Solutions to 12 Volt Batteries and Chargers Posted Here

[RegGuheert]

Is it an implication that the issue of Climate Change should be of less concern than the reduced longevity
of the lead-acid battery in modern day vehicles?

??

Do you think manufacturing two additional lead-acid batteries produces less CO2 than the little bit of savings achieved by going to a (poorly-conceived) three-stage charger in a vehicle? I don't. And, more importantly, it wastes lots of other resources and pollutes the environment to manufacture those two additional batteries, even if they are recycled.

No, this is being done to get better fuel-efficiency numbers on the sticker. 12V battery life does not show up there, so that be damned. We are simply destroying our environment by doing dumb things like this. And, as I said, there is no good reason for it. You can make a three-stage vehicle charger which does not prematurely destroy the battery AND gives the higher fuel efficiency. But they don't do it.

 

[AndyH]

Maybe. Lead acid is the most recycled battery in the developed world at over 98% last time I found numbers.

Waste is waste. Recycling after three years when it could have been ten is a BIG waste.

Heat kills batteries of any type, and my car's starting batteries had regularly short lives in Tucson...

Granted, as I stated.

... - but they didn't last nearly a decade even in Michigan's cooler climate.

But extreme cold also kills lead-acid batteries, particularly if they are not kept at full charge. The lead-acid batteries in my other vehicles typically last seven years. Eight in my Honda Civic Hybrid. If they would use a three-stage charging system as is found in most maintenance chargers, they would last even longer. Advanced pulse-based desulfation like the BatteryMinder has would get you past ten years, IMO.

Nothing personal here...Michigan's climate is not 'extreme cold' - any more than Illinois or Kansas has 'extreme cold'.
Maybe your batteries did last seven years. Virginia's got a very moderate climate and a starting battery has a very easy life there in what's essentially a 'Goldilocks' zone. (Yes, I've spent a lot of time - in all four seasons - from Orange to DC to Bristol.)

No lead acid battery in an EV will see anything close to a starting load. I seriously doubt they're sulfating at 80% charge, but essentially storage at less than 100% charge is death for lead acid.

The LEAF is the PERFECT vehicle for something like the BatteryMinder approach. No need to do anything different than it does today for READY mode, but since it charges for many hours for each hour of driving, a better approach to ensuring the 12V battery is completely charged when plugged in and charging would go a long way toward extending the life of the 12V batteries. But the engineers didn't take advantage of this golden opportunity to extend battery life without impacting range one bit.

I've done my own maintenance work all my life and have worked with various types of rechargeable batteries the entire time - mostly lead, but more recently lithium. I don't think a battery minder is going to give one 10 years or even 8 years of service if a lead acid battery isn't regularly overcharged.

The lead acid batteries in our EVs are essentially in 'storage' - they never see a hard starting load, and are never discharged completely. They also don't appear to receive monthly balancing charges. Without monthly overcharges, no flooded lead acid battery will give a 10 year life - battery tender or no. Won't happen. A battery tender can help if it can keep the battery closer to 100% and should guarantee that a 48 month lease results in returning the same battery the car shipped with, but it's not a good long-term solution - it's only a Band-aid for a symptom.

That's not a hit on the engineers as they were required to provide a 'good enough' and 'lowest cost' solution for a car that the parent company expected would only be leased, not purchased in large numbers.

Again - if the DC-DC isn't properly maintaining the 12V battery, the DC-DC should be fixed or replaced. If one chooses to not fix the problem, then select a battery type that thrives in the provided condition - and that's a perfect match for lithium or NiMH as neither has a 'memory' and both are very happy to sit for many years at 50-70%.

edit... I keep thinking about this and don't think it's at all reasonable to expect a 10 year life from a lead acid battery in a vehicle. That's a very hard target to hit for batteries in uninterruptible power supplies that are kept at 100% 99.9% of the time in climate controlled spaces, and it's also a very difficult target for heavy duty deep-cycle batteries with solid lead plates (not the lead sponge in starting batteries) that are properly maintained with regular overcharge to destratify the electrolyte and balance the battery.

 

[AndyH]

No, this is being done to get better fuel-efficiency numbers on the sticker. 12V battery life does not show up there, so that be damned. We are simply destroying our environment by doing dumb things like this. And, as I said, there is no good reason for it. You can make a three-stage vehicle charger which does not prematurely destroy the battery AND gives the higher fuel efficiency. But they don't do it.

Maybe you can quantify the economy different between two otherwise identical Leaf(s) taking the same test, one with a lead-acid battery at 100% and one at 50%.

