12v battery connector replacement

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T

tziegler

Member
Joined
Oct 25, 2017
Messages
12
Location
Florida
The original battery of my 2015 Leaf is dying. It has severe corrosion around the + terminal and is causing all kinds of problems. After searching on this forum, I decided to replace the battery with an AGM battery or the Optima Yellow Top. When I attempted to remove the old battery, I used baking soda and water to remove the corrosion. First, the nut that allows you to tighten/loosen the connector broke. Then after I got the connector off, I noticed the connector had basically fallen apart.
https://photos.app.goo.gl/WySNLyca8ub33Syy8 ( I couldn't get the photo from google to work with the img command.)

All the videos and instructions for replacing the battery show the connectors in pristine connection.
How do I remove the old connector? Do I have to replace the fusible link that it is attached to? I don't want to break anything so I am wary of just yanking on it. Thanks in advance.
 
Howdy Tom,

Soak it in a cup of 5% vinegar and then inspect and see how it looks again, it's not clear that anything is broken in your picture--you may just need a new nut.
 
Personally, I would replace the connector given the multitude of problems that can occur from a faulty 12V system. It should be easy to get a used replacement part from someone scrapping a Leaf or from ebay, etc. A new part from Nissan may not be expensive also, if that part is available separately.

According to the service manual, the 12V positive cable/connector should be attached to (and can be disconnected from) the 'fusible link box'.
 
goldbrick said:
Personally, I would replace the connector given the multitude of problems that can occur from a faulty 12V system. It should be easy to get a used replacement part from someone scrapping a Leaf or from ebay, etc. A new part from Nissan may not be expensive also, if that part is available separately.

According to the service manual, the 12V positive cable/connector should be attached to (and can be disconnected from) the 'fusible link box'.
Click to expand...
I have a part number for the connector. They aren't that expensive. From the parts breakdown illustration, it looks like the connector can be disconnected from the fusible link box. I just don't know what to pry to get it loose. Does the service manual give any clues on how to disconnect it?

My picture doesn't show how messed up the bottom of the connector is from the corrosion. I could soak it in vinegar, but it is obviously not in good shape. Thanks for your suggestions.
 
tziegler said:
Does the service manual give any clues on how to disconnect it?
Click to expand...

Nope, just says to disconnect it. And that installation is the reverse of removal :mrgreen: I'd soak it with penetrating oil or something if it looks fused on. Then maybe try to pry it off gently working from side to side. Maybe put vice grips on the cable then torque those to try to break it free. I'm guessing the box is plastic so obviously you don't want to use that for leverage. Best of luck.
 
goldbrick said:
Nope, just says to disconnect it. And that installation is the reverse of removal :mrgreen: I'd soak it with penetrating oil or something if it looks fused on. Then maybe try to pry it off gently working from side to side. Maybe put vice grips on the cable then torque those to try to break it free. I'm guessing the box is plastic so obviously you don't want to use that for leverage. Best of luck.
Click to expand...

I found a nut and put everything back together. After 3 tries, the car finally started, but the EV System warning light is on. I can drive the car and I think I will drive it to the local Nissan dealer. So it goes. Thanks for the suggestions.
 
I think you made a good decision,. It looks like the kind of job that could cause much bigger problems if it doesn't go well so why take the chance?

The EV warning could just be from the fact that the 12V battery was disconnected. The manual has about 10 things that are supposed to be checked/reset/calibrated after the 12V battery is removed. I don't remember hearing much about that here in the forum though, so maybe most of it is unnecessary or can be done with LeafSpyPro or something.
 
When I took the car to the dealer, I was told there was a recall so they are doing that fix as well as the battery replacement. They are also doing some sort of diagnostic check for another $150. I haven't had to pay anything for maintenance in the 2 years that I've owned the car. Just new tires. I guess my luck has run out.
 
goldbrick said:
The EV warning could just be from the fact that the 12V battery was disconnected. The manual has about 10 things that are supposed to be checked/reset/calibrated after the 12V battery is removed. I don't remember hearing much about that here in the forum though, so maybe most of it is unnecessary or can be done with LeafSpyPro or something.
Click to expand...

Did I get lucky? No such issues for me after having my 12v battery out of the car for ~24 hours. Just a few minor preference settings that needed to be input over again.
 
I replaced the original batteries in my 2011 and 2015 when they failed with Optima Yellow Top (deep cycle AGM) batteries. I will replace the OEM battery in the 2019 with an Optima Yellow Top as soon as I notice weakness or excessive gassing to avoid problems. Some error codes may be set when the battery is disconnected or when the voltage drops to a very low level when the battery fails, but they can be cleared using Leaf Spy.
 
goldbrick said:
I think you made a good decision,. It looks like the kind of job that could cause much bigger problems if it doesn't go well so why take the chance?

The EV warning could just be from the fact that the 12V battery was disconnected. The manual has about 10 things that are supposed to be checked/reset/calibrated after the 12V battery is removed. I don't remember hearing much about that here in the forum though, so maybe most of it is unnecessary or can be done with LeafSpyPro or something.
Click to expand...

