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Discussion Starter #1
Well after my 2015 VW Jetta Build hit some snags, especially around making Making Nissan EV stuff talk to the VW ICE stuff that I needed to leave in the car to pass compliance (such as all the safety gear) I was on the hunt for a new car.

After some back, forth, up, down, left, and right, I managed to whittle my plans down to:

  • Mid 90's Mitsubishi Nimbus
  • Mid 90's Lancer
  • 2002-2009 Proton Jumbuck (basically a Mitsubishi Lancer ute)
These were the best cars because
  • No CANBUS, so no interface required
  • New enough to be comfortable or made comfortable
  • Parts readily available for non EV bits
  • FWD drivetrain
  • Good carrying capacity
So anyway, from what it looks like, I'll be able to drop the entire front subframe including motor mounts out of the eNV and slide it into the Jumbuck with minimal issues, I may need a new bonnet as the 4G15 is a very short motor and the eNV setup with the charger on top us comparatively taller.

Now the Jumbuck is narrower than the eNV, 1490 for the eNV compared to 1450 in the Jumbuck, but at 25mm a side, I don't think that will be a huge issue. I'll be getting custom front shafts made to retain the Jumbuck gear at the front because rims are easier to find.

As for weights, the eNV weighs in at an obese 1,667kg unladen, of which ~300kg is the battery and 124kg from the Drive Unit Assembly.

So we're looking around the 419kg mark on that gear.

The Jumbuck by comparison comes in at 1,045kg with a payload of 500kg, however the fuel tank full weighs just over 60kg and the 4G15 weighs in at 115kg, the transmission in the Jumbuck weighs in around 35kg dry, so looking maybe 40kg wet.

So 215kg out of the Jumbuck brings us down to 830kg for the car as it is.

Then adding our electric gear back in at 419kg, I'm gonna round to 420 because why not, brings us to 1,250kg which is only an increase of 205kg over the standard Weight of the Jumbuck and we'll within its rated payload.

This is also a good 417kg less than what the eNV200 weighs in at. I'm told every 10kg ≈ 1km of range, so if the eNV could do 180km as it was, I should get ~220km with it in the Jumbuck.

That's not counting the fact I'm going from a brick with bad drag over the flat back to a ute that, once I drop a tonneau on her, it will be fairly efficient by comparison.

Plus, at a GVM of 1,680kg and a Tare in at 1,250kg still gives me a payload of 430kg, which isn't bad.

However I could probably do a bit of jiggery pokery with the suspension and brakes (like discs in the rear) to then upgrade that more so I go back to having a full payload.

Now I tell you, my wife was utterly mortified when I got home yesterday and told her I've found a canary yellow Jumbuck for $600 on Facebook.

Attached is the only picture I have, because by the time I picked it up it was 8PM and I didn't get home and unloaded until well past 10PM, so I'll get more pics tomorrow.

But it needs:
  • Whole new dash (Will acquire Lancer dash)
  • Whole new front end and bonnet (Again will go lancer front end, more readily available)
  • Probably a whole rebuild of suspension and steering, it looks tired, it feels tired, probably is tired.
  • New rims and tyres, got those fully sick stockies on there for maximum skids at the moment
  • Tonneau cover, it just doesn't have one at the moment
  • LED conversion on all the lighting
  • Full Digital dash Conversion
120044
 

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Discussion Starter #2
Ok, so I have measured my under-tray area and I can concievably cone up with ~1,600 long X 1,180 wide area to mount the pack.

So assuming that the eNV200 pack isn't much bigger than the Leaf at 1570.5 x 1188 then I should be able to make it work by moving the shocks a little bit and maybe different leaf springs.

Anyway, here are some photos:

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Discussion Starter #4
Yep, so a quick rough measure of the eNV200 pack seems to be in the same ballpark as a LEAF pack, so ideally I won't have to do any Pack Splitting to get this in. Even better!
 

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Discussion Starter #5
So the next thing I need to look at is the height, so from the eNV subframe to the top of the charger comes in at ~680mm which is nice
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However at maximum, the Proton engine seems to sit in at around the 650 mark, which is a bit short. That's from where it's current subframe sits.

