Anybody with 2011 or 2012 interested in upgrade to new battery?

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Valdemar said:
Interesting, I thoughts there were reports stating the car is put into restricted power output mode after a "bootleg" battery is installed, it can be driven but it won't go faster than 30mph or so.
Ah, thanks for the warning, I did not have the vehicle up to speed yet.
Indeed, the car accelerates fine until 25 and then it flattens out and will not reach 30 MPH until it is paired.
It looks like the pairing is simply writing the VIN into the BMS, does anyone know if that can be done by anyone else than Nissan?
No problem to go to the dealer, but I need to do this now on 2 cars, so rather avoid both cost and questions.
 
Dealer is your best bet. Problem is the pairing process is slightly more complicated than you think as it requires a special digital key card that comes with a new battery and after a new pack is installed the card has to be returned to Nissan, They may have to request it from Nissan in a case like this. Unless I missed it there were no confirmed reports so far a dealer helped in such a situation, so you'll be the first to try it and I'm very much interested to learn how it turns out.
 
Cor said:
Unrelated but relevant is that Nissan has apparently tried to hide pack capacity loss when they reprogrammed the Leaf,
because the 2011 pack has only 52.68 Ah capacity (was originally 64 Ah) so the SoH is 80% and Hx is only 63%
yet the Leaf displays 11 bars which seems wildly optimistic for a loss of 11.32 / 64 = 17.7% capacity. NOTE that this is more than 1/6 of total battery capacity that is lost, so one would reasonably expect that of 12 bars, at least 2 would have disappeared after more than 1/6th loss as that is more than 2/12th: at least 2 bars out of 12. Hmmmm...
Anyway, this pack is still doing OK for a 2011 pack, apparently not suffered much from heat.

52.6 should be right on the threshold of loosing the second bar. I have a 52.52 aH battery in a 2013 that is waiting to loose it's second bar. Hopeing the 3rd and 4th bars don't hang on so long....
 
Valdemar said:
Dealer is your best bet. Problem is the pairing process is slightly more complicated than you think as it requires a special digital key card that comes with a new battery and after a new pack is installed the card has to be returned to Nissan, They may have to request it from Nissan in a case like this. Unless I missed it there were no confirmed reports so far a dealer helped in such a situation, so you'll be the first to try it and I'm very much interested to learn how it turns out.
OK, we will ask the dealer about this and I will probably end up dropping the pack one more time,
going through the nasty effort of opening it (the 2013+ packs are closed with a sealant all around and only a few bolts, whereas
the 2011-2012 packs have a solid rubber gasket and a bolt every 6 inch to keep the pack closed)
then I will need to swap all contents into an empty 2011 shell (since the gasket will be ruined) and add the original BMS that is already
paired to the car, so it will be recognized and the car will be happy to operate normally again.
Then I will also have my car's BMS back so I can then take that to add to my car's pack and have my salvage Leaf be a little more happy also.
 
Hopefully this is something your dealer can help with. I spoke to mine some time ago and they said swapping packs between 2 2011 cars is something they can easily do. I didn't follow up so take it with a grain of salt as dealers are known to be not very knowledgeable about Leafs. If the first dealer refuses try another.

Additional thoughts on pack surgery,

1. You will have to be creative with mounting 2015 modules in the 2011 housing as the mechanical design has changed. I heard it's doable but not exactly bolt-on

2. Read somewhere that newer modules charge to higher voltage, so while some capacity might be inaccessible when using 2015 modules + 2011 BMS it should be safe, the reverse can be unsafe, I suggest you research it more before starting using 2011 modules with 2015 BMS, if that is what you plan to do anyway.

3. It'll take some time for the BMS to learn the new modules, so the GOM will be off. You may want to see a dealer after anyway to perform BMS reset.


Edit:
4. Hopefully the restricted power mode is not sticky, that is once you put the original BMS everything will be back to normal.
 
Valdemar said:
Hopefully this is something your dealer can help with. I spoke to mine some time ago and they said swapping packs between 2 2011 cars is something they can easily do. I didn't follow up so take it with a grain of salt as dealers are known to be not very knowledgeable about Leafs. If the first dealer refuses try another.

