Solutions to 12 Volt Batteries and Chargers Posted Here

[essaunders]

I've read a bunch of the posts but not found an answer to my question: What is a recommended 12V battery replacement?

I did provide this post which details the different suggestions which have been provided by various posters.

What I've found:

My local dealer wants $95 for the battery ($164 installed) but that only has a "12/12" warranty.

The local Interstate shop will sell me a "NP51R" for $118 (installed or not).

It looks like I can order an Optima YellowTop (YELD51R) from my local PepBosy for $190 for installation tomorrow.

Walmart has a MAXX_51R for $107 with 3 year warranty

AAA will come out and (supposedly) sell me a new installed battery for no more than ~$163. (LEAF isn't listed on their quote system, but a Nissan GT-R which also uses a 51R quotes out at $116)



Is it worth getting an AGM? I did spring for an yellowtop in my '07 prius.

Personally, I recommend purchasing a normal, flooded 51R from Costco. I purchased one of those for my Mom's Honda Civic Hybrid about 6 months ago and paid about $73 for it with a 36-month warranty (IIRC). This link indicates that Costco's fitment code 11 is the 51R.

But I don't recommend replacing it unless it is dead or mostly dead. Is yours having issues?

I did find your post most informative - it was the starting point for my search.

My car was 'dead' this morning. It hadn't been run or charged since Thursday Early morning. I had left the EVSE not plugged in.
I measured ~4v (or similar) this morning. The AAA tow truck came, hooked their box up. The dome light instantly came on and the car booted (with chime - something I had long ago turned off). for lack of a better option, I let the car 'idle' while I ate breakfast etc (~30 min) plus my ~10 min drive to work.
I popped the hood at lunch today and the battery measured 12.06v. I figure it is pretty tired. I'll find out in a few minutes whether it'll start tonight.

The Costco path isn't an option.

 

[RegGuheert]

The Costco path isn't an option.

O.K. The Walmart batteries are also very good, only more expensive.

A BatteryMinder 1510 *might* recover it, but if you don't have one on hand, then you'll need to charge it with something else until you can get your hands on one. Any low-amperage charger (2A) will do for now. It's probably easiest to just buy a battery...

 

[dhanson865]

The Costco path isn't an option.

O.K. The Walmart batteries are also very good, only more expensive.

A BatteryMinder 1510 *might* recover it, but if you don't have one on hand, then you'll need to charge it with something else until you can get your hands on one. Any low-amperage charger (2A) will do for now. It's probably easiest to just buy a battery...

wow, I just looked up the BatteryMinder 1510 and I'm not impressed. I'd recommend the CTEK3300 or CTEK7002 instead. Much more capable.

The 1510 doesn't play nice with AGM batteries and is only 1.5A so it charges very slowly

BatteryMinder 2012 plays nice with AGM and is 2A so barely faster but is overpriced compared to the CTEK lineup.

The CTEK3300 plays nice with AGM and is 3.3A still not as fast as I want but way faster than 1.5A (worst thing is the SOC indicator is low or full, nothing else)

The CTEK7002 has better display of battery SOC (4 steps low to full, still not very granular but better than the lesser models) and it is 7A so it charges way faster.

 

[RegGuheert]

wow, I just looked up the BatteryMinder 1510 and I'm not impressed. I'd recommend the CTEK3300 or CTEK7002 instead. Much more capable.

I don't like that CTEK chargers because they desulfate at 15.9V. If you charge a badly-sulfated battery at such a high voltage, you can cause the paste to flake off the plates and fall to the bottom, which is always bad for the cell and sometimes even shorts it out. The BatteyMinder 1510 never raises the voltage above 14.5V and gently desulfates the battery using high-frequency (50-Hz) pulsing.

The 1510 doesn't play nice with AGM batteries and is only 1.5A so it charges very slowly

Charging a lead-acid battery more slowly is better than charging it faster, particularly if you are trying to recover capacity cause by sulfation.

