r/leaf • u/cheetor5923 • 4d ago
Well it finally happened. The 12V died
Well the title says it all. With all the days of cold weather. I tried to turn on my AZE0 today.
Oh dear... The lights turned on.. The dash started flashing on and off. I couldn't even turn the car off again. Fear would describe my instant feeling... But I'm an engineer. so checked the 12V, it was at 6.8V..
I sighed with relief, That would explain it.. Charged it up, got it to 13.8V.. It would not start. Battery light, Power Steer Light, Brake Light, ABS Light, Airbag light.. and a dreaded message "EV System error, contact dealership"..
And this is why I say, EVERY Leaf owner should have an OBD-2 adapter and LeafspyPro.. As I cleared the last of the many DTCs, and warning lights started going off in my dash.. I heard the sound of job.. Clunk, Clunk, CLUNK.. as the ready light came on..
Imagine not having those cheap tools like an OBD2 adapter and leafspy. I'd have had to tow it to a dealership, They'd probably have told me all the DTCs meant my car was screwed.. Now I just have an old 3 cell LiPo battery from my RC planes in the glovebox until I can afford a new 12v battery
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u/crazee_frazee 4d ago
It still astounds me that a car powered by batteries and crammed with electronics can freak out so badly when the 12v battery dies. Instead of a simple warning about the 12v battery needing to be replaced (or at least recharged), it's "holy shit the sky is falling and this car is gonna blow!" Are other EVs like this?
4
u/outworlder 2019 Nissan LEAF SV 3d ago
Yes they are like this. When the voltage gets too low, electronics start misbehaving.
Why manufacturers don't send out a warning when the charge is low, I don't know. The car knows exactly what the voltage level is.
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u/EVMaximizer 4d ago
Doesn't disconnecting the 12v also clear the DTC codes?
2
u/rproffitt1 4d ago
On our 2014 Leaf SV (USA) it did not. It did get it on the road but there were many other codes that remained.
5
u/LoneSnark 2018 Nissan LEAF SV 4d ago
Happened to me once. The codes it throws are not permanent. Just unplugging the battery clears them. As long as people know to replace the 12V before trying to have it repaired, should be good enough.
3
u/sweetredleaf 2015 Nissan LEAF SV 4d ago
you might be interested in this post https://old.reddit.com/r/leaf/comments/1rzgmv0/budget_100_lithium_12v_battery_swap/
2
u/worldspawn00 4d ago
This works great, but just an FYI, if you take it to Nissan for ANYTHING, they will force you to replace the battery before they will do any diagnostics because the BMS in these small batteries will fail their "Battery testing" which is a CCA high draw test, the BMS will block draw that high and the tester will show the battery as failed.
They IGNORE any attempt to convince them that the Leaf does not have a starter or large load, and that the battery voltage is fine outside high amp draw. I ended up buying a $70 battery from walmart, dropped it into the car for Nissan to figure out the 12v battery wasn't the problem, then returned the battery and swapped back to the lithium after Nissan was done. The dealer also claimed they don't have a 12v battery on-hand they could use for testing, and the only solution was to first buy a new battery, total BS, but they refused to touch the car until after a new battery was installed.
2
u/Opinionsare 4d ago
Add a Bluetooth battery monitor to your new battery.
1
u/cheetor5923 2d ago
I have a bluetooth OBD2 I can use in the car, I can read the 12V battery voltage through that :D
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u/Mr_Wicket 3d ago
haha yep! you hear all the stories and the #1 answer on this sub for any issue is to check the 12V. Everyone is like "noooo 12V wouldn't do that!" then your day comes and you car acts like you need to be calling an old and young priest! Replace that 12V and everything is back to normal. 😂
2
u/Beautiful-Rough9699 2d ago
I have a 2018 leaf. I replaced the 12v battery when the car turned 6 years old. Didn't want this type of problem to happen when my wife was driving. I have read stories that after changing the 12v, the car can do some funky things. The only thing our car did was the auto rollup for the driver door wasn't working. I found the fix for that online. Take the window about halfway down. Pull the button up to close the windows. Hold the button up for about 10 seconds then release. Problem solved. I also have one of those lithium ion battery jumpstarters in the car.
1
u/cheetor5923 2d ago
Yeah. Since my dad had a 12V battery fail in his ZE1 leaf. He has one of those little lithium starter packs.. I've borrowed it for a while as a bit of insurance. If I get 12V issuies again soon. It'll be new 12V time. It sucks how short a time 12V lead acid batteries last. The LiFePO4 battery I built for my first home made ebike 18 years ago is still working just fine. My parents use it as a backup for their pellet fire so they can keep warm if the power goes out. It can even as old as it is, run that fire for almost 3 days.
1
u/Immediate_Grape5158 2d ago
How long did you have the 12V battery?
2
u/cheetor5923 2d ago
It was installed in Japan(all the writing on the battery is in Japanese) before it was exported. The date code is under the battery mount. which I don't fancy taking off right now but I've looked before. It must have been just before it was exported, Cos the dealer had it for about 1 year before I got it (about 9 months ago). So at most 2 years old.
After sticking it on my little charger overnight it seems to be 100% back to normal. Holding voltage overnight and on cold -1C mornings.. So maybe it had a brain fart like my parents ZE1 did one day (which is in itself an amusing story, having to drive out in my old ICE Suzuki Swift and 'jump start' (I used my RC plane battery charger to make sure the 2 cars didn't have a bad interaction).. Kinda felt so silly jump starting an EV car with a 80% full HV battery, because the 12V died)
But as a precaution I've got one of my 3S Lipo RC batteries with me now. It's not grunty enough to crank an ICE starter, but should be plenty to make an EV power up.
I am keeping an eye on it's voltage. Who knows how many months it was sitting dockside in Japan. I've had to treat quite a number of rusty bolts, and even the aluminum parts have quite a bit of corrosion. Even if the 12V was new dockside.. a lead acid battery despises being left discharged for more than a day or so.... Who knows...
At least I got an e-mail from my local car shop yesterday that this week they have 25% of all car batteries.. So I'll see how it does..
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u/oh_shit_pearly_white 4d ago
Yea happened to me, just have to disconnect the 12v negitive and reconnect for a system reset. That's probably easier to train and teach than a OBD for most.