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So there's a good chance this will necessitate a new bonnet that has a more substantial hump in it.

Thankfully Lancer bonnets and front ends 1992-1996 fit, so there's a good chance that I should be able to do some creative fabrication and get something together for the front end.
 

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Discussion Starter #6
Another important distance here will be the distance between the strut towers, which on the Jumbuck is ~900mm

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And on the eNV is closer to the 960mm

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So for length of bay from any substantial structures such as firewall to front support panel, the eNV is ~680

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And the Jumbuck is around the 810mm mark

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So essentially the only real issue here is 30-40mm of height, and this is not a fundamental structure issue of the car, in fact this is easily overcome in the grand scheme of things
 

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Discussion Starter #7
So, I'm going to be the first person to admit that I'm very big at CAD but I'm also very big it just simply making stuff fit.

My plan here with this whole build is that from here now that I have both cars I'm simply going to drop the engine out of the Jumbuck, drop the motor out of the env200, I'm going to drop the entire rear out of the Jumbuck including the rear axle, and drop the entire battery pack as a complete unit out of the Nissan.

From there I'm simply going to lift the entire subframe assembly from the Nissan into the Jumbuck and maybe a little bit of a bottom spacer, I should be able to take up the majority of the slack that would be over height from the jumbucks current setup.

As for the backend, I intend to just lift the battery pack into place underneath the Jumbuck, I'll fabricate up some mounts to hold the battery pack in place, and then I will likely design a new subframe for the suspension to bolt to. As the suspension will be my width limiting factor at the rear.
 

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Discussion Starter #8
So in direct contradiction to my previous post of "just make it fit" I'm finalising the CAD file for my rebuilt battery pack for the Jumbuck, I've finally sorted the layout, after clarifying some existing advice ended up with a pack that was waaaay too big.

Some people refer to a Module as a single battery, others refer to it as it's installed in the car, which is paired. Once I cleared that up I was back down from 570kg battery weights to a much more acceptable 260kg which is what it should be in just module weight.

Also explains why some people were saying the donor has 24 modules and some that it has 48, in fact it has both. 24 Modules made of 48 Modular Batteries. So that's what I'll find when I open the High Voltage Pack up. It will all be in pairs, which works for me. Definitely a tad confusing.

I will however be incorporating liquid cooling into the battery system, as evidenced by the blue chill plates sitting on top of and below the batteries. Not sure if I'll do a 3rd row, they weigh around 7kg each, so at this point, I think if I'm doing better than Nissan, I'm doing good enough. I doubt I'll be fast charging much or putting her under super high workloads, so this should be more than sufficient.

Total length of the pack comes in at 1,332mm and the width comes in at a respectable 700mm which should fit quite neatly up between the chassis rails.

I'm imagining that once I get the Jumbuck ripped apart and get the bracketry designed, I'll probably add around 100kg to the weight with the reinforced box that needs to be built, and then probably another 75kg with BMS, Wiring, Coolant Lines, Coolant, etc.

So next will be to CAD up the battery box in sheet metal, I have made the support beams will bolt the batteries top and bottom and ensure that they will withstand crash forces if they need to.

The lower beam will be welded to the sheet metal battery box and the upper beam will clamp via bolt to the lower beam through the batteries and chill plates holding it all together.

Then the top cover will slot over the whole lot to form the watertight box.

So this will be narrower and longer than the factory box in the eNV200, which although I could make it fit, it was not going to work well because it would have necessitated raising the back end of the ute by approx 100mm, which is 4 inches in the old money. Something that would make it harder to sign off on, look silly, and overall probably compromise the handling as it would raise the weight by that much as well.

This way I can stick all that weight between the springs and hopefully get a set of springs that will allow me to keep factory ride height, as I don't really want to go much lower as then suspension travel will cause me to slam the axle into the battery box, which over time could cause issues.

Worst case scenario I go with a minor lift, such as 25-50mm (1-2 inches) and can compensate the look by fitting something like 17" rims to the car with a half decent tyre and it won't look too off-balance.