BatteryMinder 2012 plays nice with AGM and is 2A so barely faster but is overpriced compared to the CTEK lineup.

The BatteryMinder 1510 charges/desulfates at 14.5V and floats/desulfates at 13.5V. This should be fine for just about any AGM except ones with particularly low voltages. I use mine on AGMs frequently. (I suspect the minor differences in voltages you get with the AGM-specific version you are looking at would only be important if it were connected indefinitely.)

The bigger issue is that the higher voltages of the AGMs means that the LEAF's battery-charging algorithms will keep them at an EVEN LOWER SOC than a flooded battery. 69800's AGM has a resting voltage of 13.3V when fully charged. As such, the LEAF's float voltage of 13.1V will literally discharge the battery when fully charged instead of charging it.

The CTEK3300 plays nice with AGM and is 3.3A still not as fast as I want but way faster than 1.5A (worst thing is the SOC indicator is low or full, nothing else)

The CTEK7002 has better display of battery SOC (4 steps low to full, still not very granular but better than the lesser models) and it is 7A so it charges way faster.

Thanks, but I'll continue to use and recommend the BatteryMinder 1510. It's an awesome little charger!

 

[RegGuheert]

12.87V>12.78V>12.71V>12.64V>2C4D>1C2D>12.57V>1C5D>12.44V>12.47V>12.44V>3C15D>12.57V>12.43V>12.40V>3C7D>12.49V>12.43V>12.42V>12.40V>3C10D>12.48V>2C4D>12.46

20mV lower today down to 12.46V today after 6 opportunities for the car to charge it in the past 48 hours.

I'm going to stop this simple test today after 21 full days of monitoring since the weather is getting hot now and I want to charge and desulfate the battery before the sulfate has a chance to fully harden.

If I compare these results with those obtained in August 2012, I see they are fairly similar. While this test started at a higher SOC due to external charging, the low-water mark in this test was 12.40V versus 12.39V back then. In neither case did the battery approach a full charge level due to LEAF charging (except at the very beginning of the earlier test).

 

[dhanson865]

Charging a lead-acid battery more slowly is better than charging it faster, particularly if you are trying to recover capacity cause by sulfation.

But how many days does it take to hit 100% charge at that rate.

I'm using the 3300 and I saw voltage rise still happening at the battery after a day or so. (yellowtop).

If I used the BatteryMinder at 1.5A it'd take 2 or 3 days to hit a full charge.

so long as I have a Prius and Leaf I'm going to have to charge my batteries periodically so I'd prefer to get them to full charge without idling the entire car for several days at a time.

If the BatteryMinder truly works better for desulfation, I suppose the next level would be to desulfate with the Battery Minder for part of a day then switch to a CTEK to bulk charge but that'd add more equipment costs.

 

[RegGuheert]

But how many days does it take to hit 100% charge at that rate.

I'm using the 3300 and I saw voltage rise still happening at the battery after a day or so. (yellowtop).

If I used the BatteryMinder at 1.5A it'd take 2 or 3 days to hit a full charge.

For a fully-dead 30Ah battery, it would take about 20 hours to get near full. Of course the charging current slows once you get to 14.5V, so it will spend more time one it gets to this voltage. Perhaps 24 hours total. (I'm not sure of the capacity of the LEAF battery.)

But I have never charged the LEAF battery when fully dead. As a result, it has never taken more than about 10 hours to fully charge and drop back to float. Normally, if I do it periodically, it is done in a few hours.

so long as I have a Prius and Leaf I'm going to have to charge my batteries periodically so I'd prefer to get them to full charge without idling the entire car for several days at a time.

If the BatteryMinder truly works better for desulfation, I suppose the next level would be to desulfate with the Battery Minder for part of a day then switch to a CTEK to bulk charge but that'd add more equipment costs.

