Search found 31 matches

by necrogt4
Fri, 15 Jan 2021, 12:06
Forum: Batteries, charging, management and monitoring
Topic: E63 LG 63Ah NCM battery group buy
Replies: 36
Views: 6002

Re: E63 LG 63Ah NCM battery group buy

Are you still able to source these cells or put me onto your supplier?

I'm in need of 24 to add to the 100 I'm buying from one of your previous customers.
by necrogt4
Fri, 01 Jan 2021, 10:41
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

But yeah basically it was a very expensive failure due to a very small weakness. The new pack won't be liquid cooled, but it could feasibly be done with a cooling plate sandwich. How will the cost / performance compare between the two packs? It sounds like there's quite a bit of fabrication work in...
by necrogt4
Wed, 30 Dec 2020, 20:21
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

I'm not a fan of battery cells living right on top of the motor. Electric motors get hot . On Weber's MX-5, most of the worst cells (before his recent upgrade) were on top of the motor. The closer to the middle of the block (where the motor was underneath), the worse the cells were. So if it's poss...
by necrogt4
Wed, 30 Dec 2020, 20:04
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

Not sure how happy they will be living upside down, but it's an innovative approach! I'm also working on 18650 based battery packs right now and while it might be a bit late, they do have one advantage - completely customisable shapes and sizes. Have a Look at the Prelude thread and see what you th...
by necrogt4
Tue, 29 Dec 2020, 20:15
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

So this design has a few less modules (18s4p) with more to go into the spare wheel well. I've used acetal as an insulator between modules, on busbar clamps and also for the enclosure. Aluminium is used for the frame, busbars and chill plate. There is also a 3mm thermal pad sitting on both sides of t...
by necrogt4
Tue, 29 Dec 2020, 19:44
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

As I mentioned a few posts ago, I've finally settled on a battery choice after much much design and testing. I was pretty hard set on using CATL NCM 50Ah prismatic cells, I even ordered sample cells from two different distributors in China (which I'm looking to sell now) and put them through some pe...
by necrogt4
Tue, 22 Dec 2020, 10:06
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

Nice project Luke. MX-5 is a good choice. Was the hyper 9 an obvious choice for you? Or did you dwell on it for a while? What else did you consider? Only asking as I'm just starting my own journey and also have a rear wheel drive 2 door that ways about 1 tonne. Well firstly it was a budgetary const...
by necrogt4
Sat, 19 Dec 2020, 18:13
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

The standard 1.8lt from my series MX-5 is rated at 118kw peak and 180nm peak and the Hyper 9 going in is ~115kw peak and 235nm so it's only a 30% increase in torque. If it does break I do have the option of using a gearbox from an RX-7/8 with a little bit of work. That said, if the motor is strong e...
by necrogt4
Fri, 18 Dec 2020, 10:22
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

If only I had the room for a hoist. Being able to "stand" while working under a car would be awesome. One day I'll have a shed bigger than the house to fit all these things in.

How many friends have asked to use your hoist since you've put it in?
by necrogt4
Fri, 18 Dec 2020, 09:42
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

Haha, it's always the way. There's really not much I am not confident in having a go at in fabricating, and the back and forth with engineers for parts that you can mostly make yourself seems like a good reason to make a bigger workshop!
by necrogt4
Fri, 18 Dec 2020, 07:01
Forum: General EV Discussion
Topic: SA govt to introduce road user tax for electric vehicles
Replies: 11
Views: 357

Re: SA govt to introduce road user tax for electric vehicles

So this will generate less than $1,000,000 in revenue. How much is it going to cost the tax payers for it to be put in place? And then when the next government comes along and this madness is scrapped for something a little more forward thinking? I don't see how this benefits anyone...
by necrogt4
Fri, 18 Dec 2020, 06:12
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

Hey Chris, it's moving along well at the moment, I think I've finally locked in my battery choice (simple and robust but a wee bit expensive) after iterating on a heap of different CAD designs. I've also after being screwed around with delays by two separate suppliers of gearbox adapters (~8 months ...
by necrogt4
Tue, 27 Oct 2020, 12:00
Forum: Batteries, charging, management and monitoring
Topic: Normal/Acceptable Battery Sag?
Replies: 0
Views: 326

Normal/Acceptable Battery Sag?