Additional thoughts on pack surgery,

1. You will have to be creative with mounting 2015 modules in the 2011 housing as the mechanical design has changed. I heard it's doable but not exactly bolt-on

2. Read somewhere that newer modules charge to higher voltage, so while some capacity might be inaccessible when using 2015 modules + 2011 BMS it should be safe, the reverse can be unsafe, I suggest you research it more before starting using 2011 modules with 2015 BMS, if that is what you plan to do anyway.

3. It'll take some time for the BMS to learn the new modules, so the GOM will be off. You may want to see a dealer after anyway to perform BMS reset.

Edit:
4. Hopefully the restricted power mode is not sticky, that is once you put the original BMS everything will be back to normal.
Hi Valdemar,
I am happy to report that after putting the original (2011) BMS from my neighbor's car with the Lizard cells into the old 2011 shell (the 2015 shell gets destroyed when you open it, since it is glued shut, good that I had another complete 2011 pack in shell sitting around) that the power restriction was gone, no errors were reported and the car responded normally again. Obviously the old BMS still reported the old Ah capacity, it has to re-learn the new capacity. Interestingly it immediately showed 10 bars whereas the old pack was down to 9 bars...
The neighbors were overjoyed when I gave them their 2011 back, knowing that they will soon again see 12 bars and 66 Ah capacity!

The mounting of the cells (brackets) is identical between 2011 and 2015, the same bolt holes for the brackets. What is *not* identical is the wiring or the wiring routing. Even the bus bars are routed slightly different on the horizontal stacks - instead of going left to right across the 4-high stack 4 times, the bus bars follow the module stacks and only jump across on the top and the bottom. The result is that the mounting of the connections is at slightly different locations, also the contactors have a different layout, the wiring is routed in a more logical way around the battery box and there have been several other component and weight saving changes.
So, in order to play it safe, I removed the 2015 wiring completely from the Lizard pack,
moved the lizard pack into the 2011 shell as bare modules, then added the original 2011 wiring, service disconnect, contactors and front plugs and finally the original 2011 BMS. The only thing I had to modify were the power connections on the 24 vertical modules, since the relayouted mechanics interfered with the positioning of the contacts from the 2011 pack, so I used the 2015 contacts and I will have to be
creative to use the 2011 power contacts with the 2015 wiring in my own Leaf, so that I can re-use the 2015 BMS that is paired to my car.
But that is a concern for another day, I am happy that I was able to put the lizard modules into a 2011 shell and swap wiring without
any problems.
I will have to be careful to charge only to 80% when I used the 2015 BMS on the 2011 pack in my own Leaf.
To complicate things (but make logistics much simpler) this was not a simple swap between 2 Leafs, but a 3-way exchange,
I had already bought a Leaf pack from Washington state (cool, so it still has decent capacity) which I mounted in my own Leaf
after I dropped its 2015 pack, so that my Leaf could move and not sit disabled in the garage, otherwise I would not have place to put the neighbor's Leaf in there also *and* work on 2 battery packs, since I have a 2-car garage. With my own Leaf out of the garage, the neighbor's Leaf and 2 battery packs were manageable.
Since the neighbor's pack was down to 75% (48Ah) I removed those cells from the shell (they expanded quite a bit when releasing the compression bolts - it would not be possible to simply bolt it together again, I would need clamps to compress those cells again, so much internal pressure was present in those cells) and I re-used the empty shell to put the Lizard modules in after destroying the 2015 shell.

Good thing is that I now also have my BMS back, so I can make my Leaf happy by putting the BMS + wiring onto the Washington state pack.

Main reason I did the swap myself (which cost me 2 full days of slaving on cutting the 2015 pack open, undoing all bolts from every module and every part, also undoing every bolt in the old 2011 pack, moving those modules, putting the 2015 modules into that shell, re-thinking the wiring options, removing the sensing wiring from the 24-module stack and swapping it with the old bus bars, redoing every single bolt in the pack, double-checking all voltages in the pack and finally plugging in the original BMS - the main reason for this was that the dealer said that he was not sure if they could re-program a used battery, they had only requested keys for new packs from Nissan, never for an existing pack that was swapped. Only Dealers can do this BTW, I asked two independent shops and it requires access to official Nissan (corporate?) servers, which nobody has except the dealers.
Also the dealer wanted $700 for the pack mounting and $300 for the (attempt) to reprogram the BMS.
Since I knew I could guarantee that it would work by swapping BMS, I took that route and saved money (just spent time).