It's interesting to see what happens when charging a discharged, sulfated battery. With a normal charger (I have another regular charger which is also 1.5A), the voltage simply goes up to 14.5V and the current quickly drops to a low value and then the charger drops to its float value. With the BatteryMinder, the voltage goes up fairly quickly at first, but since it desulfates *while* it is charging, the voltage then stops rising and reverses and drops back to some lower value as the impedance of the battery drops. This allows for more charge to be absorbed while more desulfating also is achieved.

I have literally seen cases where the normal charger will finish in about 30 minutes and then I will connect the BatteryMinder and it will charge it for many hours before going to float (at which point it continues to desulfate the battery).

 

[dhanson865]

I have literally seen cases where the normal charger will finish in about 30 minutes and then I will connect the BatteryMinder and it will charge it for many hours before going to float (at which point it continues to desulfate the battery).

You do realize that the CTEK is a desulfating charger as well don't you?

Either way with a CTEK a Batteryminder or both you can just unplug / replug to start over and either one will continue to desulfate again.

 

[RegGuheert]

You do realize that the CTEK is a desulfating charger as well don't you?

Yes. But it does some of that with 15.9V. BatteryMinder is *lowering* the voltage when desulfating a battery. CTEK uses brute force, which could be damaging. BatteryMinder uses a more gentle approach.

Either way with a CTEK a Batteryminder or both you can just unplug / replug to start over and either one will continue to desulfate again.

No need to unplug the BatteryMinder. It *always* desulfates.

 

[RegGuheert]

12.46

I'm going to stop this simple test today after 21 full days of monitoring since the weather is getting hot now and I want to charge and desulfate the battery before the sulfate has a chance to fully harden.

But I have never charged the LEAF battery when fully dead. As a result, it has never taken more than about 10 hours to fully charge and drop back to float. Normally, if I do it periodically, it is done in a few hours.

Today's charge starting from 12.46V was the first one I have done in over three weeks. The BatteryMinder 1500 took 6.6 hours to complete the bulk and absorption phases before dropping down to float. It spent less than two hours in bulk phase before getting the voltage up to the absorb voltage of 14.5V, so the time to complete the charge using any faster charger would only be reduced by some amount smaller than those two hours.

 

[69800]

essanders was asking what type of battery to buy.

The type of battery you use does not really matter. I chose the Exide AGM because these gas mat batteries are a little less prone to sulphation. But there is no way around the fact you have to put a full charge to the battery once a week. You could just use a cheap battery and plan on replacing it more often. Even an old sulphated battery will go a long time in the leaf if it is driven daily since it is never used as a starting battery. Just don't park it at the airport for 4 days and expect it to start when you get back.

On a side not if the Tesla is running 14.1 volts I would think their battery would last a long time. That is about the same voltage all ICE cars run at and so they are always fully charged. The Tesla AGM look to me about the same as the Exide AGM except the Exide has a standard post on it.

 

[RegGuheert]

Personally, I recommend purchasing a normal, flooded 51R from Costco. I purchased one of those for my Mom's Honda Civic Hybrid about 6 months ago and paid about $73 for it with a 36-month warranty (IIRC). This link indicates that Costco's fitment code 11 is the 51R.

I just wanted to follow up on the warranty provided on the Costco batteries. I looked at the battery and it says "100-month Limited Battery Warranty". Then I found this link which gives details on the warranty. It appears to be 36 months for a full refund and prorated thereafter:

On a side not if the Tesla is running 14.1 volts I would think their battery would last a long time. That is about the same voltage all ICE cars run at and so they are always fully charged. The Tesla AGM look to me about the same as the Exide AGM except the Exide has a standard post on it.

My guess is the real issue with the Tesla Model S is that it has so many loads that run when the car is off that it takes a significant portion of charge away every night. No matter how much you drive it, it is likely to be a real challenge to ever get that battery topped off. (Or, possibly they are overcharging it and gassing off the water.)

So, while both cars likely have room for improvement in their charging systems, I doubt Tesla will ever be able to achieve an 8-year 12V battery life.

