It's that 12V battery again.

Faults and Technical chat for the Nissan Ariya
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PeteTranter'sSister
Posts: 12
Joined: Wed Aug 30, 2023 5:04 pm

Post by PeteTranter'sSister »

You may recall my long posts over a year ago about my 12V battery discharging when on a timed charge through my ProjectEV home charger and the mega hassle getting into the boot (trunk) to access the battery to recharge it. It turned out that my Ariya isn't 'fully compatible' with the ProjectEV home charger, whatever that means.

Tuesday night we had 4" of snow in Nottingham. Not excessively cold, down to about -2C. On trying to start at 8am the 12V battery was almost flat and I couldn't boot the software so it could self charge off the traction battery, even with a lithium battery pack. I had the joy of breaking into the frozen boot (trunk) to access the 12V battery and yet again put it on charge using my old battery charger, for several hours until it held enough charge to boot up the software and then it self charged.

Absolutely no warning signs and no indication whatsoever as to why the 12V battery was flat. No idea. Possibly some sort of sensor overload due to the weight of the snow or the cold weather, who knows. Completely unacceptable.

I'm also holding a raffle as to when the electric seat heater part from Japan will arrive. It's been 11 months now.

Fantastic car to drive but I've had enough of it now, it is far, far too complicated to own and operate, the software is loaded with bugs. No support from Nissan whatsoever. It will be sold in January 2025, just after the 2-year warranty subsides. Hopefully, they will have repaired my heated seat by then.....

PTS

Cosmyc
Posts: 385
Joined: Fri Jul 08, 2022 6:08 am

Post by Cosmyc »

I'm definitely replacing my 12V battery with an AGM one when the current one fails.
Xuana
Posts: 8
Joined: Mon Nov 25, 2024 4:18 pm

Post by Xuana »

That sounds brutal, especially with no warning signs. I’ve had my fair share of battery issues in the cold, but nothing like breaking into a frozen trunk just to get the car going—can’t imagine how frustrating that is. The lack of support from Nissan makes it even worse. I get the appeal of EVs, but all those software bugs and little things piling up would make anyone think twice. Hopefully, the seat heater arrives before you sell it, but it sounds like you’ve already made up your mind, and I can’t blame you.
GraceCourt
Posts: 20
Joined: Mon Sep 30, 2024 11:57 am

Post by GraceCourt »

Hmm. I was puzzled when our local Nissan Service Centre recently carried out the 1-year service on our Ariya - bought in October 2023 - and advised that they'd replaced the 12V battery under warranty... so much so, that I checked to make sure that they really had.

Maybe there's a more subtle problem with the auto-charging of this? Replacing a 1-year-old battery seems to indicate that something's not right?
Nissan Ariya 178kW Evolve 87kWh (Oct 2023) - Burgundy & Pearl Black
Cosmyc
Posts: 385
Joined: Fri Jul 08, 2022 6:08 am

Post by Cosmyc »

GraceCourt wrote: Mon Dec 02, 2024 8:00 pm Hmm. I was puzzled when our local Nissan Service Centre recently carried out the 1-year service on our Ariya - bought in October 2023 - and advised that they'd replaced the 12V battery under warranty... so much so, that I checked to make sure that they really had.

Maybe there's a more subtle problem with the auto-charging of this? Replacing a 1-year-old battery seems to indicate that something's not right?
Like a deeply discharge during shipping and storage for a lot of months? Seems about right.
Milkfloat
Posts: 169
Joined: Wed May 25, 2022 1:52 pm

Post by Milkfloat »

There is something very strange about how the 12 volt battery is managed in the Ariya. My wife's PHEV is superficially managed in the same way in that it is supplied with a potential well in excess of 14 volts when charging. Drive it for 20 minutes and then leave it for an hour and the voltage will measure well north of 12.5 volts. Do the same in the Ariya and the battery voltage will be well under 12 volts. So, one is charged to 90% plus and the other to 40% at best. It has never given me a problem but I'm sure this low voltage operating system pertains to the issues that people have. Does anyone have an explanation as I haven't heard a credible reason yet?
Cosmyc
Posts: 385
Joined: Fri Jul 08, 2022 6:08 am

Post by Cosmyc »

The Ariya has a DC-DC converter saving energy function, in which after some minutes of a driving session the converter stops providing a fixed boost of ~15V to the 12V system and then works with a lower voltage for the rest of the driving session, this target voltage is variable depending on instantaneous consumption on given conditions, so when the driving session ends the 12V battery doesn't have to be fully charged necessarily.

The unit that judges this is the IPDM with voltage, current and temperature of 12V battery measurement, then tells VCM and then VCM tells to DC-DC converter, which generates variable voltage when the boost period finishes, that is between 13V-15V.

When a problem in the "saving energy feature" is detected the system enters on fail-safe mode which provides fixed 14V like a conventional old school alternator.

My opinion on this is that this is a great feature... if you have a good AGM battery that behaves well at low state of charge, if you have a conventional (not even EFB) battery that is well used on its life cycle and sits at half state of charge it can generate some problems, and since this is true for all factory 12V battery on Ariya's then... yeah.

I'm having no problems yet.
Milkfloat
Posts: 169
Joined: Wed May 25, 2022 1:52 pm

Post by Milkfloat »

Thanks for the additional information as to how it is controlled Cosmyc. Perhaps Nissan has a different understanding of lead/acid battery performance than you, I and, indeed, other auto manufacturers.
Xuana
Posts: 8
Joined: Mon Nov 25, 2024 4:18 pm

Post by Xuana »

The 12V battery issue is seriously concerning, that shouldn't be happening. And the heated seat saga? Unbelievable! I'd be furious. Seriously considering selling it sounds like a perfectly reasonable reaction.
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