BTW, anyone considering opening a battery pack: be aware that inside the shell you find 400 Volts of lethal potential, so if you do not know how to operate a Volt Meter and have no experience working on high voltage and are very aware of how to work safely on High Voltage, please do not open the pack.
As long as the pack is closed and the CAN plug not connected, there is no chance to get any power outside so you can safely work on the car and handle the battery shell. But know what you are doing when you open the shell!
And high voltage gloves alone do not make you safe, since it is easy to hurt yourself when accidentally shorting the pack or cause other accidents. Or when you are safe, but someone else comes by and touches high voltage.
In fact, I do not have high voltage gloves, I work on the pack with bare hands and steel tools. But I do know exactly what I am doing and I use a digital voltmeter almost every day.
 
Wow, congrats on getting out more or less cleanly out of this mess! Hopefully one day someone will figure out how to swap packs as a unit.
 
Great work, and I hope you or someone else can swap my pack (hopefully, without all the labor of disassembly/reassembly) if I eventually decide I want to replace my OE pack.

But by doing all that extra work, I believe you made important observations of how the BMS/Lithium Battery Controller estimates and reports battery capacity.

Cor said:
... I am happy to report that after putting the original (2011) BMS from my neighbor's car with the Lizard cells into the old 2011 shell (the 2015 shell gets destroyed when you open it, since it is glued shut, good that I had another complete 2011 pack in shell sitting around) that the power restriction was gone, no errors were reported and the car responded normally again. Obviously the old BMS still reported the old Ah capacity, it has to re-learn the new capacity. Interestingly it immediately showed 10 bars whereas the old pack was down to 9 bars...
The neighbors were overjoyed when I gave them their 2011 back, knowing that they will soon again see 12 bars and 66 Ah capacity!...
Please report back if that happens, or whatever else the BMS/LBC reports.

Nissan apparently changed the way the BMS/LBC (and the dash capacity bar display?) estimates battery pack capacity loss at least once, in early 2013.

Nissan stated this was to correct the overestimation of capacity loss The BMS/LBC showed in 2011 to (early) 2013 LEAFs, reflected by the premature (and overly "pessimistic") loss of battery capacity bars on the dash.

Therefore, IMO it would not be surprising if the Ah reports and dash display using a 2011 BMC/LBC never match those you got for the same modules installed by Nissan in another 2011 LEAF, using another BMS/LBC.

So, from your work, we now know the same modules from a pack replaced by Nissan in 2015, in a 2011 LEAF:

Showed 12 capacity bars (and had the Ah reports as quoted below) when still installed in that 2015 replacement pack, using its 2015 replacement BMS/LBC, in your donor 2011 LEAF.

Showed 11 capacity bars (and had the Ah reports as quoted below) when installed in another 2011 LEAF, still using the BMS/LBC Nissan replaced in 2015.

And showed 10 capacity bars (so far) when installed in that same LEAF, using its original equipment 2011 BMS/LBC.

Is all that right?

=edatoakrun
="Cor"
...Unrelated but relevant is that Nissan has apparently tried to hide pack capacity loss when they reprogrammed the Leaf,
because the 2011 pack has only 52.68 Ah capacity (was originally 64 Ah) so the SoH is 80% and Hx is only 63%
yet the Leaf displays 11 bars which seems wildly optimistic for a loss of 11.32 / 64 = 17.7% capacity. NOTE that this is more than 1/6 of total battery capacity that is lost, so one would reasonably expect that of 12 bars, at least 2 would have disappeared after more than 1/6th loss as that is more than 2/12th: at least 2 bars out of 12. Hmmmm...
Anyway, this pack is still doing OK for a 2011 pack, apparently not suffered much from heat
Do I understand you correctly, that the 2015 replacement pack displayed 66.14 Ah when in the totaled LEAF, and displayed only 52.58 Ah and 11 capacity bars on the dash, after you installed it in your neighbor's 2011?...
 
edatoakrun said:
So, from your work, we now know the same modules from a pack replaced by Nissan in 2015, in a 2011 LEAF:

Showed 12 capacity bars (and had the Ah reports as quoted below) when still installed in that 2015 replacement pack, using its 2015 replacement BMS/LBC, in your donor 2011 LEAF.