I'm running some battery tests of 50Ah NCM cells (supposedly CATL) that are rated to be able to handle 5-8C. Pulling 200A / 4C out of these cells sees a voltage drop of about~1.6V (~0.5V per cell) from three cells in series with 12.3V of charge (3.7V nominal, 4.2V max per cell). The voltage ticks do...
by necrogt4
Tue, 20 Oct 2020, 08:50
Forum: Technical and conversion discussion
Topic: Running PTC heater core under voltage range
Replies: 1
Views: 205

Running PTC heater core under voltage range

My knowledge of PTC heater cores is limited, but from what I can gather they're really just a big resistor. I'm curious to know, what sort of issues would / could there be when running a PTC heater core under the specified voltage. For example, running a heater core rated between 200-400v DC at ~100...
by necrogt4
Thu, 10 Sep 2020, 15:11
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

I decided to get serious about tools and workspace a bit over a year ago now and upgraded from my Ikea kitchen bench to a set of cheap Ebay shelves and some Bunnings supplies. I wanted something standing height that would have everything I needed within arms length. So from this: https://drive.googl...
by necrogt4
Thu, 10 Sep 2020, 14:54
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

CZal wrote: Wed, 09 Sep 2020, 18:01 Nice looking car Luke!
Thanks! It'll look even better once it's moving under it's own electricity...
by necrogt4
Thu, 03 Sep 2020, 20:21
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

There will be a large battery box in the engine bay that sits behind the front axle that holds 80 cells and another smaller box in the fuel tank cavity that will hold a further 40 cells, the charger, contactor, fuses and DC/DC converter. The fuel tank cavity (see below) is pretty small. One of the r...
by necrogt4
Thu, 03 Sep 2020, 15:11
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

I also mentioned lighter seats, there's two reasons for this.
  • I'm too tall for the standard seats
  • These seats are half the weight and look twice as good (IMO).
Image
by necrogt4
Thu, 03 Sep 2020, 15:09
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Re: Luke's 2001 NB MX-5

As I was saving for a house and the HyPer 9 motor I decided to get busy with convenience electronics and teach myself how to use Arduino. I'm not a fan of manually holding power window buttons down, it's a thing. So now I don't have to... A couple of four relay boards 12V -> 5V signals into the Ardu...
by necrogt4
Thu, 03 Sep 2020, 14:58
Forum: Batteries, charging, management and monitoring
Topic: Pack Busbar Sizing
Replies: 14
Views: 488

Re: Pack Busbar Sizing

For whoever is interested, I've started a build thread...

/viewtopic.php?f=33&t=6647
by necrogt4
Thu, 03 Sep 2020, 14:57
Forum: Members Machines
Topic: Luke's 2001 NB MX-5
Replies: 27
Views: 1026

Luke's 2001 NB MX-5

So I started collecting parts a couple of years ago while saving for a house so things we're pretty slow going. I've bought the house and have a lot of time at home these days so things are moving along much much quicker. The first few posts will be a bit of a catch up, here's the short and curly of...
by necrogt4
Tue, 01 Sep 2020, 11:58
Forum: Batteries, charging, management and monitoring
Topic: Pack Busbar Sizing
Replies: 14
Views: 488

Re: Pack Busbar Sizing

Ok, well I'd better get into gear and put some photos and words up... I've been collecting parts and saving for a house since last year. I've got the house now and plenty of time at home in Melbourne so things are moving along pretty quickly now. Re the Carbon Fibre walls, I don't know much about th...
by necrogt4
Tue, 01 Sep 2020, 09:29
Forum: Batteries, charging, management and monitoring
Topic: Pack Busbar Sizing
Replies: 14
Views: 488

Re: Pack Busbar Sizing

Laser welded actually. Well that's the plan at the moment. Good point regarding the very very thin plastic wrap. I am intending on using carbon fiber walls for the enclosure, I could quite easily have some more cut to size to create dividers. Technically I'd only really need it between each module. ...
by necrogt4
Mon, 31 Aug 2020, 12:34
Forum: Batteries, charging, management and monitoring
Topic: Pack Busbar Sizing
Replies: 14
Views: 488

Re: Pack Busbar Sizing

What you have there will work except for the first(last?) module. You just need to make sure the current enters and leaves each module from opposite corners. That's such a good (and obvious now that I look at it with fresh eyes) point!! Thanks. Copper is superior to aluminium in all but weight. Cor...
by necrogt4
Mon, 31 Aug 2020, 10:55
Forum: Batteries, charging, management and monitoring
Topic: Pack Busbar Sizing
Replies: 14
Views: 488

Re: Pack Busbar Sizing

Sounds like I'm going to need a meatier busbar. Moving to 25mm x ~4mm should cover 95mm2 but I'm assuming you mean copper? I'm looking to run the cells in parallel modules like so (see picture). How does one ensure current is evenly shared? https://drive.google.com/uc?export=download&id=1GGVdY8gAS58...