anytime you are bridging terminals with a material I think it is important. Besides, fishpaper is very tough stuff.
I think in our case durability is equal to having insulation. This video surprised me that arcing can occur at DC 80V 6A. The arc occurs when he pulls the wires apart, so drawn arcs don’t require very high voltages.
I have a feeling this could happen in our packs, but the cell fuses should help.
estimates for an arc of one millimeter distance in normal air are anywhere between a kilovolt and 3 kilovolts depending on the weather. a possible arc distance at 50v would be a guess at .05mm. arcing isn’t a worry but rubbing things together, as in this video above, is.
So propose an alternative. The use of fishpaper as a thin insulator is pretty standard stuff, not sure why you don’t like it.
fish paper is pretty standard but maybe something tougher with less dielectric strength is safer. there potentially could be a lot of rubbin going on in the pack and bet insulation breakdown from that happens way more often than an arc through a material.
I would rather not have anything rubbing. You need to use some foam rubber after you heat shrink your pack. Still, you should get your hands on some fish paper, it is tough.
shrink it and suspend it in silicone. nothing rubs.
but to be safe, i wrap my packs in fresh rabbit hide. Kill a fresh rabbit for every pack. Can’t wait for easter, gonna have a battery sale.
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this is my 10s14p. it’s a BEAST
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how much flex does the silicone give? I’m liking it. ever tried then gluing the cells to the board with silicone? off topic but related and somehow it came up. but i see bunnies so anything is on topic at this point.
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Do we have a german word for fishpaper? 
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I am a bit struggling to understand what is spot welded and what is soldered with a classical iron. This is probably due to my poor english understanding. Can someone help me here ? I see two main connections :
- fuse (thin wire) to the positive end of the cell (classical weld ?)
- fuse (thin wire) to the large strip - nickel or copper plated (classical weld ?)
Where is the spot welding ? Is it that you spot weld the negative pole of the cells directly to a nickel strip without fuse ?
look at the top first post from chaka.
It´s all there with pics 
Fantastic. I can’t understand how I did not see these images. Thank you !
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Why did it prove to be a better method than your printed holders? Beside the space gain.
Build time, vibration resistance, strain relief to name a few.
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Have you tried extending the strips on the positive terminal so they bend up and just over to the top of the cells like on the negative side and then welding a thinner strip between the positive strips and the bus bar on the top of the packs to act as the fuses?
Means you’d be able to completely avoid soldering and would also mean you’re not bending the fuses (ie the weak points) over the edge of the cells? I think the biggest issue I had when I soldered fuse wires between the bus bar and the positive terminals is that heavy vibrations would sometimes cause the bend point in the fuse wires to break
Bend it over a pencil or a drill bit. (4mm?), and do it slowly so the wire doesent heat up.
*I’m serious.
While that might help, it doesn’t really solve the issue of the the fuse wire being more of an unnecessary mechanical weak point than it needs to be and the idea would also be to try and completely remove the need for soldering fuse wires.
Fuse wires also end up sticking out from the rest of the side of the pack just slightly because they’re thicker than nickel strips which means that you need to take this into account when shrink wrapping the pack etc as the fuse wires will end up digging outwards slightly and become the first point of contact with external objects in the case that your battery isn’t 100% secure etc.
Fish paper, is the adhesive used flammable? I know that was a concern raised about the circle isolators.