much showed the same decline as in
one research I already linked before - x-axis hours, voltage drop after finishing charging, different float voltage scenarios:

Voltage will drop no matter what. There are some specific types of batteries (not regular flooded) that have slightly different
voltage curve but we are not really interested in those. 100% SOC is not sustained even for an hour. It drops to equilibrium level very fast.

Anyway my test has been finished as rapid drop has stopped. I could do the test again and again with different batteries
and I will see similar results with all of them. New batteries must not be tested as they are not stable during few first cycles.
Summary: Floating stopped at 13.8V (2.3V cell). voltage a moment after: 13.64V. Timestamps in 0,1V drops.
13.54V (2,25V cell) @ 2 min,
13.44V@5min,
13,34V@10min,
13,24V@18min,
13,14V@31min,
13,04V@50min (hour),
12,94V@100min (2hour),
12,84V@200min (3hour),
12,74V@350min(6h),
12,64V (2,15V cell) @1050min(17,5h).
3 days later battery is at 12.59V (2,1V cell).
To compare my results on this graph divide voltage with 6.
Note that graph is done on massive battery cell and it is slow to react in the beginning compared to mine.

I would like to add that Leaf stops using 13V mode somewhere around 0C +3C. It is constantly in 14.5V mode. '
Resting voltage is still around 12.5V. Higher float voltage is fine due to cold electrolyte not absorbing juice anyway.

I think I was wrong when I thought 12.5V is SOC below 70%. I suspect 100% SOC is something imaginary lead acid
battery companies just agreed (to show bigger capacity numbers) :lol:

 

[BrockWI]

Nubo - we have already concluded, that if battery has been somehow discharged, as soon as Leaf has been turned on (or is connected to grid) it will rapidly charge 12V battery. If harm is already done (discharged for many days) then it only charges as much as battery absorbs. It is most likely true that Leaf is not programmed to deal with damaged batteries and doesn't even tell the user to do something with that. But it is Nissan and not BMW. Totally different companies with different values.

Where to start. I am not saying my situation is normal or typical, but something sticks on sometimes on our 2013 S leaf. I have never figured it out, but it has happened randomly about 20 times now.

What I can add is that I now do a weekly charge and most weeks the battery will be topped off in 10 to 30 minutes or so and go in to float. Every so often I get a 10 to 15 hour charge time before hitting adsorb, this is using a deltran 1.25 charger. So at that point the battery is significantly down.

The next thing and again this is my experience, if the battery is dead for some reason and you jump it, then you can drive it or leave it on for an hour or charge the traction battery full and the aux battery is not charged, it will still take 20+ hours to get to absorb. Now if the leaf were charging they way most good 4 stage charges do, this wouldn't be the case. I have seen it many times that the Leaf drops out of absorb WAY to soon, way before the battery has excepted enough charge to do any good, this is called deficit charging.

I know I have two problems here, the phantom drain and then the lack of good absorption on the cars part. I do believe that if you never had a phantom load you could "get away" with a battery lasting a few years this way, but why, why let a battery slowly fall lower and lower state of charge, which is what I have seen with my car and this almost exactly matches with RegGuheert posted, so I know it's not just my car.

I have replaced the stock battery with a larger one and this give me more room before it runs dead and usually I catch it with my weekly charge or when we notice the 12v battery light come on, on the dash. And someone tell me why in the world with the car on the 12v battery light should ever come on? But ours does and then I let it charge for the 10+ hours with the deltran and I am good.

Call me crazy or say I am wrong, but this is what happens to us. I know it isn't a solution, but a band-aid and it works.

 

[macnut]

Should I be surprised that I can't get a higher resting voltage than 12.51V in a battery that is less than 6 months old?

Please ensure the following when you make this measurement:
1) ELM327 is not plugged in.
2) You do not open any doors following the charging cycle. In other words, open the hood before you start charging so that you can measure the voltage without waking up the car electronics.

thanks,
1) was not the problem, but I think 2) was.
reconnected the CTEK until it showed completed charge again, and made sure the sleep circuits were not awakened before measuring voltage, and got 12.79V this time.

That's more in line with what I expect from a fully charged car battery with some float charge.

 

[arnis]

Call me crazy or say I am wrong, but this is what happens to us. I know it isn't a solution, but a band-aid and it works.

Deltran 1.25A charger is hardly an absorption charger.
For me Deltran charger is not something I couldn't even take into consideration as a source of information about battery SOC.
I do not trust random company that has one LED on their charger that shows when charger "drops off absorption mode".
It might be either current or time or voltage or whatever else dependent. Down to charger temperature and AC input voltage ripple.

