2012 Leaf Constantly Charging 12v system (3rd LED always blinking when parked)

Hello all,

First real post here. Nice to see an active forum community!!

I’ve recently acquired a 2012 leaf for absurdly cheap. It has a well-balanced but seriously degraded pack (from what I can tell, see screenshots of leafspy below) and a gremlin or two I’m tracking down. I’ve eliminated the airbag light, TPMS light and a few other things. I am thoroughly enjoying the car and the ability to use LeafSpy to see so much in depth information.
Current concern that has me stuck – the vehicle is always charging the 12v system. When sitting idle (after a drive cycle, parked) the 3rd LED is always flashing, battery voltage is supported at about 14.45V. When plugged in and the charge is finished it reverts back to the 3rd blinking light, but while plugged in to j1772 it floats it about 13.10 volts.
I was told by the previous owner that he swapped the pack for another 2012 or possibly 2011. After the swap it was limited to 25mph and he limped it to Nissan. He says Nissan helped him out, did something (he didn’t know what..), and returned the car to him fully functioning but that light has flashed ever since.
- I have no codes on Leaf Spy
- Brand new 12v Battery
- Happens 100% of the time
- After I’m able to force the car to stop supporting 12v (see below), I do not seem to have any abnormal current draw / parasitic drain
A couple of weird things noted:
- When in this 12v support mode, the car will not power down when the 12v battery is disconnected, it continues to have 14.4 volts across the terminals even when the negative is not on the actually 12v battery. Should it have a resistance check that stops the support if the 12v becomes open / disconnected?
- I have to disconnect the negative terminal, then go in the car and cycle the drive rail on and off, then the car will power down / shut off and stop supporting the 12v (to allow an amperage draw test)
- After above process to make it stop supporting and waiting 5-10 minutes, I have about .4 amp draw, at about 10-15 minutes this drops to .05 amps (the Bluetooth dongle is responsible for about .035 of that). No reason to suspect any parasitic draw is causing it.

I realize that as far as 12v problems go, this is probably much better than being under supported, but with such low range to begin with the 10 mile drop per day drop of lost energy is huge and makes it so I can’t park the car without being plugged in for more than a few days.
If anyone has any guidance or suggestions, I’d love to hear them. Also happy to perform any tests or inspections that might be of use.
Thanks,
Colin


(MOD: fix image link)

Photobucket is blurring the screen shot of LeafSpy, but it appears that you may have two bad or at least weak cells. I don't see how this is directly related to the 12 volt battery, but you never know. This is a new one by me. You may want to check the current sensor on the negative terminal of the 12 volt battery.

LeftieBiker said:

Photobucket is blurring the screen shot of LeafSpy, but it appears that you may have two bad or at least weak cells. I don't see how this is directly related to the 12 volt battery, but you never know. This is a new one by me. You may want to check the current sensor on the negative terminal of the 12 volt battery.

Click to expand...

I have re-uploaded the photo with imgur, it is not blurry anymore.

I have done a visual inspection of the 12v current sensor, and it seems fine. Leafspy also seems to relatively accurately display the amperage (goes up when does open, and goes up when the PPW SSOFF relay starts freaking out )


I also just got a 240v charger, and the SOC has read substantially higher over the last couple of full charges. It appears to stop charging around 90%, then with a few hours sitting it will reach mid 90s as seen in the below screen shot. Not sure if this helps diagnosis at all, but figure i'll include it.

cfz said:

Hello all,

First real post here. Nice to see an active forum community!!