Thankfully I don't have to waste a battery pack by slamming it into a barrier, they are happy for me to send them the CAD files and they will test this all in simulation, which is bloody awesome. Though the criteria under VSB14 are actually not that bad, it's only 20G, I think the limiting feature here would in reality be the actual Jumbuck itself, I'm not so sold the car itself wouldn't tear apart at 20G

So as a bit of a summary, I'm looking that including cooling in this setup, as well as chill plates, I'll be around the 430kg mark once the whole pack is completed, wired, and full of coolant.

Though as some of you may have ascertained, this is partially why I was chasing the axle weights that are allowable on the Jumbuck, as there may have been the need to look into increasing the axle weight limit over the back end.
As it stands, I won't be able to do much more than toss the dogs in the back, however that's probably more than enough for my purposes, as it's going to be the run to work and back car, the nip into town car, the get around car.
Once done though I am more than happy to take it to shows and stuff, and you guys just wait until you see the interior I have planned!

Hopefully I may be able to shed some weight off her in that department, as there's really no need for some of the stuff that's inside the car, I might find myself a really nice vinyl flooring that lightweight, and I'm sure a lot of the heavy, pretty, trim can be replaced with thinner, lighter, and just as functional appointments.
I believe the real weight savings will be in the driveline, as I understand there is a hell of a lot of steel in the Engine and Gearbox alone, which means that I should be well suited to be replacing this with the all alloy EM57 setup from the eNV200

So the 4G15 on paper is 115kg, and the gearbox is around the 40kg mark (I was told 70-80lbs by all the Lancer forums, Proton may have re-jigged the box, but I doubt it will vary that much), so a total of around the 155kg mark, whereas the EM57 Drive Unit comes in at 58kg, so that's a saving of 97kg over the front end.

I mean, the EM57 looks heavier, but hey, it's also all aluminum and heatsinks, so really it can't be that much weight in there.

My biggest concern here is that the front end would be too light, which I had the opposite in my old Jumbuck where the 5 Post bar made her understeer as the front end was too heavy. Now I may encounter the exact opposite problem as the front end may be too light, causing the same issues.

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So an update as I wrote most of the post while rendering images, and then decided to start doing the actual structural frame.

The Lower Mounting Brace comes in at 35.807kg and the upper in at 35.749kg, which did strike me as a bit odd until I remembered there would be a poofteenth of material for the threads, and 48 thread holes is a lot of thread holes.

So this has brought my entire weight up to 335.329kg according to Fusion 360, which isn't great, but it's not terrible.

Oh, what's that, got sidetracked with a brain spark on how to fold the sheet metal problem I've been having, and that was punch some holes in it to avoid intersections, in the real world I can always just weld those up later.

So back into fusion I went and made myself a box. Now an overly pretty box, but it's a box, and it will work as a box, and it will be the battery box. And basically my lid can now just be a lid, nothing special, just a flat piece of 2.5mm plate straight across the top.

120084

So the weight of the box alone as it sits is 37.496kg, brining my total weight up to 372.824kg

So now I have to CAD up tomorrow:
  • Coolant Fittings
  • Coolant Lines
  • Coolant Line Junctions
  • Punch holes in the box to run the coolant lines through
  • All of the wiring
  • A lid
  • The plugs that need to go on the outside
  • Then I should be pretty much done
  • Bolts, McMaster Carr doesn't have appropriate bolts
I'm still not sure if I am going to put the BMS INSIDE the battery box or not, I'm thinking I won't, I might instead run all the lines in a loom down to a plug on the box, then just run a plug, that way if a BMS fries itself, then I can just replace the BMS without dropping the whole pack.

That way too I can change what BMS I am running if I later build a secondary pack and stick it somewhere else. As long as I keep the pinout, which I'll probably go with a 24 PIN Sealed plug and modules 1-24 will be pins 1-24, and on plug 2, pins 1-24 will be modules 25-48 which will also be easy to remember if I put them on the side of the bank they are on (Or I could cross them over for fun and be a real shit to the next guy that works on it)

Now I'm not sure at this stage if I want to go for weight reduction and trim every last gram off this setup, there is room for improvement certainly, but my target is <450kg and if I get to 390kg and then spend a week making it 370kg and then making it 3x more expensive to build, have I really gained anything? I think not.

