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Discussion Starter #1
Hello all,
I am researching the re-use of individual "Leaf" modules
...ones that have been, removed from Nissan Leaf vehicles

Here is some good info on them,
https://www.youtube.com/watch?v=vYQJatWpBXY&t=20s


* I currently have a 48V 45AH pack, out of a Chevy Volt, on my El Moto
https://www.diyelectriccar.com/foru...ectric-motorcycle-upgrade-lithium-198097.html


Being that this "Volt" battery pack is only 12S (45V nominal), the top charge voltage is only ~49.8V
…& geared @5.4:1, my top speed is only ~35MPH
…plus, with the 45AH capacity, my range is only ~25 miles.

So, it looks like, if I move up to/use (7) of these Leaf modules which would be 14S (52.5V nominal)
...it would have a top charge voltage of ~54V (which should increase my top speed a bit)
...& with a 66AH capacity (my range should increase a bit too)


Maybe something like this (~$475.00)
https://www.ebay.com/itm/Solar-RV-N...sh=true&autorefresh=true&shqty=1&isGTR=1#shId

It's (7) individual Leaf cells
…& a BMS
...plus a printed circuit board (for connecting the BMS)

But, while researching, I've come across some negative (-) info about these cells (like loosing capacity)
https://www.mynissanleaf.com/viewtopic.php?f=27&t=26662

This is very concerning, when contemplating buying these type of cells, individually
...especially, pre-used ones

So, I am interested in any opinion &/or info on re-using these Leaf cells
…& also, this printed circuit board, BMS connection concept (in eBay ad)


Goal for 2020: Non-confrontational learning
 

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It is unfortunate how badly the laef cells degrade. Since they are used then i doubt they will have full capacity anymore. Don't know if it is an inferior chemistry or lack of cooling that causes the decay, but there are lots of nice looking laefs out there with little to no useable range left. It's sad to see these throw-away cars, no good solution for a crappy pack.
 

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It is unfortunate how badly the laef cells degrade. Since they are used then i doubt they will have full capacity anymore. Don't know if it is an inferior chemistry or lack of cooling that causes the decay, but there are lots of nice looking laefs out there with little to no useable range left. It's sad to see these throw-away cars, no good solution for a crappy pack.


We in the LEAF community have reached the conclusion that it was a combination of the lack of active cooling and a poor choice of battery chemistry.

That said, the packs introduced in 2015, which we affectionately call "Lizard" packs, appear to be holding up quite a bit better than the original Gen1 packs did.

In my own LEAF, the original pack at 4 years was down 3 capacity bars and had a remaining range of approximately 50 miles, which I still personally considered pretty respectable and could actually live with so long as I was mindful of the new reality.

On my Lizard pack, which was replaced under warranty in the winter of 2015, I am down just one capacity bar and, educated guess (I really don't drive that far anymore) still has a range of approximately 70 miles. However, the last few weeks, I've sort of been feeling like I might be getting ready to drop another bar, but it has also been cold so maybe it's just that I'm not getting the same energy density.

BTW, both my driving patterns and the way I care for my pack have changed significantly between my first and my second - I changed jobs so I drive a lot less, and it's almost all city driving now rather than highway driving before. And I'm far more careful now to only fully charge when I need to and time it so that charging and balancing are done just before I go to use the car rather than letting it sit fully charged for hours on end. So a direct comparison between the performance of the two is not really fair.

Ask any LEAF driver with a modicum of experience with EVs and I think they'd all say that, even with the added complexity of such a system, the LEAF would have been a much better car with active thermal management.

I am a bit disappointed to see that, 9 years on, rebuild cells for LEAF battery packs have not yet come to market from aftermarket vendors and to buy a cost-subsidized replacement Nissan pack is still several hundred dollars per kWh.

I also happen to think that $80 and up for a degraded LEAF module with maybe 2/3rds the original capacity, if you're lucky, is a bit steep. Though I'm guessing those here who have been around this scene for long enough probably consider that a fair price, if not a bargain?
 

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There was also the "Wolf" pack introduced around March 2013. They're better than the original modules, but not quite Lizard. The 30kW packs had some weird issues, too.
 

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Discussion Starter #5
We in the LEAF community have reached the conclusion that it was a combination of the lack of active cooling and a poor choice of battery chemistry.

That said, the packs introduced in 2015, which we affectionately call "Lizard" packs, appear to be holding up quite a bit better than the original Gen1 packs did.

In my own LEAF, the original pack at 4 years was down 3 capacity bars and had a remaining range of approximately 50 miles, which I still personally considered pretty respectable and could actually live with so long as I was mindful of the new reality.