My process whenever I disconnect the 12V battery (about once a month to put my maintainer on it to top it off):
1) Reset all codes via leafspy. Expect to see Brake Controller Pwr Code.
2) Back car out of garage into driveway. Let it sit there until the radio time resets via GPS
3) Setup charge timer and climate control timers
4) Roll driver window all the way down and up. When window is fully up, pull the control to raise the window. Hold for 3 seconds, release. This resets the automatic window up/down mechanism, which can get confused by a power outage.
5) Pull car back into garage

P.S. I have a batteryMinder desulfator. Do I have to keep disconnecting the battery when I use it, or is it safe to use when the car is still hooked up to 12V? :)
 
Those of us who use or used battery maintainers don't worry about disconnecting the battery. If this is a low amperage desulfator I don't think it would cause problems. A big unit with lots of amperage might.
 
With my recently acquired LEAF I disconnected my battery coupla weeks ago to recharge it and had no issues whatever with the car when I reconnected, other than the trip odometers reset to zero and I lost the time of day - this latter reset itself first time I drove the car.
Anticipating future battery woes, I've hardwired a pigtail to it to suit my Optimate motorcycle battery tender, which charges at 0.6A. Slow, for sure, but it gets there if you're patient.
 
That rusted connector is still savable.. Soak it in a cup of white vinegar for 24 hours, and use a wire brush to loosen the corrosion. You will be amazed at how well it works...
 
Lothsahn said:
P.S. I have a batteryMinder desulfator. Do I have to keep disconnecting the battery when I use it, or is it safe to use when the car is still hooked up to 12V? :)
Click to expand...

A Low-power maintainer is probably ok. But who knows what the "desulfator" is doing? Whenever I read about "desulfation" I get more of a black-arts than science vibe. I don't suspect there is any standard, but whatever the designer conjured to "break up sulfate crystals". Assuming for a moment that this voodoo actually works, any electrical pulse sufficient to actually do that is probably something I wouldn't want on my 12V bus. The best solution to sulfation is prevention -- keeping at full charge. I'd just turn off the desulfator (if that's an option?) and let the minder do its thing.
 
Nubo said:
Lothsahn said:
P.S. I have a batteryMinder desulfator. Do I have to keep disconnecting the battery when I use it, or is it safe to use when the car is still hooked up to 12V? :)
Click to expand...

A Low-power maintainer is probably ok. But who knows what the "desulfator" is doing? Whenever I read about "desulfation" I get more of a black-arts than science vibe. I don't suspect there is any standard, but whatever the designer conjured to "break up sulfate crystals". Assuming for a moment that this voodoo actually works, any electrical pulse sufficient to actually do that is probably something I wouldn't want on my 12V bus. The best solution to sulfation is prevention -- keeping at full charge. I'd just turn off the desulfator (if that's an option?) and let the minder do its thing.
Click to expand...

That was actually my concern, Nubo. Apparently, it does the charging in pulses around the resonant frequency for Sulfate crystals. While this isn't a high voltage desulfator like a pulse desulfator (which sounds like something you would NOT want connected to the car), it does involve frequency pulses on the bus. I really wonder if that's... OK.

The desulfator I've been using is this one:
https://www.northerntool.com/shop/tools/product_200332201_200332201

They sell cables to connect it permanently to a car, and even to connect it through the ODBII port. I'm assuming it's safe, but I was hoping for more verification, specifically on a Leaf.
 
Lots of interesting discussion on this thread. Here's the end to my story:

Nissan replaced the battery with an Autocraft AGM battery and marked the price up 20%. I could have bought one at Advanced Auto for $199. Nissan charged me $240.

They replaced the connector. After looking at what they did, I never would have been able to figure out how to disconnect it. The connector only cost $15.

They did not charge me for the $150 multi point inspection. Everything else was OK.

They did the recall fix at no charge.

Total with labor was $446. All I had to manually reset was the clock.

After I dropped the car off yesterday, they couldn't get it restarted so it sat in the service lane until the Leaf tech got there the today. He got it started and moved me to the front of the queue for repairs. They were done by mid morning . In addition, they charged the car, vacuumed the interior, and put it though a car wash. Under the circumstances, I think i got value for the price paid.
 
tziegler said:
Lots of interesting discussion on this thread. Here's the end to my story:

Nissan replaced the battery with an Autocraft AGM battery and marked the price up 20%. I could have bought one at Advanced Auto for $199. Nissan charged me $240.

They replaced the connector. After looking at what they did, I never would have been able to figure out how to disconnect it. The connector only cost $15.

They did not charge me for the $150 multi point inspection. Everything else was OK.

They did the recall fix at no charge.

Total with labor was $446. All I had to manually reset was the clock.

After I dropped the car off yesterday, they couldn't get it restarted so it sat in the service lane until the Leaf tech got there the today. He got it started and moved me to the front of the queue for repairs. They were done by mid morning . In addition, they charged the car, vacuumed the interior, and put it though a car wash. Under the circumstances, I think i got value for the price paid.
Click to expand...

Not bad! Good to hear! Glad they used an AGM, and $15 for the connector sounds like a more than reasonable price. :)
 

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