Search found 85 matches

by hallkbrdz
Sep 25 2020 10:41pm
Forum: Battery Technology
Topic: Tesla battery day announcement
Replies: 38
Views: 917

Re: Tesla battery day announcement

At this point everything is a WAG! It's still in development, they don't even know yet what the final specs will be. :wink:
by hallkbrdz
Sep 25 2020 8:55pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

I’m still waiting to get the bus bars laser cut, but battery support frame construction has proceeded. Pictures tomorrow hopefully (drag it all outside in the sun), but for now here is a teaser of future things. Just for fun I quickly rendered what my clean-sheet EV kart would look like using the ne...
by hallkbrdz
Sep 23 2020 8:48pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

MOT wire still not here :( , so I worked on the KWeld. I replaced the tungsten electrodes with copper electrodes (since tungsten and nickel bond really nice). These work great, welding .2mm nickel to .2mm nickel with about 30J as well as to battery cells and let me get into much tighter spaces than ...
by hallkbrdz
Sep 23 2020 10:26am
Forum: Battery Technology
Topic: Tesla battery day announcement
Replies: 38
Views: 917

Re: Tesla battery day announcement

Unless Tesla improves their parts and distribution to aftermarket repair shops, that's going to be really expensive. I've thought about opening up a EV only garage, but working on Tesla's is a sketchy proposition. ??I've been using an old Tesla 15s module for 5 years now for DR. They could surely m...
by hallkbrdz
Sep 22 2020 9:12pm
Forum: Battery Technology
Topic: Tesla battery day announcement
Replies: 38
Views: 917

Re: Tesla battery day announcement

People like me who keep their cars for 10-15 years. And people who want to use them as second life behind-the-meter storage. Unless Tesla improves their parts and distribution to aftermarket repair shops, that's going to be really expensive. I've thought about opening up a EV only garage, but worki...
by hallkbrdz
Sep 22 2020 6:47pm
Forum: Battery Technology
Topic: Tesla battery day announcement
Replies: 38
Views: 917

Re: Tesla battery day announcement

So here are my quick takeaways: Simplified manufacturing, simplified chemistry to end product, and form factor to support structural use. All reducing their costs (good) and allowing for faster production. From a non-Tesla perspective however (unless they actually sell cells direct at some point), t...
by hallkbrdz
Sep 21 2020 6:31pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

I updated the bus bar design to allow more space between parts. Some sites said you should have 1.5x the material thickness for distance to allow better lead-in. Not sure if that is true, but I've mailed the file and specs to a local company to see what they say. Hopefully it is a go and not too cra...
by hallkbrdz
Sep 19 2020 2:18pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

I decided to try and find someone local to try out laser cutting the copper sheet for the bus bars. The target sheet is 24"x24" and this takes up most of it with a little space left on the sides and bottom. I elongated the holes to 8x10mm to make it easier to spot weld across the split in the nickel...
by hallkbrdz
Sep 19 2020 2:09pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 362
Views: 62532

Re: Spot Welding Copper Strips to 18650 Battery Cells

Happy to send you a DXF if you sketch what you want 2D DXF will be fine, no dims or writing needed just make sure you get the scale and units right. Thanks Bob. It worked, mainly the move/copy portion I found very tricky to get to work, along with the direction for the pattern (array). With enough ...
by hallkbrdz
Sep 19 2020 8:39am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 362
Views: 62532

Re: Spot Welding Copper Strips to 18650 Battery Cells

Laser cutting thin metal sheet can be cheap and lots of places do it. - machine cost might typically be 30 an hour. Pretty standard for steel fabrication shops. Recommend you do a DXF for them to make their life easy (recommend "Fusion 360" free software) So I did that yesterday. Fusion 360 has to ...
by hallkbrdz
Sep 19 2020 8:32am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 362
Views: 62532

Re: Spot Welding Copper Strips to 18650 Battery Cells

So I weld the 0.15mm nickel plate to the 2.0mm perforated copper plate first. Then flip it over and weld THROUGH the holes in the copper plate so I'm welding 0.15mm nickel to the cell. You are not going to be able to weld that with the KWeld. The copper sinks the heat too quickly. A WAG would be 15...
by hallkbrdz
Sep 18 2020 5:15pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

Schedule of where this pack build is at - SO many things to do (and still buy)!

https://drive.google.com/file/d/1BVIJ29 ... sp=sharing
by hallkbrdz
Sep 17 2020 4:33pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

For the MOT soldering project that I'll use to solder the copper to the bus bars, I'm going to try with 4 AWG wire. But while waiting for that to arrive, I was curious how many loops of 1/0 I could fit. Two is the answer. :D No, that won't work...
IMG_20200917_142144.jpg
IMG_20200917_142144.jpg (203.58 KiB) Viewed 346 times
by hallkbrdz
Sep 15 2020 7:07pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