 

[RegGuheert]

I seriously doubt they're sulfating at 80% charge,...

The discharge reaction for a lead-acid battery produces lead sulfate, so, yes, they are sulfating at 80% charge. If it is left there long enough, the lead sulfate will harden. The hardening happens faster in hot weather.

...but essentially storage at less than 100% charge is death for lead acid.

Yep, because the lead sulfate eventually hardens and capacity is lost.

I don't think a battery minder is going to give one 10 years or even 8 years of service if a lead acid battery isn't regularly overcharged.

It has used hardly any water after four years and the lead sulfate has apparently been brought back into service. What failure mode do you think will kill it before 10 years?

Again - if the DC-DC isn't properly maintaining the 12V battery, the DC-DC should be fixed or replaced.

I've been pushing Nissan to fix this problem for years. It's not something that replacement fixes. It needs to be engineered to work properly. The problem is not the chemistry of the battery, it is the design of charging algorithm.

 

[RegGuheert]

Maybe you can quantify the economy different between two otherwise identical Leaf(s) taking the same test, one with a lead-acid battery at 100% and one at 50%.

The one maintaining the battery at 100% (during LEAF charging) will save the owner about $250 over 10 years (2 batteries) and will probably cost them an extra $10 in electricity, if that. There will be no difference in driving range if the algorithm in READY mode is not changed (not that the 12V battery has much impact on range in any case).

 

[AndyH]

I don't think a battery minder is going to give one 10 years or even 8 years of service if a lead acid battery isn't regularly overcharged.

It has used hardly any water after four years and the lead sulfate has apparently been brought back into service. What failure mode do you think will kill it before 10 years?

A lead acid battery will fail prematurely just as a lithium pack will if the cells aren't kept balanced. Cells allowed to progressively weaken will have a higher resistance and will generate heat when charging and discharging. The electrolyte will stratify as well, at different rates depending on state of charge, and cells can short if enough of the normal sulfate crystals are allowed to settle. Long life requires regular overcharging. Long-term storage at 100% is not enough. No battery charger can recover a battery damaged by hard sulfation.

Again - if the DC-DC isn't properly maintaining the 12V battery, the DC-DC should be fixed or replaced.

I've been pushing Nissan to fix this problem for years. It's not something that replacement fixes. It needs to be engineered to work properly. The problem is not the chemistry of the battery, it is the design of charging algorithm.

My use of the word 'replace' here means to remove the DC-DC that is not properly maintaining the battery with one that will. I'm not talking about someone with an IQ of 14 simply replacing one underperforming black box with another just like it.

As I've already said, though, I don't expect Nissan will see the 'problem' the same way some here see it. The battery's a wear item like tires and wiper blades. They likely have a spreadsheet that clearly shows that it's least expensive to leave it as it is considering that most owners are leasing. Their liability is likely much lower with this DC-DC than it would be to overcharge the battery as it requires and 'assume' that owners will check the water levels from time to time. Good luck with that.

I charged my smart to 100% overnight, and disconnected the 12V battery today. After sitting one hour open circuit, it's sitting at 13.04VDC - a very lovely voltage indeed. I guess that's another potential solution for early Leafers - get a smart.

 

[RegGuheert]

A lead acid battery will fail prematurely just as a lithium pack will if the cells aren't kept balanced. Cells allowed to progressively weaken will have a higher resistance and will generate heat when charging and discharging. The electrolyte will stratify as well, at different rates depending on state of charge, and cells can short if enough of the normal sulfate crystals are allowed to settle. Long life requires regular overcharging. Long-term storage at 100% is not enough. No battery charger can recover a battery damaged by hard sulfation.

Overcharging kills batteries by causing flaking, which removes the active material from the plates. The advanced approach to maintaining/restoring battery health developed by BatteryMinder is, by far, the best practice:

With BatteryMINDers'® ability to fully charge, without ever overcharging, no matter how long left connected, there is no reason battery sulfation should ever become an issue. Further, without sulfation ever reaching damaging levels and the battery never subjected to overcharging, life and performance can be expected to be several times better than any battery left to self-discharge.

Overcharging is a crude, outdated method used for desulfation, trading a lesser evil for a worse one. With advanced, inexpensive, pulse-based desulfation available today, overcharging is only useful for batteries in stationary applications which need occasional stirring. That's fine when it is used on deep-discharge batteries which are designed to withstand the overcharges (by having thicker plates, more material on the plates, and deep open spaces at the bottom to catch the flakes that fall off during the overcharge). But the LEAF does NOT have such a battery and it does not need electrochemical stirring. It gets stirred mechanically by driving the vehicle.

