12 Volt Lead Acid Battery Replacement

[QueenBee]

I replaced mine with a lithium and it has been nearly a year of problem free 12 volt battery maintenance

I bought my LEAF 4.5 years and 48,000 miles ago and have had a problem free 12 volt battery. Anecdotes are not an effective way to calculate MTBF. There are reasons that even Tesla uses lead acid batteries. I have no doubt that eventually EVs with non lead acid batteries will become common but not until they are high quality, mass produced, reliable and cost effective.

 

[knightmb]

I replaced mine with a lithium and it has been nearly a year of problem free 12 volt battery maintenance

I bought my LEAF 4.5 years and 48,000 miles ago and have had a problem free 12 volt battery. Anecdotes are not an effective way to calculate MTBF. There are reasons that even Tesla uses lead acid batteries. I have no doubt that eventually EVs with non lead acid batteries will become common but not until they are high quality, mass produced, reliable and cost effective.

It's not an anecdote, just a data point. My lead acid battery was failing and only had 1/3 of its original capacity when tested. The lithium battery has been trouble free and still maintains nearly 99% of the original capacity it was rated for. As was stated in many pages earlier (maybe?), Lead Acid is reliable when used and maintained for how it is designed. Unfortunately, the Leaf does not seem to follow this and thus, can and probably will greatly shorten the life of Lead Acid batteries used in the 12 volt power storage role. People living in colder climates are more likely to encounter the problem than those living in more modest temperature climates. That is why my opinion is that Nissan should just forgo the Lead Acid in the Leaf because it does not need cold cranking amps, but some more temperature flexible power storage to get the vehicle online.

 

[Flyct]

Sounds like yours has one dead cell so is showing 10.5v instead of 12.5v.

Definitely a dealer issue once they replace the battery and determine the running away is fixed consider the lithium replacement.

A shorted (dead) cell would be my guess also. That's easily diagnosed.

EDIT: I just measured my 12 volt battery. After sitting for a day it reads 12.51 volts. A DEAD Cell would cause a 2 volt loss, so if yours is reading 10.5v, BINGO you have a bad battery.

I would be not comfortable installing a Lithium Ion 12 volt battery. The charge rates are much different and the leaf computer is designed to charge at lead acid battery rates.

There also could be warranty issues with the car.

 

[DjDemonD]

You can pick your preferred flavour of battery. There is much less real world long term data on lithium ion used as a vehicle starter battery. However I changed mine to save weight and I saved 8kg so it's not insignificant, and also to get rid of the lead which seems an awful material to have in a modern eco friendly car, and because I wanted to, there not much you can modify or upgrade on a leaf.

Andecdotes are not evidence, but whilst I've had countless lead acid battery failures over the years I've only had one lithium ion starter battery, 1 year on and its looking strong.

 

[knightmb]

Sounds like yours has one dead cell so is showing 10.5v instead of 12.5v.

Definitely a dealer issue once they replace the battery and determine the running away is fixed consider the lithium replacement.

A shorted (dead) cell would be my guess also. That's easily diagnosed.

I would be not comfortable installing a Lithium Ion 12 volt battery. The charge rates are much different and the leaf computer is designed to charge at lead acid battery rates.

There also could be warranty issues with the car.

There are no warranty issues if you purchase a lithium that is a drop in replacement for lead acid. Now if you just wired a bunch of free cells together and it causes a fire or warranty issue, that would be a different beast all together. As far as charging rates, I've not seen any lead acid battery that can compete with a lithium at the same rated capacity. In my experience, lead acid discharge and charge rates are always less than what a lithium can handle. There would be no reason to fear a lithium replacement for that reason. Search the forum for some other post about the 12 volt battery, many other users complain that the leaf is actually not properly programmed to maintain lead acid batteries. A go between solution if you want to stick with lead, are deep cycle AGM batteries that can handle the extended low voltage periods longer without capacity damage.

 

[DjDemonD]

I know that my LiFePO4 battery can handle up to 10C charging which would be 200amps! Leafspy shows far lower charging rates and as long as the charging voltage does not go over 14.4v, and it doesn't I have monitored it for over a year, the lithium ion battery is quite safe and promises a longer lifespan at least at typical average UK temperatures than a lead acid unit. Id be surprised if it weren't still capable of performing it's job after 7-10 years.