I’ve recently acquired a 2012 leaf for absurdly cheap. It has a well-balanced but seriously degraded pack (from what I can tell, see screenshots of leafspy below) and a gremlin or two I’m tracking down. I’ve eliminated the airbag light, TPMS light and a few other things. I am thoroughly enjoying the car and the ability to use LeafSpy to see so much in depth information.
Current concern that has me stuck – the vehicle is always charging the 12v system. When sitting idle (after a drive cycle, parked) the 3rd LED is always flashing, battery voltage is supported at about 14.45V. When plugged in and the charge is finished it reverts back to the 3rd blinking light, but while plugged in to j1772 it floats it about 13.10 volts.
I was told by the previous owner that he swapped the pack for another 2012 or possibly 2011. After the swap it was limited to 25mph and he limped it to Nissan. He says Nissan helped him out, did something (he didn’t know what..), and returned the car to him fully functioning but that light has flashed ever since.
- I have no codes on Leaf Spy
- Brand new 12v Battery
- Happens 100% of the time
- After I’m able to force the car to stop supporting 12v (see below), I do not seem to have any abnormal current draw / parasitic drain
A couple of weird things noted:
- When in this 12v support mode, the car will not power down when the 12v battery is disconnected, it continues to have 14.4 volts across the terminals even when the negative is not on the actually 12v battery. Should it have a resistance check that stops the support if the 12v becomes open / disconnected?
- I have to disconnect the negative terminal, then go in the car and cycle the drive rail on and off, then the car will power down / shut off and stop supporting the 12v (to allow an amperage draw test)
- After above process to make it stop supporting and waiting 5-10 minutes, I have about .4 amp draw, at about 10-15 minutes this drops to .05 amps (the Bluetooth dongle is responsible for about .035 of that). No reason to suspect any parasitic draw is causing it.

I realize that as far as 12v problems go, this is probably much better than being under supported, but with such low range to begin with the 10 mile drop per day drop of lost energy is huge and makes it so I can’t park the car without being plugged in for more than a few days.
If anyone has any guidance or suggestions, I’d love to hear them. Also happy to perform any tests or inspections that might be of use.
Thanks,
Colin

(MOD: fix image link)

Click to expand...

Colin,

You in the Kentucky area? There was a fellow there that swapped a 2011 Leaf battery into a 2012 and had those exact symptoms. You can't do that. The reason you can't do that is the 2011 pack doesn't have the cold weather package, but the 2012 does. This causes an incompatibility between the VCM and the BMS because the BMS doesn't have the necessary cold weather functions that the VCM is expecting. I wonder if you got that exact car or if someone else made a similar mistake...

In this mode, the 3rd light is lighting up because of 3 reasons, shown on page 28 here:
https://owners.nissanusa.com/content/techpub/ManualsAndGuides/NissanLEAF/2012/2012-NissanLEAF-owner-manual.pdf

The indicator will also flash when the following
system are operating:
. Climate Ctrl. Timer
. Remote climate control
. Li-ion battery heater


The car will drive properly, but it will lose 10-20% of the range per day keeping the computers active (and possibly overcharging the 12V battery). Basically, it looks like the car is looking for the Li-ion battery heater and can't find it.

If you do have a mismatch between BMS and car, that would explain it. The only way to fix this would be to replace the BMS (inside the battery pack) with a 2012 BMS. You will need an entire pack (minus the cells), including the wiring harnesses, battery heater, etc. Keep in mind that this is a complicated swap: You have to drop the battery from the car, open it up, and replace all your battery cells into the donor pack. You also need a specialized tool (Nissan Consult or evsenhanced's tool) to pair the new BMS to the car.

Also keep in mind that the wiring harnesses changed between 2011/2012 and 2013+. If you use the wrong wiring harness for the BMS, you *will* fry your BMS. I don't know if there were any wiring harness changes between 2011 and 2012.

If you're doing a pack swap, it's *probably* best to just get a better condition pack, so you get a range upgrade at the same time.

Note: it is safe to swap a 2012 battery into a 2011 Leaf, but *not* the other way around. The 2011 simply will not activate the battery heater.

I agree the pack is well balanced and you don't appear to have any low cells. However, the pack is quite degraded, as you said.

