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

Fri Oct 21, 2016 7:08 am

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.
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macnut
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Re: LEAF's 12V battery behaviors - and why they go bad

Fri Oct 21, 2016 3:39 pm

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.
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LeftieBiker
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Re: LEAF's 12V battery behaviors - and why they go bad

Fri Oct 21, 2016 3:56 pm

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.
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RegGuheert
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Re: LEAF's 12V battery behaviors - and why they go bad

Fri Oct 21, 2016 3:57 pm

macnut wrote: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.
macnut wrote: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.
RegGuheert
2011 Leaf SL Demo vehicle
10K mi. on 041413; 20K mi. (55.7Ah) on 080714; 30K mi. (52.0Ah) on 123015; 40K mi. (49.8Ah) on 020817; 50K mi. (47.2Ah) on 120717; 60K mi. (43.66Ah) on 091918.
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arnis
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Re: LEAF's 12V battery behaviors - and why they go bad

Fri Oct 21, 2016 6:35 pm

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:
Image
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:
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BrockWI
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Re: LEAF's 12V battery behaviors - and why they go bad

Fri Oct 21, 2016 7:33 pm

arnis wrote: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.
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macnut
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Re: LEAF's 12V battery behaviors - and why they go bad

Sat Oct 22, 2016 10:11 am

RegGuheert wrote:
macnut wrote: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.
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arnis
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Re: LEAF's 12V battery behaviors - and why they go bad

Sat Oct 22, 2016 11:19 am

BrockWI wrote: 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.

macnut wrote: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.
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JimSouCal
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Re: LEAF's 12V battery behaviors - and why they go bad

Sat Oct 22, 2016 11:59 am

arnis wrote:
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...

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

Sun Oct 23, 2016 12:40 am

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