12-v battery charge warning light

[minecraft00z]

Hello everyone.

I'm new to electric cars and cars in general. Recently, by the virtue of chance, I became the owner of a 2015, 24 kW/h Leaf.
Unfortunately, after the purchase, while I was busy with all the paperwork and other bureaucratic issues, it sat in a garage unplugged for a month or so.

Once I finally carved out some time for my new purchase, I happily jumped in, pushed the "Power" button, and was greeted with the "The key is not recognized" message. The keyfob battery was dead, so I replaced it, tried again - it turned on successfully.

Then I noticed that the red 12-v battery charge warning light was on. Since the car still had its original 12-v battery I figured that it's probably time to replace it too. So I went ahead and bought a fresh new 12-v battery and swapped it with the old one.

After that, the car was fully functional and ready to be driven except that the 12-v battery indicator still was showing up when the car was in the "ON" mode. When I switched to the "Ready to DRIVE" mode it disappeared, but still was illuminating when in the "ON" mode.
I measured the voltage on the 12-v battery - it read around 12.63-12.64V which seems like within the normal range.

THE PROBLEM (TLDR)
I can't figure out why that 12-v battery charge warning light illuminates only in "ON" position. The 12-v battery is good, the main traction battery was charged up to 100%, the keyfob is fine, what can be causing that?

Maybe the car still thinks that it has the old battery and that error is just "stuck"? How do I "clear" it, if so?
If you have any ideas, please help me out here, I'm completely new to this and have a lot to learn.
Thanks!

 

[PrairieLEAF]

You might try disconnecting the 12 V battery for a few minutes and then reconnecting it. While you're there, maybe clean the battery posts and the insides of the battery post connectors.

***edit...didn't read that it was in on mode and not ready mode. Huh, now I want to see what this car does.

 

[WetEV]

In "ON" mode, the 12V battery is not charged from the HV battery. Generally, don't use "ON" mode, and if you do remember to limit the time you use it for. Heat and AC will not work as well, only fan.

"ReadyToDRive" is just fine for most situations where the car is parked and accessories are being used, like radio, climate control, etc.

 

[Nubo]

The fact that the light goes out in READY mode seems to rule out a problem with the DC-DC converter.
How much time (if any) have you spent driving the car since you replaced the battery? It may be that the VCM still thinks it needs charging. And yes that's possible even if you're measuring 12.6V under no-load. I'd give it an hour or so of driving to see if this issue goes away on its own. That, or remove the battery and place on external charger until 100% charge.

If the problem remains then examining and resetting DTCs with LEAF Spy may be worth a try.

 

[GerryAZ]

Since the 12V battery is not charged by the DC-DC converter when in "ON" mode, it is normal for the charge warning light to be illuminated. As long as the warning light does not glow in "Ready" mode, the DC-DC converter is fine.

 

[minecraft00z]

Ok, so following your advice I tried disconnecting the 12-V battery for a few minutes, charging it up to 12.74V with an external smart charger, driving the car for about 2 hours straight, - the warning still shows up when in "ON" mode.

As GerryAZ mentioned, maybe it's not a problem at all and I'm here just being silly?

I guess I'll have to find another Leaf owner and ask if they have the same battery warning in "ON" mode as mine. Only where could I find someone with the Leaf? Maybe on the forum that's called "mynissanleaf" ?

Seriously, guys, I'd be really grateful if someone here could check this warning on their Leaf in "ON" mode.

If this is intended behavior, then I'll be able to continue learning to drive properly and not constantly thinking that I have some kind of malfunction in the 12-V battery-related system.

Have a nice day!

P.S. What if the purpose on this mysterious "ON" mode anyway, if everything that works in it just drains the 12-V battery? Need to dig in more on this one.

 

[LeftieBiker]

The jury is "out" on why we have "on" mode, and no, it isn't normal to have the 12 volt system warning light lit while driving.

When you replaced the 12 volt battery, did you fully charge it before installing it? When you measured the rest voltage, was the car Off for at least 20 minutes?

 

[minecraft00z]

The jury is "out" on why we have "on" mode, and no, it isn't normal to have the 12 volt system warning light lit while driving.

When you replaced the 12 volt battery, did you fully charge it before installing it? When you measured the rest voltage, was the car Off for at least 20 minutes?

It's not lit while driving, only when in "ON" mode. Today I disconnected the battery and charged it to 100% with the external charger, it took about an hour or so. So, the car was off at least an hour.

The warning still shows up in "ON" mode though.

 

[LeftieBiker]

Sorry about that - I'm tired and on my way to bed. It likely IS normal to have that light lit when in On mode and not driving - it's a warning to not use it for too long, I imagine.

 

[minecraft00z]

Sorry about that - I'm tired and on my way to bed. It likely IS normal to have that light lit when in On mode and not driving - it's a warning to not use it for too long, I imagine.

No worries, I just want to know for sure that it's ok to have this battery warning in "ON" mode. If other Leaf owners could confirm this for me, this would've been great!

 

[Nubo]

Sorry about that - I'm tired and on my way to bed. It likely IS normal to have that light lit when in On mode and not driving - it's a warning to not use it for too long, I imagine.

Yep. When I checked my car I confused "on mode" with "park". Lol, I always think of "on mode" as "accessory mode" and it didn't click with me. As per the owners manual the 12 volt charge warning is supposed to illuminate during "on mode".

 

[PrairieLEAF]

Yes, there's probably some ambiguity about the modes.

I think "accessory mode" is the proper name for the mode being discussed in this thread (pressing the power button without the brake pedal).

Accessory mode can be used to operate the 12 V systems for short periods (audio, seat heaters, power ports) without the high-voltage system being activated. Extensive or frequent use of accessory mode is discouraged, as it discharges the small 12 V battery, which the car may not properly recharge.

What I consider "On mode" is when the car is plugged into a charger and the power button is pushed with the brake pedal. In this mode, all systems except propulsion can be used (climate, audio, seat heaters, etc.) without drawing down the 12 V battery.

I'm heading out soon to check for the battery light in accessory mode.

 

[goldbrick]

^ That makes a lot of sense to me as well but I think Nissan and the owner's manual specifically have an 'ON' mode already. It may be poorly named but that genie is out of the bottle.

 

[LurchOR]

With my 2015 SL, the 12V battery warning light is present when car is in the "On" mode and goes out when in the "Ready" mode. Never paid any attention to that before, just kinda assumed it was a POST sort of thing.

 

[PrairieLEAF]

I was wrong--there is an on mode with two button presses and no brake pedal, and yes the battery light stays on in that mode. Not sure what that mode could be for.

 

[minecraft00z]

Thanks, everyone for your response!
I'm glad that we sorted this out. Now I can safely continue learning how to drive and getting to know my new electric companion better.
I'm really happy that there is such a supportive community.