Lothsahn said:

Colin,

You in the Kentucky area? There was a fellow there that swapped a 2011 Leaf battery into a 2012 and had those exact symptoms. You can't do that. The reason you can't do that is the 2011 pack doesn't have the cold weather package, but the 2012 does. This causes an incompatibility between the VCM and the BMS because the BMS doesn't have the necessary cold weather functions that the VCM is expecting. I wonder if you got that exact car or if someone else made a similar mistake...

In this mode, the 3rd light is lighting up because of 3 reasons, shown on page 28 here:
https://owners.nissanusa.com/content/techpub/ManualsAndGuides/NissanLEAF/2012/2012-NissanLEAF-owner-manual.pdf

The indicator will also flash when the following
system are operating:
. Climate Ctrl. Timer
. Remote climate control
. Li-ion battery heater


The car will drive properly, but it will lose 10-20% of the range per day keeping the computers active (and possibly overcharging the 12V battery). Basically, it looks like the car is looking for the Li-ion battery heater and can't find it.

If you do have a mismatch between BMS and car, that would explain it. The only way to fix this would be to replace the BMS (inside the battery pack) with a 2012 BMS. You will need an entire pack (minus the cells), including the wiring harnesses, battery heater, etc. Keep in mind that this is a complicated swap: You have to drop the battery from the car, open it up, and replace all your battery cells into the donor pack. You also need a specialized tool (Nissan Consult or evsenhanced's tool) to pair the new BMS to the car.

Also keep in mind that the wiring harnesses changed between 2011/2012 and 2013+. If you use the wrong wiring harness for the BMS, you *will* fry your BMS. I don't know if there were any wiring harness changes between 2011 and 2012.

If you're doing a pack swap, it's *probably* best to just get a better condition pack, so you get a range upgrade at the same time.

Note: it is safe to swap a 2012 battery into a 2011 Leaf, but *not* the other way around. The 2011 simply will not activate the battery heater.

I agree the pack is well balanced and you don't appear to have any low cells. However, the pack is quite degraded, as you said.

Click to expand...

This makes total sense! Thank you!

I am not from Kentucky, I currently live in Idaho and is also where this swap was done. I am in close contact with the previous owner, friends actually, and he still has the original battery pack that came out of the car. He has 5 Leafs total and built 3 running / driving ones out of them. He still has 2 of the ones that run with 2 'parts cars'. He swapped the pack that i currently have (the '11) for fun just to see if the range would increase. He stated he noticed no notable difference in the range of the current pack ('11) and the original pack ('12). He was unaware that Leafspy was even a thing, so has no detailed numbers, just what he saw on the guess o meter.

A few questions, i very much appreciate any response:

- Since i have access to the original '12 pack (and an additional '12 pack), would it be most logical to just swap it back? Or will i run into programming issues since the current configuration has already been programmed by nissan to run. I am very familiar with Tesla vehicles and any time you swap a software'd component you have to update that part (or the whole vehicle) to new / similar software. Will i run into this if i put the original pack back in or is it likely that the original pack has kept the same software as the rest of the vehicle and will mate up and communicate just fine?

- Is it possible to trick the car into thinking there is a battery heater? If the wiring / logic is outside of the pack, is assume I could wire in a resistor or something. I'll assume the battery heater is controlled by the BMS, which would mean it is downstream/inside the pack, which voids this option as an easy solution

- Rebuilding a pack / swapping modules or components is nothing that scares me and in fact i am relatively familiar with all of it. If i do in fact have access to 3 '12 packs, and all the equipment to do the swaps / rebuilding, would it be most logical to build one really good pack out of all of them? I have done a fair bit of research and havent found any conclusive information regarding how to test the modules / packs outside of being installed to a vehicle to tell what the better modules would be. If there is a link or reference for this please link me

- maybe more simply, if i have 3 2012 packs in front of me, what is the most economical way of figureing out which one is the best?