Plus mine only cost around 125 euro or $134 and has a built in cell balancing circuit. Its a no brainer against a $100 lead acid battery which would be unlikely to give me 5 years (the longest guarantee I can find on one).

 

[Stanton]

^ ^ ^ THIS!
Good to see some folks enjoying the trouble free life of a 12v Lithium battery. I'm going on 2+ years with my LiFePO4 replacement with no problems whatsoever. For those interested, search for a "12v replacement" thread posts from a couple of years ago.

 

[DanDietrich]

I have read all of these battery threads, and I'll make a point and ask a question.
First, the point. Those of you who replaced the lead acid battery because it wasn't green had to do something with the old battery, right? Lead acid batteries right now are something like 98% recycled, so they would actually qualify as green by some standards, and replacing a functional item that didn't need replacement isn't green at all.
Now, here is my question. Someone in some post said something about Li On batteries failing if they are completely discharged, perhaps by a dome light being left on. Is this true? I live in the real world, and everyone in my family, myself included, makes mistakes. I would hate to buy an expensive battery and then lose it because I left a light on. By the way, I read all of these posts because this exact thing has happened to me twice now, and I think my battery is on the way out. My experience with motorcycle batteries has been that smaller batteries don't handle abuse well, so I will probably buy a slightly larger replacement, but still lead acid. I also saw prices quoted in these posts of over $500 for some of these Li On type batteries. That's crazy money that would wipe out a lot of fuel savings.

 

[knightmb]

I have read all of these battery threads, and I'll make a point and ask a question.
First, the point. Those of you who replaced the lead acid battery because it wasn't green had to do something with the old battery, right? Lead acid batteries right now are something like 98% recycled, so they would actually qualify as green by some standards, and replacing a functional item that didn't need replacement isn't green at all.

I wouldn't replacement mine to be green, I did it to make the vehicle more reliable.

Now, here is my question. Someone in some post said something about Li On batteries failing if they are completely discharged, perhaps by a dome light being left on. Is this true?

In a Leaf? No, even with a lead acid battery, the Leaf will shut off a dome light. Try leaving all the doors open in your car at night and come back 30 minutes later and the whole car will be dark. Most modern cars are smarter now to shut off internal lights you leave on by accident.

I live in the real world, and everyone in my family, myself included, makes mistakes. I would hate to buy an expensive battery and then lose it because I left a light on.

Most Lithium 12 volt replacement batteries have a built-in BMS to prevent that very thing, over-discharge that damages the battery.

By the way, I read all of these posts because this exact thing has happened to me twice now, and I think my battery is on the way out. My experience with motorcycle batteries has been that smaller batteries don't handle abuse well, so I will probably buy a slightly larger replacement, but still lead acid. I also saw prices quoted in these posts of over $500 for some of these Li On type batteries. That's crazy money that would wipe out a lot of fuel savings.

The Leaf does not need cold cranking amps, it has no starter to run. It merely switches on the 400v battery pack to bring the car online. The stock lead acid battery that the Leaf has is a 36 Ah. But is is not a AGM or deep cycle battery. The issue reported around in other topics is that depending on how often you drive your Leaf, the battery may not have enough opportunity to stay charged up properly. This is no big deal to other battery chemistry (NiMH, Lithium, etc) but to Lead it damages the capacity anytime the battery isn't fully charged.

You don't need to buy a 36ah lithium 12-volt counterpart, those are very expensive. You only need enough to power the vehicle in standby and switch on the main battery pack. This is where the lithium battery shines, it stores energy much better and you don't need a big one because there is no starter motor to crank. I am using a 20ah lithium 12-volt replacement. It is physically half the size and 1/3 weight of my old battery. I had to adapter my battery holder to keep it from sliding around, but it works very well in cold weather. I had the chance to test that out last winter. My old lead battery was failing in the cold weather.

 

[Nubo]

Now, here is my question. Someone in some post said something about Li On batteries failing if they are completely discharged, perhaps by a dome light being left on. Is this true?

True. Over-discharge of Lithium cells can damage them and then they can be dangerous to charge. However, any Lithium-based 12V automotive replacement should have a battery management system that removes the Lithium cells from the circuit if voltage passes below a certain threshold, just like the LEAF does with it's Lithium pack.

