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In my recovery time I've had time to study automotive stuff. My dream is to create my own EV from the ground up. Studying which companies supply different parts needed to do what I would like. Many things will begoing into the dream car and by choosing intelligently I can make it upgradeable. Thread
07:56 PM - May 03, 2023
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First is deciding what type of vehicle to make. I chose an SUV/work van for practical reasons. I want it to be comfortable, safe, utilitarian and lightweight. This means thinking about noise, vibration and harshness (NVH), crashworthy and pedestrian friendly, about to haul 8×4 panels and decent load
08:03 PM - May 03, 2023
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capacity and the lightweighting involves lightweight materials.
So, after looking into mateirals I chose carbon fiber (CFRP) and Dyneema/CFRP for structural and CFRP for the skin along with structural foam for NVH and crashworthiness. Also, attaching using 3M structural glue to simplify assembly.
So, after looking into mateirals I chose carbon fiber (CFRP) and Dyneema/CFRP for structural and CFRP for the skin along with structural foam for NVH and crashworthiness. Also, attaching using 3M structural glue to simplify assembly.
08:11 PM - May 03, 2023
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3D design & finite element analysis are now available for free through Onshape and this design will be open to the public on their site. I plan to do a Body in white (BIW), skin, powertrain, suspension & battery pack in the first phase. Suspension, powertrain, suspension & battery are off the shelf
08:17 PM - May 03, 2023
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The cool part is instead of trying to fit these into and existing chassis and having to modify, I can tune the vehicle to the requirements. I also decided to do body on frame. This again allows for more design flexibility.
That's about all for right now. Have a great evening. Will return.
That's about all for right now. Have a great evening. Will return.
08:27 PM - May 03, 2023
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Well, why I'm sitting here staring at Off Mane St Salon, I thought I'd add to this thread.
Wheels or Why I'd rather have 16" or 17" rims. practical reason is tires are cheaper. There's more sidewall which means less NVH and less chance if popping tires off rims. Wide tires are another thing...
Wheels or Why I'd rather have 16" or 17" rims. practical reason is tires are cheaper. There's more sidewall which means less NVH and less chance if popping tires off rims. Wide tires are another thing...
02:45 PM - May 04, 2023
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Wide tires means less efficiency and more cost to replace. Something like a 205/55R16 is cheap compared to 22s. This is a practical vehicle, not a car show daily driver.
So, now we can move on to practical, but ridiculous. There are many types out there, but the 4 link suspension is going ...
So, now we can move on to practical, but ridiculous. There are many types out there, but the 4 link suspension is going ...
02:52 PM - May 04, 2023
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... on both front and rear. Gasp! you're not making a rock crawler are you?! No. But why?! This has to do with tons of factors. Rear was already a given, but front had me looking at vehicles that don't break under reasonable conditions. Since I'll drive on pavement, gravel and dirt...
02:57 PM - May 04, 2023
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... it evolved into this decision.
Well, Dianna's back gotta go.
Well, Dianna's back gotta go.
03:00 PM - May 04, 2023
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Powertrain is an elusive beast I don't need 800HP, but I don't want a 40 hp go kart. Using recovered motors with aftermarket controllers seems to be the best of both worlds. You can use motors however you need & not have to pay for a subscription. I would need torque as I'm not planning on racing.
11:23 AM - May 05, 2023
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There are a plethora of choices, since this is in planning stage it's a toss-up between VW and Tesla motors. I can find plenty of Tesla drive units on ebay cheap, relatively. There are plenty of aftermarket controllers that replace the factory and they usually come with the entire subframe. Bonus!
11:28 AM - May 05, 2023
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Given the entire geometry will have to change to shaove in the used subframe it means I would get to recycle a lot of aluminum. So, there's a company that bought GMs magnetorheologic suspension system (Cadillac Escalade ESV). BWI. It turns out the make a ton of other cool things too.
11:38 AM - May 05, 2023
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BWI makes Suspensions, Air Suspension, Brakes system and Motor Mounts. This includes active 4 link bars. All with the capability of reducing NVH. This means less guessing and more real world numbers in the design.
11:47 AM - May 05, 2023
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So, I covered powertrain, suspension and now I should probably talk about power. This is a moving target. Right now there are many packs available on ebay and other sites, but as the market changes the packs get more dense. Some of the newer technologies may even remove a need for cooling.
03:34 PM - May 10, 2023
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So, the question is do I wait or build with what is available? Also, of what is available, which companies will be around when time comes to change out the packs? What I'm reading about manufacturers pretty much states CATL then everyone else. That's frustrating to say the least. I could make them.
03:39 PM - May 10, 2023
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The tech to make a pack is not that difficult and I could recycle cells instead of entire packs. This will probably be the way to go if I want to guarantee tight tolerances. Time for more research.
