2013 Leaf - Dead 12-Volt Battery every 2 Weeks

[cwerdna]

^^^
I don't ever leave my phone in my car if I'm going to be away for more than a few minutes. But yes, sometimes I accidentally leave LeafSpy running, while not at my car, but it doesn't seem like there's enough BT range between my garage at home and where my phone is. I suppose it's possible it's an intermittent connection, which could cause a drain.

My Leaf's driven virtually every weekday for at least 25 to 30 miles. On weekends, it's all over the map, sometimes not much. But yes, in terms of time, each session isn't that long.

[ElectricEddy]

Trickle charging right now, 24H should get me about 2 weeks as usual.. Tops at 12.85V and in another 2 weeks I will re- charge it when it sits at about 12.2V, not real effective engineering. When this becomes a weekly cycle, I will shell out for a better battery.

[dhanson865]

It seems goofy that the car won't automatically start charging the 12 volt from the HV battery if it gets below a certain voltage.

It only checks every x hours and if it goes low before it checks, tough luck.

To force it to check you have to turn the car on (ready mode) like you are going to drive. At that point it'll start charging from the main pack to the 12v.

If you really want it to charge faster you have to turn on your windshield wipers once every 2 minutes or somesuch. (turn them on for one wipe, turn them off watch the leafspy voltage for the 12v until it drops again, then start the cycle over).

It is pretty stupid that a multi thousand dollar device has worse battery management than my cell phone.

[Nubo]

...It seems goofy that the car won't automatically start charging the 12 volt from the HV battery if it gets below a certain voltage.

Or, at least give the driver an option to "jump charge" the 12V with the DC/DC converter. The equipment is right there in the car; why strand someone?

[RegGuheert]

Or, at least give the driver an option to "jump charge" the 12V with the DC/DC converter. The equipment is right there in the car; why strand someone?

It's possible that at 10 V or below the car is not able to communicate sufficiently over the CANBus to make that happen.

Edit: OTOH, I cannot think of a scenario in which you would want to charge the 12-V battery to below 12.7 V.

OTOOH, if there is a cell shorted, then perhaps the car detected that and quit charging rather than cooking the other five cells.

[TimLee]

... Or, at least give the driver an option to "jump charge" the 12V with the DC/DC converter. The equipment is right there in the car; why strand someone?

Hard to fathom what the LEAF engineers were thinking on quite a few things.

But they probably were focused on the LEAF operation could be unsafe if 12V voltage is too low.

But it does seem like they could have allowed what you are suggesting IF emergency brake is set AND vehicle movement were disabled until the LEAF has determined 12V system is now recharged.
Of course with a very dead 12V system, they might not trust indications of the emergency brake being set?
That is probably why they thought leaving it dead in the water was a safer choice.

As many have observed the LEAF does a poor job of monitoring the 12V system.
It can be downright dangerous if it does start and the 12V voltage sags badly.
I observed that myself when 12V had apparently lost a cell.
The braking was absolutely non-existant and that was in a level parallel parking spot.
Only thing that stopped it moving was putting it in Park.
On the highway it would have been a total disaster.

[cwerdna]

After trying to charge my 12 volt overnight w/my Tecmate Optimate 4, it's hit the voltage retention test stage and it's failing. I've not had a legitimate failure before on my Leaf or Prius (e.g. opening a door will drop the voltage and cause a "failure", which isn't a real failure).

From the manual, basically, it means the battery was unable to maintain voltage during a 30 minute period while not being charged. So, either the battery's not holding a charge or there's a drain somewhere.

I was digging on Nissanhelp and I wonder if some of these dead 12 volt battery problems are addressed via TSB NTB14-083

2013 - 2014 LEAF; VEHICLE 12VDC CHARGING SYSTEM STOPS WITH DTC P0A94 AND/OR B2902 PRESENT.

This bulletin supersedes NTB14-061 and has had DTC B2902 added to the title and to the If You Confirm section. No other changes have been made to the body of the bulletin. Please discard all previous versions.

APPLIED VEHICLE VIN AND DATE: 2013 LEAF (ZE0) All
2014 LEAF (ZE0) Built before 1N4AZ0CP(*)EC 332878 / Jan 30, 2014

IF YOU CONFIRM
The EV warning light is ON.
And
CHARGER / PD MODULE (Power Delivery Module or PDM) DTC P0A94 (DC/DC Converter) and/or B2902 (PDM Memory Error) are stored.
And
The vehicle’s current CHARGER / PD MODULE software version is in “Table A” on page 9.

Refer to step 20 on page 9 in the SERVICE PROCEDURE to check current CHARGER / PD MODULE software version.
ACTION
Reprogram the CHARGER / PD MODULE using the Service Procedure and CONSULT-III plus (C-III plus) starting on the next page....

You can find the TSB at http://x.nissanhelp.com/forums/Knowledgebase/links/783/. A free account lets you download 2 PDFs/day.

[RegGuheert]

After trying to charge my 12 volt overnight w/my Tecmate Optimate 4, it's hit the voltage retention test stage and it's failing. I've not had a legitimate failure before on my Leaf or Prius (e.g. opening a door will drop the voltage and cause a "failure", which isn't a real failure).

From the manual, basically, it means the battery was unable to maintain voltage during a 30 minute period while not being charged. So, either the battery's not holding a charge or there's a drain somewhere.

Were you charging with the battery disconnected from the LEAF? If so, did you happen to record the voltage during the 30-minute rest?

Basically if it immediately drops into the 10 V range, then you have a shorted cell. If it slowly drops into the 12 V range, then you have a fully sulfated battery. A sulfated battery is what the LEAF's charging algorithm tends to cause, but shorted cells can happen as latent failures due to manufacturing defects (plus other possible reasons for shorts, but I doubt the LEAF has those).

[cwerdna]

After trying to charge my 12 volt overnight w/my Tecmate Optimate 4, it's hit the voltage retention test stage and it's failing. I've not had a legitimate failure before on my Leaf or Prius (e.g. opening a door will drop the voltage and cause a "failure", which isn't a real failure).

From the manual, basically, it means the battery was unable to maintain voltage during a 30 minute period while not being charged. So, either the battery's not holding a charge or there's a drain somewhere.

Were you charging with the battery disconnected from the LEAF? If so, did you happen to record the voltage during the 30-minute rest?

Basically if it immediately drops into the 10 V range, then you have a shorted cell. If it slowly drops into the 12 V range, then you have a fully sulfated battery. A sulfated battery is what the LEAF's charging algorithm tends to cause, but shorted cells can happen as latent failures due to manufacturing defects (plus other possible reasons for shorts, but I doubt the LEAF has those).

No, unfortunately not. It was connected to the car still.

I disconnected the charger and measured the voltage. It was in the 11.3x volt (or was it 11.5x?) range. Anyhow, it was insufficient to put the car into ready.

It's possible my Optimate 4 is charging too slow vs. the battery's capacity since it will only go up to 0.8 amps. However, it's not supposed to enter its voltage retention test phase until it thinks it's w/the charge phase is done (limited to 48 hours). It wasn't charging anywhere near 48 hours yet and decided to go to the voltage retention test.

I had to use my jump pack to take to the car to the dealer. Since it was late in the day, I'm leaving it overnight. I suspect they'll be unable to put it into READY mode in the morning.

Unrelated, two kill 2 birds w/1 stone, I had them apply NTB14-017 (touchy brakes and low speed TSB), since this used Leaf clearly didn't have it applied.

[BrockWI]

I could just be a bad 12v battery, which would be an easier fix