I'm also using Steel in places I could use Alloy, and might have to change stuff where Alloy can touch steel to avoid electrolytic corrosion of the metals, but I plan to have all the alloy anodised and the steel brace bars coated in rubberised speedliner, so they shouldn't rub through those coatings anytime soon. Hell, this ute has Rhino Liner in the bed and I've already been told by the painter that I can go and get....well, you figure out the rest...if I want him to take that off, so it's hard wearing stuff. The coating probably cost what I paid for the ute.
 

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You refer to the EM57 drive unit as "all aluminum", but only the motor and gearbox housings are aluminum. The gearbox is filled with steel gears, and the motor is backed with iron laminations, copper windings, and some chunks of permanent magnet, on a steel shaft... no aluminum inside at all, and little air space in the motor. An electric motor is much more dense than an engine (more mass for the same volume).
 

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Discussion Starter #10
You refer to the EM57 drive unit as "all aluminum", but only the motor and gearbox housings are aluminum. The gearbox is filled with steel gears, and the motor is backed with iron laminations, copper windings, and some chunks of permanent magnet, on a steel shaft... no aluminum inside at all, and little air space in the motor. An electric motor is much more dense than an engine (more mass for the same volume).
Still, I'm pulling out a cast steel block, unless the numbers I'm finding on the weight of the EM57 are wrong, it's still a significant weight saving.
 

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Still, I'm pulling out a cast steel block, unless the numbers I'm finding on the weight of the EM57 are wrong, it's still a significant weight saving.
Yes, the motor plus single-ratio gearbox is lighter than the engine plus multi-speed transmission... just not because of aluminum housings.

Of course the challenge of EV weight is that even more certainly that the motor will weigh less than the engine which it replaces, the battery will be heavier than a full fuel tank.
 

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Discussion Starter #12
Yes, the motor plus single-ratio gearbox is lighter than the engine plus multi-speed transmission... just not because of aluminum housings.

Of course the challenge of EV weight is that even more certainly that the motor will weigh less than the engine which it replaces, the battery will be heavier than a full fuel tank.
Oh exactly, I won't have much room beyond me, the wife, and the dogs in payload.

But I'll still be a LOT under what Nissan was running in the Van
 

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Discussion Starter #13
Ok, so after another day of adventuring through the countryside and getting stuff done, I didn't get much time on CAD today.

So today's effort has been to get the Coolant Lines installed into the front of the battery box, the Jumbuck stock radiator has 35mm inlets, I decided that I likely don't need 35mm of cooling to go into the pack at once, so I went with 25mm due to packaging constraints.

As none of the off-the-shelf fittings appeased me, I simply CAD'd my own, which is fairly simple to machine up anyway, so it's not much of a drama in that department. Yay! More custom stuff.

What I did decide to go with though was an external BMS, this will be in the cab and will make it easier to access and replace if the BMS decides it doesn't want to live anymore. I'm getting hit and miss reviews on every single BMS I'm looking at, so I'll just play it safe, I have the room external, I'll just make it easily replaceable.

So for this I went with the Plug Socket P48 48 Pin Straight Flange Male Receptacles Right Angle Female Plug Connector For BMS


Elecbee Part No:EB-401-6008

This unit will do all 48 modules on one loom (Huzzah!) and reminds me of the overly complicated and over-engineered stuff I used in the Military, so it's a bit like the flag of Switzerland here, a big plus.

Then I was looking at HV Connectors and decided on the EV Battery Connector HVIL 2Pin 200A Socket For Power Solutions


Elecbee Part No:EB-406-0005

This is big enough, but not too big, and seems to be fairly robust for my use. Space is at a semi-premium under this car so I have to factor in not only the size of the components, but how they will fit internally and externally, no use getting a you beut overkill 1,000A Plug if it then makes the pack 50mm too big to fit in the car.

