Mazda MX-6 build thread (EV conversion)

[freebeard]

What they say on EVTV is once the battery boxes are in the job's half done.

That's a lot of support. Will it be heated/cooled?

[thingstodo]

Originally Posted by freebeard

What they say on EVTV is once the battery boxes are in the job's half done.

That's a lot of support. Will it be heated/cooled?

The support is intended to have the battery case intact but bent, and still within the confines of the car cabin, after an end-to-end rollover. Hopefully the terminals are not shorted on the aluminum bracing

The battery box is inside the car's cabin, so it will be the temperature of the cabin, plus or minus a bit.

So far, I plan to insulate the battery box, so it will be warmer than the cabin most of the time.

I have a supplier that tells me he can do flat PTC heaters in a custom size, with a 2 inch bend radius, as long as I tell him the wattage. But he's a salesman so I will see what I get when I figure out the required wattage.

For the design parameters - I need to warm up the batteries - insulation R value of about 1.5 for the windows plus R10 on the battery box, from 0F (-18C) to a charging temperature of 40F (5C) in about 2 hours from a 110V supply that will give me about 1440W. This is all worst case stuff.

No active cooling - ventilation from outside air coming in, exhaust from the sunroof - our weather here has not reached 95F (36C) in several years so as long as I keep the sunny side windows shaded I hope to avoid air conditioning the battery pack. I didn't remove the A/C from the car as yet - I may connect it if I have enough battery pack ... but I doubt it!

I will be logging temperatures (there are RTDs .. or maybe thermocouples? .. buried in the Better Place packs) while driving and throughout the day .. when I get that far.

[freebeard]

Well, then. let's hope it doesn't roll sideways.

I've thought about the same for my Baja Beetle. I figured to start with a 6- or 8-point roll cage and make the battery box a brace inside that. Steel angle on the tubes holding a basalt fiber box because it's an electric insulator.

[thingstodo]

Originally Posted by freebeard

I've thought about the same for my Baja Beetle. I figured to start with a 6- or 8-point roll cage and make the battery box a brace inside that. Steel angle on the tubes holding a basalt fiber box because it's an electric insulator.

Are the 'holes' in the roll cage small enough that the smallest battery won't fit through?

Basalt fiber box - I don't think I've seen or dealt with Basalt fiber.

I'm using the 3 racks, or cages .. I think racks are a better term .. that came with the better place pack. As you know, 16 cells fit together with beefier end caps, and 4 threaded rods strung through the whole stack.. 3 of those side by side. Rigid styrofoam insulation on the bottom and sides. I need something translucent and insulating for the top .. not sure what as yet ...

On top of what-ever-that-is .. aluminum tubes across and front to back.

[freebeard]

I'm not talking about stuffing the roll bars tubes with cells, if that's what you suggest. It would be a[n angle-iron] box or boxes welded to the roll cage.

Basalt fiber:deejaaa showed some samples. IDK if he reported any test results.

I haven't used it myself, but I follow developments at Basalt Guru. It's similar to fiberglass and carbon fiber, but has interesting admixtures like nano-glass coating so resin doesn't discolor it and graphene additives to radically skew the physical performance.

It has interesting properties like low embodied energy because it's basically melted and extruded rock.

[thingstodo]

Originally Posted by freebeard

I'm not talking about stuffing the roll bars tubes with cells, if that's what you suggest.

Sorry for the confusion.

A roll cage, in my limited experience, has tubes in different directions. They look structural, but there are gaps. I was asking if it was important that the battery pack not be able to fit between the tubes if the battery mounts rip loose during a colission.

Basalt fiber:deejaaa showed some samples. IDK if he reported any test results.

I haven't used it myself, but I follow developments at Basalt Guru. It's similar to fiberglass and carbon fiber, but has interesting admixtures like nano-glass coating so resin doesn't discolor it and graphene additives to radically skew the physical performance.

It has interesting properties like low embodied energy because it's basically melted and extruded rock.

That sounds very cool.

[thingstodo]

Two updates for today since they have no audio.

Mazda MX6 Day 480 Video 038 Oct 22, 2015

https://youtu.be/pA2jUbJT-x4

Mazda MX6 Day 481 Video 039 Oct 23, 2015

https://youtu.be/1E8kKqz99Jg

I'm on vacation - so I have time to edit old videos!

[freebeard]

http://www.thesamba.com/vw/forum/viewtopic.php?p=3796308&sid=2907cde3b8d4024e632717 d801d5f419#3796308
An example from thesamba.com. The box would rest in the area the rear seat cushion fits and be as high as the rear package shelf, held down by angle iron brackets.

Engineered to roll slowly onto the roof, not multiple end-over-end flips.

[thingstodo]

As always, pictures help!

The roll cage I was visualizing was the size of the front seat. Maybe those are only used in race cars?

[thingstodo]

Last update in my backlog

Battery frame in, lots of sheet metal and woodworking to do to plug holes in the floor, between floor and battery frame.

https://youtu.be/YekxqhtgjVI