12.79V - That's more in line with what I expect from a fully charged car battery with some float charge.

Very well said. Charged battery with some float charge still in. That float charge degrades pretty fast.

It appears most cars keep their lead acid batteries around 12.5-12.6V. This includes Leaf.

 

[JimSouCal]

Bought a CTEK charger as a result of that understanding, as it runs a pulse cycle to reduce sulfating. Seems to work; but time will tell.

You've been misinformed about desulfation due to normal market competition. It is not really possible to revive thick sulfation as no current will flow through it. It is only possible to do with lighly or mildly sulfated battery with high charging voltage and higher temperatures. Any charger that charges the battery is providing somewhat raised voltage. Therefore any charger desulfates. Going above 14.4V speeds the process but also hurts the battery in other ways.

<snip>

It is in human nature to accept the first way of notion, not the second or third. I bet JimSouCal understands and agrees with that.

Not sure exactly what you are saying Arnis (whether I'd agree or disagree), but I can say that Porsche Rebrands the CTEK and sells it as their OEM battery maintainer. The CTEK manual describes a six stage charging program with a test diagnostic near the end... The diagnostic seems to check for holding the charge before supposedly going to a long term maintain and periodic pulse mode.

I've found that Porsche engineering is on the high side of rigorous, and so far, my 2011 original 12V battery seems to be good to go... For what it's worth... I've been running the CTEK for a full cycle about once a week for a couple of months... As mentioned before, so far, so good. In the minimum, the CTEK seems to be a good float maintainer in the least... I bought the .8 A version. Use on the ICE and the LEAF...

 

[FalconFour]

Nice to see this thread is still alive and kicking... :lol:

I have been servicing cars for 40 years, and I have found that too many users here get into disputes over tires, mechanics, or things like the "proper battery charging algorithm". Many people forget that the battery is just a box with electricity. Keep it charged (or topped off), and it will last longer. If the 12v battery dies, yes, the Leaf will not run (like any car). Put in a new battery, and it will run... For most of us, that is all that we need to know..

In my experience, the LEAF is particularly susceptible to low, and even marginal 12V battery. It's unlike most cars in important ways. For example, in an ICE car you become acutely aware of low battery condition because the starting event is a big current draw and makes a weak battery instantly recognizable. In effect, every internal combustion car has a built-in load tester for the 12V battery that is invoked every time you drive.

In the LEAF, the "starting current" is trivial and so the battery can drift down and become quite weak without giving any indication. And then when the 12V does drop below a certain threshold, it can result in any number of bizarre symptoms including anomalous braking performance that aren't immediately obvious as 12V problems, and are dangerous besides. Not everyone is prepared to read 24 separate DTC codes, realize they all have one root cause(12V supply), and clear them to get the car normalized again. Been there. For these reasons I think it is quite reasonable that LEAF drivers become wary of 12V issues and seek to understand and stay ahead of them.

^^ This is basically it, all of it. LEAF's problem is that it was half designed with ICE in mind (starter-style battery) and half with EV in mind (weird charging behaviors), while leaving huge gaping holes - like absolutely no detection of low battery voltage. What it should have done is pop up a little message in that center multi-function display saying "Low 12V Battery" and refuse to start when voltage is below what's needed to operate - instead of inducing the so-called "Christmas Tree Effect" and setting every code in the book, bricking the car until codes are cleared. Even one step beyond that, how about simply keeping an eye on the voltage and then running a "maintenance charge" (if HV SOC% > 30%, say?) instead of just running on a timer?

My biggest beef with all this is, if we could think of and observe all these problems and things they could have done to fix it, why didn't they? A huge amount of money to every major OEM is dedicated to trying to solve and prevent 12V battery problems -- when under warranty, 12V replacement batteries are a huge cost to automakers. You'd think Nissan would be trying to put some effort into fixing this, not just doing the bare minimum to kick every Leaf down the road out of the warranty period... because in a lot of cases, they won't make it out of warranty with problems like this.

 

[Nubo]

Nubo - we have already concluded, that if battery has been somehow discharged, as soon as Leaf has been turned on (or is connected to grid) it will rapidly charge 12V battery. If harm is already done (discharged for many days) then it only charges as much as battery absorbs. It is most likely true that Leaf is not programmed to deal with damaged batteries and doesn't even tell the user to do something with that. But it is Nissan and not BMW. Totally different companies with different values.