 

[Redwomack]

Interesting discussion. Waiting for 2nd appointment with Nissan Marin this Friday. I tried to quick charge the 12 volt with a noco lithium booster--to no avail. Put a smart charger on the 12 volt lead/acid for 2 hours and the voltage never rose to 12 volts even though my Fluke meter said the charger was putting in 14 volts. Turned charger off and voltage fell back consistently to 10.5 volts at rest. Bought hydrometer and checked all 6 cells--finding the final cell Dead in the Red--the other cells were OK in the Green. so now I will lean on Nissan dealer to replace the 12 volt. They never responded to my first complaint about the 12 volt having a low voltage of 10.5. Apparently the service department is to busy to worry. Thanks to the Leaf forum for contributing much information about battery SOC issues. The dealership in Beaverton, Oregon was also lazy and indifferent--they should have checked the 12 volt routinely on a new car sale--since it was apparently on their lot for over a year. I had to ask them to charge the Li-ion battery pack up fully. They were going to give me the car not fully charged. I also had to remind them to give me the 24 month complimentary charge card. Not much quality control stateside at Nissan based on my experience so far. In Japan, it's an insult to cause others to lose face(Leaf owner standing by car with jumper cables looking for help)--it often results in people drawing their swords to rectify the insult.

 

[TimLee]

...Waiting for 2nd appointment with Nissan Marin this Friday. ... Put a smart charger on the 12 volt lead/acid for 2 hours and the voltage never rose to 12 volts even though my Fluke meter said the charger was putting in 14 volts. Turned charger off and voltage fell back consistently to 10.5 volts at rest. Bought hydrometer and checked all 6 cells--finding the final cell Dead in the Red--the other cells were OK in the Green. ...

As I reported previously, when my second 12V developed a bad cell, I also experienced the no braking while parking once.
With the 12V proven to be bad, and the braking performance demonstrated to be dangerous, seems unwise to be waiting till Friday to get the problem corrected :shock: :roll:

 

[Redwomack]

Thanks Tim. I agree. I think I'll call the dealer and see if they can get me a battery now rather than later. I have another car, but basically foolish to try to go somewhere with the bad 12 volt. Car ran fine yesterday, but this is something the dealerships should be very alert on--and respond.

 

[Stanton]

Good answer(s) "knightmb"!
Replacing my 12v lead acid with a 12v LiFePO4 (designed as a drop-in replacement) was the best thing I ever did for my Leaf (along with replacing that pitiful horn).

 

[Redwomack]

Finally got through to a person on the phone. They hadn't returned my call at Nissan Marin--now under new ownership. Took the new Leaf in today now 2nd time same problem (370 miles)--low 12 volt battery voltage. Service advisor told me the 12 volt is only necessary for turning on the Li-ion pack. So the 12 volt couldn't be the problem. So I said once you energize the Li-ion pack you could just disconnect the 12 volt because you wouldn't need it, right? She said she didn't know about that. Said the 12 volt had been "checked" two weeks ago when I brought it in with the same complaint--and they did the brake software campaign to update. Didn't replace the 12 volt. It only registers 10.5 v. consistently. I said, so why has it run away with me 3 times, gone dead, refused to shift into forward or reverse? 'Never heard of that happening on a Leaf before.' Told her the electrolyte in the 1st cell near the positive battery post registers dead red on the float. The other 5 cells register in the green. I would think that the 12 volt would have to maintain sufficient voltage to energize the switching mechanism that turns on the main lithium pack. And other systems seem to be dependent on the 12 volt--otherwise why have this separate battery in addition to the lithium pack?

 

[TimLee]

^^^ You really need to go to a LOT better Nissan service department.

At the very least elevate this level of service advisor ignorance to the service manager.

If the service manager is similarly ignorant flee immediately to a different Nissan service department.

 

[knightmb]

Yeah, sounds like they only know the basics of the Leaf. The 12 volt powers the steering, fans, brakes, etc. The power inverter for the 12 volt system can only produce so much power (it's not infinite power of course) so if you have a bad lead acid battery in the mix, it is basically sapping the power that the rest of the systems need to function. The 12 volt battery is used to turn on the 400 v battery, that is true, but the basic car systems still use the 12 volt for safety reasons (can you imagine using 400 volts for your lights and other system?).

As others here have mentioned, if the battery is bad and still under warranty, have them replace it. If they refuse, work your way up the chain of command until you find someone that will listen. It is more than just dealing with a wonky lead acid battery, your safety is involved if the brakes are not working properly.