Thanks a ton!!
Colin

cfz said:

Lothsahn said:

Colin,

You in the Kentucky area? There was a fellow there that swapped a 2011 Leaf battery into a 2012 and had those exact symptoms. You can't do that. The reason you can't do that is the 2011 pack doesn't have the cold weather package, but the 2012 does. This causes an incompatibility between the VCM and the BMS because the BMS doesn't have the necessary cold weather functions that the VCM is expecting. I wonder if you got that exact car or if someone else made a similar mistake...

In this mode, the 3rd light is lighting up because of 3 reasons, shown on page 28 here:
https://owners.nissanusa.com/content/techpub/ManualsAndGuides/NissanLEAF/2012/2012-NissanLEAF-owner-manual.pdf

The indicator will also flash when the following
system are operating:
. Climate Ctrl. Timer
. Remote climate control
. Li-ion battery heater


The car will drive properly, but it will lose 10-20% of the range per day keeping the computers active (and possibly overcharging the 12V battery). Basically, it looks like the car is looking for the Li-ion battery heater and can't find it.

If you do have a mismatch between BMS and car, that would explain it. The only way to fix this would be to replace the BMS (inside the battery pack) with a 2012 BMS. You will need an entire pack (minus the cells), including the wiring harnesses, battery heater, etc. Keep in mind that this is a complicated swap: You have to drop the battery from the car, open it up, and replace all your battery cells into the donor pack. You also need a specialized tool (Nissan Consult or evsenhanced's tool) to pair the new BMS to the car.

Also keep in mind that the wiring harnesses changed between 2011/2012 and 2013+. If you use the wrong wiring harness for the BMS, you *will* fry your BMS. I don't know if there were any wiring harness changes between 2011 and 2012.

If you're doing a pack swap, it's *probably* best to just get a better condition pack, so you get a range upgrade at the same time.

Note: it is safe to swap a 2012 battery into a 2011 Leaf, but *not* the other way around. The 2011 simply will not activate the battery heater.

I agree the pack is well balanced and you don't appear to have any low cells. However, the pack is quite degraded, as you said.

Click to expand...

This makes total sense! Thank you!

I am not from Kentucky, I currently live in Idaho and is also where this swap was done. I am in close contact with the previous owner, friends actually, and he still has the original battery pack that came out of the car. He has 5 Leafs total and built 3 running / driving ones out of them. He still has 2 of the ones that run with 2 'parts cars'. He swapped the pack that i currently have (the '11) for fun just to see if the range would increase. He stated he noticed no notable difference in the range of the current pack ('11) and the original pack ('12). He was unaware that Leafspy was even a thing, so has no detailed numbers, just what he saw on the guess o meter.

A few questions, i very much appreciate any response:

- Since i have access to the original '12 pack (and an additional '12 pack), would it be most logical to just swap it back? Or will i run into programming issues since the current configuration has already been programmed by nissan to run. I am very familiar with Tesla vehicles and any time you swap a software'd component you have to update that part (or the whole vehicle) to new / similar software. Will i run into this if i put the original pack back in or is it likely that the original pack has kept the same software as the rest of the vehicle and will mate up and communicate just fine?

- Is it possible to trick the car into thinking there is a battery heater? If the wiring / logic is outside of the pack, is assume I could wire in a resistor or something. I'll assume the battery heater is controlled by the BMS, which would mean it is downstream/inside the pack, which voids this option as an easy solution

- Rebuilding a pack / swapping modules or components is nothing that scares me and in fact i am relatively familiar with all of it. If i do in fact have access to 3 '12 packs, and all the equipment to do the swaps / rebuilding, would it be most logical to build one really good pack out of all of them? I have done a fair bit of research and havent found any conclusive information regarding how to test the modules / packs outside of being installed to a vehicle to tell what the better modules would be. If there is a link or reference for this please link me

- maybe more simply, if i have 3 2012 packs in front of me, what is the most economical way of figureing out which one is the best?

Thanks a ton!!
Colin

Click to expand...