Showed 11 capacity bars (and had the Ah reports as quoted below) when installed in another 2011 LEAF, still using the BMS/LBC Nissan replaced in 2015.

And showed 10 capacity bars (so far) when installed in that same LEAF, using its original equipment 2011 BMS/LBC.

Is all that right?
I am afraid that I forgot to correct earlier confusion in this thread when someone quoted my reporting 11 bars in my 2011 Leaf, that was *not* the 66Ah 2015 pack, but the (in my opinion overly *optimistic*) display of the 52.68Ah remaining in the "Washington State" original 2011 pack.
I calculated that 52.68 out of 64Ah should be 9 or 10 bars depending on rounding, but obviously Nissan did want to show as positive as possible results, that is why they probably base the newer software bar display on some "guaranteed new battery minimum capacity" instead of the supposed nominal 64 Ah capacity.

Anyway, the 2015 pack with 2015 BMS showed 66 Ah and the same cells with an original 2011 BMS that was trained to see a 48Ah pack and 9 bars, still showed 48Ah (because it still needs to learn the new capacity) but displayed 10 bars immediately without any charging or driving,
just disconnect from its own pack, reconnect to the new pack and turn the car on and run LeafSpy.
I am indeed interested to see how quickly it will re-learn its capacity.
I noticed this morning that my neighbors have taken the Leaf out today, so I will ask them in a couple days what they see the car report. Luckily they are enough nerds to also run LeafSpy, in fact I did not need to plug my ELM 327 into their car, they have their dongle connected permanently, I only needed to pair it to my Android phone.
 
BIG *warning* for anyone who plans to swap BMS between 2011/2012 and 2013+ packs.
I had already noticed that there is a minor routing difference between the bus bars on the horizontal modules (2+2+4+4 stacks)
between the 2011 and the 2015 packs, while the plugs that connect into the BMS harness appeared to be the same.
Just to be on the safe side, I had put in the effort of removing *all* bus bars and sense wires from the 2015 lizard cells
and re-install *all* original 2011 bus bars and sense wiring from the old pack onto them before plugging in the original 2011 BMS.
I am now *SO* happy that I took the extra time and effort to undo and re-fasten those ~100 extra bolts on my neighbor's pack,
because today I wanted to make sure if I needed to go through this effort once more on my own 2011 pack in order to connect
the 2015 BMS that my car is paired to, or that I could simply plug into the sense wire plugs on the 2011 stacks with the harness
from the 2015 BMS (there are 2 connectors right behind the service disconnect).
So, I verified that the plugs mechanically are identical. I also verified that the sense wires are essentially running to the same
points on the pack, then I took my Multimeter and measured where the negative most terminal was connecting on the two
identical plugs on the 2011 and 2015 harnesses.
Oh oh!!!!!
The wiring in the identical plugs is *different* between the 2011 and 2015 packs, so *do not* mix the harnesses because even
though they will mechanically fit, where the negative most sense wire runs to a pin on the corner of the 2011 plug (which makes sense),
it runs to the 5th pin from the *other* corner on the 2015 plug, so they are *not* electrically compatible!
You *will* blow up your BMS if you plug the harness of your BMS into the sense wires of the other type of pack!

NOTE that it is *impossible* to plug the 24 vertical modules into the wrong BMS as the 2013+ redesign has eliminated the intermediate harness and the sense wires plug directly into the BMS, using colored and 2 mechanically different connectors.
But I am talking about the other two connectors that have a short harness going to the back of the service disconnect and there plug into
the sense wires of the two horizontal sub-packs. Those two connectors are mechanically identical but wired differently, so it is easy to confuse them and blow up your BMS if you use the wrong combination. You have been warned....
 
