2013 Nissan Leaf Not Fully Charging, 12V Issues

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Joined
Jun 17, 2024
Messages
5
Location
USA
Hello everyone,

My partner and I bought our 2013 Nissan Leaf with around 20k miles a few months ago through a private sale. The car has both charging CHAdeMO and J1772 charging ports. We really love this little toaster, but it has developed an issue with charging.

The car charged up to our 80% target SOC fine for the first few weeks of ownership, but then started to fall short of that, consistently stopping around 65%, and would display an error icon on the dash upon startup. The scheduling/timing function was not active and the issue was reproduced on both our level 1 and level 2 J1172 chargers. The CHAdeMO fast charging works reliably though.

I read online that our cars are very sensitive to issues with the 12V battery, so I checked its voltage. With the car turned on, I was reading around 12.5V. Coming from ICE land, I was expecting to see 14V or higher. The battery was also a few years old, so I replaced it. I later load-tested that old battery and found it to be in pretty healthy condition, though.

With the replacement 12V battery, the car charged flawlessly for another couple of weeks, but then the same issue returned. I added a battery tender to the 12V battery, which we plug in any time the car is parked. With the battery tender, the issue once again went away for a few weeks, but is now back again, but more sporadically this time.

I downloaded leafspy pro and read the codes following the most recent failure to complete a charge and there are a variety of error codes. Some are about unexpected voltages or currents in various systems. I've attached the screen shot.

I've searched around the forums via google, but have not found this exact issue. Any insight about what might be going on would be greatly appreciated.
 

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The 1st thing that comes to mind is a draw on the 12 volt battery, as replacing it with new and then adding a trickle charge both made the symptom go away for a time. Neither are the answer as you found out, but point toward a possible cause.
check for a key off draw., clear codes and see what codes reappear first.
 
Lots of low voltage power supply DTCs point to an issue with the 12V supply.

Only reading 12.5 with the car in READY mode is not normal, absorption charge level should be closer to ~14.4 [can test by running the windshield wipers], and the float charge level is usually closer to ~13.1 [the usual level most all the time when the car is running].

The "U1nnn" codes are faults of the CAN Buss communications and typically related to rodent damaged wiring, corroded connector contacts, or weak 12V supply.

Measure the 12V battery voltage, then disconnect the negative terminal and measure again. Clear the codes, then take it for a drive and read the codes. Then try to charge with EVSE and read the codes.
 
Thank you both for taking the time to comment on my post.

I finally had the chance to spend some time probing around the car. Here's what I found.

12v battery after resting overnight, car off (no EV charger, no trickle charger):
12.67v

12v battery with car on:
13.09v

12v battery with car on, wipers and HVAC on:
14.38v

I also probed around for resistance in the grounding cables. Between the 12v battery and the big aluminum cover was near 0, as low as my tool can read. However, between the 12v battery and the chassis, the resistance was very high, over the limit of what my tool could read at the relevant setting for checking ground continuity.

I did not check the current draw yet, and I know there may be a more complicated issue at play.. but I am confident that this is causing at least some sort of problem, since so many systems use the chassis as ground.

I've had this exact issues in more than a few ICE cars that have spent their lives in Maine exposed to road salt, and have even lost an engine to this issue when the fuel injectors washed the cylinders out because the ECU was referencing an inaccurate voltage at idle due to high grounding resistance.

I've attached a photo of the big grounding strap that goes between the EV stuff, 12v batgery, and the chassis that is reading nearly infinite resistance. When I get the chance, I will remake this cable with welding cable, or I will look up the PN and order a new one from Nissan if the price isn't atrocious.
 

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Yeah, it looks like it has lost its connection to the chassie. 4 ga battery cable should be plenty, putting the "flag" on mid run is going to take a little searching for what can be found.
May want to choose another place to ground as the bolt area looks quite rusted.
I think you are well on the way to a solution. Even if this isn't the whole problem, it is a problem that needs to be addressed.
 
Looks like you found the culprit. The copper wire is probably okay, but that rust around the chassis bolt is not a good conductor. :ROFLMAO:

There is another threaded chassis hole nearby that might be used. i might try to clean the rust and oxidation with a light acid like vinegar, then go stronger if needed to get down to bare metal. Neutralize with baking soda solution. Rinse and dry, then redo the ground connection and coat it with either dielectric (silicone) grease, or seal it with rubber undercoat paint.
 
Looks like you found the culprit. The copper wire is probably okay, but that rust around the chassis bolt is not a good conductor. :ROFLMAO:

There is another threaded chassis hole nearby that might be used. i might try to clean the rust and oxidation with a light acid like vinegar, then go stronger if needed to get down to bare metal. Neutralize with baking soda solution. Rinse and dry, then redo the ground connection and coat it with either dielectric (silicone) grease, or seal it with rubber undercoat paint.
It's hard to see in the photo, but the wire itself is heavily corroded. The copper has turned green and become hard. It has tons of resistance, even if I jam the multimeter probe directly into the exposed strands. That's why I think I have to replace it.

Usually the threaded hole isn't too bad in my experience. I just run a tap through it a few times and wire wheel where the terminal would rest against the surface. Then wire wheel the bolt threads and slather everything in dielectric grease for reassembly.
 
Try some vinegar on the copper wire--the green and blue will usually come right off and leave shiny copper.

But if broken strands then replace it, especially if it is a stock item.
 
I cleaned up the cable ends and the chassis ground bolt. Tested for continuity and resistance and it seems better.

However, the aborted charge problem has only gotten worse. It may be related to the weather, since we have been in a heat wave this week with temps over 90F for most of the day. Unless we charge at night when it is cool, it will now abort charge after only 10-20 minutes or so, which makes it very difficult to get usable range out of the car.

Last time I scanned, I did not see any codes related to the water pump or cooling system. But the heat related severity does have me wondering if something is up. It looks like that is a problem that other Leaf owners have had.
 
Resetting and reading the DTCs is the next step for sure, but I haven't done it yet. My partner and I work alternating schedules, so her and the car are gone most of the time when I am home with free time. It's made the diagnostic process a real pain!
 
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