2013 Leaf - Dead 12-Volt Battery every 2 Weeks

[Stanton]

Are you still getting them? When was the last one? I've not gotten any since around February. I didn't change anything on my car, and as best as I can tell they are still set up correctly in the car and in the web portal. They stopped about 1 month after the new version of the app came out (but the app shouldn't have anything to do with it).

I have always received them...except when I did the modem changeover. Since we know the backend/servers aren't down (or no one would get them), I suggest doing a "reset" of sorts on your CarWings account; that may not sound fun, but at this point you have nothing to lose.

[linhou1051]

I just bought a 2015 SL & have not upgraded the TCU and after reading this thread and others related to the topic, I probably won't.

Would having transmission of data turned off be enough to stop the drain? Does the TCU searching for a 2G network to transmit drain the 12v battery? Would I be better off just having the 2g TCU deactivated?

I really don't want to deal with a drained 12v battery, I just want to get in & drive.

Thanks.

[GerryAZ]

I just bought a 2015 SL & have not upgraded the TCU and after reading this thread and others related to the topic, I probably won't.

Would having transmission of data turned off be enough to stop the drain? Does the TCU searching for a 2G network to transmit drain the 12v battery? Would I be better off just having the 2g TCU deactivated?

I really don't want to deal with a drained 12v battery, I just want to get in & drive.

Thanks.

There should be no battery drain issue on a 2015 without the upgraded TCU. There is no need to deactivate the original TCU, but you can turn transmission of data off in the menus on the display unit. The upgrade is free for 2015 so you could wait a few months to see if Nissan fixes the problem and offers a revised upgrade.

I personally like the charge complete messages and remote access so I accept an occasional TCU problem. If I miss charge complete and plug in reminder messages, I know I need to pull the fuse or disconnect the battery briefly to reset the TCU before I leave the car parked for extended time. I have only needed to reset the TCU a few times since getting the upgrade in December 2016.

[baustin]

I have to do a fuse pull about once a month to reset the TCU, but other than that it works without issue.

When you say "works without issue", I've a question:

Are you getting text messages? My TCU, with the occasional fuse pull, works just fine for remote status, but I haven't gotten a text message (or app notification) like "charging complete" for a few months.

I do get the text message and email updates. I am able to use the app on my Samsung phone and AT&T Tablet to Check Status, Start Charging, Activate Climate Control, and set a Climate Control Timer Activation. Whenever the messages stop, or the response to the app stops, I do a 30 second fuse pull, accept the Data Sharing with Nissan again, and all is good for a few more weeks.

I did replace the original battery with a Bosch AGM battery last fall. That seems to have eliminated the low 12v issues that were causing more frequent fuse pulls. I do not leave the ELM unit connected to the OBD port. I only plug it in to take a reading once a month. The car is plugged in whenever it is not being driven. Especially now that it is getting warmer, I activate the climate control for 10 to 20 minutes before driving.

[Stanton]

I do not leave the ELM unit connected to the OBD port. I only plug it in to take a reading once a month. The car is plugged in whenever it is not being driven.

This action alone (bolded above) will result in a "drained" 12v battery, and has been well documented on this forum (maybe not this thread). It's amazing how much confusion surrounds the TCU/modem and 12v battery. There should be no issues in a MY 2015 Leaf with a 3G modem upgrade! Only the older MY's (like mine) have issues...but those are easily solved if you just listen to advice given by folks like @cwerdna and @GerryAZ

[jlv]

I did replace the original battery with a Bosch AGM battery last fall. That seems to have eliminated the low 12v issues that were causing more frequent fuse pulls. I do not leave the ELM unit connected to the OBD port. I only plug it in to take a reading once a month. The car is plugged in whenever it is not being driven.

Replacing the battery won't eliminate the 12V battery problems - if you have the TCU lockup issue, it just starts the drain on the new battery. Given time, the new battery will start to have problems. That's been reported in this thread early on.

I have left an ELM plugged into the OBDII port almost 4 years without ever having an issue with the 12V. Some people *have* had issues, but I think it is specific to the particular brand/model of ELM being used. I even left the ELM in while I was out of the country for 2 weeks without a problem.

As reported about, leaving the car plugged in when not being driven *can* cause 12V problems. You really don't want to do that.

[lorenfb]

Replacing the battery won't eliminate the 12V battery problems - if you have the TCU lockup issue, it just starts the drain on the new battery. Given time, the new battery will start to have problems. That's been reported in this thread early on.

It's as simple as that. For minimum probability of battery problems, avoid the using the TCU function!

[baustin]

I did replace the original battery with a Bosch AGM battery last fall. That seems to have eliminated the low 12v issues that were causing more frequent fuse pulls. I do not leave the ELM unit connected to the OBD port. I only plug it in to take a reading once a month. The car is plugged in whenever it is not being driven.

Replacing the battery won't eliminate the 12V battery problems - if you have the TCU lockup issue, it just starts the drain on the new battery. Given time, the new battery will start to have problems. That's been reported in this thread early on.

I have left an ELM plugged into the OBDII port almost 4 years without ever having an issue with the 12V. Some people *have* had issues, but I think it is specific to the particular brand/model of ELM being used. I even left the ELM in while I was out of the country for 2 weeks without a problem.

As reported about, leaving the car plugged in when not being driven *can* cause 12V problems. You really don't want to do that.

Leaving the car plugged in may cause 12v drain issues for some cars. It has never been a problem for me.

When I bought the car, the 12v battery was very low on fluid. It took a half gallon of distilled water to top off all the cells. I got another 2.5 years out of it before replacing it with the AGM battery.

[baustin]

I do not leave the ELM unit connected to the OBD port. I only plug it in to take a reading once a month. The car is plugged in whenever it is not being driven.

This action alone (bolded above) will result in a "drained" 12v battery, and has been well documented on this forum (maybe not this thread). It's amazing how much confusion surrounds the TCU/modem and 12v battery. There should be no issues in a MY 2015 Leaf with a 3G modem upgrade! Only the older MY's (like mine) have issues...but those are easily solved if you just listen to advice given by folks like @cwerdna and @GerryAZ

You are adding to the confusion by spreading the above information as if it is the gospel truth. Leaving the car plugged in MAY cause 12v drain issues for some cars, it is not an issue for all the LEAF vehicles produced. I have owned my LEAF for over three years. It is always plugged in when not being driven. This has never resulted in a drained or dead 12v battery.

I did have issues when I first bought the car, but that was due to low fluid levels in the 12V battery. After using a half gallon of distilled water to top off all the cells, and charging the battery, those problems went away. I used that original battery for another 2.5 years before replacing it with the AGM battery.

There are issues with the 3G TCU. They are not consistent for everyone. I get occasional lockups that require a fuse pull, but I have never had 12v drain or dead battery issues due to the upgraded TCU.

[GerryAZ]

2011 and 2012 Leafs WILL drain the 12-volt battery if left plugged in and not actively charging for extended time. Later models MAY drain the 12-volt battery depending upon conditions. My 2015 draws more residual current from the 12-volt battery when plugged in and not charging than it does when not plugged in.