Wow - that is what you meant by "creative placement of 2015 components in a 2011 shell...
The layout of the accessories in the 2013+ packs has been redesigned/optimized compared to the 2011/2012 packs.
I needed to place them in a 2011 shell since my car is paired to a 2015 BMS, which has quite different wiring harness and I did not
want to mess up my BMS, so here is my journey and the decisions/shortcuts I took.
BTW, the end result is a success - I lifted the front of the pack up to my car (which is sitting on 2 jack stands, because I found that
the minimum required to remove/install a battery is to jack up *one* side of the car high enough (one but last stop on my jack stands
and the max height that my hydraulic floor jack will go). The only other tool that I use is a furniture dolly and that is all there is to it.
Rolling the assembled pack back under the car, position the jack under the front support beam of the pack and carefully raise it
in the designated space until the pack's front is close enough to the two front 17mm bolts next to the power plug, to reach under the car
from the side (don't lay under there while the pack is only on a jack!) and use your fingers to turn the bolt several turns into the car frame.
Just one bolt is strong enough to hold up the pack, so then you can slide under, plug in the HV cable, latch it in place and plug in the OBD
and contactor control cable and latch its connector.
The car no longer reports a problem with the pack, only with the Airbag (the ones that blew when the previous owner crashed the car)
so once I am home from work I will bolt the pack down, tidy up the 3 belly pans and get it out of the garage to check that it has indeed
full power again. Then it is time to put on a new fender and windshield. Anybody know a silver driver side fender?

OK but first what I encountered when putting the 2015 wiring into the 2011 shell together with the 2011 battery modules:
In preparation, I had checked that the BMS wiring is indeed different on the horizontal stacks of modules, so I had to swap those two bus bar assemblies.
I had also removed all the sense wires from the 2015 bus bars for the 24 vertical modules, so I had to add that wire loom to the bus bars
from which I took the 2011 sense wires. Not complex, luckily all wires still had their shape indicating their original position so I just had to
push them back into the retainers. I actually then went through all 49 contacts and to my relief found that the two connectors (24 pins and 32 pins) had all the sense wires in ascending voltage order across the two connectors, so each connector does not carry more than about 100 Volts and no more than 8 Volts between two adjacent pins (the 4 Volt steps of each cell are on 2 adjacent row pins, so 8V between pins in the same row). Very good.
So I confidently bolted that assembly onto the 2011 modules of the "Washington State" pack that I will run in my car.
Then came time to put the service disconnect and contactors into the 2011 shell... Oh no! bolt positions have completely changed.
Not only that, but the current sense has been moved from the contactor box to the bus bar attached to the service disconnect.
It did not look like the same sensor and I did not want to risk plugging into the 2011 sensor to find out that the pinning might be different on the 2015 pack, so I was forced to go with the 2015 contactors and service disconnect. The mounting is a challenge, the 2015 pack has eliminated the mounting bracket for the contactor and instead has 4 bosses that bolt down the 2 contactors so that the rest of the contactor box actually hangs off of the contactors. Two self-drilling screws found some "meat" and now hold down a contactor each.
The service disconnect has an almost fit to the 2011 mounting holes, but has two additional nubs that should have a positioning hole in the box. I simply cut them off and banged on the post that takes the bolt to bend it slightly, so I was able to bolt all 4 corners down as it should.
The reinforcement beam across the pack is different, so I simply used the original 2011 beam and became a bit creative with the wiring attachment positions.
The 2015 high power wiring is too short to attach to the 2011 bus bars since the bolts are much higher up, so the wiring has to shortcut across the corners of the 2-high stacks next to the service disconenct. I made sure to put some of the orange corrugated hose around the wring in those positions to protect it from rubbing through.
The front power plug is different on the 2011 than 2015 (different mounting base as well as different length of wires to contactors)
so I removed the 2011 power plug itself (orange piece) and after filing a slot into the 2015 plug, was able to bolt that into the 2011 base that fit onto the 2011 shell. There are new bus bars between that power plug and the contactors, they have a back support that contains a ferrite core, apparently common mode noise is a problem. The bracket's bolt holes are just a bit different position than the 2011 holes for the contactor bracket, so it will have to stay put on a single bolt.
The rest of the actual wiring loom can easily be routed in the same way as where it came from, just the wire support attachments are not the same, most notably the holes in the back of the modules shells for the temp sensors and wiring.
Then the big surprise: the service disconnect, while the size of the 2015 service disconnect luckily is the same as the 2011 so the hole in the top shell is the same, the bolt pattern is not.
I actually had to file the 4 corner holes about 1/8" closer together in order to be able to put the bolts into the 2015 service disconnect in the 2011 shell. Other than that - piece of cake!
Next - test drive with the "new" 2011 pack and 2015 BMS to verify that it indeed has full power and can go faster than 25 MPH.
I will need to make sure to only charge to 80% if the "Lizard" BMS indeed charges the cells higher than the original BMS.
 
