Aftermarket iMiEV battery upgrade project

[antiscab]

Whot you mean about battery Molicel INR-21700-P42A?
Maximum charge is 8.4A. With use 15pcs. We have max charge 126A. This is enought for DC-DC charging (max. 125A)

https://www.imrbatteries.com/content/molicel_p42a.pdf

In europe cost 1pcs 4.3€. One LEV50 = 65€. All pack 5720€.

that's a lot of welding to do, using such little cells
most of the cost would be in labour for assembly

[jonescg]

I'm going to be using 2300 individual 18650 cells for the Prelude battery. Not looking forward to it.
In the case of repacking the iMiEV modules it worked out to be not much better than the original cells because of the wasted volume, but 21700 cells might be a better fit.

[nuggetgalore]

Whot you mean about battery Molicel INR-21700-P42A?
Maximum charge is 8.4A. With use 15pcs. We have max charge 126A. This is enought for DC-DC charging (max. 125A)

https://www.imrbatteries.com/content/molicel_p42a.pdf

In europe cost 1pcs 4.3€. One LEV50 = 65€. All pack 5720€.

5720€ = about AUD 9440 . Add to that freight and cost of manually assembling into 88 cell units and 12 modules. If your labour cost is zero, maybe a proposition.
The amount of effort Chris put into preparing the 60Ah prismatic cell modules would be dwarfed by the amount of work required to do that with cylindrical cells. The only thing maybe a bit easier would be the the connection to the BMS boards as the paralleled cells could be placed in a straight row compared to the LiYuan 60Ah in a zigzag fashion.

[dracekvo]

My opinios is That use 60Ah is not good idea. This cells have max. charge only 60A (1C). This battery will be quick degradation with DC charging or full recuperation.
I want make cell from 21700 exactly dimension like LEV50. Yes my work cost zero. After that i can replace only some worst LEV50 and testing.

[Pierantoine]

Replacing only worst cells is not a good solution because of the voltage / current curve.
To be interesting the voltage difference between a group of good and bad must be really high. it can happend if there is a problem on one cell or two but if it s just because the pack is too old the difference between the best and the worst will not be high.

[adoepner]

Could one of the proponents of this project please provide a link to the 93AH cells used? I did not see anything of 93AH with screw terminals on liyuan's website (http://www.liyuanbattery.com.cn/en/prod ... 81261.html) currently. Were they a custom order?

Just a lurker in Canada here, but watching this with great interest for an eventual upgrade to my 2012. For now the original battery is still under warranty (until 2022).

Thanks,

Andrew

[coulomb]

Could one of the proponents of this project please provide a link to the 93AH cells used?

No, there isn't one.

I did not see anything of 93AH with screw terminals on liyuan's website currently. Were they a custom order?

Yes, a custom order. Basically, "put as much NMC as you can into this LFP case which almost fits". Once volumes increase, it might turn into "put as much NMC as you can into this custom case that will fit even better". That might be closer to 100 Ah, perhaps even over 100 Ah.

[adoepner]

Glad to know they would entertain a custom order. There must have been a significant cost premium, particularly on a small production run. None of the cells currently listed on their website (even LFP) are even close to a drop-in for LEV50.

If there ever is a bulk order of cells in the future, keep me in mind. I'll come on board if the price is reasonable and I'd happily re-purpose the older LEV50s in my car to a stationary application.

Andrew

[SalmonFish]

Could one of the proponents of this project please provide a link to the 93AH cells used? I did not see anything of 93AH with screw terminals on liyuan's website (http://www.liyuanbattery.com.cn/en/product-788672-81261.html) currently. Were they a custom order?

Just a lurker in Canada here, but watching this with great interest for an eventual upgrade to my 2012. For now the original battery is still under warranty (until 2022).

Thanks,

Andrew

Please, reply to this message when you get the answer. I'm also interested in 93AH cells.
Thanks in advance,
Eugene

[coulomb]

I'm also interested in 93AH cells.

You should both contact Oz-DIY (the EV arm of Suzi Auto), as Graeme recently called for expressions of interest in cells or complete iMiEV/Minicab upgrades.

https://www.ozdiyelectricvehicles.com/contact-us

[tonyw]

Mike, how is the spoofing progressing?