I have also countersunk the holes in the upper mounting frame, this way I can use Torx bolts with a countersink on them and save me from having an air gap at the top of the pack simply to accommodate the bolts. Bolts are flush, lid will sit flush.

Anyways, onto some photos:

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Location of HV Mounting Plate (Yellow), the BMS Connector (Green), and the Brass Coolant Lines that I have made in CAD.

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View from inside the pack showing where the placement of coolant lines and connectors is in relation to other things, there is a decent 20mm gap between the lowest battery connectors and the coolant lines, so that should be good, now I have to make a Coolant Junction Block to run Coolant to all 24 Chill Plates and then make it all combine again from 24:1 Line to return. I plan to attempt to use equal length hoses, so every plate gets equal flow and equal drain, otherwise no matter where I place the lines some plates will cool more effectively than others. I don't want this.

I will not be CADing up the coolant lines and wires, after looking into how it is done in Fusion, nope, no way, I could spend literally weeks doing it and still not come close to being done, it's not a fun walk, especially if you want to make equal length anything, I'm better off just building the pack and running the lines myself.

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Probably an unnecessary render, however I have changed the colour of the contersink to show in yellow so that it's easier to see against the black powdercoat.

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The pack! Complete! It now has a lid and the major fittings on the outside as well!

Also if you note along the bottom there is a rail running along, I have to re-do this, as some of the bolt holes intersect, however there will be 24 M10 High Tensile Bolts each side for a total of 48 High Tensile Bolts holding the pack into the rails that I make for the car (Need to strip car next to finalise design for that part, I may not even CAD, I may bolt it together and then just weld it up once it's in the car)

The whole pack will also be bolted to the car by my estimate, around 8 M17 Bolts either side utilising Triangular Braces and utilising body mounts that I will steal from a Toyota Landcruiser welded to the body of the car, this will have the unsightly effect of going through the tub to some plates, but a thick rubber tub liner with some grooves will alleviate the visibility of that.

This will also help dampen the pack from any vibrations or harshness of the road, although yes it will effectively become a moving weight at this point, and according to Fusion, 395.296kg of Steel, Stainless Steel, Aluminium, Lithium, and Plastic. Oh, and some Brass and Rubber.

Honestly, for a home project, I'm probably overkill on the effort, however the last thing I want if to one day get in a crash if it happens, plan for the worst, expect the best, but in a crash the last thing I want to do is flip the car and send a 400kg battery straight through the front of a McDonald's or a School and then have it catch fire.

Next up I will be running simulations on the pack once I have it "bolted together" in CAD and I can crash test it in theory, which if the results are accurate and pending the engineer re-doing the simulations, I'll be all gravy to send the plans to a local Fab Place and get them to CAD it up. I may send along a Leaf Module for reference, as I'm not 100% on the bolt holes being millimetre perfect even if the overall pack Dimensions are.

The hardest bit will be the box itself, for that I have to get it out of Melbourne from a laser cutter, as only one person I have found so far can laser cut such a large piece of sheet and then have the facilities to bend it. Thankfully, I have contacts down there that can handle the logistics of getting it from the fab shop to the powdercoaters and then onto a truck for me. Is good to run a 4x4 Accessories business sometimes. But with the state of Victoria in Stage IV Lockdowns at the moment, and if things don't improve, Stage V, then I might have to source the box from somewhere like NZ or elsewhere, which will be painful with the shipping costs. Might have to get it cut there and bent here, which is not a desirable outcome, as that could lead to issues with the alignment of things.

Thankfully the rest of the frame can be done just 10km down the road at a local fabrication shop, same place I am getting to build me a car trailer, so he's frothing at the mouth for this project, he's keen to buy the car off me when I'm done. Might just build him one instead.

I have to say, I didn't expect the kind of reception that I am getting from some people, I expected the naysaying, however every fabricator I have talked to, every Auto Sparky, and every HV Electrician I have discussed things with has been really keen to know more. Driving my wife nuts on this, because I go out for one tool and come back an hour later after a good chinwag, and most people see the advantage of a car that can do 150km on a charge, as expected, most people are driving less than that round trip daily, and when I tell them how cheap it will be to run, they want one.