Few more random observations:
- belly pan plastic is different between the 2011/2012 and the 2013+ so when you get a different pack, you also need a different belly pan.
Luckily the front piece that covers the HV wiring and OBD connection, is the same - the middle and rear pieces are a different shape
due to the re-design of the 2013+ battery box. Since the bottom of the battery pack is pretty flat anyway, I am not too worried about
driving with only the front piece in place.
- service disconnect plug no longer has a fuse in the 2013+ version, it is simply a strip of metal in a plastic cover and handle. The fuse is now inside the service disconnect bracket.
- the fuse in the 2013+ service disconnect is rated for 225A so 90kW is the max continuous power out of the pack when it is fully charged.

I test-drove my salvage Leaf with its "new" 2011 "Washington State" pack and the 2015 BMS. Plenty of power, so the car is fully accepting
the re-assembled pack as its own.
Biggest thing I did discover during the test drive is that the alignment is seriously off, so it is not just a fender to take care off, also the
alignment must be corrected - possibly frame damage or steering components were bent...
I also received the (online ordered) front marker light (the tail end of the headlight) for a 2013+ and it fits perfectly on my 2011.
Still trying to find a Silver front driver (left) side fender.
 
BTW, while I was putting my pack back together with the 2015 BMS, I could not resist looking at the BMS a little closer.
Others have done an in depth about the 24 ASICs that measure the voltages from every of the 96 cell pairs and also balance them.
I happen to notice that there is a 25th ASIC sitting to the side, not sure what exactly is the function of that one,
one part that I did want to discover is how the BMS stores its historic data and likely also its pairing information.
Besides the processor 70F3236 and the ASICS there are not many chips on board, just one CAN interface PCA82C250; several voltage regulators and one 8-pin chip that puzzled me why it had only 3 of the 8 pins connected and 2 of those are ground. As I suspected, this is a fancy type of "Zener" diode, a low power high precision (0.05%) voltage reference LT1634 that only requires 10uA so it can be powered
continuously without strain on the battery, while giving a precise reference to the processor.
Well the last chip I checked, what do you know, IC9 is a S93C86 which is a serial bus EEPROM of 16kbits.
So, it should be trivial to remove this from the board (or lift 4 legs for power, clock in, data in and out) and read the entire chip
or simply drop it into a programmer, read and copy it and if necessary add a small ZIF socket to the BMS board to easily modify and
drop it back in - or have a small break-out board with jumpers whether the memory should be in circuit or accessible from external.
NOTE that the board deals with 400 Volts so be careful when it is wired up to the pack,
but the first step of reverse engineering if the BMS can be paired to a different car is to study the contents of several dumps of different days,
so it is clear where the historic info is stored and what is fixed info....
 
I posted this in another thread, someone on a foreign Leaf forum claimed he hacked the 2011 BMS, he even posted a screenshot of a hex editor (EEPROM image?) and pointed to locations that keep the AHr and the capacity bars. He said he could store whatever values he wanted at those locations effectively restoring the capacity gauge to 12 bars (temporarily of course). Or he could "pair" a 2011 BMS to a 2011 Leaf without Consult III (not clear if battery disassembly was required). Same person said he couldn't hack the 2013+ BMS, or at least not yet, so even with his knowledge your job wouldn't have been easier.