That box you showed on the previous page - where does it connect? Does it connect to the swamp of intelligence under the rear seat? Or does it hang out from under the dashboard?

I'm assuming you don't have to drop the battery out to make adjustments to the spoofing.

[coulomb]

Mike, how is the spoofing progressing?

We're waiting for the next set of cells, to test on the next vehicle.

That box you showed on the previous page - where does it connect?

It has to connect between the battery (or in the battery box, but hard to adjust) and the BMU. The needed wires are in shielded cable, so it's easiest either just outside the battery box (where I put it for the first Minicab), or under the left rear seat (where I think it should go in an iMiEV car). In a Minicab, it might be better to put it near the BMU (in the left back somewhere), but I didn't get the opportunity to try that with the first cell replacement.

It's still not totally clear whether we will want/need to adjust the spoofing in the final design. It's looking to me that we might.

But if we don't, it might make sense to put the spoofer inside the battery after all; people from interstate could ship up the battery box, Oz DIY changes over the cells and adds the spoofer, and the battery with spoofer is shipped back to the owner. So then interstate people "just" need to find someone that is able to swap battery boxes. Oz DIY can sell the old cells to make the price more attractive. At least, that could be one option.

[adoepner]

You should both contact Oz-DIY (the EV arm of Suzi Auto)

Done! Thanks.

Andrew

[tonyw]

It's still not totally clear whether we will want/need to adjust the spoofing in the final design. It's looking to me that we might.

Perhaps there is a case (pardon the pun) for a programmable spoofer, accessible via the CAN bus from outside...

[SalmonFish]

I'm also interested in 93AH cells.

You should both contact Oz-DIY (the EV arm of Suzi Auto), as Graeme recently called for expressions of interest in cells or complete iMiEV/Minicab upgrades.

https://www.ozdiyelectricvehicles.com/contact-us

Thanks for sharing. I'll get back here when I contact them!

[Kudra]

*waves* newbie here. I've been considering purchasing an older minicab-miev if upgrade becomes an established reliable option, I'm located in Melbourne if there are any locals with one I could have a peek at?

I also have a question. There's another thread about solar panels on an minicab-miev which is an interesting idea, I understand the pluses and minuses, but I'm curious if it might not be a good option to have a second battery back installed that you can swap between, so you could be charging one while the other is in use and basically acts as a back up on the go charging port? The report of someone in Brisbane who has a second battery bank and overcomes the software issues to achieve range made me wonder if there isn't another way which also makes a second battery useful for other purposes. I want a work vehicle with 240v, but with the option to use that battery bank for either work stuff, OR increased range? And to be able to say, drive out to an off-grid location for a week at the absolute edge of range, and then slowly charge back up to full with solar?

This question could probably be equally posed in the solar minicab-miev thread, but I think it is relevant to both because the object of upgrades largely is increased range? Is there a way to make a second battery easily swappable, wiring-wise?

Cheers
Kudra

[whimpurinter]

I have an imiev and they are lightly-built. I've had a small car with a certain number of batteries which made it thump around if the speed wasn't low or the undulations reasonable. In that car, the battery mass was quite noticeable through the handling with heavy-ish steering and when changing throttle position.

So I wonder what sort of imiev it would be with any significant increase in battery load. Also, if we worry about leaf and mitsubishi outlander battery degradation where the batteries would be fairly consistently made but not tesla-battery controlled, you're going out on a limb intending to go to extreme range with that equipment, let alone have the time for solar recharging, what with cloudy days, low input from panels to many small batteries etc.

Having been through the previous experience, I lost faith in aftermarket-equipment-reliability compared to a 'bought one'. It seems to me that what you want is the promised Tesla 4WD thing which, it is said, will have the battery-bank-gear version for tradespeople.

So, I don't believe you should imagine a high-performance ev for a song (although so many do .) Songs are light entertainment.

People here love to play with electronics, or they buy brand EV's, drive them and discuss the early-adopter issues that arise. They don't love electronics and drive what they made, unless they live to play with them (outside work hours ).

Edit: Added )

[mark_hetho]

Kudra - the battery pack weighs 300+kg and requires the car up on a hoist to easily remove. A car really has to be designed around battery swapping, and have a specialised station to do it at due to the weight involved. You might be able to break a battery into 10s of small modules that could be individually swapped, but it would eat a lot more volumne.