 

[lorenfb]

On one of the very rare SoCal days when it rains heavily requiring headlights and wipers,
the LeafDD provided some very interesting 12 volt lead-acid charging voltages.
During a driving interval of 45 minutes in the Leaf, the charging voltage was maintained
at a level of 14.3 to 14.5. Typically, during the day, i.e. when most all my driving occurs,
the voltage is 12.9 - 13.0 volts.

When charging the Leaf, e.g. using a QC, the 12 volt battery will begin to charge
at 14.5 volts and over a period of a minute then decline to 13.0. It appears
that the system is determining the SOC of the 12 volt battery by either measuring
its impedance or measuring its short duration pulsed charging current. Based on
that result, it most likely decides at what voltage to charge the 12 volt battery when
the lithium battery is being charged.

It appears that the Leaf has a more complex charging algorithm than some
appear to not fully understand, resulting in false conclusions about the adequacy
of the Leaf's charging algorithm. Some have also concluded that Toyota has a
similar 12 volt battery charging issue. Are we to conclude that both Nissan and
Toyota lack engineering competence compared to those in this thread?

So, we're still waiting for the 12 volt battery load and impedance data over time
to corroborate the conclusion that the Leaf inadequately charges that battery
when charging at 13 volts resulting in significant sulfation thus shortening the
Leaf's 12 volt battery life. This thread has provided basically no useful data in
in arriving at any valid conclusions, e.g. the amount of sulfation verses time
and charging voltage.

If one attempted to submit a research paper based on data in this thread to an
IEEE publication, most likely that submission would find its way to the most
common "filing cabinet". Or worst yet, if a EE PhD candidate submitted a research
paper with the conclusion of some based on data presented in this thread to his/her
advisor, most likely that advisor would suggest that the candidate consider other
career options.

 

[DaveEV]

This thread has provided basically no useful data in in arriving at any valid conclusions

Well, thanks for contributing to the signal to noise ratio, then. :roll:

I don't see anything in your last post that adds to what we already know. It appears that you've only posted simply to bash on everyone else contributing to this thread, so perhaps next time, if you don't have anything useful or new to add to the thread and at least be nice about it, please refrain.

 

[QueenBee]

I too have noticed LEAFSpy reporting 14+ bolts during a drive on a couple occasions, unfortunately both times I instinctively turned the car off before confirming with a multimeter. Each time turning the car off results in the normal build up to 14+ and then back down to 13 volts.

 

[QueenBee]

I too have noticed LEAFSpy reporting 14+ bolts during a drive on a couple occasions, unfortunately both times I instinctively turned the car off before confirming with a multimeter. Each time turning the car off results in the normal build up to 14+ and then back down to 13 volts.

Hah, so the wiper motors must require a higher voltage as when I turn them on the voltage goes up to 14.43 on my fluke DMM and 14.32 reported by LEAFSpy. Turn off the wipers and shortly after it goes back to 13.

I'm not going to admit it rains much up here but I'm guessing my battery has spent much more time at higher voltages than other areas

 

[RegGuheert]

On one of the very rare SoCal days when it rains heavily requiring headlights and wipers,
the LeafDD provided some very interesting 12 volt lead-acid charging voltages.
During a driving interval of 45 minutes in the Leaf, the charging voltage was maintained
at a level of 14.3 to 14.5. Typically, during the day, i.e. when most all my driving occurs,
the voltage is 12.9 - 13.0 volts.

I too have noticed LEAFSpy reporting 14+ bolts during a drive on a couple occasions, unfortunately both times I instinctively turned the car off before confirming with a multimeter. Each time turning the car off results in the normal build up to 14+ and then back down to 13 volts.

Hah, so the wiper motors must require a higher voltage as when I turn them on the voltage goes up to 14.43 on my fluke DMM and 14.32 reported by LEAFSpy. Turn off the wipers and shortly after it goes back to 13.

That's an awesome find!

