Nubo
Well-known member
lorenfb said:
You have to remove one of the terminals first. Why not choose the one that reduces risk? In the rare case that someone can't identify the terminals they're no worse off for the recommendation.
DIY 12v Battery Change
- Thread starter NewcastleFalcon
- Start date
Help Support My Nissan Leaf Forum:
You have to remove one of the terminals first. Why not choose the one that reduces risk? In the rare case that someone can't identify the terminals they're no worse off for the recommendation.
powersurge
Well-known member
This has become a circus.....
All you people arguing whether to remove a + or a - first !!!!!
Get a grip and move on!!! Looks like too many people do not have enough to do during National Lock Down Days...
This is why I often question whether to leave any posts on this site or not.
My Prediction: Someone will attack me for this post of "sanity"...
All you people arguing whether to remove a + or a - first !!!!!
Get a grip and move on!!! Looks like too many people do not have enough to do during National Lock Down Days...
This is why I often question whether to leave any posts on this site or not.
My Prediction: Someone will attack me for this post of "sanity"...
Are you asking us to vote...?
powersurge said:
People are arguing because there's a safety issue involved with the order of the terminals and the OP is a newbie asking for advice. Warning an inexperienced person of a potential safety issue is something that, reasonably, kind people take seriously--especially if the original instructions posted by the newbie are unsafe.
NewcastleFalcon
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Thanks for the replies.
The procedures as reported in my post are straight from the horses mouth of the Nissan Leaf Service and Repair Manual. The procedure is straightforward and I will be following it.
My concern was to get some practical info from others of their experience of the potential effects of the disconnection, albeit a very brief disconnection, when swaping the old battery for a new one. So far no real scare story has emerged, regarding the list of items mentioned in the manual at PG86 requiring "special repair requirements" when removing 12V battery Negative terminal. My Nissan Leaf has the heat pump so I just pulled out the elements relating to this in the Heater/Air conditioning control system section below.
Any further contributions welcome.
To recap.
REgards Neil
The procedures as reported in my post are straight from the horses mouth of the Nissan Leaf Service and Repair Manual. The procedure is straightforward and I will be following it.
My concern was to get some practical info from others of their experience of the potential effects of the disconnection, albeit a very brief disconnection, when swaping the old battery for a new one. So far no real scare story has emerged, regarding the list of items mentioned in the manual at PG86 requiring "special repair requirements" when removing 12V battery Negative terminal. My Nissan Leaf has the heat pump so I just pulled out the elements relating to this in the Heater/Air conditioning control system section below.
Any further contributions welcome.
To recap.
NewcastleFalcon said:
REgards Neil
powersurge said:
Nobody will attack you unless you say something so eminently stupid that it puts someone else in danger of damaging their vehicle or hurting themselves, then passive-aggressively double down on the stupidity.
Now that is an ad hominem attack lorenfb can take to the bank with my blessing.
Neil,NewcastleFalcon said:
I added comments/explanation after each item in bold. One item not mentioned is the steering wheel position sensor which is used for the tracking lines on the camera display (and probably also with the Propilot system, if equipped). Turning the steering wheel to full lock in each direction a couple of times with the car in ready mode should recalibrate the sensor. There is little risk of the DC-DC converter turning on while you are changing the battery because the main contactor requires 12 volt power from the battery to close its contacts so it will not close after the first cable is disconnected. For safety sake (as others have already mentioned), disconnect the negative terminal first and reconnect it last.
NewcastleFalcon
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Thanks Gerry excellent post.
Regards Neil
Regards Neil
GerryAZ said:
Given all the additional efforts/procedures required, the result of a disconnected 12V power source, one might consider the earlier post;
https://mynissanleaf.com/viewtopic.php?f=6&t=31054#p582055
Furthermore, without having access to a diagnostic tool, Nissan Consult II or LeafSpy, losing the 12V system voltage could result
in a trip to a Nissan dealer.
There is no need for Consult 3+ unless the HVAC compressor settings have been changed from factory defaults (unlikely unless someone paid a dealer to do it for improved cooling while stopped). I recommend against connecting a booster battery to the terminals while replacing the battery.
