07-05-2020, 11:23 PM | #1 |
Not Yet Wild
Join Date: Nov 2019
Location: Indio, CA
Posts: 49
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Nissan Leaf Cell Issue
Hi-
I bought this pack back in December 2019: 2014 Nissan Leaf 36volts 5kwh 120AH 10s Lithium Battery 36V Golf Cart, I ran into a recent issue and I need your opinion. Maybe a Cell Replacement? I have the old resistor, swiper type of acceleration setup on my 1988 western cart. Lithium pack has been great, but I saw this the other day: (see attached pic 1) The bottom part of cell 2 has melted the aluminum casing or it was rubbed away. I think the swiper has been rubbing up against the side and maybe creating a slight electrical connection and melting it. I repositioned the pack. The swiper doesn't touch anymore and placed a plastic spacer to help eliminate any possible electrical connection, secured with velcro stickys. (see attached pic 2) I did a voltage check on each paired up section. All measure 8 volts except the first two pointed out. the melted one is the one with my index finger on it, it measured 7.97 volts: (see attached pic 3) So here are my questions. Should I replace the melted section, one cell? I am prone to leave it since the voltage is close to the rest of the pack and keep an eye on it. I am in the process of getting the Zeva BMS system, it is just going to take 3-4 weeks to get here from Australia. I think it will help to balance out the section. Thanks for everyone's help ahead of time Jeff |
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07-06-2020, 05:50 AM | #2 |
Gone Wild
Join Date: Oct 2012
Location: Southwestern Pa.
Posts: 6,205
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Re: Nissan Leaf Cell Issue
Lemme preface this with "I'm no Engineer"....but
In order for that kind of heat to occur (enough to melt the aluminum...like 1,200 degrees) don't you have to have the positive and the negative make contact? So....even if the "swiper" (which I assume is running the positive current) did contact the module's aluminum housing.....where is the negative connection coming from? I thought that all carts did NOT use the frame for the negative connection? I know that doesn't directly address your question.....but I thought I'd ask. As for that module....being a conservative fellow as my nature, I'd replace it as you don't know how hot the actual "stuff in the inside bag" actually got. But that's me. |
07-06-2020, 01:30 PM | #3 | |
Not Yet Wild
Join Date: Nov 2019
Location: Indio, CA
Posts: 49
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Re: Nissan Leaf Cell Issue
Quote:
If I do replace, can I replace just the one module? Since it doesn't look like there is any internal damage, could I just watch it? OR am I playing with a potentially dangerous situation here? |
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07-06-2020, 04:42 PM | #4 |
Gone Wild
Join Date: Oct 2012
Location: Southwestern Pa.
Posts: 6,205
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Re: Nissan Leaf Cell Issue
Replace vs "watch" is a really tough call. If you go the "watch" route you may not know anything is wrong until you get the dreaded thermal-runaway.
For the cost of a new module, I'd go that route......and yes....I realize it's a PITA to replace even just one module in the pack. Other's may chime in here and give you their thoughts. |
08-07-2020, 12:07 AM | #5 |
Not Yet Wild
Join Date: Nov 2019
Location: Indio, CA
Posts: 49
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Re: Nissan Leaf Cell Issue
A few weeks back, I replaced the toasty module with a new one from bigbattery.com
All is good again Surprisingly with the damage, it is still holding a charge |
08-07-2020, 06:59 AM | #6 | |
Gone Wild
Join Date: Oct 2012
Location: Southwestern Pa.
Posts: 6,205
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Re: Nissan Leaf Cell Issue
Quote:
Stay safe......don't drive to fast!! |
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08-07-2020, 07:38 AM | #7 |
Gone Wild
Join Date: Sep 2012
Location: Charlotte, NC
Posts: 9,329
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Re: Nissan Leaf Cell Issue
How did You get the new module balanced against the old modules?
I noticed no BMS taps on the pack, are You using "bottom balancing" on the modules? Any Low Voltage detection devices to disable the pack? |
08-08-2020, 12:36 PM | #8 | |
Not Yet Wild
Join Date: Nov 2019
Location: Indio, CA
Posts: 49
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Re: Nissan Leaf Cell Issue
Quote:
Also, I was able to get my Zeva BMS installed earlier this week, so I have that working for me as well for any minimal differences :) |
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08-09-2020, 06:54 PM | #9 |
Gone Wild
Join Date: Aug 2016
Location: Prescott, AZ At a really nice Country Cub
Posts: 242
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Re: Nissan Leaf Cell Issue
I am glad you replaced the module and also received the Zeva BMS. I agree with Dave Lithium are great batteries but you don’t want to risk a chance on thermal runaway.
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08-10-2020, 06:50 AM | #10 |
Gone Wild
Join Date: Oct 2012
Location: Southwestern Pa.
Posts: 6,205
|
Re: Nissan Leaf Cell Issue
BTW, you can set the ZEVA to do "Dynamic Balancing" (See page 8 in the instructions) which will balance your cells (IIRC) on a constant basis. Especially during a charge.
I don't think you should use this Dynamic setting constantly as it may reduce the lifespan of the ZEVA. Dynamic will constantly shunt balance your cells and heat up the ZEVA which may (will?) reduce the lifespan. I was having some cell out-of-balance voltage differences that kept increasing when the pack was low and ready to charge again. I set the ZEVA to the Dynamic setting during one charge and that "fixed" the OOB of the cells. So now all the cells discharge at about the same rate. (The differences when I need to charge now are far less and within a reasonable range) I hope what I posted makes sense!! |
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