Finally got through to a person on the phone. They hadn't returned my call at Nissan Marin--now under new ownership. Took the new Leaf in today now 2nd time same problem (370 miles)--low 12 volt battery voltage. Service advisor told me the 12 volt is only necessary for turning on the Li-ion pack. So the 12 volt couldn't be the problem. So I said once you energize the Li-ion pack you could just disconnect the 12 volt because you wouldn't need it, right? She said she didn't know about that. Said the 12 volt had been "checked" two weeks ago when I brought it in with the same complaint--and they did the brake software campaign to update. Didn't replace the 12 volt. It only registers 10.5 v. consistently. I said, so why has it run away with me 3 times, gone dead, refused to shift into forward or reverse? 'Never heard of that happening on a Leaf before.' Told her the electrolyte in the 1st cell near the positive battery post registers dead red on the float. The other 5 cells register in the green. I would think that the 12 volt would have to maintain sufficient voltage to energize the switching mechanism that turns on the main lithium pack. And other systems seem to be dependent on the 12 volt--otherwise why have this separate battery in addition to the lithium pack?

 

[QueenBee]

Yeah, sounds like they only know the basics of the Leaf. The 12 volt powers the steering, fans, brakes, etc. The power inverter for the 12 volt system can only produce so much power (it's not infinite power of course) so if you have a bad lead acid battery in the mix, it is basically sapping the power that the rest of the systems need to function. The 12 volt battery is used to turn on the 400 v battery, that is true, but the basic car systems still use the 12 volt for safety reasons (can you imagine using 400 volts for your lights and other system?).

I'm pretty sure that the LEAF is smart enough to not continuously dump the 125+ amps that it can into the battery. It would be interesting to use LEAFSpy to watch the charge profile it uses on a bad battery like this.

 

[Redwomack]

Thank you folks for helpful details on how the 12 volt is integrated into the Leaf's operation. I'm glad this forum is here. Otherwise owners who are interested in how their cars work wouldn't have much recourse. I will indeed climb the ladder with this local dealership if they don't put a new 12 volt in today. I think it would be useful to contact Nissan operations and register dissatisfaction with failure to correct a problem that triggers liability if a runaway Leaf crashes into something or someone. Complete negligence on their part. Were it not under warranty I, like many, would have replaced the bad battery with a good one right away.

Was looking at Leafy Spy app. It looks good. It appears to be designed to run on Android devices. I have an iPhone. There may be an Android app that would run Leaf Spy on an iPhone. Otherwise have to buy an Android, right? You would be able to monitor the voltage on the 12 volt as well as the lithium. If the the Leaf only needs 10.5 to operate--because I dd drive it to the dealership this morning to drop it off--then there should only be a 10.5 volt battery in the car--according to the reasoning of the service advisor. Anybody running Leaf Spy on iPhone?

If there is a bad 12 volt or one with a bad cell as this one has--does the system set a DTC? I learned from this forum that a conventional ICE OBDII scanner won't work on a Leaf. Different parameters. No conventional combustion pollutants. Dealership said they checked the 12 volt--how? Must not have set a code due to low voltage. You would think Nissan engineers would make sure a low voltage 12 volt would set a code--since the car doesn't operate correctly or safely with a bad 12 volt.

 

[knightmb]

Yeah, sounds like they only know the basics of the Leaf. The 12 volt powers the steering, fans, brakes, etc. The power inverter for the 12 volt system can only produce so much power (it's not infinite power of course) so if you have a bad lead acid battery in the mix, it is basically sapping the power that the rest of the systems need to function. The 12 volt battery is used to turn on the 400 v battery, that is true, but the basic car systems still use the 12 volt for safety reasons (can you imagine using 400 volts for your lights and other system?).

I'm pretty sure that the LEAF is smart enough to not continuously dump the 125+ amps that it can into the battery. It would be interesting to use LEAFSpy to watch the charge profile it uses on a bad battery like this.

Smart in that it will know if something is wrong and probably not continue to do this, but as others have have shown, you can hook a very power hungry inverter into the 12 volt system and pump out thousands of watts of AC without the Leaf doing anything different. The Leaf can't tell the difference between a battery and inverter, so it might be possible for a battery to turn into a heater?