2016 Leaf SV 12V battery draining

Just got a NEW 2016 SV. Right away at the dealership, went to turn it on and drive it home, it was dead. It was Friday after service had closed. Dealer was able to jump it and said it was probably a drained battery from sitting dormant in shipping as it has just arrived the night before. Took hit home, it drove just fine. Took it out a couple of times that night. The next morning parked it at my church which is just 5 miles away and afterwards it was dead again. Dealer towed it and gave me an SL to drive as a loaner. Said it was bad cell in 12v. Replaced the battery and let it sit overnight, then verified that 12v was still good the next morning with no "ghost loads" that could be detected. Took it home, drove it for a day, and once again, took it somewhere, turned it off, after 2 hours came out and the 12v was too low to run the car. Towed it back in again, waiting to hear status now.

After 3rd time you should be able to apply Lemon Law.

I have no proof, but from all my experience when the 12v battery gets low or weak, something turns on or tries to to on and then it runs the 12v dead. What it is suppose to do is "turn on" and charge the 12v via the traction battery, but when the 12v battery is weak it starts the process and then dies before it can turn on to charge itself. Again this is just my observation.

Once I swapped to a larger size battery (although I now believe any good battery would work) I have never had an issue again. I would be really curious to know if the dealer truly swapped your 12v battery and if they did it would need a good 3 stage charge to make sure it was full.

Here is the thread with more information.

http://www.mynissanleaf.com/viewtopic.php?f=9&t=18129&p=439206#p439206

BrockWI said:

Once I swapped to a larger size battery (although I now believe any good battery would work) I have never had an issue again. I would be really curious to know if the dealer truly swapped your 12v battery and if they did it would need a good 3 stage charge to make sure it was full.

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Your second point is a good one (did they really swap the battery), but putting a larger 12v battery in a Leaf is completely useless. In fact, I replaced the original 12v lead-acid with a 20A Lithium (about half the capacity that shipped with the car) and have no issues.

Your second point is a good one (did they really swap the battery), but putting a larger 12v battery in a Leaf is completely useless.

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There is anecdotal evidence that larger capacity batteries get charged more by the car's charging system, possibly because the voltage rises more slowly under charge, thus allowing the charging system to stay active longer. The theory has been floated that Nissan designed the car with a higher capacity 12 volt battery in the system, then cheaped out in production and used the little starting batteries instead.

Hello all. Well I wanted to post and let everyone know how it turned out. I got it back from the dealer a few days ago and haven't had a single problem since. I've done long trips, short trips, headlights, etc and it all runs perfectly.

The techs at the dealer had this to say:

It's possible that the battery that they replaced the bad one with wasn't well charged. They admitted that they didn't actually check it.
Also, sometimes with the new cars there are grounding points in the car that get enough paint between the wire and the contact point that they don't really ground well. They thoroughly cleaned and re-fastened all of these.

I'm guessing that it was a combination of the replacement battery not having a full charge combined with the fact that since I didn't have my L2 installed yet I was using the trickle charger. Since then I've mostly charge with the L2 and once with a DC.

I will admit that since being spooked by all of this I did go out and buy a $50 jump starter and I'm also getting a small DC plugin voltage monitor (about $12 on Amazon) just for peace of mind to keep an eye on things.

Logged 94 miles today with 22% left. Loving it!

I'm guessing that it was a combination of the replacement battery not having a full charge combined with the fact that since I didn't have my L2 installed yet I was using the trickle charger. Since then I've mostly charge with the L2 and once with a DC.

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L-1 charges the battery pack for much longer, and thus the 12 volt battery as well. It doesn't fully charge it, but shortening the charge time isn't going to help with charging the accessory battery. The problem was likely a new battery with low charge out of the box, that wasn't charged at the dealership as it should have been. Your driving habits are letting the car adequately maintain the charge on that battery now.

It's simple: he had a bad battery! Why all the convoluted "small battery/big battery" theories? Same thing happened to my kid's car last month: they thought everything under the sun was wrong with his car since they had just replaced the 12v battery, but when I forced them to look at it again, it was bad (probably from the moment they put it in)!

Let's face it, 12v lead-acid batteries suck, but they aren't going to put $500 alternatives (like I did) in cars just because.

kanjitattoo said:

Hello all. Well I wanted to post and let everyone know how it turned out. I got it back from the dealer a few days ago and haven't had a single problem since. I've done long trips, short trips, headlights, etc and it all runs perfectly.

The techs at the dealer had this to say:

It's possible that the battery that they replaced the bad one with wasn't well charged. They admitted that they didn't actually check it.
Also, sometimes with the new cars there are grounding points in the car that get enough paint between the wire and the contact point that they don't really ground well. They thoroughly cleaned and re-fastened all of these.