Again - if the DC-DC isn't properly maintaining the 12V battery, the DC-DC should be fixed or replaced.

I've been pushing Nissan to fix this problem for years. It's not something that replacement fixes. It needs to be engineered to work properly. The problem is not the chemistry of the battery, it is the design of charging algorithm.

My use of the word 'replace' here means to remove the DC-DC that is not properly maintaining the battery with one that will. I'm not talking about someone with an IQ of 14 simply replacing one underperforming black box with another just like it.

From page one of this thread:

It might be worthwhile to have the DC-DC checked/replaced (not just have the car checked for error codes, but to have the DC-DC actually tested and probably replaced. Otherwise the next battery will have a short life as well.

This quote shows that you do not appreciate that there is a deficiency in the DESIGN of the charging algorithm in the LEAF. I have seen no evidence, ever, on this site that anyone with a MY2011/2012 LEAF has had a defective DC/DC converter. Why you think that could be the problem is beyond me.

As I've already said, though, I don't expect Nissan will see the 'problem' the same way some here see it. The battery's a wear item like tires and wiper blades. They likely have a spreadsheet that clearly shows that it's least expensive to leave it as it is considering that most owners are leasing.

More likely, their spreadsheet shows it as a way for their dealers to make at least a little bit of money from LEAF owners.

Their liability is likely much lower with this DC-DC than it would be to overcharge the battery as it requires and 'assume' that owners will check the water levels from time to time.

Again, I am NOT promoting the idea of EVER overcharging the battery in the LEAF. It simply needs to be charged to full on a frequent and consistent basis. Pulse-based desulfation would further extend battery life.

I charged my smart to 100% overnight, and disconnected the 12V battery today. After sitting one hour open circuit, it's sitting at 13.04VDC - a very lovely voltage indeed. I guess that's another potential solution for early Leafers - get a smart.

Clearly the Smart has a different chemistry than the LEAF. That is a typical voltage for many flooded deep-cycle batteries (which is a better choice of battery for this application, IMO).

 

[69800]

Lead-acid batteries that receive the best possible care, are brought to full state-of-charge regularly, consistently last the longest --- eventually wear out as result of the effects of positive grid corrosion.
Lead-acid batteries that, for a large variety of different reasons, are consistently undercharged, are not brought to full state-of-charge regularly --- fail prematurely as result. Sulfation occurs when a lead acid battery is deprived of a full charge.

Lead acid must periodically be charged 14–16 hours to attain full saturation.

The most important thing for you to know is that you should keepsulfation from happening rather than trying to fix your batteries.

There are two types of sulfation: reversible (or soft sulfation), and permanent (or hard sulfation). If a battery is serviced early, reversible sulfation can often be corrected by applying an overcharge to a fully charged battery in the form of a regulated current of about 200mA. The battery terminal voltage is allowed to rise to between 2.50 and 2.66V/cell (15 and 16V on a 12V mono block) for about 24 hours. Increasing the battery temperature to 50–60°C (122–140°F) further helps in dissolving the crystals. Permanent sulfation sets in when the battery has been in a low state-of-charge for weeks or months. At this stage, no form of restoration is possible.

 

[RegGuheert]

Thanks! It would be great if you could zoom on the Y-axis so that we can see the downslope. Is that a possibility?

One thing that jumps out at me regarding the use of an AGM in a LEAF is that since the voltages are higher in an AGM, then it may be maintained at an even LOWER SOC than was the flooded OEM battery. It will be interesting to see what happens.

Also, do you happen to have a plot of the SOC versus voltage for that style battery? If so, can you please post it? If not, I can provide a plot from another manufacturer of AGMs that I have.

For reference, here are a couple of marketing brochures on the Exide Edge batteries:

Exide Edge 4-Page Booklet (non-spread)

Exide Edge 6-Page Spread

Unfortunately, those brochures only have marketing "graphs" with no overly-useful data included.

 

[RegGuheert]

If I can manage to let the LEAF sit for another 24 hours, I'll see what the voltage is at this time tomorrow. My guess: 12.70V.

O.K. Today's reading, another 24 hours after yesterday's reading is 12.71V. Slightly better than my projection. Here are the voltage results for this test, so far (each -> represents 24 hours):

12.87V->12.78V->12.71V

It seems the battery is holding charge a bit better than it did a couple of years ago when I made the graph in the OP.

