12V battery died, SOH and SOC messed up after replacing 12V

[ARG]

2 days ago, my LEAF 2013 did not start in the morning. The 12V battery was reading 6V over ODB2 and it was too low to even operate the door locks. I jump-started the car and drove it to a battery shop. Replaced the battery. The old one was 5 years old. The car started and I could drive it but the yellow light was on.

OBD2 showed 0% SOH on the battery pack (a few days ago it was ~90%). The dashboard SOH indicator showed 12 bars.
Drove ~15 miles. Started the car. Now SOC on the dash board and OBD2 was 0% (was 80% in the morning with 160-mile range).
Despite SOC indicators showing 0%, I drove home 13 miles without going into turtle mode. Plugged in the car. The charging did not start.

Next morning, I turned on the car and drove to work. SOC on the dashboard showed 80% and did not go down a single point after driving ~16 miles. Then it showed 0% again.

I took the car to Nissan dealership. They kept it for the day, but could not figure out what happened. The tech said that the car should not be able to drive with these errors but it does. I'm told that there is an error in communication with the battery. Nissan promised to reset the system by tomorrow.

Any ideas what may be going on? Could the battery replacement corrupt the computer system? I think the yellow light was on before I replaced the battery but I may be mistaken. In any case, I would have attributed it to the dead 12 V battery, not to the problem with the indicators.

Some background. I bought this LEAF 2013 in February 2023 with 75k miles on it and a dead original 24kWh battery. The dealer got it from an auction in Arizona where EV registration is cheap, and battery packs go before the warranty expires. I installed a 62kWh battery with 92% SOH on it from my old LEAF that got totaled (the battery pack was intact). I drove it happily for 9 months, charging nightly to 80% SOC, driving every day for commute. I had to explain why LEAF 2013 had a 62kWh battery pack. The Nissan tech was a bit puzzled.

 

[dhyatt]

2 days ago, my LEAF 2013 did not start in the morning. The 12V battery was reading 6V over ODB2 and it was too low to even operate the door locks. I jump-started the car and drove it to a battery shop. Replaced the battery. The old one was 5 years old. The car started and I could drive it but the yellow light was on.

OBD2 showed 0% SOH on the battery pack (a few days ago it was ~90%). The dashboard SOH indicator showed 12 bars.
Drove ~15 miles. Started the car. Now SOC on the dash board and OBD2 was 0% (was 80% in the morning with 160-mile range).
Despite SOC indicators showing 0%, I drove home 13 miles without going into turtle mode. Plugged in the car. The charging did not start.

Next morning, I turned on the car and drove to work. SOC on the dashboard showed 80% and did not go down a single point after driving ~16 miles. Then it showed 0% again.

I took the car to Nissan dealership. They kept it for the day, but could not figure out what happened. The tech said that the car should not be able to drive with these errors but it does. I'm told that there is an error in communication with the battery. Nissan promised to reset the system by tomorrow.

Any ideas what may be going on? Could the battery replacement corrupt the computer system? I think the yellow light was on before I replaced the battery but I may be mistaken. In any case, I would have attributed it to the dead 12 V battery, not to the problem with the indicators.

Some background. I bought this LEAF 2013 in February 2023 with 75k miles on it and a dead original 24kWh battery. The dealer got it from an auction in Arizona where EV registration is cheap, and battery packs go before the warranty expires. I installed a 62kWh battery with 92% SOH on it from my old LEAF that got totaled (the battery pack was intact). I drove it happily for 9 months, charging nightly to 80% SOC, driving every day for commute. I had to explain why LEAF 2013 had a 62kWh battery pack. The Nissan tech was a bit puzzled.

you have a 12v system problem... not an Ev problem... I would disconnect the 12v battery. wait 10 minutes. Reconnect it (neg or pos side).. you will have to start the car several times before the computer pulls its head out of its @$$. But use a volt meter to measure voltage across terminals... and across posts...i
if not the same, you have battery cable problems.

 

[TobyHolland]

I've found on many Leaf 12v battery changes that a Zillion faukt codes can occur - after a 12v swap, the first thing I always do is delete ALL the fault codes......please try that first
#MnMSzerviz

 

[AlanD]

I agree with the above.

 

[moapys]

I've found on many Leaf 12v battery changes that a Zillion faukt codes can occur - after a 12v swap, the first thing I always do is delete ALL the fault codes......please try that first
#MnMSzerviz

GM - facing a failing (2nd/non-OEM) 12v on my 2012: Is it preferred - so as not to confuse the EMS, cause relearning, etc - to "jumper" the 12v leads with a small external cell during the exchange? E.g. just keep continuous 12v to the hot and gnd, safely of course, during the main battery swap?

I've done it for years on picky BMW's that otherwise want to be reacquainted with their new battery at the stealership - and it seemed sensible practice on these non-ICE/highly-computerized vehicles as well....?