I have a theory that 2013+ cars have a slightly different BMS than that which comes with new replacement packs intended for installation into 2011/12 cars, for one new Leafs have 3 temperature sensors but 2015 replacement packs in older Leafs still show 4 in LeafSpy. As such, it may never be possible to swap the battery as a unit from a 2013+ Leaf to 2011/12, and moving modules will remain to be the only available option.
 
Valdemar said:
I posted this in another thread, someone on a foreign Leaf forum claimed he hacked the 2011 BMS, he even posted a screenshot of a hex editor (EEPROM image?) and pointed to locations that keep the AHr and the capacity bars. He said he could store whatever values he wanted at those locations effectively restoring the capacity gauge to 12 bars (temporarily of course). Or he could "pair" a 2011 BMS to a 2011 Leaf without Consult III (not clear if battery disassembly was required). Same person said he couldn't hack the 2013+ BMS, or at least not yet, so even with his knowledge your job wouldn't have been easier.

I have a theory that 2013+ cars have a slightly different BMS than that which comes with new replacement packs intended for installation into 2011/12 cars, for one new Leafs have 3 temperature sensors but 2015 replacement packs in older Leafs still show 4 in LeafSpy. As such, it may never be possible to swap the battery as a unit from a 2013+ Leaf to 2011/12, and moving modules will remain to be the only available option.
Hmm interesting.
Definitely there are differences between 2011/2012 and 2013+ BMS, that is why the later ones have colored connectors (grey on side and one dark blue instead of the 4 white ones at the bottom) Also the ASIC chips appear to be a different version of that chip, even communication with the ASICs is different as seen by the guy that is replacing the BMS processor with a programmable device.
But the differences between the programming for a 2013+ BMS to be compatible with and older car is only software, although having an extra tempsensor in the pack is definitely a different hardware and wiring harness, but if a 3-sensor 2013+ pack gets a software that simply doubles the reading of one sensor to simulate a 4th for the car then there is no need to physically change a 2013+ for an older car, except that the OBD and contactor control connector at the front has a different pinout. I never understood why that was necessary, but oh well.

The discussion about the temp sensors also made me think about the function of the 25th ASIC that I saw on the BMS board and I now suspect that it is used to measure the temp sensors. Although it would also be easy for the control processor to do that task, since it has 100 pins and uses only a handful for the serial communication on CAN and the serial EEPROM and the serial communication with the 24 ASICs in daisy-chain. I am getting the impression that a 16 or 24 pin device would have been sufficient, but who am I.

I agree that swapping new cells into old packs (retaining the 2011/2012 shell that can be opened and bolted shut again) complete with the old contactors, service disconnect, wire loom, sensors, bus bars and BMS - just swapping out the cells themselves (still retained in their end plates, so you have 3 modules: the half-pack of 24 vertical modules and two quarter packs of horizontal modules. All can be moved by 2 strong people, though you may need protective gloves. The weight of the 300+ pound halfpack was enough to almost break skin when carrying it by its brackets with bare hands. It is just a lot of time to undo and re-do almost 300 bolts in a safe way. The only creativity needed is to move mounting brackets for wire loom attachment to the new pack, since it has mounting bolts every 2 modules instead of every 3, and to remove the power connection ends of the old bus bar and attach them to the new bus bar, because the old bus bar interferes with the brackets on the new half pack. Also the temp sensors cannot be inserted at the same module positions, but that is not a big deal.
Total amount of time is more than a full day work. I actually cut myself on a sharp bracket when my wrench slipped from a very tight nut, so I had to stop a few days halfway re-assembling the new pack, because I needed 2-hand dexterity to allow safe working on this. Also I was doing a 3-way swap and this cost me at least 2 full days, spread over almost a week, after the initial attempt to simply bolt the new pack into my neighbors Leaf and finding the reduced power due to the pairing issue, I had to:
- remove their old modules from my old neighbor's pack
- install the new Lizard modules
- re-install all bus bars (I had taken the 24-module bus bar completely apart to adapt to the new modules)
- then put all original 2011 wiring, contactors, disconnect and wiring loom back in the 2011 shell with the new modules
- retrieve their original BMS from my secure storage and plug it in after a quick prayer
and then bolt it back into their car,
turn the car on and confirm *no more error lights*!
Then secure everything, add belly pans and button everything up and take it onto the street to confirm full power and no speed limiter.
*Then* I had to put the gutted 2015 shell away (anybody interested? I still have it, together with 2015 belly pans that fit this pack)
and retrieve the "Washington State" pack from my own Leaf, open it and remove everything except the modules.
Then the creativity started: how to put the 2015 contactors (with different plug wiring and current sensor delete) and disconnect (with new current sensor attached) together with the new wiring loom and bus bar wiring all in the 2011 shell with different mounting positions?
That was the slowest part of the job, but I found solutions for all issues, sometimes hacking off or bending away extra mounting references, or banging a leg to bend it enough that an almost-fitting mounting hole could be used, sometimes inventing new fastening. And a couple things I simply re-used the original 2011 part such as the mid-pack reinforcement bar.
So yeah, this is not something that a business would easily do but a shade-tree person like myself can spend their own time on it and get their own car to run normal with a new pack.
I still have the reduced-to-75% original pack from my neighbors, together with another pack that I picked up from Sac City auto dismantler
and those two will go into my EV truck to give that a range comparable to a 2016 Leaf's 30kWh pack... So many projects, so little time. Good that I can re-use the Leaf BMS'es on those two packs, I will need to write some SW for the CANary project to read the two CAN buses from the two BMS'es and present the two packs as well as alert on overcharge (turning charger off) and under-dis-charge to alert the driver to stop driving or even override the accelerator to draw ever less power from the pack and in case of emergency, drop contactors.
 
