knightmb
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Leaf Number: 414897
Location: Franklin, TN

Re: 12v Battery

Tue Aug 09, 2016 12:35 pm

JimSouCal wrote:
RegGuheert wrote:
JimSouCal wrote:Appreciate the update as an encouragement. I've used a CTEK a few times on the weekend. I'd inadvertently left the OBD reader plugged in for 16 day to find a drained 12V battery. With a 2011 wondered if I'd just killed the lead acid battery, but so far, it's holding voltage... Wouldn't want to push it under load though.. We'll see... Thanks..
I think I had sulfation that had hardened for YEARS, but it seems it has finally been returned to "active duty". The key to desulfating a battery is "patience". It takes quite a bit of time for the sulfation to get broken up. I do think desulfating works better in the heat of summer. I'm not convinced it does much in the wintertime.

Today, I charged the 12V battery to full and then drove it. When I returned, I put a voltmeter on the 12V battery and it rose up to 12.85V after about an hour. I have *never* seen this battery go to such a high voltage after shutting off the LEAF. That's the kind of voltage I tend to see only with brand new flooded batteries.
I am left to wonder WHY modern cars, especially the LEAF, don't have an integrated desulfication routine? Perhaps because less lead acid batteries would be sold? Humm....

They don't run long enough to be useful. It takes a lot of time to break up the sulfur.

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RegGuheert
Posts: 5546
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: 12v Battery

Tue Aug 09, 2016 12:46 pm

It would be best if the LEAF simply kept the 12V battery properly charged. Then there would be little or no need for desulfating.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

dhanson865
Moderator
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Leaf Number: 16156
Location: Tennessee

Re: 12v Battery

Tue Aug 09, 2016 3:25 pm

JimSouCal wrote:
RegGuheert wrote:
JimSouCal wrote:Appreciate the update as an encouragement. I've used a CTEK a few times on the weekend. I'd inadvertently left the OBD reader plugged in for 16 day to find a drained 12V battery. With a 2011 wondered if I'd just killed the lead acid battery, but so far, it's holding voltage... Wouldn't want to push it under load though.. We'll see... Thanks..
I think I had sulfation that had hardened for YEARS, but it seems it has finally been returned to "active duty". The key to desulfating a battery is "patience". It takes quite a bit of time for the sulfation to get broken up. I do think desulfating works better in the heat of summer. I'm not convinced it does much in the wintertime.

Today, I charged the 12V battery to full and then drove it. When I returned, I put a voltmeter on the 12V battery and it rose up to 12.85V after about an hour. I have *never* seen this battery go to such a high voltage after shutting off the LEAF. That's the kind of voltage I tend to see only with brand new flooded batteries.
I am left to wonder WHY modern cars, especially the LEAF, don't have an integrated desulfication routine? Perhaps because less lead acid batteries would be sold? Humm....


I think if you look at viewtopic.php?f=9&t=19471 you'll see the Leaf does desulphate, it just doesn't keep the battery charged enough for that desulphation phase to keep up with the sulphation caused by low charge. It's a long thread so I'm not sure where in the thread it was mentioned, worth a read if you are curious.
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mayanktanwar
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Re: 12v Battery

Fri Aug 12, 2016 8:53 pm

A 12 V lead-storage battery consists of six cells, each producing approximately 2 V. The actual standard cell potential is obtained from the standard reduction potentials. Modern SLI batteries are lead-acid type and provide 12.6 volts of direct current, nominally 12 V. The battery is actually six small batteries, or cells, connected in series. The 12-volt car battery is the most recycled product in the world.

ClarD
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Joined: Mon May 02, 2016 8:17 pm
Delivery Date: 06 Apr 2016

Re: 12v Battery

Mon Oct 10, 2016 3:14 pm

dhanson865 wrote:
1. ...You might have to spray some water on the wipers/glass first or use the wiper fluid occasionally to keep from shredding the wipers.


