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

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GerryAZ said:
strowger said:
jjeff said:
^^^ I think your right on what might have happened, 5ah isn't much capacity for running a large fan. As a backup should this happen when out and about, I might suggest a smallish portable 12v Li battery jumper. I always carry one in the back of my Leaf for just such occasions. It came with a 12v cigarette lighter adapter or small jumper cables, oh and it also has a 5v USB output for charging portable things that use USB.
All in all for the <$30 I paid for it on sale, I believe $39 regular price, I hope it's worth it, if I ever ran into a weak 12v battery :)
I bought mine at a big box hardware type of store(Menards) but I believe Amazon and other places sell similar models.

Be careful with assuming that those LiIon jump-start packs will jump-start a Leaf with a discharged 12V battery.

The ones I have used, will only output 12V for jump-starting for a second or two - because they are small, their cables are small, and the current required to crank an engine would set fire to them in a few seconds.

The Leaf will not charge a 12V battery which is very deeply discharged - for example, if the voltage is too low. I have seen this with mine when the 12V battery went bad and was down to <11V. The Leaf would "start" on the power button and drive, but the DC-DC converter stayed off, because the 12V battery "looked bad" to the Leaf's electronics.

This second or two of power from a LiIon jump-start pack is not long enough to both power-on the Leaf, and have the Leaf decide the 12V battery is good enough to charge & start charging.

It depends upon the quality of the Li jump starter. I have used mine to start a 4.0L inline 6-cylinder, several different V-8 engines, motorcycles, and my 2015 Leaf (completely dead battery). Both of my Leafs (2011 and 2015) started just fine and recharged their 12-volt batteries after being completely discharged.
I don't have my little jump starter in front of me now but I can say that it doesn't have small wiring, I'd say 10 gauge minimum and the Li battery itself is somewhat substantial as I recall. I've always wondered myself how well something like this would work to jumpstart a ICE vehicle(probably the main reason they are sold) but I really feel it would add just enough Oomph to a weak 12v Leaf battery to boot the computer and start the DC to DC charging. I guess I won't know for sure unless I ever need it and considering I do a weekly or biweekly charge/desulphify routine on my Leaf battery, hopefully I won't have to try it for some years to come.
 
I can't speak to the Li-ion packs, but I keep a 9ah sealed lead acid and unfortunately I have used it many times. I just have #14 leads (30a inline fuse) and clip it in parallel, let it sit for 30 seconds or so, then start the leaf, then disconnect the SLA battery and I am off.
 
Thinking of picking up a lithium jump pack. Schumacher makes the SL1 which looks decent using Lithium Iron Phosphate (LiFe) cells, which are more stable and have a wider temperature range. I like that it has a voltage meter, safety cutout logic, and a 12V socket output for running something like a tire pump, or perhaps keeping a mini fridge running while the car is parked for an hour or so. Looks like it could function as a 12V UPS in that regard.

I can see these booster packs being handy to help other motorists without risking damage to the LEAF's systems.
 
So I take my '13 SL with 22,300K miles to my dealer for a car wash. They have it sitting there for 30 minutes with the flashers on. It's getting late, so I go to reclaim the car, (which hasn't been washed yet,) and there is no light on the started button..completely dead.

They put a fast charger on the 12V for about 3 minutes and everything is good to go. I am told to drive it for about an hour and this will charge back up the 12v. I am driving home, (about 5 miles away,) and are about 1/2 way there when a huge warning comes on..Massive power failure. You have 5 seconds to pull the car to a stop and apply the parking break." Like a sudden heart attack!! I manage to do this as I am in city traffic, but with no advance warning, should I have been on an interstate..oh my God!!

I called a service who came with a portable battery, which they hooked up and left under the hood, allowing me too then drive to their garage where they replaced the OME battery with a new Interstate Megatron, (500CCA..MT51R battery,) which has a 72 month warranty. ($129.95 for the battery.)

I see this as VERY dangerous..no advance warning...I felt like I was Captain Skully and fortunately I was not at 30,000 feet or just taking off and over the river!!