On my Lizard pack, which was replaced under warranty in the winter of 2015, I am down just one capacity bar and, educated guess (I really don't drive that far anymore) still has a range of approximately 70 miles. However, the last few weeks, I've sort of been feeling like I might be getting ready to drop another bar, but it has also been cold so maybe it's just that I'm not getting the same energy density.

BTW, both my driving patterns and the way I care for my pack have changed significantly between my first and my second - I changed jobs so I drive a lot less, and it's almost all city driving now rather than highway driving before. And I'm far more careful now to only fully charge when I need to and time it so that charging and balancing are done just before I go to use the car rather than letting it sit fully charged for hours on end. So a direct comparison between the performance of the two is not really fair.

Ask any LEAF driver with a modicum of experience with EVs and I think they'd all say that, even with the added complexity of such a system, the LEAF would have been a much better car with active thermal management.

I am a bit disappointed to see that, 9 years on, rebuild cells for LEAF battery packs have not yet come to market from aftermarket vendors and to buy a cost-subsidized replacement Nissan pack is still several hundred dollars per kWh.

I also happen to think that $80 and up for a degraded LEAF module with maybe 2/3rds the original capacity, if you're lucky, is a bit steep. Though I'm guessing those here who have been around this scene for long enough probably consider that a fair price, if not a bargain?
Thanks, I appreciate your guys's input.

Is there a visual way to tell if a module is from a "Lizard" pack (newer than 2015)?
...other than the manufacturers paper sticker, anyways

* I have noticed, in pics, that the modules listed as Gen 2 seem to have (3) lines near each corner, on the terminal end,
...like these https://www.ebay.com/itm/Nissan-Leaf-Battery-G2-Module-Lithium-Ion-500-wh-7-6v-per-module-Lot-of-7/113027240986?_trkparms=aid%3D555018%26algo%3DPL.SIM%26ao%3D1%26asc%3D20131003132420%26meid%3Da34e09ff7fca4a0c91963cdda53dbbf8%26pid%3D100005%26rk%3D4%26rkt%3D12%26mehot%3Dpf%26sd%3D142938700116%26itm%3D113027240986%26pmt%3D1%26noa%3D0%26pg%3D2047675&_trksid=p2047675.c100005.m1851

I haven't seen these (3) lines, in pics, on any modules listed as Gen 1
 

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Thanks, I appreciate your guys's input.

Is there a visual way to tell if a module is from a "Lizard" pack (newer than 2015)?
...other than the manufacturers paper sticker, anyways

* I have noticed, in pics, that the modules listed as Gen 2 seem to have (3) lines near each corner, on the terminal end,
...like these https://www.ebay.com/itm/Nissan-Lea...a=0&pg=2047675&_trksid=p2047675.c100005.m1851

I haven't seen these (3) lines, in pics, on any modules listed as Gen 1

You have to be careful. They went from the fully enclosed "tuna can" to the open style in 2013, and those cells only got a minor chemistry tweak. Those might be the "Wolf" cells Tremelune was talking about (though I've got to be honest, I've around the LEAF community for more than 11 years now and have never heard that term before). I really don't know if you can tell the 2013 cells from the 2015 ones visually. Edit: LEAF forum says "No" - 2013 and 2015 look the same. However, the doubled-up cells from the 2016 30kWh pack are easy to differentiate.
 

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Discussion Starter #7 (Edited)
You have to be careful. They went from the fully enclosed "tuna can" to the open style in 2013, and those cells only got a minor chemistry tweak. Those might be the "Wolf" cells Tremelune was talking about (though I've got to be honest, I've around the LEAF community for more than 11 years now and have never heard that term before). I really don't know if you can tell the 2013 cells from the 2015 ones visually. Edit: LEAF forum says "No" - 2013 and 2015 look the same. However, the doubled-up cells from the 2016 30kWh pack are easy to differentiate.
Thanks again,

Looking around, I found some of these modules also available from Greentecauto (a fellow forum member)

Here's (8) modules for ~$470.00 (~$59.00 per module)
https://www.ebay.com/itm/Nissan-Leaf-Battery-Module-G2-Lot-of-8-2014-7-6V-TESTED-43AH/223782336889?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D20160811114145%26meid%3Df6d2142213954f1e82ce610e8c745166%26pid%3D100667%26rk%3D6%26rkt%3D8%26mehot%3Dnone%26sd%3D124046844753%26itm%3D223782336889%26pmt%3D0%26noa%3D1%26pg%3D2334524&_trksid=p2334524.c100667.m2042

The ad says,
"Nissan Leaf Battery Module G2 Lot of 8 2014 7.6V TESTED!!"
"43AH. Tested all modules at 43Ah. Tested from 8.3v to 5v at 20 amps."