Bladecar - the replacement cells being proposed are generally of a higher capacity for the same weight (or less weight and same capacity). I agree with your thoughts on needing reliability, and generally that meaning you need to pay for it.

[Blake_S]

Battery weight difference and any mods done to the battery pack casing or internal structure will need an engineer's assessment for it to be approved in South Australia. Not sure what the rules are for other states.

[jonescg]

I think if anything the battery weight will be identical...

[antiscab]

Battery weight difference and any mods done to the battery pack casing or internal structure will need an engineer's assessment for it to be approved in South Australia. Not sure what the rules are for other states.

only if you tell them

[nuggetgalore]

Ok, after a long delay I can now report that the 60 Ah cells that originally were in Perth are finally installed in my iMiEV in Melbourne.
There is some good news and some bad.
As far as the physical work of fitting the CMUs into the frames and base I am quite proud of what I have done. Once I had the pack out, it became obvious that a lot of re-engineering was necessary to accommodate the varied aspects of securing the modules and ancillary equipment and also retain to some extent the airflow both from the aircon and the hot air exhaust fan.

and a view of the front row with the A/C duct and service plug base. I had to build a special jig to suspend the service plug base in the correct position in mid air to fit the busbar to the negative of CMU 07.

I think I did a reasonably good job of pre-balancing the cells, the half pack volts both read 175.3 V and full pack 350.6 V (both EvBatMon and i909 confirmed the pack V at 350.4 V.
And now the bad news: All CMUs report their correct total voltages and cell volt differences of less than 0.01 to 0.02 V.
Except cells 33 and 34 (CMU 05 cell A & B) where the voltages jump from as low as 0.57 to as high as 5 (!) V.
CMU 05 cell monitor IC and all other data reports normal except volt underflow and volt overflow on cells A &B FAIL .
Nevertheless the car goes into ready and with the traction control off it happily spins the wheels.
Sadly ,but not unexpectedly, it refuses to charge, i909 reports (P1A39 =charge state signal error [BMU] (1/3)s well as
P1A62 = CMU 05 cell voltage high.
So what did go wrong there? Did I damage the BMS board? The cell monitor reports normal as do the voltage sensor and reference volts.
Is maybe the connection from the cells to the board poor? Could I despite the double and triple checking of the connections have missed this one?

[coulomb]

Ok, after a long delay I can now report that the 60 Ah cells that originally were in Perth are finally installed in my iMiEV in Melbourne.

Well done.

Is maybe the connection from the cells to the board poor? Could I despite the double and triple checking of the connections have missed this one?

Yes, I'd say so. It seems that when a BMS sense wire (or track in this case) goes open circuit the BMS reads one very low voltage cell and one very high right next to it. Some of the BMS voltage sense connections also have a thermal sensor. I hope that these sensors connect thermally to the cell terminals.

[nuggetgalore]

Ok, after a long delay I can now report that the 60 Ah cells that originally were in Perth are finally installed in my iMiEV in Melbourne.

Well done.

Is maybe the connection from the cells to the board poor? Could I despite the double and triple checking of the connections have missed this one?

Yes, I'd say so. It seems that when a BMS sense wire (or track in this case) goes open circuit the BMS reads one very low voltage cell and one very high right next to it.

Thanks for the reply.
The battery obviously will come out again and since the BMS boards (except on CMUs 6 and 12) are readily accessible I may find the culprit.

Some of the BMS voltage sense connections also have a thermal sensor. I hope that these sensors connect thermally to the cell terminals.

.
The thermal connection from cell tabs on the LEV50s to the BMS board is short and direct.
Right from the start I have had some concern that the thermal connection will be poor to non existing for all intents and purposes with the long thin tracks on the intermediate board and flywires. That is why I added a temperature sensor inside the centre of CMUs to have a more realistic idea of how hot the cells get. The wires for these can be seen coming out of the cold air inlet on the picture of the front set of cell units. They are currently just poking out into the passenger seat area, not connected yet to the digital displays, first I have to fix the real problem!

[jonescg]

Well done Andreas! Yes it's always a bigger job than first imagined. Glad you got everything to fit in the end. The two 4-cell modules weren't too difficult to manage?