 

[Bob]

... there is a deficiency in the DESIGN of the charging algorithm in the LEAF. I have seen no evidence, ever, on this site that anyone with a MY2011/2012 LEAF has had a defective DC/DC converter...I am NOT promoting the idea of EVER overcharging the battery in the LEAF. It simply needs to be charged to full on a frequent and consistent basis...

You specifically called out MY2011/2012. I suspect MY2013 is the same. Do you have any reason to believe that MY2013+ charges the 12V battery differently than the MY2011/2012?

Do you have a general rule of thumb as to what no-load voltage is too low or how often to externally charge the 12V battery?

I have a Battery Tender Plus and can clamp it on any time I like but wasn't planning to open the hood and charge the 12V battery every night when I drive the car daily.

Bob

 

[RegGuheert]

You specifically called out MY2011/2012. I suspect MY2013 is the same. Do you have any reason to believe that MY2013+ charges the 12V battery differently than the MY2011/2012?

No. In fact, it seems there may be bugs in the MY2013s and later that occasionally causes the battery to be drained, which makes matters even worse.

Do you have a general rule of thumb as to what no-load voltage is too low or how often to externally charge the 12V battery?

Not really, since you can't learn very much from a single voltage measurement. I will say that if you are seeing resting voltages (hood up, sitting for 30 to 60 minutes before measuring) of 12.2V or lower, then your battery is at a low SOC and likely is headed for trouble. If you see something below 12V, then it really is time to take some sort of action with your battery (and there are many different routes you can take).

But OP and I are looking at something a bit more interesting than just a single voltage measurement. We are looking at how the voltage drops over time. Since I have a baseline from a couple of years ago, I can compare to see if my battery is performing the same, better or worse than it did at that time. Right now it looks better! I'm pleased that the battery is close to full after sitting for two full days, even if the charge immediately prior came from an external charger.

I have a Battery Tender Plus and can clamp it on any time I like but wasn't planning to open the hood and charge the 12V battery every night when I drive the car daily.

A while ago, I bought a BatteryMinder On-Board Desulfator OBD-12 to install on the LEAF. Once I received it, I decided not to install it for the following reasons:

1) It only desulfates when the battery is above 13.5V, which is somewhat rare on the LEAF (as you can see in 69800's latest plot). (It would be great if this thing pulsed above 13.0V, but that would cause some battery types to get discharged when just sitting.)
2) The negative ring terminal is too small to fit over the ground lug on the DC/DC converter in the MY2011/2012 LEAF. Plus, the ground lug has a captive washer, meaning you MUST put the ring terminal between the built-in washer and the DC/DC converter, which gave me pause WRT possibly making the ground connection less effective.

Anyway, I'm again thinking of installing this unit in the LEAF. The reason is that I have, on occasion, seen the LEAF dwell at 14.4V for longer than normal when the traction battery is charging. The hope is that the pulsing would minimize the hardening of lead sulfate by breaking it up more frequently. If I can figure out how to get it installed and working property, I'll let everyone know how things go. (Unfortunately, it will be difficult to determine if this thing is helping or not...)

 

[69800]

Thanks! It would be great if you could zoom on the Y-axis so that we can see the downslope. Is that a possibility?

One thing that jumps out at me regarding the use of an AGM in a LEAF is that since the voltages are higher in an AGM, then it may be maintained at an even LOWER SOC than was the flooded OEM battery. It will be interesting to see what happens.

Also, do you happen to have a plot of the SOC versus voltage for that style battery? If so, can you please post it? If not, I can provide a plot from another manufacturer of AGMs that I have.

If you look at page one of this thread I put an SOC chart for both lead acid and AGM.

I cannot zoom in but I will redo it with more numbers

 

[Nubo]

Thanks! It would be great if you could zoom on the Y-axis so that we can see the downslope. Is that a possibility?

One thing that jumps out at me regarding the use of an AGM in a LEAF is that since the voltages are higher in an AGM, then it may be maintained at an even LOWER SOC than was the flooded OEM battery. It will be interesting to see what happens.

Also, do you happen to have a plot of the SOC versus voltage for that style battery? If so, can you please post it? If not, I can provide a plot from another manufacturer of AGMs that I have.

If you look at page one of this thread I put an SOC chart for both lead acid and AGM.

I cannot zoom in but I will redo it with more numbers

Here is the manual for the battery I chose:

http://www.solar-electric.com/lib/wind-sun/techmanual.pdf" onclick="window.open(this.href);return false;

 

[69800]

I went back to page 7 and added an update to my 7 day chart to show more voltages.

