Mitsubishi I-Miev Forum

Hi Enginerd,

Who is your supplier for the LG 21700s?

Andrew

Adoepner wrote:Hi Enginerd,

Who is your supplier for the LG 21700s?

Andrew

Hi,

NKON has them for €4,95. https://www.nkon.nl/de/lg-inr21700-m50-5000mah-7-3a.html

Do the LG 21700 cells have a high enough current rating? They are rated for 7.3A.

An LEV50N is capable of 300A continuous (https://pushevs.com/2015/11/04/gs-yuasa ... vs-lev50n/). You would need 41+ of those LG cells in parallel to be able to deliver a rated 300A. I don't think there is enough room to replace each LEV50 with 41 21700s. A practical maximum I've seen is in the neighbourhood of 20x21700 per LEV50 using this circle packing calculator (https://www.engineeringtoolbox.com/circ ... _1905.html).

Unless we know with certainty what the maximum current the car will draw under any circumstance, I'd only be comfortable replacing like-for-like as far as battery specs are concerned. Lower amperage cells have a higher internal resistance and heat up more under load (and charge).

Andrew

Enginerd wrote:20 x 21700 LG M-50 cells ordered and on their way for initial testing.

....

Enginerd, Did you try the 21700 cells already?

Here's a chinese spot welder https://www.banggood.com/de/10_8V-Spot-Welders-Welding-DIY-Homemade-Small-Battery-Spot-Welder-Pens-Welding-Equipment-Machine-for-18650-Battery-Box-Assembly-p-1639625.html?rmmd=preorder&cur_warehouse=CN

jray3 wrote:Good luck to you, Enginerd! The similar Aussie effort has stalled, and now that I have a 75 mile one-way commute, MR BEAN in on greatly reduced duty, only doing about 250 miles per week of wifely driving, while I do that much per day on a 27 kWH Kia SOUL and my company car, a z2012 LEAF that we have upgraded to 40 kWH with an 2018 battery.

Hi all,
am I correct that "The similar Aussie effort" refers to the 60 Ah cell replacement started in Perth WA?

https://forums.aeva.asn.au/viewtopic.php?f=49&t=5515
or a bit further down:
https://forums.aeva.asn.au/viewtopic.ph ... &start=275
Anyway, I am now continuing this project.
There are still many questions to be answered, many of those issues only become known as the project advances.
Because of the different shape of the LiYuan cell compared to the LEV50,
the project was started with the cells standing up rather than laying on their sides. Yes that works as far as physically fitting them into the base
The BMS boards will be mounted onto a specially made board so each cell can be connected to the correct spot on the BMS board.
Thinking about that a bit further,I am concerned now that the module may overheat. Two main reasons for that concern are that
a) on the original modules the BMS board including the temperature measuring devices are hidden at the sides of the modules away from the cooling air that hits the cell bodies.
b) worse is that with the BMS boards sitting on top of the cells, the cooling air is going to cool the temperature sensors rather than the cell bodies, giving a false reading of what on the original set up is more like an ambient module or pack temperature.
Any comments would be greatly appreciated.

Enginerd, glad to see that you're moving forward. I read that the project in Perth is having trouble in that the pack works and the car drives beautifully, but the additional capacity is not recognized because the car won't go past a 49 Ah discharge, regardless of cell voltages. That's interesting, and very different from an early LEAF. I wish all of you the best of luck.

jray3 wrote:Enginerd, glad to see that you're moving forward. I read that the project in Perth is having trouble in that the pack works and the car drives beautifully, but the additional capacity is not recognized because the car won't go past a 49 Ah discharge, regardless of cell voltages. That's interesting, and very different from an early LEAF. I wish all of you the best of luck.

The project you are referring to is using 93 Ah cells and is in Brisbane.

The "Perth" project (with 60 Ah cells) is now in Melbourne and waiting for the covid -19 restrictions to end for further progress.

Sorry guys.

It seems only fair to update this thread seeing as I kicked it off again this year, even though I have no information to further the subject.
My whole project is in fact on hold for the time being.
Unfortunately my wife was diagnosed with a terminal condition about 3 weeks before the country went into full lockdown and I am currently in the process of renovating our property having moved into temporary accommodation. So this EV battery project is obviously off the table completely for now.

I think things should have settled down within the next twelve months and I should be able to pick this up again. I am still very interested in learning all this stuff and I still have the vehicle and all the equipment I purchased so, as with many things in 2020, I'll just have to grin and bear it.

Cheers.

So sorry to see this condition for your wife. Continue taking care of her, and thanks for popping back in. If you do restart the battery project, hopefully some of us will have more info to contribute. Good Luck, Jay