I'm guessing that it was a combination of the replacement battery not having a full charge combined with the fact that since I didn't have my L2 installed yet I was using the trickle charger. Since then I've mostly charge with the L2 and once with a DC.

I will admit that since being spooked by all of this I did go out and buy a $50 jump starter and I'm also getting a small DC plugin voltage monitor (about $12 on Amazon) just for peace of mind to keep an eye on things.

Logged 94 miles today with 22% left. Loving it!

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glad to hear your car is doing great!

things to keep in mind; NEVER NEVER NEVER use accessory mode in your LEAF. There are no known cases of death from inhaling electrons, so no reason whatsoever to use this mode. This mode does not maintain the 12 volt system....only drains it.

The jump box is a good investment against future 12 volt issues but I use mine for a lot of things including charging my electronic devices when camping or on picnics. Best money I ever spent! I have 2 12 volt ports on mine but also have a 4 port USB charger and SEVERAL times all 4 ports were in use!

LeftieBiker said:

Your second point is a good one (did they really swap the battery), but putting a larger 12v battery in a Leaf is completely useless.

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There is anecdotal evidence that larger capacity batteries get charged more by the car's charging system, possibly because the voltage rises more slowly under charge, thus allowing the charging system to stay active longer. The theory has been floated that Nissan designed the car with a higher capacity 12 volt battery in the system, then cheaped out in production and used the little starting batteries instead.

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you are arguing against someone who has already pretty much proven that the Nissan 12 volt charging profile is a poor fit for lead acid. Now a larger capacity lead acid battery is a bandaid fix at best as it will also eventually run down. Several cases here support that. There is a type of driving style that is not a good fit. I have never had 12 volt issues but my 12 volt battery does live closer to the edge than I prefer...

DaveinOlyWA said:

things to keep in mind; NEVER NEVER NEVER use accessory mode in your LEAF. There are no known cases of death from inhaling electrons, so no reason whatsoever to use this mode. This mode does not maintain the 12 volt system....only drains it.

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...except when you don't want someone to drive off with your car! I'm amazed at the activity these 12v threads get. Just last week I was "showing off" my car after delivering an EV presentation, and folks wanted to see what the dash/console looked like...and I didn't want them driving my car off by accident, so I put it in accessory mode. I've listened to baseball games on the driveway plenty of times in the same mode with no issues; after all, the car is designed to "top off" the 12v when needed (just not from the dead).

DaveinOlyWA said:

you are arguing against someone who has already pretty much proven that the Nissan 12 volt charging profile is a poor fit for lead acid. Now a larger capacity lead acid battery is a bandaid fix at best as it will also eventually run down. Several cases here support that. There is a type of driving style that is not a good fit. I have never had 12 volt issues but my 12 volt battery does live closer to the edge than I prefer...

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Read your website posting on your experience with the 12 V battery in the Leaf - gives us all a better understanding of the actual workings of the 12 volt "system".

It did "spark" my interest in that it appears the best battery type for the Leaf's service is either a LiFePO4 or a traditional FLA deep cycle. I looked inside one of the cells in my Leaf's battery - it appears to be traditional automotive design with mesh type lead anode rather than a solid plate (as in deep cycle). Not sure why Nissan would choose this type battery as I cannot think of a scenario that would require the 600 amps for a few seconds that traditional ICE starters require.

On the charging side, again the Leaf's DC/DC converter could be more akin to solar PV MPPT charge controllers than the simple voltage regulated alternator of the ICE. I'd guess that the DC/DC converter at least has a good charge profile (like a good MPPT CC) to extend the life of the battery - but maybe not. Your measurements of voltages seems to question that it does!

I'm not a battery expert, but from my off-grid/solar experience, the Leaf's selection of battery seems in question. I'd sure encourage more input on this as it would seem to affect any replacement recommendations.

It's simple: he had a bad battery! Why all the convoluted "small battery/big battery" theories?

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I never wrote that he didn't have a bad battery. I think that his dealer replaced a bad one with an undercharged good one. There is nothing "convoluted" about noting that the OEM battery is both the wrong type for this application and too small. If someone has a driving style that quickly drains the OEM battery, then I agree that a larger battery is just a band-aid. However, there are people here who suffer dead 12 volt batteries only after a fairly long time with no issues, and in these cases a larger, at least partially deep-cycle SLA battery would probably be all that they need.

Stanton said:

DaveinOlyWA said:

things to keep in mind; NEVER NEVER NEVER use accessory mode in your LEAF. There are no known cases of death from inhaling electrons, so no reason whatsoever to use this mode. This mode does not maintain the 12 volt system....only drains it.

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...except when you don't want someone to drive off with your car! I'm amazed at the activity these 12v threads get. Just last week I was "showing off" my car after delivering an EV presentation, and folks wanted to see what the dash/console looked like...and I didn't want them driving my car off by accident, so I put it in accessory mode. I've listened to baseball games on the driveway plenty of times in the same mode with no issues; after all, the car is designed to "top off" the 12v when needed (just not from the dead).