BTW, here is what the future motor will be like. This is the hawk60 for comparison to what the size you see for the rather inefficient Motenergy motors.
hawk60sm.jpg
hawk60sm.jpg (459.03 KiB) Viewed 379 times
by hallkbrdz
Sep 15 2020 2:34pm
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 362
Views: 62532

Re: Spot Welding Copper Strips to 18650 Battery Cells

I used the emachineshop.com CAD program and setup my main bus bars with square cutouts. For a quantity of 38 it would be $7.43 each with a $141.21 setup fee. The 24x24 copper sheet I bought was about $95 with shipping, which was enough for those plus 2 each of two other similar parts with some left ...
by hallkbrdz
Sep 15 2020 9:31am
Forum: Battery Technology
Topic: Spot Welding Copper Strips to 18650 Battery Cells
Replies: 362
Views: 62532

Re: Spot Welding Copper Strips to 18650 Battery Cells

67carguy wrote:
Sep 13 2020 10:50pm
Instead of round holes, I was thinking of squares, to accomodate the essentially square pattern of the weld points.
I like that idea, just not the price for the dies. But for your project with SO many cells, maybe it makes sense for something like this:

https://www.mcmaster.com/3449A71/
by hallkbrdz
Sep 14 2020 2:43pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

Thanks... On the motor I decided on the ME1302 over the ME1616 due to a number of factors: 1. Our "local" kart club only has two classes now, B&S 206 and TAG 100cc. I will initially run with the 206 senior heavy group until I get a second battery built. For 206 I only expect to have to run at most 5...
by hallkbrdz
Sep 11 2020 8:51am
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

So the stock KWeld spot welding tips are not going to work, especially on the thick bus bars, for the nickel to cell connections. I think the old STTOS line "bear skins and stone knives" applies here. The holes are 5/8" (roughly 8mm), and although I could make them larger, I'd rather retain more cop...
by hallkbrdz
Sep 10 2020 6:20pm
Forum: Large EV General Discussion
Topic: EV helper spreadsheet
Replies: 4
Views: 500

Re: EV helper spreadsheet

Version 20200909

Added / Changed:

Added more motors
Added more controllers
Added current configurations for various ekart battery packs

https://drive.google.com/file/d/17zbJZl ... sp=sharing
by hallkbrdz
Sep 09 2020 8:49pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

OK, battery setup sorted with the H8, now works great for the nickel to cell connections! Resistance is Futile - However the nickel to copper bus bar assembly will have to wait a little bit. Both the "thin" 0.032 inch (0.8128mm) and 0.08 inch (2mm) copper plates to 0.2mm nickel are just a bit too mu...
by hallkbrdz
Sep 09 2020 10:44am
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1193
Views: 170302

Re: kWeld - "Next level" DIY battery spot welder

This morning for the 0.2mm nickel with 0.8128mm copper plate I tried 100J and placed one electrode on the nickel side and the other on the opposite side of the copper plate. Better weld, but still not complete. Increasing the strength caused a timeout, so I'm going to try two of these batteries in s...
by hallkbrdz
Sep 08 2020 8:14pm
Forum: Battery Technology
Topic: "Copper/nickel sandwich" buses for series connections
Replies: 22
Views: 965

Re: "Copper/nickel sandwich" buses for series connections

Did some experiments tonight with this technique using a KWeld... Welding 0.2mm nickel (8mm with a slit) to some scrap 0.52mm copper plate took 80J consistently. No issues whatsoever. Great bond. Then I tried the 0.2mm nickel with 0.8128mm copper plate and I couldn't quite get a strong weld. Last su...
by hallkbrdz
Sep 08 2020 7:58pm
Forum: Battery Technology
Topic: kWeld - "Next level" DIY battery spot welder
Replies: 1193
Views: 170302

Re: kWeld - "Next level" DIY battery spot welder

I haven't used Pb batteries myself, but have collected feedback from other users on the kWeld product page. A 65AH battery (the 'normal' size for cars, likely also your Subaro) seems to be in the 1000A region, and larger 100AH models are around 1400A. :warn: :warn: Can I make a poll from you guys u...
by hallkbrdz
Sep 06 2020 8:09pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

Set up the kwelder today. I have too much current - so I'll have to use thinner leads or a weaker battery.

One H8 AGM battery with about 760mm of 2GA copper leads is too much for the record... :)
by hallkbrdz
Sep 05 2020 1:22pm
Forum: Large EV General Discussion
Topic: EKartGo Project
Replies: 18
Views: 816

Re: EKartGo Project

Raw footage time lapse of the current 42S10P battery pack. This is the second layer. It uses 420 new Molicel INR-18650-P26A cells that will be tied together with copper plate / nickel strip sandwiches. Cells were measured and sorted into groups of 3.3v, 3.35v, 3.4v, 3.45v, 3.5v, 3.55v, and 3.6+v. Th...