I tested mine and confirm the same thing: I started the car and waited until it dropped down to 13.1V. Then I turned on the wipers. The first wipe the motor struggled to drag the wipers across the dry windshield, but the voltage slowly rose to 14.4V and stayed there. Subsequent wipes were signficiantly more brisk! Then after turning off the wipers and waiting about one minute, the voltage dropped back down to 13.1V.

It is quite well known that electric motors do not like low voltage and it typically leads to early failure. This might have been a factor or perhaps the car simply failed some test with snow or frost in which the wipers would not wipe. (BTW, the life issue is the opposite than what you get with halogen headlights, as a PP pointed out upthread. Those will last SIGNIFICANTLY longer at 13.1V than at 14.4V.)

I'm not going to admit it rains much up here but I'm guessing my battery has spent much more time at higher voltages than other areas

Yes, it seems driving your LEAF around frequently with the wipers on will save your 12V battery!

Anyone want to discuss the trade-off between wiping a dry windshield to save the 12V battery versus the cost of replacing a scratched windshield and worn wiper blades?

 

[essaunders]

Hi. I'll chime back in. My solution: do nothing (so far). I had one jump and 'ran' the car to 'charge' the battery. I've not had a failure again. I still am carrying a multimeter and my wrenches though.

I'm loathe to replace the battery after a single failure - especially without a load test ( I don't have a load tester). I also don't want to bandaid the situation by getting a jump pack or similar. I guess i figure if the car fails to start (or exhibits other wonky symptoms) I'll replace the battery then. I'll either buy AAA's battery or go to Walmart and get theirs.

Maybe I'll park the car in the driveway tomorrow during any rain and just run the wipers....

 

[lorenfb]

Anyone want to discuss the trade-off between wiping a dry windshield to save the 12V battery versus the cost of replacing a scratched windshield and worn wiper blades?

I failed to mention that after reaching my destination and parking the Leaf for about a hour,
I began my return trip. The rain had stopped and it was clear. To test whether the lights
and the wipers had an effect on the charging, both were turned on multiple times during
the return trip. At no point during the return trip did the voltage ever increase beyond 13.0 volts.
Some might conclude that the rain loaded the wipers such that the wiper motor required more
voltage, I doubt it. By the way, my headlights are LEDs.

The wiper speed and required voltage to function properly at 13.0 versus 14.5 is negligible,
i.e. the motor won't reach a stall condition requiring a voltage greater than 13.0
to function properly. A typical wiper current is 10 - 15 amps at most at the highest speed.
Furthermore, the wiper motor load would be greater in the no rain condition, given the
greater friction without rain. And the wiper mode being used during the rain was the
intermittent mode at its lowest frequency. Yes, the starting current for the motor in the
intermittent mode will be greater than its running current in the non-intermittent mode,
but 13 versus 14.5 should not affect the starting of the wiper motor.

So, the only conclusion one might arrive at based on this situation is that the Leaf charging
system entered a mode where it charged at 14.3 to 14.5 for a lengthy time period. No real
data from this event would indicate any logical causality as to what factors determine what
charging mode the Leaf enters.

 

[RegGuheert]

I failed to mention that after reaching my destination and parking the Leaf for about a hour,
I began my return trip. The rain had stopped and it was clear. To test whether the lights
and the wipers had an effect on the charging, both were turned on multiple times during
the return trip. At no point during the return trip did the voltage ever increase beyond 13.0 volts.

How long did you leave the wipers on? Also, how often does LeafDD sample the voltage of the 12V bus? As I mentioned, the voltage ramped up slowly after I turned on the wipers. It probably took 15 seconds to get to 14.4V. It stayed at that voltage during the entire period that the wipers were on and then it it stayed up for about one more minute after I turned off the wipers before dropping back to 13.1V. I did it multiple times and it was repeatable. Whether it does this *every* time is not known, but I will be watching for it now.

By the way, my headlights are LEDs.

Only your low beams are LEDs. Your high beams are halogens.