Hello,
I’d like to fix my battery with some foam but all I have is polystyrene and I suppose it is not a good idea…
What do you guys use?
Neutral cure silicone is very good.
What are the circumstances you need to optimize for?
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Velcro or resin seem to be the most popula. Personally I use double sided foam tape and the compression of the enclosure
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My battery is too short for my enclosure, and don’t say “change of battery” 
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Pack it with closed cell foam
Pro
Cushioning helps fight agains vibrations
Con
keeps heat in
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About the highest temperature rating you’re going to find for a polymer/rubber foam or RTV is around 400°F. Considering that batteries on fire get hot enough to melt aluminum and can, for large LiPo’s, even melt copper you’re not going to resist any of the heat from batteries on fire for very long unless you’re using something rated to do that like certain types of fiberglass or mineral cloths.
I wouldn’t worry about having a fire-rated padding. Concentrate more on what you want it to do and what form do you want it in…sheets, tubes of RTV, etc.
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Does it mean polystyrene foam would be ok…?
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As long as you also have heat and insulation resistance between the polystyrene and any contacts I don’t see any issues.
Over time the heat and compression will disform the polystyrene and won’t be as tight as fit and may start wobbling
Polystyrene also is a pore conductor but dose conduct electricity a bit.
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Isn’t that a rigid foam? That won’t provide as much vibration/impact protection but could be used to take up some space.
If rigid, the foam will not spring back into shape if slowly being dented/compressed by the pack over time. That means the pack will start sliding around more and more over time.
Best to use a “springy” foam like polyurethane, polyethylene, or neoprene. Unless the polystyrene foam is already springy. 
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Ohhhhhhh
I’ve just used closed-cell foam blocks from random packaging material. But it’s probably flammable. If your cells are on fire, there are already other drastic problems, I think once you reach that state, it’s a lost cause.
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Yeah my fear was more foam burning due to heating components.
I actually have no idea how hot components can be in there…
Normally most electronics cap at 90deg ish at the hottest point but few mm away this of drops below 40deg
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thermal throttling starts at 80 or 85c on the vesc
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If anything is hot enough to melt the foam then it’s too hot.
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There melt (as in turn to liquid) and then there’s deformation
Making your board fireproof is the wrong way to make your board safe lol
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That’s why fuck fireproofing
#psychotillerbatteries
#westcoaststandards
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So shall I fill the empty space with wood chips soaked in gasoline? 
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You could the self ignition point of petrol is 257degC so the heat generated in a enclosure wouldn’t blow it up. Any dodgy connections or mosfet switch proberbly would tho
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but isn’t it conductive? It could turn my board into a fireball
Ok, interesting!
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