Colin:

1) Yes, the best plan is to just swap it back. It will have to be paired, either by Nissan (using their consult tool) or Evsenhanced's battery pairing tool. If you use evsenhanced, you will need LeafSpy to clear the DTC's prior to pairing. By going back to the original pack, you will have the heater and expected hardware, which has two advantages: a) The battery will not be damaged by extreme cold (<0F) and b) All of the battery drain issues will go away. Also, simply disconnecting the 12V battery to do the swap will likely cause a lot of DTC codes, all of which can be cleared by LeafSpy except the battery pairing code (which requires the specialized tool). The car will operate before the battery pairing, but will show errors and refuse to drive over 25 MPH.

2) There is no known way of tricking the car into thinking there is a battery heater. That would require a reprogram of the VCM or the BMS, I believe. I recommend #1.

3) If you have access to the original pack, swapping it back makes the most sense. Your current pack is not in good health, and honestly, all 2011/2012 packs have bad chemistry, so just go back. It's not like your current pack is super healthy where you want to get crazy.

4) If you have 3 2012 packs, they're probably all bad. I wouldn't bother with trying to find the best one, because the difference is likely 10% or less. 2011-March 2013 chemistry was bad and wears out quickly. To figure out the best one, you have two options: a) Make an adapter to hook up LeafSpy direct to a pack b) Plug each one into a car and use LeafSpy to diagnose the pack SOH. You do NOT need Nissan to pair the pack to only fetch the SOH. Here's such an adapter: https://evsenhanced.com/products/obd2-to-leaf-battery-adapter/

If you're up for rolling up your sleeves and getting your hands dirty, you have two options to improve your range:
1) Find a good health 24 kWh pack, buy it, open it up, and swap all the battery cells from that pack to your pack. ONLY swap the cells--keep all of your busbars, wiring, heaters, and BMS modules. Changing any of those components can destroy your BMS. Your car will still indicate a low number of capacity bars but the range will dramatically improve. Prefer packs built 2015 or later, as they have the latest chemistry and degrade slowest. You can ONLY do this with 24 kWh cells--if you try to use 30 or 40 cells it won't work as the voltage curves are different and will confuse the BMS.

2) Get a good health 40 kWH pack and swap it with your car. Install a muxsan CAN adapter as your car cannot directly talk to the larger capacity battery. This would give you around 120 miles range--not dashboard indicated, but actual range. See: https://muxsan.com/#nissan-leaf-battery-swaps/upgrades

3) You also always have the option of paying Nissan $5500 and one of your battery packs. They'll install a brand new warrantied 24 kWh pack on your car.


Sell or use the extra 2011/2012 packs you have lying around. They're excellent for solar storage. 12 kWh may only get you 20-30 miles in your car, but it'll power your house for quite a while. If you put 4 of them together, that's likely days of energy consumption.

4) If you have 3 2012 packs, they're probably all bad. I wouldn't bother with trying to find the best one, because the difference is likely 10% or less. 2011-April 2013 chemistry was bad and wears out quickly.

Click to expand...

That should read "2011-March 2013 chemistry was bad" as the newer 'Wolf pack' chemistry was implemented in April. There is evidence that a couple of April build cars may have gotten the old chemistry but the great majority of them did not. I drove an April build for 5 years and turned it in with 12 bars. If an April build has more than 10 capacity bars, it should be the newer chemistry.

LeftieBiker said:

4) If you have 3 2012 packs, they're probably all bad. I wouldn't bother with trying to find the best one, because the difference is likely 10% or less. 2011-April 2013 chemistry was bad and wears out quickly.

Click to expand...

That should read "2011-March 2013 chemistry was bad" as the newer 'Wolf pack' chemistry was implemented in April. There is evidence that a couple of April build cars may have gotten the old chemistry but the great majority of them did not. I drove an April build for 5 years and turned it in with 12 bars. If an April build has more than 10 capacity bars, it should be the newer chemistry.

Click to expand...

My bad. Fixed.