 

[TobyHolland]

GM - facing a failing (2nd/non-OEM) 12v on my 2012: Is it preferred - so as not to confuse the EMS, cause relearning, etc - to "jumper" the 12v leads with a small external cell during the exchange? E.g. just keep continuous 12v to the hot and gnd, safely of course, during the main battery swap?

I've done it for years on picky BMW's that otherwise want to be reacquainted with their new battery at the stealership - and it seemed sensible practice on these non-ICE/highly-computerized vehicles as well....?

It obviously may help - BUT, many of the fault codes can occur as the 12v dies, before it is changed, so in practice, it just adds unnecessary complication to a very simple job

 

[moapys]

@TobyHolland - thanks; but fortunately no fault codes yet (and would like to keep it that way). I'm seeing poor general charge levels on my lead-acid battery now - per intelligent testing-charger, and a series of external load tests from fully charged state. I've been doing monitored "top-up" charges from ~25% depletion following a few local errands...

I think I'll be swapping it out for AGM tomorrow, and see if the comparative performance / SoC figures improve with the replaced unit. Once that's done, I'll report back on findings

 

[moapys]

Belatedly stumbled onto the (expected) thread, for which I was looking, discussing jumpering another 12v source, during the battery exchange: https://mynissanleaf.com/threads/diy-12v-battery-change.31054/post-582055

 

[vectormax]

Being a 62kWh pack... Wasn't this a custom swap? You might want to check with the shop that did the swap to check that the modules are correctly looking for a 62kWh pack and not the original pack. I believe the swap requires custom software to be flashed from what I remember.

Nissan Leaf Battery Upgrade Frequently Ask Questions - Leo & Sons Auto Repair of Lawrence Massachusetts

"We are an official distributor for EV’s Enhanced, a New Zealand company that makes an array of aftermarket products for the Leaf including the translators we use to adapt newer batteries to older cars."

 

[moapys]

@TobyHolland - thanks; but fortunately no fault codes yet (and would like to keep it that way). I'm seeing poor general charge levels on my lead-acid battery now - per intelligent testing-charger, and a series of external load tests from fully charged state. I've been doing monitored "top-up" charges from ~25% depletion following a few local errands...

I think I'll be swapping it out for AGM tomorrow, and see if the comparative performance / SoC figures improve with the replaced unit. Once that's done, I'll report back on findings

The swap went perfectly: I did jumper-in a small 12v "keep-alive" during the surgery, until the fresh AGM* was installed. No codes, anomalies, etc; just a healther pack under-the-hood...

*...The standard (small) auto battery was swapped for a parallel pair of 18AH AGM cells, for a 12v@36AH "battery": It seems to retain capacity better, and definitely has the improved discharge profile of deep-cycle cells. It isn't pretty (owing to soldered lugs and outboard +/- posts), but it is functional!

 

[mrlithium]

Question: The constant up and down cycling that the 12V battery endures does not lead to a long lifespan for the lead acid battery. So, wouldn't a lithium replacement be better ? ..
Thoughts from leaf owners wanted on this subject.

 

[dhyatt]

2 days ago, my LEAF 2013 did not start in the morning. The 12V battery was reading 6V over ODB2 and it was too low to even operate the door locks. I jump-started the car and drove it to a battery shop. Replaced the battery. The old one was 5 years old. The car started and I could drive it but the yellow light was on.

OBD2 showed 0% SOH on the battery pack (a few days ago it was ~90%). The dashboard SOH indicator showed 12 bars.
Drove ~15 miles. Started the car. Now SOC on the dash board and OBD2 was 0% (was 80% in the morning with 160-mile range).
Despite SOC indicators showing 0%, I drove home 13 miles without going into turtle mode. Plugged in the car. The charging did not start.

Next morning, I turned on the car and drove to work. SOC on the dashboard showed 80% and did not go down a single point after driving ~16 miles. Then it showed 0% again.

I took the car to Nissan dealership. They kept it for the day, but could not figure out what happened. The tech said that the car should not be able to drive with these errors but it does. I'm told that there is an error in communication with the battery. Nissan promised to reset the system by tomorrow.

Any ideas what may be going on? Could the battery replacement corrupt the computer system? I think the yellow light was on before I replaced the battery but I may be mistaken. In any case, I would have attributed it to the dead 12 V battery, not to the problem with the indicators.

Some background. I bought this LEAF 2013 in February 2023 with 75k miles on it and a dead original 24kWh battery. The dealer got it from an auction in Arizona where EV registration is cheap, and battery packs go before the warranty expires. I installed a 62kWh battery with 92% SOH on it from my old LEAF that got totaled (the battery pack was intact). I drove it happily for 9 months, charging nightly to 80% SOC, driving every day for commute. I had to explain why LEAF 2013 had a 62kWh battery pack. The Nissan tech was a bit puzzled.

