It's that pesky 12V battery yet again...

[karltk1]

Ah, ok. That is interesting. The last time I washed the car it died. But the alarm kept going off this time. Several times in fact. Even if I had the key with me or not. That's happened 3 times all in all. Maybe all the other electrical gremlins are tied up in this also. Can be a sign of a faulty BCM. No expert though, especially on electric cars. Is the BMS limited to how much it will keep the 12v battery alive?
Or does it get confused. I have had DC to DC fault codes a few times to, plus charging fault codes. Not sure if they are related. Fingers crossed this solves the problem. Could explain other users having 12 v issues to. The last fault was the car tried to lock after walking away, but folded the mirrors and flashed the lights but gave a very odd long ISH tone? It also didn't lock either. This could of been happening ever since I had the car. BCM faults have been common but ignored.

[Cosmyc]

I can look those fault codes on the service manual for you, maybe I could identify something in common.

In READY position the car always charges the 12V battery with variable voltage and current as needed, if the DC-DC intelligent management fails it will work on safe-mode on which it charges the battery permanently with 14V during normal driving, like a traditional alternator.

In OFF position (or also called deep sleep) the charging algorithm is designed to top up always the 12V battery every 24 hours since last drive session for 10 minutes on LHD Ariya's and 7 minutes for RHD, as long as there is at least 12% or more charge on the high voltage battery and the hood is closed, this top up is a fixed time, independent of 12V battery voltage.

When the car is in the ON position (not Auto ACC, OFF or READY) the car checks continuously the 12V battery consumption and voltage, and if needed it will start the DC-DC converter indefinitely as long as the user wants the car to be in the ON position, turning on the climate control will always trigger this inmediately, as the car is programmed to never use 12V battery with the climate turned on.

Also the car checks every 4 hours the 12V battery voltage looking for "emergency charge need" when seeing it below 11V or so, this emergency charge lasts 2 hours and then the function rests for 1 hour and repeats this process if the condition persists.

I will leave here some diagrams and info for you, in case you find it helpful.

System Description.pdf

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System Description2.pdf

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System Description3.pdf

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System Description4.pdf

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System Description5.pdf

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[Milkfloat]

Cosmyc, thanks very much for posting the above information that gives insight as to what is happening. Do you also know the maximum rating of the charger so that we may understand the amount of energy that the 12 volt battery could receive in its RHD 7 minute charge period? The logic seems slightly perverse to me, I have to say. Charging to a given voltage with time limits would make more sense with a daily voltage check to see if any charging were necessary. Have you unearthed any rationale for different LHD & RHD charge duration? Is it due to DC to DC module location or rating?

[ashleycarr]

I haven't experienced anything like this, I have a battery monitor but it always reads circa 14v. I wonder if it has anything to do with how you are charging. I always set my charge point to initiate the charge. Works every time.

[karltk1]

I can look those fault codes on the service manual for you, maybe I could identify something in common.

In READY position the car always charges the 12V battery with variable voltage and current as needed, if the DC-DC intelligent management fails it will work on safe-mode on which it charges the battery permanently with 14V during normal driving, like a traditional alternator.

In OFF position (or also called deep sleep) the charging algorithm is designed to top up always the 12V battery every 24 hours since last drive session for 10 minutes on LHD Ariya's and 7 minutes for RHD, as long as there is at least 12% or more charge on the high voltage battery and the hood is closed, this top up is a fixed time, independent of 12V battery voltage.

When the car is in the ON position (not Auto ACC, OFF or READY) the car checks continuously the 12V battery consumption and voltage, and if needed it will start the DC-DC converter indefinitely as long as the user wants the car to be in the ON position, turning on the climate control will always trigger this inmediately, as the car is programmed to never use 12V battery with the climate turned on.

Also the car checks every 4 hours the 12V battery voltage looking for "emergency charge need" when seeing it below 11V or so, this emergency charge lasts 2 hours and then the function rests for 1 hour and repeats this process if the condition persists.

I will leave here some diagrams and info for you, in case you find it helpful.

System Description.pdfSystem Description2.pdfSystem Description3.pdfSystem Description4.pdfSystem Description5.pdf

Thanks for the info, will dig out the mystery codes at some point. The system sounds like it covers things well enough as you would think it would. But waiting for the battery to drop below 11 v can't be good for battery?

So something in the charge procedure is clearly messed up in my car? I am now more intrigued as to why after washing the car this seems to kill the battery on occasion. Could be coincidence I suppose.

The nissan leaf I have as a courtesy car work very well. Oh and one pedal driving. First time I have fully experienced it. Wish the Aryia had that.

Cheers again for your educated invites.

[Cosmyc]

Cosmyc, thanks very much for posting the above information that gives insight as to what is happening. Do you also know the maximum rating of the charger so that we may understand the amount of energy that the 12 volt battery could receive in its RHD 7 minute charge period? The logic seems slightly perverse to me, I have to say. Charging to a given voltage with time limits would make more sense with a daily voltage check to see if any charging were necessary. Have you unearthed any rationale for different LHD & RHD charge duration? Is it due to DC to DC module location or rating?

The DC-DC converter is capable of 11.7V to 15.4V at 160A (250A for Ariya's with ProPilot 2.0 since it has to charge two on board 12V batteries) which is massive, 14V at 160A is more than 2kW of power, basically the 12V battery is physically the limiting factor here on charging speed terms, it will be charged at full speed. Taking into account that the Ariya has a 50Ah battery, that's around 0,6kWh capacity, that means the car can charge that battery from flat to full with that DC-DC power in 20 minutes, assuming that the battery can accept that kind of speed. So seeing the charge logic the car has and this calc, it will keep up a 12V battery that discharges up to one third of its full charge each 24 hours, in other words the system doesn't expect the 12V battery to deplete fully by itself in less than 3 days which is reasonable, otherwise that would be a clear abnormal consumption, imagine a regular petrol car that depletes its battery in 3 days, and has no ability to charge it while the engine is stopped on that timeframe, crazy.

DC-DC converter is always located on motor room, no explanation on service manual why the difference on less time for RHD or more time for LHD on that matter, I would say that since 12V battery is in motor room on LHD Ariya's like mine it could "suffer" a bit more due to temperature there and 3 extra minutes are added? not sure why is like that honestly

No issues with my 12V battery on my Ariya so far, in fact it has been acting wonderfully in that regard.

[karltk1]

Where is the second 12v battery for pro pilot 2 cars?

[Cosmyc]

Where is the second 12v battery for pro pilot 2 cars?

It's under rear seats, it's a 12V lithium one, with integrated controller board and relay.

[karltk1]

If only they put a lithium battery in the boot to. Might be able to handle the power requirements better.

[PeteTranter'sSister]

It turns out that my Ariya is not 'compatible' with my ProjectEV home charger. So I have to set the charger to charge overnight, and not the car. Sorted then, but it's still unacceptable that there is no 12V battery monitor or warning with the car, it can go flat at any time and I am none the wiser. So the replacement 12V battery was likely not necessary.

Steering wheel changed, alarm sorted, but the driver's heated seat elements have still not arrived from Japan, after 6 months, so they couldn't repair the seat. Apart from the random lumbar support movement, random weird software glitches and the occasional change from mph to kmh, the car is now behaving.