[mizlplix]

As i have the original contactor, i am not worried.

But if i was stuck with it, i would try using a small 24vdc coil relay, signaled by the controller to trigger 12vdc for the contactor coil. (Kind of a bandaid type work-around).

It was such a nice compact unit i couldnt resist buying one. Afterwards i learned of the issues with it.

Has anyone used one on 12volts only?

[mizlplix]

If you all would excuse me, I will not be posting anything for a week or two.

I am just doing the wiring, but it includes the entire car, lights-accessories-everything. Not much to report.

I always am reminded of the Golden Rule of things electrical: "If you let the smoke out of the wire, you can not put it back in and need to start all over".

I have always considered myself good at wiring in general, but several years ago, I worked in a fleet of 200 School Buses. They have an incredible amount of wiring and involve a good deal of current. It taught me patience.

Later, Miz

[piotrsko]

[QUOTE=mizlplix;256512 I have always considered myself good at wiring in general, but several years ago, I worked in a fleet of 200 School Buses. They have an incredible amount of wiring and involve a good deal of current. It taught me patience.

Later, Miz[/QUOTE]

And the wiring diagram never matches what you have in front of you. Good luck

[mizlplix]

Just a short update: I have been doing the wiring, mounting the coolant pumps for the motor, transmission and controller systems. Making a tip-up seat mount so I had easy battery access. fabbing the top clamping frames for the front and rear battery packs.

Nothing tremendous to report. I am shooting for a December roll-out.

I have some small things left to do. Like, The "Vee" windshield frame, mounting and finishing the grille shell and hood top cover. I guess the final item would be the paint. I might drive the car in red oxide primer first though. In the Great American Hotrod tradition...LOL

I am planning a short video of the first drive.

Miz

[mizlplix]

Greetings to all: I promise, I have been working on the car. Just not much to report or to take pics of....until now.

The subject of a cold plate has comes up from time to time. There are about 3-4 different versions that are in use.

1. One version has two halves with milled channels and is bolted together.
I am leery of the way the hose barbs are screwed into the plate in the crack between them. Pipe fittings are a tapered thread and you are wedging the plates apart possibly causing a leak later.

2. The other versions are OK if you have room for them, but I am in a tight spot and my plate can not be more than 1" thick at most.

Then I met Ivan, a fellow EV'er. He is a very talented guy with a thirst to build and create. His past projects include an electric bike, a diesel Gen Set, a CNC table and an airplane. He can be contacted at ivan@ivan5.net or go to his web site http://ivanbennett.com

He has designed a really simple, effective cold plate that fits into a small space but yet is arguably the most efficient I've seen. He was kind enough to bring me a unit to try on my Roadster build.

OK, This might generate some hate mail, but here it goes.....

Heat conduction through metal takes time. The thicker the metal, the longer it takes. The best design would have been if Curtis had just made passages in the controller, which would have been the best and done us all a great favor. Some motor and controller makers do it all the time. The single down side of this approach is corrosion over time.

Lets get real. An automotive ICE requires 240+ degrees and thousands of heat/cold cycles to see the corrosion we are used to in our cooling systems. Even then, Aluminum radiator cores are .040-.060 thick and take years to corrode through.

Our usage is a lot different. Without a converter, an automatic transmission gets about 140 Degrees F. This leaves the controller as the hottest thing in the system. My system has 2-3 gallons of fluid capacity. It uses a 20 pound heat exchanger and three dedicated pumps. It sounds like overkill and probably is, but the radiator holds the nose of the car and to remove it and build a tubing frame, just to replace it with another heat exchanger was expensive and just wrong somehow.

My point is that I am never going to see over maybe 140 Degrees F, ever. Given the proper fluid, I am looking at a lifetime of use with minimal corrosion.

This cold plate uses an open face and runs the fluid directly against the 1" thick aluminum controller base. .........<he ducks>......



It is 5/8" thick with a 1/2" deep fluid chamber. My inlet is on the bottom and outlet is on the top/right corner to eliminate any trapped air. I have a solid 3/8" thick aluminum sub-base bolted to my firewall. This just sandwiches between the controller and the sub base using anerobic sealer and heat sink paste on the sub plate for a little extra heat conduction....(ok more overkill)

I will be installing it today. Miz

[JRP3]

Very interesting. I wonder if machining channels that provided a definite flow path would have been better than the "bathtub" design. I don't know if you might have a stream of coolant just flowing from the inlet to the outlet with pockets of stagnation on the sides, creating hot spots. Probably not, just over thinking out loud.

[toddshotrods]

Originally Posted by JRP3

Very interesting. I wonder if machining channels that provided a definite flow path would have been better than the "bathtub" design. I don't know if you might have a stream of coolant just flowing from the inlet to the outlet with pockets of stagnation on the sides, creating hot spots. Probably not, just over thinking out loud.

Actually, I had the same thought but got pulled away for some business stuff before I could reply. I would have done channels and probably a few inlets/a few outlets...

Has anyone ever considered bending tubing and casting it in an aluminum plate?

[mizlplix]

Both good points.

In my world...<heh>...it is based on the thermo-siphon principal like the very early auto and tractor cooling systems. The warmer liquid will always rise. The cooler liquid will fill the bottom like filling a swimming pool, pushing the warmer-top liquid out the top/right outlet. That is supposing the inlet volume is slow to medium...

But, it would be easy to insert a bent copper strip to create channels. If I only knew where the localized hot spots on the controller were.

Todd: Funny you should mention that....



Miz

[JRP3]

Did you have to machine the bottom of the controller or is it flat enough to create a seal? I think I saw someone actually machine the base of the controller with passages and bolt a plate to it.
I was toying with the idea of just putting a coil of tubing between the controller base and my aluminum mounting plate and bolting them together. Maybe running the coil through a roller to flatten the tubing out some and increase contact area.

[toddshotrods]

Originally Posted by mizlplix

Both good points.

In my world...<heh>...it is based on the thermo-siphon principal like the very early auto and tractor cooling systems. The warmer liquid will always rise. The cooler liquid will fill the bottom like filling a swimming pool, pushing the warmer-top liquid out the top/right outlet. That is supposing the inlet volume is slow to medium...

I get that, in theory, but the top half of the tank would always be pretty warm. Since inlet volume has to be relatively slow, you can't really suck the hot fluid out fast enough. Maybe you can find out which side of the controller can tolerate the most heat?

Originally Posted by mizlplix

...Todd: Funny you should mention that....
Miz

Great minds right? I wonder what an engineer would think about thermal conductivity between the two metals? If I happen to catch my partner with a spare moment, and remember this, I'll ask him. He's a materials science guy. Ideally aluminum tubing, cast in an aluminum plate would be awesome. What did you bend with? It's collapsing your tubing.