My Leaf was acting bonkers after I replaced the 12v battery.. I started it 3 times and it has been normal ever since. Do NOT replace it with a Nissan Dealer battery. Go to the auto parts store or AAA and get a high quality high cold cranking amps battery about the same size and same polarity (+ on the same side...)

 

[TronJockey]

Question: The constant up and down cycling that the 12V battery endures does not lead to a long lifespan for the lead acid battery. So, wouldn't a lithium replacement be better ? ..
Thoughts from leaf owners wanted on this subject.

The 12V accessory battery in the Leaf doesn't see anything close to the up and down cycling that it would see as a starter battery in an ICE vehicle. This is why they can easily last well over 5 years in the Leaf if properly maintained. The issue as I see it is that if the 12V lead acid battery is of low quality, old, has been stressed by extreme temperatures and or has been too deeply discharged for some reason and starts to deteriorate, the Leaf's 12V charging system may not be able to resurrect or bring it back. Under most conditions the Leaf only applies a 13.0V float charge to maintain the battery which, for the application the lead acid battery serves in the Leaf, is usually more than enough to keep it healthy. As well the Leaf will apply roughly 14.35V for about 90 seconds each time the Leaf is powered up before dropping back to 13.0V (it will also see a 14.35V charge level whenever the windshield wipers are on). This regime is suitable for a healthy lead acid battery used in this application but won't likely be enough to maintain a highly stressed, damaged or dying 12V lead acid battery. Using a LiFePo chemistry instead of lead acid in this application has been done although I don't know how successful this was in the long run. The charging profile used by the Leaf is intended for lead acid batteries and may not adjust for temperatures below freezing (0C) where charging LiFePo will damage it. The LiFePo selected should have an internal circuit to prevent it from accepting a charge below 0F (the more expensive ones do). Most Li-ion chemistries also have lower internal resistance than that of lead acid. This presents a lower resistance to the DC-DC converter/charger circuitry allowing for a possibly higher charging and in-rush currents and may damage the charger circuitry over time. As well, the Leaf's 13.0V float or maintenance charge may not be sufficient to keep a LiFePo charged. A LiFePo used in an ICE vehicle will typically see between 13.8V and 14.5V from the alternator which is well within a LiFePo's sweet spot. However, in the Leaf this could be an issue over time. I would enjoy hearing from Leaf owners that could reflect on any long-term experiences (and hopefully successes), after replacing their lead acid accessory batteries with LiFePo.

 

[knightmb]

Using a LiFePo chemistry instead of lead acid in this application has been done although I don't know how successful this was in the long run.

I'm still on my original after +9 years, another forum member installed one a year earlier and they are over +10 years now. The LiFeP04 is certainly the best, they even make them with built-in battery heaters now. The big issue is the cost. When I bought mine back in 2015, it cost roughly $240 for a 20AH version. Now you can buy them for +$60 in that size everywhere, but it takes a little custom wiring to make it work. Getting a large lithium in the 51R format for the 12V battery cost a lot more (100AH capacity) for simple drop in placement to work unfortunately. So compared to a cheap SLA or better AGM, most probably got the cheaper route. All of my friends and relatives though, they all have LiFeP04 as that's what I recommended to them if they planned on keeping the Leaf until the wheels fell off.

 

[knightmb]

The charging profile used by the Leaf is intended for lead acid batteries and may not adjust for temperatures below freezing (0C) where charging LiFePo will damage it.

The Leaf doesn't blast 100A into the 12V battery when temperatures are freezing outside, SLA/AGM have the same charging limitations (though better the colder you get) that Lithium does when you get below freezing. I would have to dig around this forum for it, but I did experiments years back where in freezing temperatures you could see the Leaf would only trickle charge the 12V battery no matter if it was a depleted SLA or Lithium.

 

[BillAinCT]

Can you use just any say 20Ahr LiFePO battery that has a BMS (I might expect they all will). There are $60 ones on Amazon. Can you charge with too much current? I would think the BMS would set that accordingly. One I see says cannot jump an auto, but the Leaf isn't an auto in this respect.

 

[mrlithium]

All the $60 or so battery specs I looked at on Amazon all use the same low rate cells. 20A max with some with 40A peak with the smallest BMS / PCB. None of these would work in an EV or any car in my opinion (after 12 years of being involved in the Li battery business ). And, Amazon return policy says it can only be returned in Unused condition. I think price is the driving factor for people when replacing 12V batteries. A 3 year warranty lead acid is about $200 in auto parts stores. A lithium version is also $200 from LithiumMoto.

 

[sygall]

Walmart R51 form factor 460 amp
is $60 in tucson (lead acid one year warranty)

 

[Joaozinho]

Can one buy a 51 instead of a 51R? It's my understanding that the only difference is that the terminal positions are reversed. Are the Leaf's cables long enough?

 

[cornbinder89]

There isn't much slack in the cables but it might work.