I concluded the previous blog post about making and installing the components of the cooling system by finding the right connectors for the controller. This blog post is about the expansion tanks / swirl pots. Perhaps I would like to explain this first.
Expansion tank / swirl pot, why?
Although the temperature differences will not be great, the coolant will expand and contract. It then wants to go somewhere or come from somewhere. An obvious solution is to simply make an expansion tank analogous to the original closed cooling system of the Amazon that is connected to a thin tube. However, I also want a so-called ‘swirl pot’. Because the coolant flows in along the edge, a rotating movement is created and it vents automatically.
Machining aluminium
So I measured a few things and bought some aluminum. I had never actually worked with that before.
From Mischa I learned that for a nice result it is best to provide the lid with a round edge. After looking at some Youtube examples, I got to work on it myself. First of all, by making a mold. This is a round disc with a diameter slightly smaller than the intended lid and a rounded edge (with a router).
And then sand them nice and smooth.
Then I cut a circle out of aluminum and attached it and then hammered it around.
Pretty nice for a first time.
It will also be the place where I will fill the cooling circuit, so I bought a weldable radiator neck.
And unscrewed the lid so that it fits in.
And then the beginning is there.
The next step was to make the connection to the controller. I still had an aluminum AN8 adapter that I could use. Just increase the inner diameter a bit.
It then goes into the elbow that comes out of the controller.
Then I made a pipe to screw on it.
And then it has to be welded to the swirl pot.
Just to be sure, I tried it on with the bonnet on, but there is more than enough space there.
This way the liquid flows nice and low in the swirl pot so that it can go below the level and you don’t hear a ‘waterfall’.
A similar approach for the swirl pot of the battery cooling circuit.
Batteries Cooling Circuit Expansion Tank
There was also the question of whether the holes for the hoses were not too high.
Those corners are quite tight. First I had to make a distribution block.
Hmm, that doesn’t hold up. A little too little wall thickness. Let’s grab another block.
That’s better, now the tapered nipples can be tightened properly.
It should be something like that after I rounded the back.
Conclusion: the holes in the battery box should be lowered. In this way, a ‘waterfall’ is almost inevitable or the level must be very high. In addition, it remains tight in terms of hoses. So I marked where there is space in the box and made new holes.
Yes, that looks a lot better. Now the pipes run nicely horizontally in a slight curve.
That triggered a new layout issue. The controller and batteries swirl pot are then exactly on top of each other so it was a question of how the controller return pipe should run. The swirl pot at the back of the batteries wasn’t pretty, so I went inside.
Moving controller swirl pot
In that case, the hose would have to kink after the battery swirl pot, or the controller swirl pot could not stay on the corner. I chose to make a new and shorter intermediate pipe. I omitted the AN8 adapter and made the correct male thread myself.
First I twisted a piece of aluminum tube on the lathe to the correct outer diameter and then cut wire with the cutting plate. Just for this wire I don’t have the change wheels to be able to make it with the lathe. Anyway, that’s how it can be done.
Twisted the pipe into elbow and made it fit in the right orientation on the outside wall of the swirl pot. Analogous to this, I also made an outgoing pipe.
The hose that comes on top of it must then be attached to the top connection of the radiator. However, it was not yet in the same plane.
Again I made a zig-zag gradient out of aluminum that sticks through the bonnet trap.
And in this way allows for a movement forward and down and thus fits precisely.
Input manifold front battery box
The input manifold of the front battery box is a bit simpler. It just comes directly against the box. I can then make the same connections on these as those on the battery modules.
So first I drilled out the hexagonal aluminum on the lathe.
And then make the holes in it according to the drawing.
Hmmm, but wait a minute. That’s very little space next to the hole. That will be difficult to seal. Just grabbed a new block of aluminum. At the same time I made a tube on the lathe which is then screwed into the bottom for the supply.
However, the corner at the bottom is beveled so that it ends up exactly at the pump with a 45 degree silicone hose.
In addition to the fork to the three modules at the front, there must also be a branch to the rear for the battery modules there. Directly on the pipe just gets a bit tight.
So I made a connection to the distribution block itself. Because there are 5 modules at the back and it has to go all the way to the back, I wanted to make that connection well in the direction of power.
It just doesn’t look very pretty. After sparring with Ben (Tinustuning) he indicated that it doesn’t really matter at the current speeds I’m dealing with. So I opted for a right-angled connection.
I use the hole at the top that I made to be able to drill out to place a temperature sensor. The distribution block itself was a bit too short for that, so I made an adapter.
That’s starting to happen. Now all I have to do is make holes and tap wire for the ‘quick connect’ connections.
New lids expansion tanks
Now that I had gained some more experience in working with aluminum, I was no longer so satisfied with the first lid I made for the swirl pot. So I made a new attempt. Step 1: mark and make a circle.
This time I took a bigger round.
That is more difficult to make because more material has to shrink to be able to turn the corner, but it does give a nicer result (if I do say so myself).
Now another significant piece of the puzzle has been completed. That is, prepared to be welded.