You could always lift the wipers off the glass. Then they could dance instead of drag :)

mskiin
Posts: 9
Joined: Wed Dec 04, 2013 4:07 pm
Delivery Date: 30 Nov 2013
Location: Glens Falls, NY

Re: 12v Battery

Wed Oct 12, 2016 10:23 pm

I have a 2013 with 45k I drive 88 miles round trip to work 5 days a week charge twice a day and have never even thought that the lead battery could be an issue. I drive there at 3 and home at 11pm so in Upstate NY it's fairly easy on the batteries. They're always used, always warm and I hadn't had an issue yet. I will definitely check now. I'm coming up on my 3rd winter now so I'm expecting some kind of issues. Good thing I came across this post. Id hate to be stuck in 10 degree F weather because my stupid electric car that I charge twice a day can't maintain a lead batt.

arnis
Posts: 725
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Leaf Number: 015896
Location: Estonia, Europe

Re: 12v Battery

Thu Oct 13, 2016 3:41 am

RegGuheert wrote:It would be best if the LEAF simply kept the 12V battery properly charged. Then there would be little or no need for desulfating.


Correct. Older Leaf (charger in the trunk) had this algorithm for 12V charging:
Always charging while vehicle is ON.
Always charging if vehicle is charging HV battery.
Always charging if vehicle is preheating/precooling.
Automatic charge after 120 hours of nothing happening (5 days) for 5 minutes.


Nissan most likely noticed a big problem with that and new Leaf (charger under the hood) works that way:
Always charging while vehicle is on.
Always charging if vehicle is charging HV battery.
Always charging if vehicle is preheating/precooling.
Automatic charge after 24 hours of nothing happening (1 day) for 4 minutes.
This solved the problem in most scenarios.


For those who own older Leaf, ran out of warranty and plan to keep the Leaf for longer period I would STRONGLY recommend
to replace 12V battery with AGM 12V battery next time.
It costs more but it offers more reliability, especially in this
lousy situation: Leaf draining battery for 5 days and then charging it only for 5 minutes :(
AGM battery is capable to survive deeper discharges with less sulfation happening.
AGM battery is capable to absorb charge faster than regular flooded battery, especially in cold temperatures. Therefore it is able to absorb more during 5 minute period.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
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Marktm
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Re: 12v Battery

Thu Oct 13, 2016 7:23 am

I got this for my birthday (rather than socks!). It will stay in my trunk. Great backup for my smart phone charging (battery going bad in it). I have an emergency generator (6500 watts) with electric start. Hoping this will start it - (it's not an easy start). Will post results. I'm quite sure it will enable the Leaf's 12 volt system - even with a dead battery.

https://www.amazon.com/DBPOWER-12000mAh-Portable-Charging-Flashlight/dp/B01D42YN6W/ref=pd_lpo_263_tr_t_3?ie=UTF8&psc=1&refRID=D9NS1P6X3THSGXPMMA69
2012 Leaf SL; 36,000 miles. Battery replaced November 1st, 2016.
Rural cabin with 6750 watts Grid tied PV. Off-grid solar Leaf charging capable (level II).

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RegGuheert
Posts: 5546
Joined: Mon Mar 19, 2012 4:12 am
Delivery Date: 16 Mar 2012
Leaf Number: 5926
Location: Northern VA