The initial charge rate may be high, but does not necessarily solve the problem. I was very much reminded of the limitations of resting voltage measurement when my car started acting funny. Battery seemed to be charging ok and I could find no phantom draws. It was only when load testing the battery that the problem became obvious. The voltage dropped like a rock even under a small load. The battery was shot. In an ICE application the weak battery would have been caught much earlier and probably before it caused any computer-level weirdness. The thing missing on LEAF is a load test. It would be fairly cheap for a manufacturer to implement such a thing as part of the startup self-diagnostic routine. And change the 12V problem handling from reactive to predictive.

Not sure about BMW, but I can say that 12V problems have also troubled Tesla drivers so even high-end manufacturers may not "get it".

Even our home-alarm system uses predictive failure for the 12V backup battery; regularly placing the system on battery power and monitoring the the change in voltage. When it alarmed LO BAT last week, the SLA battery had a resting voltage of 12.9V But the system had predicted it no longer had sufficient capacity. Sure enough I put a small load on and voltage quickly dropped to 9.8V. If ADT can do it, Nissan and Tesla could certainly do a predictive test. But 12V systems are probably not "sexy" enough.

 

[GerryAZ]

Even ICE vehicles can do strange things with a low 12-volt battery. I had an SUV assigned to me at work that would crank over normally, but not start if the battery got too low. Apparently the computers required higher voltage than the starter motor needed to crank at what sounded like normal speed. There was no indication of a problem (no error codes or warning lights), it just would not start and acted like the spark plugs and/or fuel injectors were disconnected. After a few minutes of troubleshooting at night at a construction site, I finally thought to connect a booster battery and it started fine. The only reason I tried the booster battery is because I remembered that the LEAF's computers do strange things when its 12-volt battery gets too low.

Gerry

 

[DaveinOlyWA]

great post but have to dispute your statement that not having Solar panels will cause issues. I noticed this pathetic 12 volt charging profile several years ago and also noticed that my 2011 SL with solar panel had a lower 12 volt battery reading. I figured it was due to CARWINGS and its associated 12 volt load.

On my 2013 S that did not have CARWINGS, I was averaging .2 volts higher. Now part of the problem stems from my car being garaged but I checked the differences between Summer (lots of Sun here) and Winter. (lots of clouds) and saw a minimal difference and after we account for the 30-40º drop, I have to say it did not make a difference.

http://daveinolywa.blogspot.com/2014/10/new-battery-observations-no-not-that.html

http://daveinolywa.blogspot.com/2013/01/12-volt-battery-management-part-2.html

 

[DaveinOlyWA]

Dead-on, FalconFour! Thanks!

Here, I'll explain how the Leaf's 12V system behaves, and why those of us without 12V solar panels on the back are screwed so bad.

The 12V solar panel makes very little difference. The HIGHEST voltage I have ever seen on the LEAF's battery when parked in the sun is 13.25V. That is only slightly better than the 13.1V that the car normally operates. The problem is that this voltage occurred in the cool of the morning. Once the sun got higher in the sky, the PV panel heated up and the voltage dropped back down to 12.8V. That thing truly is just an ornament. The BEST it can do is to reduce the amount of charge lost during the daytime.

Thoughts?

Note that you get 14.4V whenever the wipers are on, so those in rainy or misty climates may do a bit better with their 12V batteries. Also note that sometimes during charging of the Li-ion battery you will get 14.4V continuously (or at least for a long time). I'm not sure how it decides when to do this.

agreed. my solar panel actually lowered the voltage but guessing it was due to overhead from CARWINGS which my 2013 does not have. But if the solar panel puts out 13 volts, it may not charge the battery but will prevent the battery from being drained by the various systems in the LEAF

 

[GerryAZ]

great post but have to dispute your statement that not having Solar panels will cause issues. I noticed this pathetic 12 volt charging profile several years ago and also noticed that my 2011 SL with solar panel had a lower 12 volt battery reading. I figured it was due to CARWINGS and its associated 12 volt load.

On my 2013 S that did not have CARWINGS, I was averaging .2 volts higher. Now part of the problem stems from my car being garaged but I checked the differences between Summer (lots of Sun here) and Winter. (lots of clouds) and saw a minimal difference and after we account for the 30-40º drop, I have to say it did not make a difference.

http://daveinolywa.blogspot.com/2014/10/new-battery-observations-no-not-that.html

http://daveinolywa.blogspot.com/2013/01/12-volt-battery-management-part-2.html

You are correct, the solar panel does not do anything. I don't know about the 2013, but the 2015 has a better charging algorithm than the 2011. The charging voltage on the 2015 stays at 14 until the current into the battery drops to a much lower level than on the 2011.