Valdemar said:
Read somewhere that newer modules charge to higher voltage, so while some capacity might be inaccessible when using 2015 modules + 2011 BMS it should be safe, the reverse can be unsafe, I suggest you research it more before starting using 2011 modules with 2015 BMS, if that is what you plan to do anyway.
This concerns me a bit, because this is exactly the situation that my Leaf pack is now in.
So, I wanted to ask if you can share some typical values of charging a 2011 pack and I can compare that with what my 2015 BMS reports,
hopefully the cell voltages to SoC ratio will tell if this is indeed an issue or not.
Some points of reference: I did charge my pack to what the BMS reports as 88.8% and the pack voltage was 394.01V and the cell voltages were centered around 4.106V with one cell (highest) voltage 4.120V
Earlier (before charging) it was reporting 68.4% at pack voltage 385.08V and cell avg 4.013, max 4.020
Before removing the 2015 BMS from it pack of Lizard cells, I saw it report SoC 89.8% at a pack voltage of 394.11V with
Cell voltage avg 4.106, max 4.117V

And I have a measurement how the old 2011 BMS reported a pack of 394.30V saying the avg cell voltage is 4.101 and max 4.116V
and reports this as 91.7% SoC so it seems indeed that the 2015 BMS expects that it will charge a little higher, seeing that essentially the same
cell and pack voltage is reported as 2 to 3% lower SoC
But this means that the difference between the two versions BMS should be about 9 - 14mV per cell if my calculation is correct:
88.8% - 68.4% = 20.4% representing 93mV so the 2 - 3% difference in reported SoC for the same cell voltage means that the same SoC would correspond to 2 or 3 x 4.6 mV or about 9 - 14mV for the 2 - 3% reporting difference. That means slightly higher charge voltage for the 2013+ pack but not really that much to worry about, it is about the same as the spread between the cells. If I wanted to charge to the same voltage, it seems I would need to tell the BMS to charge to 78% iso 80 and to 98% iso 100%.

Please confirm if this is along the lines of what you have heard about the difference between the two BMS'es.
 
I didn't investigate too much into the differences at the time and no longer have the original pack in my 2011, so can't provide much useful data here. A 2015 replacement pack in my 2011 Leaf charged today to min/avg/max=4.104/4.114/[email protected]%SOC and 281Gids.
 
My 2016 pack at max charge is currently giving me 4.090, 4.106, 4.123 mv, 91.5 SOC, 275 GID, and 394.1V.

My wore down 2011 pack was 4.077, 4.084, 4.091 mv, 95.7 SOC, 173 GID and 392.16V.
 
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