Any thoughts or comments? If not, BE WARNED!!
 
greengate said:
Any thoughts or comments?
A normal functioning car will recharge the 12v while being driven. It sounds like this did not happen in your car.
So while I don't doubt your 12v was ready for replacement, I suspect that a separate problem related to 12v charging may be present. In your shoes I would buy a digital multimeter and keep a close eye on the new battery.

I suppose an alternative explanation is that the battery was so far gone that only a power charge could power up your 12v a little, while the normal functioning charger of the car could not. I don't know enough about batteries to say.
 
A normal functioning car will recharge the 12v while being driven. It sounds like this did not happen in your car.

A normally functioning Leaf will NOT recharge the 12 volt battery from flat to anywhere near full in one hour. Maybe in four hours, on a very good day. And given that they actually ran it flat, they also damaged it. That dealer owes you a check for the new battery. They were assuming that the Leaf has a high-amperage alternator forcing power into the battery, and they should have known that this is not how it works with an EV.
 
I have had a total of 3 instances of discharged 12-volt batteries--2 with the 2011 and 1 with the 2015. In all cases, the DC-DC converter charged at a high rate (80 amperes or so into the battery), there were no ominous messages, the car performed normally, and the battery was fairly well charged by driving 30 minutes. The second case on the 2011 was when the battery was failing, but it was still able to accept some charge and the car acted normal.

In Greengate's case, the battery may have shorted or opened internally. Since the car measures charging current and voltage, the VCM may have recognized that the battery was not taking a charge and provided the ominous warning to get the car shutdown (although 5 seconds is not much time to react). I have seen cases with gas engine vehicles where the high output alternator was not able to keep the engine running after the booster battery was disconnected (depends upon failure mode of battery).
 
greengate, good on you for heeding the dash warning and pulling over immediately. Any 12v battery problems should be taken very seriously as the brake booster is electrically powered and relies on the 12v to deliver initial current. There is a member on this forum who had total brake failure and rear-ended another car after having EV warning lights on the dash. In that case the dealer told him to drive away and everything would be fine, just as they told you:
http://www.mynissanleaf.com/viewtopic.php?f=30&t=23730&
 
LeftieBiker said:
A normal functioning car will recharge the 12v while being driven. It sounds like this did not happen in your car.

A normally functioning Leaf will NOT recharge the 12 volt battery from flat to anywhere near full in one hour. Maybe in four hours, on a very good day. And given that they actually ran it flat, they also damaged it. That dealer owes you a check for the new battery. They were assuming that the Leaf has a high-amperage alternator forcing power into the battery, and they should have known that this is not how it works with an EV.
Well, if we count 60% "not anywhere near full" then it's true. But 60% is good enough to resume half day later.
Also slow charging the vehicle will also constantly charge the 12V battery. During the night while vehicle charges.

Let's stop assuming everybody drives 2011/12 model. And if we talk about those, let's be more specific.

Running 12V battery flat doesn't damage it automatically. Keeping it that way for days does.
Deep cycling a battery doesn't damage it. It degrades. Cycle degradation. Lead Acid battery has only 100-200 cycles til 20% degradation.
 
Running a lead-acid battery flat (below 12 volts) for more than a few seconds does damage it, no exceptions. If there is enough capacity then the damage is masked, but capacity has been reduced. Being able to still use the battery after recharging it does not mean that it wasn't harmed. This issue, BTW, extends through the 2013 MY, not just 2011-2012, and maybe through the '14 MY as well.
 
LeftieBiker said:
Running a lead-acid battery flat (below 12 volts) for more than a few seconds does damage it, no exceptions. If there is enough capacity then the damage is masked, but capacity has been reduced. Being able to still use the battery after recharging it does not mean that it wasn't harmed. This issue, BTW, extends through the 2013 MY, not just 2011-2012, and maybe through the '14 MY as well.

Want to double down on this! My last new battery (lucky #5) in the car (currently at the dealer for the 3rd time for this 12V discharge issue) was only able to charge to 68% of it's original (ie: 100%) capacity. That's after one discharge (read: damage) cycle from the car that forced it to well below 10V.