But I bet most don't want to do the work to get one.
 

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I will however be incorporating liquid cooling into the battery system, as evidenced by the blue chill plates sitting on top of and below the batteries. Not sure if I'll do a 3rd row, they weigh around 7kg each, so at this point, I think if I'm doing better than Nissan, I'm doing good enough. I doubt I'll be fast charging much or putting her under super high workloads, so this should be more than sufficient.
While I don't think there's any question that an active thermal management system is good for performance and reliability, I'm not sure how much benefit there will be in this case. Each module is a stack of four pouch cells, and this pack is composed of double modules, so each double module is a stack of 8 cells. That means that there is a chill plate on the face of each module, adjacent to one cell but further away from the other cells. In the two-layer scheme, the upper double modules are sandwiched between chill plates top and bottom, but the lower double modules have a chill plate on only the top side. If cooling (or heating) is attempted at a significant rate, there will be a substantial temperature difference between cells, depending on how far they are from the closest chill plate.

In module of stacked pouch cells designed for liquid cooling, there is either a fin with circulating liquid between each pair of cells (the LG Chem design for the Chevrolet Volt), or a thermally conductive sheet between each cell pair contacts a chill plate along the long edge of the cell (such as the LG Chem design for the Chrysler Pacifica and Chevrolet Bolt). That's a lot more even than cooling (or heating) the top face of a stack of horizontal cells.

It would be interesting to place temperature sensors at extreme locations within the pack and see the temperature distribution while actively cooling (or heating).
 

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The whole pack will also be bolted to the car by my estimate, around 8 M17 Bolts either side...
Do you really mean M17 bolts, and sixteen of them? I don't think I've ever seen a bolt that large on a car. M14 is about the top end; wheel bolts are typically only M12. What size are the bolts holding the packs up into the NV200e and Leaf?

Honestly, for a home project, I'm probably overkill on the effort, however the last thing I want if to one day get in a crash if it happens, plan for the worst, expect the best, but in a crash the last thing I want to do is flip the car and send a 400kg battery straight through the front of a McDonald's or a School and then have it catch fire.
I don't think the design effort is overkill. Whether it is a single homebuilt unit or one of a million production vehicles, the hazards are the same and it is worth doing properly. The big difference is that a high-volume production design justifies more thorough optimization (for weight, and manufacturability, but mostly for cost).

I'm really impressed by the thought and attention in this design. (y)
 

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That CAD is looking amazing! Glad to see you're being careful about battery storage (I'm not, might have to fix that someday).

I have 2 things to say -- first, the Leaf/eNV200 is 96 cells, packed into 48 modules, so you need 96 (97) cell taps for the BMS.
Second, that awesome 48-position plug and socket is only rated for 125v, and if you use 2 of those there will still be ~180v across each plug. I hope you can test those thoroughly before installing - a 180v short isn't pretty.
 

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I have 2 things to say -- first, the Leaf/eNV200 is 96 cells, packed into 48 modules, so you need 96 (97) cell taps for the BMS.
Second, that awesome 48-position plug and socket is only rated for 125v, and if you use 2 of those there will still be ~180v across each plug. I hope you can test those thoroughly before installing - a 180v short isn't pretty.
Good catch - I skimmed past the BMS details so I missed both the off-by-factor-of-two pin count and the voltage rating.

It's actually 192 cells, but 96 groups of two cells in parallel each (96S 2P), so for BMS purposes the important part is the 96S configuration. The centre tap terminals of each module are actually in the CAD renderings, although they appear to be shown as identical to the power terminals (I assume they're actually smaller, as they are in a Leaf: power terminals are M6 and the centre tap terminal is M4, and the post is a smaller square). This image provided by daltonguitar in another DIY Electric Car thread nicely illustrates the terminals (of an early Leaf single module) and how they relate to the internal configuration:
 

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Discussion Starter #18
Good catch - I skimmed past the BMS details so I missed both the off-by-factor-of-two pin count and the voltage rating.

