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Here's one of the pictures I took during my cell swap. You can see if you zoom right in some of the "floating island" boards have the two tiny traces to the sensor and some don't. Most are along the top edge in the picture. It looks like the sensor is above the corner of the steel tab on the cell.

129058
 

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Lots of useful info in there too. Thanks for the link.

It seems a quite few people are going over the same ground with the theory but no one so far has gone on to invest the amount of money required to actually have a go at this and physically experiment to find out how to crack the firmware problem.
I fully intend to do that.

My most hopeful estimate is that this will cost about £6000 all in to try this, if nothing goes wrong. I think the financial risk is actually safeguarded to an extent by the fact that the batteries, which make up the bulk of the cost, have a higher private resale value than they will cost wholesale. I could simply dismantle everything and sell the batteries and mitigate the investment that way.
I regularly see cells like these for sale individually for £7 - £8 each and I'll hopefully be paying less than £3 each for about 1,800 cells (even more hopefully nearer £2) So if I sold them for £1 more than they cost me wholesale it would recoup all the costs of the project altogether.🤷‍♂️

Well... that's how I'm talking myself into this anyway.;)
 

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I just had a quote come through for 88 of these cells. £4965 shipped from China. I assume there would be import duty to add to EVLITHIUM's quote too but I haven't looked into that. Still, good performance for the money, but they said they couldn't send me just one for "testing" so I'll be continuing down the 21700 path for now.
But here's the info for everyone else to peruse.
Samsung batt.png
 

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Sorry, but I have obviously missed something. Aren't these cells the type used in the BMW i3? If so, could you not look to purchase a used pack from an i3 which would surely be cheaper? I appreciate that they will have been welded together into blocks but this saves you the job provided that you can package them into the space available within the i-MiEV?

 

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Sorry, but I have obviously missed something. Aren't these cells the type used in the BMW i3? If so, could you not look to purchase a used pack from an i3 which would surely be cheaper?
I don't think you missed anything chap. I actually didn't know these cells were used in the i3.
I guess if someone were interested in a pre-owned battery swap then even i3 cells at 80% would be better than the old LEV-50's in the I-MiEV.
I am really focused on putting new cells in a car as the primary goal for this project so I'm overlooking all those options personally but that doesn't mean it's not a viable option for others.(y)
 

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New cells + hacked BMS... or custom intermediate comms device... or cracked I-MiEV ECU... or custom replacement BMS... or entire bypass system with replacement dash... or who knows. Waaaay too early to tell.

Pretty sure the old BMS/ECU won't accept such an extreme change in capacity, though we'll see how deep into it I can get with the MUT3 equipment. I'll post updates for the project here as and when.
I am going to make some videos and put them on YouTube too once I'm all set up.
 

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Sounds like optimism will be needed.😁

The current measurement trickery sounded to be as the only viable way to use the existing BMS.

NOTE, car drivetrain and braking is totally integrated with the BMS, probably 10s of thousands of manhours required to reengineer.
 

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Knowledge is power.;)

Does anyone have any first hand experience with spot welding kit for battery assembly?

At this stage I'm looking at this unit (when it's back in stock)
 

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UPDATE: Purchased so far...

20x LG M-50 cells £60
Keenlab Battery Spot welder £344
Complete MUT-3 Equipment £555
Fluke 87 Multimeter £150
LCD Energy monitor £14
OBDLink MX £75
Hanmatak soldering station + consumables £45
Assembly materials £12

TOTAL SO FAR = £1,255.00

Once everything arrives there will be a certain amount of familiarisation required with it all before I can start to plan the actual project. Plus I should be setting up a workbench to work at so it will still be a while before I get into any actual construction etc. Still, I'm really looking forward to it.
 

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UPDATE:

The LG-M50 cells I bought have been vigorously tested at 10A continuous discharge and found to be stable with no excessive heating etc. but are only officially rated at 7.3A. This is actually a little low for the LEV-50 replacement pack I was planning which has a 300A discharge rating. The LEV-50 form factor only allows me to stack twenty 21700 cells together and so the cumulative discharge rate in parallel for the LG-M50's is 200A at best.

I can't find the post where I read it but I did see someone claim that the I-MiEV motor only draws up to 150A and that the pack is well over spec but I wouldn't bet the farm on it at this point.

So, I've been looking at alternative batteries with the LEV-50 for comparison...

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Finding wholesale prices for these is proving difficult. However the Lishen cells can apparently be purchased directly with the list price shown and have been independently tested by the excellent testing resource lygte-info.dk under the Shockli brand which is supposed to be the same battery re-branded. The problem is, well... trusting a Chinese supplier to supply what they advertise frankly.

Otherwise it would be a viable cell for the job.
 

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Looks like the best replacement pack for the LEV50s is another set of LEV50s!!!!
If I could buy them new that would definitely be the easiest option!!:D(y)

Incidentally, regarding the cycle life in my spreadsheet, these figures seem to be referring to max to min charge/discharge cycles. A BMS that keeps the cells 90/10 or even 80/20 gives you less useable capacity but is VERY good for increasing the cycle life. I've seen evidence of 4 to 6 times the cycles before the batteries reach 80%

Take 1760 of the Panasonic NCR21700A built into a 32.5Kw pack.

With 90/10 charge/discharge range set by the BMS leaving you 26Kw useable and giving say 2000 cycles to 80% (out of fresh air estimate) and an initial real world range of 120miles, the cells wouldn't hit 80% until you'd covered 216,000 miles and at that point the real range of the car would still theoretically be 95 miles.

Cheapest I've seen those cells is £4.60 though so £8,100 just for the cells. Ouch.😬
 

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Is there not a more powerful version of the LEV50 ? Like LEV50 ForS Just from memory when it was discussed say 3/4 yrs ago.
 

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KenB
Yes. LEV-50N and then the LEV-50EN I think.

But Yuasa tell me they don't make or sell them any more though they have supposedly ensured Mitsubishi have adequate stock for re-fitting the battery packs to fulfil warranty claims.
The UK Mitsubishi dealership I have been in contact with however will not even engage with me about it. Whether I enquire about a complete replacement battery pack or somehow (and very unlikely) purchasing the individual cells they seem to be ignoring such enquiries. This may be due to the current Panicdemic of course and I have put all such enquiries on hold for the time being.

P.S.
If anyone ever reads this who has any experience with purchasing new EV cells I will be happy to gain any further insight.
 

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There's an i3 pack on the bay at the moment that would meet your needs if you can get around the capacity issues:

i3 94Ah pack £3,500

33kWh at that price is a good deal, and may be worth it even if your car only uses 100% off the original capacity at least the pack is likely to last for ever.
 
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