There is incremental/nominal ~use~ and there is ~damage~. What's being discussed here is damage/abnormal use. It is reasonable that a battery will gradually lose capacity over years of use. It is also reasonable for a battery to be damaged irreparably by an exceptional circumstance. The sad thing is it seems this exceptional circumstance isn't so exceptional - or else I'd have a car right now instead of borrowing one.

Best,
Tal
 
LeftieBiker said:
Running a lead-acid battery flat (below 12 volts) for more than a few seconds does damage it, no exceptions. If there is enough capacity then the damage is masked, but capacity has been reduced. Being able to still use the battery after recharging it does not mean that it wasn't harmed. This issue, BTW, extends through the 2013 MY, not just 2011-2012, and maybe through the '14 MY as well.

Throw that Leaf out for now. Tell me about lead acid battery damage that happens AS SOON AS voltage drops below 12V (aka below 40% SOC).
I'm extremely interested WHAT PART gets damaged.
 
The plates get sulfation that won't go away again under normal circumstances. A desulfating charger might remove it, but normal use of the battery will see reduced capacity - aka "damage." You seem to be arguing that reversible damage isn't really "damage" at all. Is a scratch in the car's paint "damage" in your view? How about a ding in the metal that can be iced or popped out?
 
LeftieBiker said:
The plates get sulfation that won't go away again under normal circumstances.
The term "sulfation" normally refers to lead sulfate which has hardened (crystallized) after sitting for some time in the battery. The shortest period I have read about for lead sulfate to harden is three days (in very hot weather). Otherwise, lead sulfate is in the form of a paste and it is the normal product whenever a lead-acid battery discharges. In that form it readily dissolves and participates in the charging reaction. As such, I have difficulty seeing how a single overnight discharge could result in the hardening of any lead sulfate. That said, it is important to perform a FULL, SLOW recharge following such an event to ensure that none of the lead sulfate remains after the event. As you have said, the LEAF is certainly not up to that task!

That said, I can think of a few reasons why a battery might be damaged by such an event:
1) The battery might be damaged by jump-starting the battery, which subjects the battery to extremely high currents. Such high currents can be hard on the battery and can lead to things such as "flaking" of the lead paste from the plates, resulting in a permanent loss of capacity.
2) By fully discharging the battery, much of the lead on the plates is removed. During recharge, the lead is not replaced in the same manner as it previously existed, which can affect the battery's resistance and perhaps even reduce capacity a bit.
3) Some cells in the battery which had less charge or capacity before the incident may be forced into a reverse-voltage situation during the deep discharge, which could result in permanent damage to the battery.

My E350 van has an annoying problem with the interior lights: they don't have strong detents to hold them in place. As a result, they can be turned on simply by vibration caused by the vehicle being buffeted by the wind. The result is a frequently-dead battery. This problem has occurred on many occasions (perhaps 20). When it does, I use my 1.5A trickle charger to recharge the battery and after all those discharges it still takes the full 36-hour+ time I expect for a full charge. (If the voltage is below about 4V, the charger will not recharge the battery, so I trick it by putting a couple of D-cell batteries in series with the 12-V battery so that the charger sees enough voltage to begin its charge. Once the battery itself is above about six volts, I remove the D-cells. This allows me to fully recharge the battery without ever subjecting it to more than 1.5A of current.)
 
RegGuheert said:
My E350 van has an annoying problem with the interior lights: they don't have strong detents to hold them in place. As a result, they can be turned on simply by vibration caused by the vehicle being buffeted by the wind.

You really mean the bulbs themselves cause self-activation? Sounds like the E350's power ECU, e.g. the body
control module (BCM), may be intermittently turning the lights on (assumes the BCM controls the interior lights),
or you have door switch that intermittently activates the interior lights thru the BCM. In any case, the source of the
problem needs to be found or a dead battery at an inconvenient time may be problematic. Obviously, this also applies
to those Leaf owners who have frequent dead 12V batteries and attempt to "solve" the problem by a frequent use of
an external battery charger, i.e. without determining why the 12V battery has inadequate start-up capacity for the Leaf.
 
lorenfb said:
RegGuheert said:
My E350 van has an annoying problem with the interior lights: they don't have strong detents to hold them in place. As a result, they can be turned on simply by vibration caused by the vehicle being buffeted by the wind.
You really mean the bulbs themselves cause self-activation?
No, I mean that the lenses that you rock to turn on the lights do not have strong detents. As a result, they can move into the "On" condition just through the motion caused by wind hitting the parked van. That is the cause of the problem.
 