Cell Voltage
Maximum: 4.15V
Nominal: 3.8V
Minimum: 2.5V

Module Voltage
Maximum: 8.3V
Nominal: 7.6V
Minimum: 5V

So, these seem to be the open can, "Wolf" G2 (second generation) modules made after 2013
...but not, the"Lizard" modules made after 2015.

Now, for "safely" DIY charging, a DIY pack of used modules like these

As the ad says, it's usually recommended to only charge these type cells up to 4.15V
…or 8.3V (max) per module

But, I've noticed that most Lithium battery chargers are set to charge these type Lithium cells to 4.20V.
Which may be OK or proper on new cells but, IMO very dangerous on a pack of used cells.
I've also, seen chargers with adjustable voltages but, their usually very expensive.

As I said, in my opening post, it looks like (7) of these modules (14S) would give me the most "boost" in my (48V) situation.

But, most chargers for 14S lithium battery packs have a 58.8V top charge setting (charging them up to 4.2V per cell)
...but, that leaves NO "safety margin" what so ever.

* I know this is where a BMS usually comes into play
...but, I'm trying to set it up "simple"

** Set it up right in the beginning, monitor the voltages & only balance when & if necessary (like I've been doing with my Chevy Volt pack)

Here is a video of the Digital Battery Balance Monitor I use
https://www.youtube.com/watch?v=uzwUiSl0Azg

So, I was thinking, a standard, off the shelf charger for a 13S Lithium pack, with it's 4.2V top charge, would only charge a 14S pack up to 54.6V (3.9V per cell)
...like this one (~$100.00)
https://www.ebay.com/itm/YZPOWER-54...48V-13S-Li-ion-Battery-XT60-Plug/283423911361

It looks like this type of (13S) charger would give a 4.2V "safety margin" for the entire (14S) pack
…& this should also help to NOT "over-voltage-stress" my 48V components like contactor &/or voltage convertor.

I know these 48 components can handle ~54V (because the top charge voltage for a standard 48V Lead battery pack = ~53.2V)
...but, I'm not sure if they would be able to handle almost 59V

Make sense?
...anything I'm missing here?
 

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Definitely agree with Tremelune here. Unless you buy brand new LiFePO4 cells from the same batch, a good BMS for anything lithium is a necessity. Even small low-cell count packs can go up in flames if they go way out of balance. In addition, a proper BMS will have I/O that you can use to control the pack's charger.
 

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Discussion Starter #10
Use a BMS...It's not something I would consider optional for Lithium batteries. They catch fire.

3.6-4.1v seems like a more practical range:

https://www.diyelectriccar.com/forums/showthread.php?t=202151

"In the event of the controller or BMS failing, does the charger halt itself?"
Did you test this?
...how did it turn out?


I guess you'd call this concept the "You are the BMS"
...or maybe even a Manual BMS

I've been studying on the "safe" use of small electric vehicles/systems for a few years.

I started my ElMoto off on 36V 35AH of Lead (2017)
...then, moved up to 48V 35AH of Lead (2018)
...& now, I'm using the 45V 45AH (12S) Lithium pack (2019)

From what I understand these type of lithium batteries usually only "burst" or "outgas" "if" & or "when" over-charged
...or damaged

So, my goal has been to set up situations where this is less likely to happen
...or at least not very easily

I've also, read many, many stories of BMS's actually (inadvertently) destroying the battery packs that their supposed to be protecting
(kinda reminiscent of the Leaf battery pack issues mentioned above)
…usually it's component malfunction
...or bad design
...sometimes improper installation
...or even from the parasitic draw, of the BMS itself while trying to keep the pack balanced, like while in storage.

What I'm proposing, is to start off with a set of closely matching modules
...periodically (daily) monitor the balance
...& only charge to 3.9V per cell.
 

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Discussion Starter #12
Well, you've understand wrongly.

just ask Jack:

https://www.youtube.com/watch?v=O-PaSSTA2YE
Thanks for your input
...but, that's a "totally" different situation

You can barely hear the dialog, in the video
...but, if I heard 'em correctly, "one of my jack-ass guys/someone left something on & it went down too far. I put a charger on it & it seemed to be charging OK"

NO, just NO

First, they over-discharged the pack (probably "killed" a cell or two)
...then, "blindly" connected a charger (didn't even check the individual cells or at least the overall pack balance)
…& then, just kept on charging even while they hear it "popping"

IMO any competent EV owner/user should NEVER do any of those things

Never over-discharge
...always check before charging
…& if ya "ever" see or hear anything out of the ordinary (popping, smoke etc.) STOP & investigate


My actual question is "would there be any concerns/problems with charging a "balanced" 14S lithium battery pack with a 13S charger?
 
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