It's actually 192 cells, but 96 groups of two cells in parallel each (96S 2P), so for BMS purposes the important part is the 96S configuration. The centre tap terminals of each module are actually in the CAD renderings, although they appear to be shown as identical to the power terminals (I assume they're actually smaller, as they are in a Leaf: power terminals are M6 and the centre tap terminal is M4, and the post is a smaller square). This image provided by daltonguitar in another DIY Electric Car thread nicely illustrates the terminals (of an early Leaf single module) and how they relate to the internal configuration:
Ahh I see, as I have done 4 rows of 6 batteries, assuming each battery had 2 modules in it, for a total of 48 modules.

I then thought 48 spots to stick a wire to meant I needed 48 wires.

As for the CAD, yes, I just made them look the same as it was one of the things I didn't need to be millimetre accurate for this rendering.

As per your picture I thought the new ones were simply 2 of those stuck together?

Do you really mean M17 bolts, and sixteen of them? I don't think I've ever seen a bolt that large on a car. M14 is about the top end; wheel bolts are typically only M12. What size are the bolts holding the packs up into the NV200e and Leaf?


I don't think the design effort is overkill. Whether it is a single homebuilt unit or one of a million production vehicles, the hazards are the same and it is worth doing properly. The big difference is that a high-volume production design justifies more thorough optimization (for weight, and manufacturability, but mostly for cost).

I'm really impressed by the thought and attention in this design. (y)
Yes, M17, might go to 4 per side if I don't need that many, but that's what mounts the tray on my ute, what mounts the tow hitch in, etc. So overkill yes, but overkill is underrated.

While I don't think there's any question that an active thermal management system is good for performance and reliability, I'm not sure how much benefit there will be in this case. Each module is a stack of four pouch cells, and this pack is composed of double modules, so each double module is a stack of 8 cells. That means that there is a chill plate on the face of each module, adjacent to one cell but further away from the other cells. In the two-layer scheme, the upper double modules are sandwiched between chill plates top and bottom, but the lower double modules have a chill plate on only the top side. If cooling (or heating) is attempted at a significant rate, there will be a substantial temperature difference between cells, depending on how far they are from the closest chill plate.

In module of stacked pouch cells designed for liquid cooling, there is either a fin with circulating liquid between each pair of cells (the LG Chem design for the Chevrolet Volt), or a thermally conductive sheet between each cell pair contacts a chill plate along the long edge of the cell (such as the LG Chem design for the Chrysler Pacifica and Chevrolet Bolt). That's a lot more even than cooling (or heating) the top face of a stack of horizontal cells.

It would be interesting to place temperature sensors at extreme locations within the pack and see the temperature distribution while actively cooling (or heating).
See I didn't think the lower ones would need as much thermal management as they are basically right next to the underside so they will get some benefit from airflow over the box when driving.

I could add more plates, but at an estimated 7kg a plate, a further 12 of them is a further 84kg.

I mean, doable easily, just a weight concern, as I only have 500kg to play with over the back end here.
 

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Ahh I see, as I have done 4 rows of 6 batteries, assuming each battery had 2 modules in it, for a total of 48 modules.

I then thought 48 spots to stick a wire to meant I needed 48 wires.
It's more obvious in more typical modules, which have more cells in series (and therefore there are fewer modules)... but a BMS monitors at the cell level, so there is voltage measurement to make and possibly a discharge resistor to connect across each cell group... 96 of them in a typical modern EV pack, regardless of the number of modules.

Other modules normally have a multi-pin connector attached to connect to the BMS wiring harness, of much smaller gauge wiring than the power wiring. In the Leaf, the module BMS connector would only have 3 contacts, so instead Nissan uses a harness with individual ends to connect to each terminal, and probably only made the centre tap as large as M4 because a smaller screw is awkward to handle.

As for the CAD, yes, I just made them look the same as it was one of the things I didn't need to be millimetre accurate for this rendering.
Sure... but it's a detail that needs to be considered before you make the wiring harness.

