I had another box last week from someone who also ran into trouble. Same issue. Like I mentioned here before.
Anyway. There is a simple fix for this. Cut the heat-shrink shorter at the bottom side, the part that comes in contact with the terminal. And note that a busbar that doesn’t lines up perfectly parallel with the contact area. That may cause issues later on. Especially when the heat-shrink is just a bit too long.
Now. In case that a busbar or terminal is ‘t perfectly flat. Which is often the case. Then I use a metal chisel / hammer to make it fit.
Oh and make sure to use that FLIR camera again when you are done
It is not straight / 90 degrees on the terminal, but that should not be a problem, as long as there is not isolation in between the busbar and the terminal. Correct?
Yup. Correct. The problem is that it is often difficult to see and detect possible problems. This is why I advise people to cut the bottom of the heat-shrink a lot shorter.
Now. There’s something else that I noticed. The surface on that terminal looks really rough. Is this the one that you had installed before? Or is this just related to poor picture quality?
Both the busbar as well as the negative terminal (on which the busbar is connected) are new, fresh delivered. I’ve cleaned everything with acetone before connecting it.
Regarding the rough surface, so you mean on the left of the screw on the picture. Could be both, bad quality picture but also the material itself. When looked at it with normal eyes, the surface looks smooth and flat.
Haha. Yeah sorry. I was wondering about that surface, and couldn’t resist asking about it. Don’t want to sound too negative of course. Just trying to help prevent another issue.
I can recommend this thermal imaging camera MobIR Air.
I bought this to check all my contacts and cables. It was finally cheaper then to rent cameras over the weeks I build the system.
I checkd my installation (all screws with their corresponding torque and with the IR cam) after 6 and 12 months to be sure everything is fine.
i started doing 9 nm for those connections and I will start using only my own bolts. your story here was a bit of a wake up call to take those busbar connections a bit more serious. i am also considering replacing them with my own built copper busbars and do a bolt through solution for tightening properly. I think 5 nm leaves room for error in the sense that it would stop tightening relatively soon, even with a small air gap as a result of that heatshrink. I have been going over your story in my mind and keep coming back to the only possible cause being the heatshrink, as everything else seems to have been done properly
For everyone using a Yixiang V3, please be aware, there is a similar issue
Sound advise!
This is my Yixiang V3 box and this is how they connected the busbar to the internal T-class fuse. Both of my boxes have the issue.
Bottom left you see how the heat shrink is long, on the top you see a mirror that clearly shows how this develops a gap and causes the busbar to not sit flat on the fuse connection.
For everyone using a Yixiang V3, please be aware, there is a similar issue