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Working with Tesla Packs - Model 3

3570 Views 19 Replies 9 Participants Last post by  brian_, 
K
We are beginning to see wrecked Model 3's at the breakers :cool:

Here is the first teardown video that I've seen;

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K
Some info from the EVTV video;

'battery' weight (including charger, HVJB, DCDC, etc) 1054lbs (478kgs) :cool:

80.5kWh (78kWh usable), ~168Wh/kg
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K
Much like the Munro reports had suggested (here), it looks extremely unlikely that the large modules can be split into smaller pieces... that probably rules these batteries out for most conversions :(
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Kevin Sharpe said:
Much like the Munro reports had suggested (here), it looks extremely unlikely that the large modules can be split into smaller pieces... that probably rules these batteries out for most conversions :(
Click to expand...
Looks like you're right. This might have been partly a deliberate effort on Tesla's part to keep people from easily reusing(and abusing) Mod 3 modules. Are overall pack dimensions called out in the video? I wonder if the whole pack, possibly with the electronics hump, could be used under larger vehicles, like your van?
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electro wrks said:
This might have been partly a deliberate effort on Tesla's part to keep people from easily reusing(and abusing) Mod 3 modules.
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Perhaps, but I suspect they don't care about that. Fewer modules reduces assembly and interconnection complexity, so it seems like a natural evolution to me. They probably don't care about having to replace more cells in a single-module repair replacement, because they just replace the whole pack anyway.

electro wrks said:
I wonder if the whole pack, possibly with the electronics hump, could be used under larger vehicles, like your van?
Click to expand...
I've wondered the same thing about most EV packs (Leaf, Golf, Bolt...), since they are all basically flat plus lumps under seats, and often include at least some of these supporting components. Because there is only one lump on this one (at the back for support components), it might be a simpler and thus particularly good candidate.

I'm picturing a compact pickup truck with the pack under the rear part of the cab and front part of the box, but since large packs are quite wide, the truck would need a custom frame (not the traditional ladder frame with nearly parallel rails).
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electro wrks said:
Are overall pack dimensions called out in the video?
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I only fast-forwarded through the video (I couldn't take and hour and a half of this sort of garage chat), but I didn't see a tape measure appear at any point.

electro wrks said:
I wonder if the whole pack, possibly with the electronics hump, could be used under larger vehicles, like your van?
Click to expand...
It looks like the two longer central modules (25s) might fit in Kevin's under-floor box if they are not too long; the question is whether one both of the shorter side modules (23s) would fit across the van anywhere. Is a model 3 module more than twice as long as a Model S/X module? Fitting the whole pack, if possible, would be a more severe structural change, especially if it intruded into the rear suspension structure area.

The Model 3 is not as large as Model S or X, but it is still a large car, with 2,880 mm (113.2 in) wheelbase, so smaller vehicles seem likely to run out of length to accommodate the full pack, or even the modules (because each module runs the length of the pack).

The Tesla powered Mercedes Vito van project might be a better match for the whole-pack approach; it abandons the original structure and suspension, and has ended up with an above-floor rear hump anyway...
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Kevin Sharpe said:
We are beginning to see wrecked Model 3's at the breakers :cool:

Here is the first teardown video that I've seen;

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Crikey. An hour and a half. Have you seen it? Any good?

Enviado desde mi SM-G920I mediante Tapatalk
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el_gallo_azul said:
Crikey. An hour and a half. Have you seen it? Any good?
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It's the usual EVTV format... tons of repetition and opinion with the occasional gold nugget... I play them at 1.5x in the background while doing something else... then stop when I find something interesting :)

I think the video complements the Munro report and is worth watching if you're interested in production EVs.
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electro wrks said:
Are overall pack dimensions called out in the video?
Click to expand...
No.

electro wrks said:
I wonder if the whole pack, possibly with the electronics hump, could be used under larger vehicles, like your van?
Click to expand...
The 'hump' could be removed easily leaving a large, flat 'pizza' battery box... the box wouldn't fit under an early VW van without modifying the chassis extensively... it's possible the modules would fit between the chassis rails but I think they are longer than the space available. That said, the box would be a great fit for some of the larger RV conversions :cool:
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Martii
I don't think it's just deliberate effort but more like low production cost design. Less modules means more job done by robots less by humans assembling just 4 modules into a pack.
electro wrks said:
Looks like you're right. This might have been partly a deliberate effort on Tesla's part to keep people from easily reusing(and abusing) Mod 3 modules. Are overall pack dimensions called out in the video? I wonder if the whole pack, possibly with the electronics hump, could be used under larger vehicles, like your van?
Click to expand...
Sent from my LEX720 using Tapatalk
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K
Anyone thinking of reusing M3 modules will just have to design their project to suit these new sizes and voltages.
Shouldnt be a problem if its considered from the start of the project.
And its early days, but i would not be surprised if someone doesnt figure out how to electrically reconfigure the module voltage/Ah design for different applications......just as was done with the mod S modules eventually.
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Anyone know the voltages of these new modules?


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Martii
Just do the math for 23s and 25s
technomadness said:
Anyone know the voltages of these new modules?


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Sent from my LEX720 using Tapatalk
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Martii
Won't be that easy to change voltages. Also while there are plenty off the shelf products (especially for home storage) that will accept 6s or 7s packs there are almost none that will work nicely with 25s packs. Otherwise powerful (read expensive) dc/dc inverter is needed if you wanted to hook up 100V pack to 48V DC/AC inverter.

EV conversions are rather ok with high voltage packs the only problem is as already mentioned here: it's easier to hide more smaller packs inside converted car than putting few big ones.
Karter2 said:
Anyone thinking of reusing M3 modules will just have to design their project to suit these new sizes and voltages.
Shouldnt be a problem if its considered from the start of the project.
And its early days, but i would not be surprised if someone doesnt figure out how to electrically reconfigure the module voltage/Ah design for different applications......just as was done with the mod S modules eventually.
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I doubt there would be much interest in using these modules in 48 volt systems; the likely modification would be like the Model S/X mod. That means doubling the number of cells in series (and of course halving the number in parallel) by splitting stock cell groups in two and adding interconnections.

Doubling to 46s or 50s could allow moderate range and power with only two modules, or ~180 V system voltage with a single module... in a vehicle with a long but not necessarily wide space available.
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technomadness said:
Anyone know the voltages of these new modules?
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It's in the video...
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kennybobby
Time to get crackin' on the Cell Monitoring Board. Looks like Cell voltage on the left in groups of 12, and ? temperature sense on the right in groups of 8. Appears to be a Primary and Secondary section to the board with signal transformers for isolation of communications lines. Also an "A"(bottom 12 Cells) and "B" (top 13) section for both the Primary and Secondary sections.

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K
Jehu has produced a shorter version of the EVTV video :)

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I wouldnt mind a closer look at one of those boards :D
Wondering what chips they are using for the bms parts.
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Kevin Sharpe said:
Jehu has produced a shorter version of the EVTV video :)
...
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Excellent! :D Thanks for the link.

If this is the "less chatty" version, the original must be unbearable.

The funniest thing in this - which I realize is not intended as humour - is when they take one module off one side of the pack and the rest of the pack almost falls over to the other side because it had not occurred to anyone that half a ton of battery pack should be on an adequate table (or the floor). :rolleyes: Funny now, but that must have caused some hearts to race!

One bit of data: the cell count in a group is 46. That's an even number, so that is compatible with the idea of cutting plates to split each group in two for 46s and 50s modules... although of course BMS details are yet to be worked out.
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