As per your picture I thought the new ones were simply 2 of those stuck together?
Yes, although those early modules have complete metals "cans" and the later ones have less metal, the double modules are (in dimensions and electrically) simply two of the ones pictured, stacked together with the power terminals in opposite orientation (so the positive of one module is beside the negative of its partner). So the pair of modules have six terminals: two positives, two negatives, and two centre taps. If you connect all modules in series (as you will to use the Nissan motor), the positive of one will connect to the negative of the next, and the centre taps connect to nothing except the BMS, so in the set of 48 modules there are 49 power terminals plus 48 centre taps, and thus a total of 97 connections to the BMS.

Yes, M17, might go to 4 per side if I don't need that many, but that's what mounts the tray on my ute, what mounts the tow hitch in, etc. So overkill yes, but overkill is underrated.
Do you really mean M17, or do you mean a hex bolt with a hex head which is 17 mm across the flats (fits a 17 mm wrench)? "M17" would mean that the outer diameter of the thread is 17 mm. A typical Japanese (JIS standard) automotive M12 (12 mm diameter thread) bolt has a 17 mm head (ISO is 18 mm and DIN is 19 mm for the same M12 thread). I'm not sure about tray bolt sizes, but hitches, brake calipers, and similar major fasteners are commonly M12. A tray (or pickup box in North American terms) is commonly held by only four or six bolts and needs to contain a ton or so of load laterally, so it might have bigger bolts... but an F-150 uses six 7/16" or 12 mm bolts.

See I didn't think the lower ones would need as much thermal management as they are basically right next to the underside so they will get some benefit from airflow over the box when driving.

I could add more plates, but at an estimated 7kg a plate, a further 12 of them is a further 84kg.

I mean, doable easily, just a weight concern, as I only have 500kg to play with over the back end here.
That makes sense.
 

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It's more obvious in more typical modules, which have more cells in series (and therefore there are fewer modules)... but a BMS monitors at the cell level, so there is voltage measurement to make and possibly a discharge resistor to connect across each cell group... 96 of them in a typical modern EV pack, regardless of the number of modules.

Other modules normally have a multi-pin connector attached to connect to the BMS wiring harness, of much smaller gauge wiring than the power wiring. In the Leaf, the module BMS connector would only have 3 contacts, so instead Nissan uses a harness with individual ends to connect to each terminal, and probably only made the centre tap as large as M4 because a smaller screw is awkward to handle.

Sure... but it's a detail that needs to be considered before you make the wiring harness.

Yes, although those early modules have complete metals "cans" and the later ones have less metal, the double modules are (in dimensions and electrically) simply two of the ones pictured, stacked together with the power terminals in opposite orientation (so the positive of one module is beside the negative of its partner). So the pair of modules have six terminals: two positives, two negatives, and two centre taps. If you connect all modules in series (as you will to use the Nissan motor), the positive of one will connect to the negative of the next, and the centre taps connect to nothing except the BMS, so in the set of 48 modules there are 49 power terminals plus 48 centre taps, and thus a total of 97 connections to the BMS.
Ok so if I understand you here, I need to have 1xBMS line running to the centre post of each module, and 1 running to the positive post of each module, so that's 2 connections for each group of connection points?

Do you really mean M17, or do you mean a hex bolt with a hex head which is 17 mm across the flats (fits a 17 mm wrench)? "M17" would mean that the outer diameter of the thread is 17 mm. A typical Japanese (JIS standard) automotive M12 (12 mm diameter thread) bolt has a 17 mm head (ISO is 18 mm and DIN is 19 mm for the same M12 thread). I'm not sure about tray bolt sizes, but hitches, brake calipers, and similar major fasteners are commonly M12. A tray (or pickup box in North American terms) is commonly held by only four or six bolts and needs to contain a ton or so of load laterally, so it might have bigger bolts... but an F-150 uses six 7/16" or 12 mm bolts.
Now that I've looked into it further, I probably could get away with smaller bolts, I didn't really see the need to go at the bare minimum standard, but maybe M17 would be overkill? I suppose I could get away with 4 x M14 each side, or even 6 x M12's, I just want to be absolutely sure that it will stay where I want it.
 
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