Bob I think these batteries need to be charged as often as possible but for convenience I have decided to do it once a week .

That sun battery is made by Concord. They are probably one of the best commercial battery makers in the world. What did you pay for that? I though about it but did not want to have to mess with the terminals they use

 

[Nubo]

I went back to page 7 and added an update to my 7 day chart to show more voltages.

Bob I think these batteries need to be charged as often as possible but for convenience I have decided to do it once a week .

That sun battery is made by Concord. They are probably one of the best commercial battery makers in the world. What did you pay for that? I though about it but did not want to have to mess with the terminals they use

Not sure what the exact price was; the source I used has them now for $148 plus shipping. I purchased some M6-to-SAE adapter terminals for a few bucks on Amazon.

http://www.solar-electric.com/concorde-sunxtender-pvx-420t.html/" onclick="window.open(this.href);return false;

Note the terminal orientation is reverse of the OEM. Install on my 2012 required me to unbolt the main negative cable from the clamp cluster and route it around some other cables to get enough slack; not too hard. On the 2015 it was pretty much plug&play.

 

[RegGuheert]

If you look at page one of this thread I put an SOC chart for both lead acid and AGM.

Those numbers don't match your battery. You are showing voltages of 13.3V at 100% SOC.

 

[lorenfb]

This thread exemplifies other threads where a hypothesis is stated which lacks
longitudinal data for a valid data analysis, e.g. a linear regression, and thus fails
to provide a casual relationship supporting the hypothesis, which results in an invalid
conclusion. This potentially results in some changing their actions based on an unproven
hypothesis.

So recommending to Leaf owners that they need to externally charge their lead-acid
batteries because some think that the Leaf has an inadequate charging algorithm,
and as a result the Leaf's lead-acid battery will have potentially a shortened longevity,
does a disservice to Leaf owners without a robust analysis to support the claim.
Data have not been presented which indicate as an example what multiple in years one
can extend the Leaf's battery longevity by externally charging or what one might expect
in shortened lead-acid battery longevity by not charging externally and thus relying on
the Leaf's charging algorithm for adequate lead-acid battery charging without any
significant reduction in battery longevity.

 

[BrockWI]

We got our Leaf last spring and over June - August we had 3 cases that the 12v battery was dead, to the point the car wouldn't turn on. I have since started weekly charging the 12v aux battery with a Battery Tender and I haven't had a dead battery since. I look at this like preventative maintenance. Recommending to anyone to occasionally top up their 12v aux battery is a good thing, it can't hurt the battery, quite the opposite. As I have stated once in a while my weekly top off charge will come up to float in an hour or two, indicating the battery was in pretty good shape. Other times the battery has taken 12 plus hours to get to a float stage, which indicates the battery was not charged, for whatever the reason.

Yes we are guessing at what the real problem, and I personally believe we are on track with what the issue is. And I agree that some folks because of their driving habits or EVSE situation don't have a 12v aux battery issue, but why dismiss it when so many have had issues? That just seems illogical.

 

[lorenfb]

We got our Leaf last spring and over June - August we had 3 cases that the 12v battery was dead, to the point the car wouldn't turn on. I have since started weekly charging the 12v aux battery with a Battery Tender and I haven't had a dead battery since. I look at this like preventative maintenance. Recommending to anyone to occasionally top up their 12v aux battery is a good thing, it can't hurt the battery, quite the opposite. As I have stated once in a while my weekly top off charge will come up to float in an hour or two, indicating the battery was in pretty good shape. Other times the battery has taken 12 plus hours to get to a float stage, which indicates the battery was not charged, for whatever the reason.

Yes we are guessing at what the real problem, and I personally believe we are on track with what the issue is. And I agree that some folks because of their driving habits or EVSE situation don't have a 12v aux battery issue, but why dismiss it when so many have had issues? That just seems illogical.

That's unfortunate for you and costly. Did you consider that there might have been an excessive current
demand on the lead-acid battery when the vehicle is not in use? This can be problematic for late model
vehicles where a CAN bus fails to 'sleep' causing ECUs to not power-down. You might consider using
a clamp-on amp meter to measure the 'sleep' current draw at the battery, or carefully place a series
amp meter in the circuit without breaking the battery's connection. The 'sleep' current should be less
than about .050 amps (50 ma) and ideally less than 30 ma. In some cases, it might take as long as
a few minutes before the vehicle enters the 'sleep' mode.