03:45 PM - May 10, 2023
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Ahh, battery design. I looked at the Netgain Hyper 9" motor specs. Then, I decided LFP 32650 cells are the way to go for now. 56s4p/pack (series and parallel) would be the way to go. The case would end up roughly 72"×6"×6" including cooling plates & wiring. Still have to figure out weight per pack.
06:29 PM - May 10, 2023
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Didn't get to the edit in time. Still crunching numbers. The series portion will remain 56 due to Voltage. It's figuring out parallel numbers vs how many kwh I would like to have.
06:42 PM - May 10, 2023
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Let's say 100kwh pack. Well, if it is not stacked then it is roughly 6'×10'×6". That's awkward. So, dividing the packs into manageable chunks that can still put out the Amps needed and stack is better for the overall design. I could probably use less, but I figure start big and cut back as needed.
06:56 PM - May 10, 2023
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It turns out the pack would really be about 3" thick instead of 6". This changes many things. 6'×5'×6" is a lot smaller and can be designed around.
03:29 PM - May 13, 2023
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Totally forgot to mention the pack configuration. 56s88p. Which works out to 2 parallel packs at 56s44p stacked. This would be a full battery dimensions 5'×6'6"×6", which should fit nicely between some frame rails.
04:16 PM - May 15, 2023
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With respect to cooling, I believe dielectric coolant is the way to go. It cuts down complexity and weight. As well as making the battery easily recycled or serviced. The next part is conforming to charging standards to make life easier and making custom BMS for the packs.
04:19 PM - May 15, 2023
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Been trying to figure out seats. Car seats are rarely comfortable. Also, they are usually super heavy. I may have to design these too. Basically I would like a comfortable semi-off-road vehicle that weighs between 3-4,000 lbs kerb. So, CF frame with structural foam for the chassis. Fun times.
03:03 PM - May 18, 2023
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Well, Smooth-On sells a bunch of different densities of foam. Turns out industry standard is 4 pound density. Also, this foam makes a skin and it can maintain shape in a mould. This makes it water-resistant and cuts waste to a minimum. Frame design is next. Pininfarina is on my short-list.
06:14 PM - May 18, 2023
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So, looking at IIHS standards and kind of frustrating getting a straight answer with respect to frame design parameters. Basically, they're more worried about the intrusion bar and B-pillar and the headrest height. The placement of airbags is important as well. But frames seem to be anything goes.
12:54 PM - May 19, 2023
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My wife is much smaller than me, so I'm making some huge calipers utilizing 3 yard sticks. Measuring her seated dimensions versus mine are some huge differences. This makes placing the steering wheel and passenger dash airbags critical and being able adjust their heights to fit the person.
01:03 PM - May 19, 2023
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Side-impact airbags really only need to cover the windows and split the middle ground for head-knocking. Back seats will get the same treatment. I'm going with 2 driver + 2 passenger seats. More safety and more comfortable. Rear seats will need to be removable, though. Anyway, I digressed. Frames.
01:10 PM - May 19, 2023
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When I finish a rough draft I'll post it. 3 dimensions I would like to adjust are seat back height, headrest, and seat cushion depth. Angle adjustments, fwd/back, and height would be included. It would be a pretty sophisticated chair, but a lot safer.
01:16 PM - May 19, 2023
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Smooth-On is one incredible company. There are so many things I can utilize. It makes molding processes less wasteful and I can make different weights of foam for different parts of the car. I could even make a buck fill it with foam and carve it. Then mold the panel molds from that. Anyway lots to
11:26 PM - May 21, 2023
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do. Now I need to start with some simpler projects to build up to the main. First will probably be replacing the instrument panel cover in my old 2004 Cavalier. It literally disintegrated one day in traffic.
11:29 PM - May 21, 2023
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So, it turns out my first project will be emptying the garage. It's a herculean task, but it needed to happen anyway. Then, my first project will be making the center console in the cavalier.
01:45 PM - May 30, 2023
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I have the measurements taken from the car. Length from plane of radio to the edge of the back seat is 36". The width between seats 5.5". The height from transmission tunnel to my elbow is 14". I've been 2D designing, but once I have a space I can break out the 3D cardboard & foam to sculpt.
01:57 PM - May 30, 2023
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I thought about CAD for this, but really it will be faster and cheaper to mold to the car for an exact fit. Remove old console and layer carboard & plastic sheeting to make a tunnel conforming base and build up cardboard to fill with foam. If I build it correctly, I'll have a rough model of foam.
02:03 PM - May 30, 2023
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Finally got a shop vacuum! Fixing to go clean out the car. Yes! Weird thing to get excited over, but I am a middle-aged guy.
06:08 PM - Jun 02, 2023