Gerry

 

[arnis]

If anyone would only read those materials I collected...
12V Lead acid batteries are susceptible to failures (random and also quality dependent) across all industries, not only automotive.
Many of us can bring examples of vehicles that ran for 8 years with only one battery.
At the same time we can bring examples with batteries that die way too early.

So why do we suppose batteries themselves are not to blame?
We can clearly state that some Leaf 12V batteries fail within first year and also that some Leaf 12V
batteries last at least half a decade. This happens worldwide. Not only with Leaf and not only with cars.

Let's just use logic. If 10% of 12V batteries on Nissan Leafs from 2011 lasted for 5 years, does that mean the way
how Leaf handles 12V batteries will definitely ruin battery prematurely? Will the answer change if percentage is 30%?
Will the answer change if percentage is 3%?

Now from there. If 10% batteries die within first year on Nissan Leaf, does that mean the way how Leaf
handles 12V batteries will definitely ruin the battery soon?

Do batteries that lasted for 5 years on Nissan Leafs have superpowers like resistant to corrosion/sulfation/electrolyte loss
compared to those batteries that died during that period?

Do other vehicles that last on average 20% longer on one battery in any way prove that Leaf treats 12V batteries worse? Considering that
almost all other vehicles use different battery manufacturer, series, model, capacity or type?

 

[DaveinOlyWA]

Last quote is worthless. Very short and missing sources, low information density.
Battery tech requires more than just average Joe. I'm not able to discuss with you if you are not
taking into account new information. Please read more. Don't read opinions nor rules of thumb.

This has happened to the 12V batteries in MANY (most?) LEAFs within the course of a couple or a few years.

DATA, Data. Let's make a survey. It won't be totally balanced as many forum users use OBD adapter. Or maybe we should
also have that as an answer.


Have you ever ran out of 12V battery charge:
No (just write No, more comments not necessary)
Yes (if yes mention did you
had OBD adapter plugged in,
left for long time,
car is rarely driven (less than 3x per week)
was the battery replaced,
happened many times,
how many years after purchase

At least 100 answers as a minimum. Then we can at least estimate.
And why should it be filtered only to US? Multiple climate models there.

OBD plugged in 100% of the time covering almost 5 years on 2 different cars. no battery issues.

you need to consider things like timers, CARWINGS and any other random operation that runs when the car is off. Also time car is plugged in after the charge has been completed.

I have never used a timer

 

[arnis]

OBD plugged in 100% of the time covering almost 5 years on 2 different cars. no battery issues.

you need to consider things like timers, CARWINGS and any other random operation that runs when the car is off. Also time car is plugged in after the charge has been completed.

I have never used a timer

Thank you for valuable proof that Leaf doesn't kill all batteries be default

OBD adapter doesn't consume like crazy. If Leaf is used daily battery won't even notice. Also some adapters do fall asleep at least partly if no Bluetooth is around.
Whenever timer is activated 12V battery is instantaneously at charge state.

 

[RegGuheert]

Let's just use logic.

Good idea. The following statement by you is a logical fallacy known as a non sequitur argument:

If 10% of 12V batteries on Nissan Leafs from 2011 lasted for 5 years, does that mean the way
how Leaf handles 12V batteries will definitely ruin battery prematurely? Will the answer change if percentage is 30%?
Will the answer change if percentage is 3%?

It does not follow that if SOME batteries last five years without user intervention that there is not a problem with the LEAF's 12V charging algorithm.

 

[arnis]

Let's just use logic.

Good idea. The following statement by you is a logical fallacy known as a non sequitur argument:

If 10% of 12V batteries on Nissan Leafs from 2011 lasted for 5 years, does that mean the way
how Leaf handles 12V batteries will definitely ruin battery prematurely? Will the answer change if percentage is 30%?
Will the answer change if percentage is 3%?

It does not follow that if SOME batteries last five years without user intervention that there is not a problem with the LEAF's 12V charging algorithm.

I asked questions (notice question marks)

Give answer as "yes" or "no". If you think conclusion is not appropriate for premise you have to answer "no".
You are not supposed to fix, modify nor comment question.
Those questions are designed as guides for individuals to find an appropriate solution for question they don't know the answer to.