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What we need in the LEAF is a mode which engages the high-voltage battery WITHOUT also engaging the electric drive system. There are two reasons for this: The first one is just as Stanton has described above: If you are trying to get power from the car, you don't want it being inadvertently driven OR "advertently" stolen. The second reason is that the switching losses of the drive system are on the order of 1000W (for neutral or park). If you could keep the main inverter off instead, you could operate small loads for a much longer time.

Marktm said:

I'd guess that the DC/DC converter at least has a good charge profile (like a good MPPT CC) to extend the life of the battery - but maybe not.

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Unfortunately, it does not have a good charge profile. It has all the capability in place to do a good job, but the algorithm Nissan implemented stinks. Specifically, it does not seem to account for charge which is lost when the LEAF is off. As a result, this charge is not replaced the next time the vehicle is started (or charged). The result is that the LEAF 12V battery tends to sit around at about 50% to 60% SOC, which leads to premature failure due to sulfation.

There are three ways which I know of to get a "normal" life out of your LEAF's 12V battery:

1) Live in a rainy climate. The LEAF charges the battery like a normal car (at 14.5V) when the windshield wipers are on.
2) Use Stanton's approach of replacing the 12V lead-acid battery with a 12V Li-ion replacement.
3) Occasionally charge your 12V lead-acid battery with a high-quality trickle charger to remove the lead-sulfate before it has a chance to harden. In cold weather, monthly charging is probably fine, but in hot weather, you may need to do it weekly.

In addition, some have reported decent 12V battery life for a LEAF which is driven frequently. It's not clear if this works for everyone, or if it simply means more frequent charging due to wiper usage.

RegGuheert said:

Unfortunately, it does not have a good charge profile. It has all the capability in place to do a good job, but the algorithm Nissan implemented stinks. Specifically, it does not seem to account for charge which is lost when the LEAF is off. As a result, this charge is not replaced the next time the vehicle is started (or charged). The result is that the LEAF 12V battery tends to sit around at about 50% to 60% SOC, which leads to premature failure due to sulfation.

There are three ways which I know of to get a "normal" life out of your LEAF's 12V battery:

1) Live in a rainy climate. The LEAF charges the battery like a normal car (at 14.5V) when the windshield wipers are on.
2) Use Stanton's approach of replacing the 12V lead-acid battery with a 12V Li-ion replacement.
3) Occasionally charge your 12V lead-acid battery with a high-quality trickle charger to remove the lead-sulfate before it has a chance to harden. In cold weather, monthly charging is probably fine, but in hot weather, you may need to do it weekly.

In addition, some have reported decent 12V battery life for a LEAF which is driven frequently. It's not clear if this works for everyone, or if it simply means more frequent charging due to wiper usage.

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No lead acid technology will do well spending it's life at 50% to 60% SOC. Seems so short sighted of Nissan to NOT design a decent DC/DC converter for the battery technology they selected. The gentle use requirement (low temp/low discharge) should give 5+ years of a deep cycle FLA or AGM battery. Replacement with LiFePO4 is a definite consideration for me.

Anyone have extended experience/recommendation with the the lithium technology?

As RegGuheert suggested the DC-DC converter is fine, its the charging profile the car uses. Basically when it hits a set voltage and can hold that voltage at say 1 amp it drops back in to float mode. The problem with a smaller, weaker or reduced capacity battery this is easy to do, so there is very little time spent in the absorb phase to actually put energy back in the battery. A newer, larger, better condition battery, be it Li, sla or flooded battery it takes longer to hit that absorb setting and thus charges the battery properly.

As to why some cars have issues and some don't, is it the day they ran the batteries off the line? Maybe they have multiple suppliers? Weather conditions? All these add to the condition of the battery so who knows. We do know turning the wipers on and some other loads cause the converter to go in to the absorb phase and that helps the battery health as well.

The thing is I would be willing to bet it would be easy to change the charging profiles via software and a reduced capacity battery would work fine.

I had the same problem but the dealer fixed it.

What we need in the LEAF is a mode which engages the high-voltage battery WITHOUT also engaging the electric drive system.

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Two presses of the Start button with no foot on the brake pedal will do exactly this, IIRC, but the 12 volt battery won't be properly charged. It's still better than accessory mode.

Marktm said:

Anyone have extended experience/recommendation with the the [12v] lithium technology?

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Here's a whole thread http://www.mynissanleaf.com/viewtopic.php?f=37&t=11999 on it; I still have this exact battery installed today (3+ years). Most people stop at the price, but there are other/similar alternatives; it's important that you get one with some sort of cell-balancing built-in (the "cheap" ones don't have it). You shouldn't need voltage protection since the Leaf doesn't go above 14.4v.