I did have those settings changed to maximum compressor speed/performance on my 2015, but I have not found the description of those settings in the service manual for the 2019 (software and structure of manual has been changed so it is difficult to find detailed information and requires changes to computer settings--no longer PDF files). If I find the settings in the manual, I will wait to see how the A/C works in June here in Phoenix before deciding if I want to change them.
I did have those settings changed to maximum compressor speed/performance on my 2015, but I have not found the description of those settings in the service manual for the 2019 (software and structure of manual has been changed so it is difficult to find detailed information and requires changes to computer settings--no longer PDF files). If I find the settings in the manual, I will wait to see how the A/C works in June here in Phoenix before deciding if I want to change them.
GerryAZ said:
Presently, there're only two options to reset Leaf fault codes, the Nissan Consult tool or LeafSpy. That's why the Consult tool was mentioned.
Do you know of another option?
GerryAZ said:
And your reasoning is?
DIagnostic trouble codes (DTCs) present due to failing 12-volt battery will probably be cleared by completely disconnecting the old battery and connecting a charged battery in its place. Connecting a booster battery will keep existing codes from clearing. CAN Bus errors often require disconnecting/reconnecting the 12-volt battery in addition to using Leaf Spy to get all DTCs cleared. Although I have used Leaf Spy to clear DTCs numerous times for other issues, I did not need to clear DTCs when I replaced the failed batteries in the 2011 and 2015. I plan to just disconnect the OEM battery and connect a new deep cycle AGM battery in its place in the 2019 as soon as the OEM battery starts getting weak.
GerryAZ said:
You totally missed the point! New fault codes may be developed the result of losing 12V power to some ECUs. Furthermore, some ECUs
may boot-up to their default states requiring the use of a diagnostic tool (possibly only the Nissan Consult tool).
That's totally another issue.GerryAZ said:
GerryAZ said:
Right, and a CAN bus error may occur while an ECU is communicating with another ECU when power is removed.
Hopefully the Nissan Consult tool won't be required, i.e. still requires another effort if just using LeafSpy.
GerryAZ said:
That's anecdotal.
NewcastleFalcon
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One of the youtube vids on the subject, uses an additional 12V battery, as already mentioned in replies to this thread.
With no endorsement implied here it is for discussion/criticism.
Regards Neil
With no endorsement implied here it is for discussion/criticism.
Regards Neil
I've also seen, on older vehicles, little 9 volt batteries used to hold the logic memory.
powersurge
Well-known member
That video was recommended by Nissan for its mechanics so people do not complain that they lost the presets on their radios and other "custom settings". It has nothing to do with correct mechanics or safety.....
It is really not necessary. I like changing around my radio stations after I change a battery.
It is really not necessary. I like changing around my radio stations after I change a battery.
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There are, however, tools that plug into the electrical system that preserve the 12v power during a battery swap. I have one I used on my Toyota Highlander when I replaced the battery in it to avoid any undue complications. I don't recall if it plugs into the OBDII port or where, exactly, but it preserved all the functions/settings I had before the battery replacement.
TronJockey
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Just a thought. When the Leaf is "OFF" power to the 12V rail is provided solely by the 12V Lead Acid battery. However, when the Leaf is "ON" power to the 12V rail is provided by the HV battery (via the DC-to-DC converter). It's been a while since I've seen schematics of the Leaf's 12V system but it would make sense that when in the "ON" position the 12V lead acid battery could actually be removed and it wouldn't matter as the 12V rail is being fully supplied by the DC-to-DC converter. Again, I'm not sure this would be the case but it would be interesting to confirm this. I intend to try it this Spring as I intend to change the 12V SLA battery in my 2019 SV.
I wouldn't. It has always been a rule, do not disconnect a battery from its charging system when said system is in operation. It applys to generators, alternators, and I would think DC-DC converters.
Yes, I know people do it all the time, and I have had to repair some of the problems from doing so. You might get away with it, but the damage when you don't makes it not worth the risk.
Yes, I know people do it all the time, and I have had to repair some of the problems from doing so. You might get away with it, but the damage when you don't makes it not worth the risk.
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