LeftieBiker is incorrect and RegGuheert is mostly correct. Though:
1) Lead Acid battery can be recharged fast (in the low end) fast with no bad side effects.
It does get "surface charged" though it diminishes when charging continues for longer.
2) Only older leafs are not up to task. My 2014 EU Leaf keeps battery at 14.5V for HOURS.
Like I said before, newer Leaf charges the battery to near 80% and keeps it that way.


It is actually true that from time to time it is sometimes reasonable to overcharge Lead Acid battery.
Though trickle charger is not doing that as well. Idea is to normalize cells between each other by
applying 15-15,5V for short period (until all cells are boiling evenly, usually ~1 hour) after full charge.

Leaf and other vehicles I've services (BMWs from 1997-2010) charge at high rate with absolutely
no side effects. Voltage is kept at 14.4V. In case of Leaf voltage is kept at 14.5V for hours during normal
home charging (usually 3-8 hours). Until current drops to few amps, which means battery is
around 80% charged (this information is not available for Nissan though same algorithm for BMWs and
BMW tech manuals actually specify 80% charge state algorithm).

Yes I've understood now that older Leafs did have incorrect algorithm. Let's stop saying all Leafs if
actually it applies to early Leafs only.
 
RegGuheert said:
lorenfb said:
RegGuheert said:
My E350 van has an annoying problem with the interior lights: they don't have strong detents to hold them in place. As a result, they can be turned on simply by vibration caused by the vehicle being buffeted by the wind.
You really mean the bulbs themselves cause self-activation?
No, I mean that the lenses that you rock to turn on the lights do not have strong detents. As a result, they can move into the "On" condition just through the motion caused by wind hitting the parked van. That is the cause of the problem.

Sounds like a very minor tweak for you, e.g. re-tension a spring and/or deepen the detents. That assumes one can open
the light unit. In any case, at least you know what is causing your intermittent current draw verses some Leaf owners
and their "random" dead 12V batteries.
 
arnis said:
LeftieBiker said:
Running a lead-acid battery flat (below 12 volts) for more than a few seconds does damage it, no exceptions. If there is enough capacity then the damage is masked, but capacity has been reduced. Being able to still use the battery after recharging it does not mean that it wasn't harmed. This issue, BTW, extends through the 2013 MY, not just 2011-2012, and maybe through the '14 MY as well.

Throw that Leaf out for now. Tell me about lead acid battery damage that happens AS SOON AS voltage drops below 12V (aka below 40% SOC).
I'm extremely interested WHAT PART gets damaged.

LOL - I joined this board to listen to you guys fight about batteries. Did it ever occur to you guys that there's so many independent variables (and opinions) here that you'll never arrive at a definitive answer / cause / resolution on this observed battery behavior?
 
Scaramanga said:
arnis said:
LeftieBiker said:
Running a lead-acid battery flat (below 12 volts) for more than a few seconds does damage it, no exceptions. If there is enough capacity then the damage is masked, but capacity has been reduced. Being able to still use the battery after recharging it does not mean that it wasn't harmed. This issue, BTW, extends through the 2013 MY, not just 2011-2012, and maybe through the '14 MY as well.

Throw that Leaf out for now. Tell me about lead acid battery damage that happens AS SOON AS voltage drops below 12V (aka below 40% SOC).
I'm extremely interested WHAT PART gets damaged.

LOL - I joined this board to listen to you guys fight about batteries. Did it ever occur to you guys that there's so many independent variables (and opinions) here that you'll never arrive at a definitive answer / cause / resolution on this observed battery behavior?

And your insightful input with 33 years auto "exp"?
 
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