Re: 12v Battery

Thu Oct 13, 2016 1:44 pm

Some corrections:
arnis wrote:Older Leaf (charger in the trunk) had this algorithm for 12V charging:
Always charging while vehicle is ON.
I'll assume you actually mean READY in Nissan's terminology. Not so. The LEAF only charges for a few seconds and then spends the rest of the time at a float voltage of 13.1V. The exception is that the vehicle actually charges the battery at about 14.5V whenenever the windshield wipers are on.
arnis wrote:Always charging if vehicle is charging HV battery.
Not so. As above, it normally charges for only a few seconds and then drops to a float voltage of 13.1V for the rest of the time. The exception here is that it sometimes charges during the ful charging period. It appears this happens during very cold temperatures, but perhaps it also happens occasionally at other times.
arnis wrote:Always charging if vehicle is preheating/precooling.
While I haven't measure it, I strongly suspect this case is similar to the charging case listed above.
arnis wrote:Automatic charge after 120 hours of nothing happening (5 days) for 5 minutes.
Unfortunately, this has very little effect on the SOC of the battery since five minutes is not enough time to do much of anything with a 12V lead-acid battery.
arnis wrote:Nissan most likely noticed a big problem with that and new Leaf (charger under the hood) works that way:
Always charging while vehicle is on.
Always charging if vehicle is charging HV battery.
Always charging if vehicle is preheating/precooling.
From what I have read, the MY2013 and later use exactly the same algorithm as listed above for the MY2011-2012. The difference seems to be that those later LEAFs appear to also have a programming defect which occasionally leaves a load on when the car is turned off which drains the battery, just adding to the problem of keeping the 12V battery alive.
arnis wrote:Automatic charge after 24 hours of nothing happening (1 day) for 4 minutes.
Thanks, I didn't know about this change. It's better than nothing, but, again, 5 minutes is hardly worth the effort, IMO.
arnis wrote:This solved the problem in most scenarios.
I don't think so. It seems the MY2013 and later LEAFs have at least as many problems with the 12V battery as the earlier models, if not more.
arnis wrote:For those who own older Leaf, ran out of warranty and plan to keep the Leaf for longer period I would STRONGLY recommend
to replace 12V battery with AGM 12V battery next time.
It costs more but it offers more reliability, especially in this
lousy situation: Leaf draining battery for 5 days and then charging it only for 5 minutes :(
AGM battery is capable to survive deeper discharges with less sulfation happening.
Sorry, but I do not agree with the advice of switching to an AGM battery. Unfortunately, 13.1V is a DISCHARGE voltage for many new AGM batteries. I have one that is several years old now that sits around at 13.25V for MONTHS at a time. As you can see, the LEAF will actually DISCHARGE an AGM battery in normal operations. Additionally, my experience is that AGMs tend to sulfate FASTER than flooded batteries. I am currently trying to recover several 400 Ah AGMs which were 75% sulfated after only about three years of use. I have read of other similar experiences with AGMs.
arnis wrote:AGM battery is capable to absorb charge faster than regular flooded battery, especially in cold temperatures.
This is true. What is perhaps more important for those who live in very cold climates is that AGMs freeze at a MUCH lower temperature when they are mostly discharged. Unfortunately, a flooded lead-acid battery will freeze at about 17F if fully discharged. In my experience, freezing often ruins the battery.
arnis wrote:Therefore it is able to absorb more during 5 minute period.
Perhaps, but it is still not nearly long enough.
RegGuheert
2011 Leaf SL Demo vehicle
2011 miles at purchase. 10K miles on Apr 14, 2013. 20K miles (55.7Ah) on Aug 7, 2014, 30K miles (52.0Ah) on Dec 30, 2015, 40K miles (49.8Ah) on Feb 8, 2017.
Enphase Inverter Measured MTBF: M190, M215, M250, S280

arnis
Posts: 725
Joined: Sat Jan 23, 2016 3:21 pm
Delivery Date: 23 Jul 2014
Leaf Number: 015896
Location: Estonia, Europe

Re: 12v Battery

Thu Oct 13, 2016 4:10 pm

13.1V is definitely charging voltage. Though it is way too low for occasional use.
Is it verified with multimeter? 13.1V might be reported by LeafSpy but what about real voltage @terminals.
I checked my 2014 Leaf with voltmeter and clamp-on DC ampmeter, it charges as it is written in the literature.

Maybe you have deep cycle AGM battery? On vehicles I've never seen that kind of resting voltage.
BMW uses AGM batteries for a decade already. Almost all start-stop vehicles use AGM type.
I bought a second hand AGM battery that was tortured by 5-series for 6 years. It has more than 55% life left.

Depending on how discharged battery is it can swallow up to 4Ah during that period.

I will verify my observations in near future but I'm pretty sure 2014 Leaf does NOT have 12V battery problems.

PS! AGM batteries do not sulfate faster than flooded. Also their sulfation is not thick due to absorption mats inside.
And lead acid batteries should not sulfate AT ALL if used properly.
Short range EVs <30kWh -- Medium range: 30-60kWh -- Long range: >60kWh
Charging: Trickle <3kW -- Normal 3-22kW -- Fast 50-100kW -- Supercharging >100kW

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