CarBEN EV5 Full Sized Prototype Construction - 5 Seat Electric Car From Scratch

[NeilBlanchard]

Yes, it is great to see it in the physical world! The back is a bit smaller than I thought it would be; which is a good thing. Overall, it is a little bit smaller than I pictured it - and bit longer (due to the gluing process) and that is also good. I knew that this method of construction would not be the most efficient at doing certain parts, and I really had to make my best guess at the entire inside of the motor bay.

I am thinking that I'll use honeycomb composite boards to reinforce the suspension attachment to the foam. I like the way Gary Krysztopik (the guy building the EZ-EV open source project) is using honeycomb and a CNC - he stacks them up a lot like I am stacking foam.

The main difference between my overall method and most other car builds is that I am doing it "from the outside in" because I started with the design of the outside. I also designed the passenger compartment to try to allow for 3 tall people and 2 shorter people to fit - so the "inside" is the space occupied by the foam and the motor compartment. The structure and the suspension mechanicals and the hinges and latches and rain gutter, etc. - all have to be built after the outside and inside surfaces.

I considered doing it the conventional way, but my skill set is not in bending steel tubes or welding, etc. and I wanted to "control" what I know is the most important part of efficiency i.e. the aerodynamic drag. The structure is hopefully going to be "more than the sum of its parts" because about 8/10ths the chassis is one big piece. I'm hoping for light weight by virtue of using the chassis as a stressed monocoque shape.

Obviously, the other *key* reason for doing it this way is by using the PhlatPrinter 3 CNC machine, I was able to directly transfer the 3D virtual model into physical reality with some bit of accuracy. I know now that I would have been better off having periodic braces across the hatch door opening (and I have already added these in the CAD sections, and they need to be followed through to the foam layout sheets), but what I have will do nicely for now, thankfully.

So other people can build a CarBEN EV5 for themselves, too! With the updated g-code files that I can provide you, and a PhlatPrinter 3 and about 98 sheets of 1" Dow foam and 3-4 gallons of glue (rough back-of-the-envelope guess is the cost for all these is now ~$3,600) you can build this car up to the point I have now.

[California98Civic]

Considering "the template" and your interior space/seating goals, would a rear engine have been better for creating space in the forward areas, where "the template" shape provides more of an interior void. An engine could more readily fit in the aft, narrower area. I have to imagine you have thought of this and that there are design, construction, or marketing factors counting against it that I'm not fully aware of. What are they?

[NeilBlanchard]

The electric motor(s) will easily fit in the motor bay. I very much want it to be front wheel drive (maybe direct drive via half shafts?) because this is better for regenerative braking.

I'm inside for the first time today! Woohoo!



It seems like it will be *just* tall enough - the plywood floor is about 1" higher than the finish floor and the ceiling is still rough.



Link to full slideshow

I'm still getting used to it - I'll work on the hatch and its opening and see how it feels inside with that in place...

It's wicked cool, if I say so myself!

[MetroMPG]

Originally Posted by NeilBlanchard

I'm inside for the first time today! Woohoo!

Congrats!

Looks like you might need a haircut to fit a little better. If I recall you're about 11 feet tall though aren't you?

[NeilBlanchard]

Hah! My hair is brushing the ceiling - I'm 6'-4" FWIW. The seat height will be important. My "bucket seat" is pretty high tech, dontcha' think?

[Christ]

I think more of a "sports car" seating position will probably be plenty of room without compromising peripheral vision. Leaned back slightly with knee/leg support and 24-30" between the steering wheel and pedals from parallel lines.

[ron]

that looks very cool. I have one question about your front wheel drive . are you going to use a transmission or what . Im concerned with turning with the front wheels coupled , ref post 174

[bennelson]

We used to have the same bucket seats in my Dad's work truck.
Anytime there was a third person in there, they would flip over a 5-gallon bucket....

I DID just realize that this car would be great for anyone with a really narrow parking space or skinny garage. NO SIDE-SWING DOORS!

Another odd thought on the rear hatch/door....

When Tesla came out with that Model X, with the "Falcon Wing" doors, several people in my red-kneck-of-the-woods thought that it would be rather bad for snow. (Snow on roof/doors makes a mess, flops into middle of car, etc.)

Any thoughts on the rear hatch/door in regards to snow or other bad weather or unusual parking situations? I suppose you couldn't BACK in to a small garage.

How's the swing height of the back door for opening and closing it in a garage?

I LOVE seeing this project progress!

[freebeard]

I'm inside for the first time today! Woohoo!

What that picture suggests to me is that you should have a model with 2/4 rear seats that fold into the side walls, and anchors for a wheel chair in the driver position.

You're welcome.

[kach22i]

You are half-way towards making yourself a hovercraft.

It's not too late to change your mind.

Very cool, it's gotta be safer than an old VW Transport bus, right?

I wonder if the seat could ever be made to slide back in a front end collision, getting the driver's legs out of the crush zone. Maybe a large airbag could expand into the leg space as a precaution.

Originally Posted by NeilBlanchard

The electric motor(s) will easily fit in the motor bay. I very much want it to be front wheel drive (maybe direct drive via half shafts?) because this is better for regenerative braking...........bucket seat

FYI: if you haven't picked up all of your electrical/mechanical parts, I spotted some stuff for sale yesterday.

Classifieds

A00-4009 Advanced DC Motor
AllTrax AXE 7245 Controller 24-72V 450 Amp Limit
PB-6 Curtis Potbox
Allbright Contactor SW-200 (12V coil)
6 - Trojan T-1275 12 Volt Batteries
PFC-2000+ 110 VAC / 230 VAC 72VDC Sealed Charger
ElCon electric fuel gauge 72VDC
0-100 Voltmeter
0-400 Ammeter
Miscellaneous connectors, cables, etc.

The bucket seat comment was funny, maybe you should make one of those "inspirational posters" and see if it goes viral.