diy solar

diy solar

PP Corrugated Sheet as Insulation? Is this good or bad?

Culchee said:
Could always put 2 or 3 layers on if it’s cheap enough.... I’ve got a load of welly boots that got splits and holes.. I get through 2pairs a year.. and cut off the useable rubber for all sorts of things... prob don’t have enough for cell dividers...?
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one sheet should be plenty

Steve_S said:
Keep it simple, this stuff can make life miserable if you goof up... Is this something you want to BODGE UP or get right the 1st time out ?
IT's Your money, property & life (lives) so choose widely & smartly.... Some things you can furtle about with a bit but some, not so much.
Hell, just skip fuses & breakers to save on cost - That would be a bad bodge job.... some have done it and later donlt speak up (admit) cause they are too proud they admit they pooched themselves.
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An analogy for this isn't "skipping fuses" this is "not using 3 fuses in series and instead using 1 and considering it safe enough"

Culchee said:
Steve what do you think of the cutting boards....? I can’t see that they wouldn’t be up to the job... if the cells get extra hot then the problem isn’t the dividers..
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they're fine too
OffGridForGood said:
In my set up, the cells never get hot, or even warm - this time of year I wish they got warmer. LOL.
I work with ebikes, and am a member on a DIY forum on this topic, they talk about "Fake Fish Paper" - so watch what you buy.
Proper stuff is UL 94/ASTM D-635 compliant. I don't say this is better than the FR, just seems adequate as a separator between the cells to ensure no electrical contact is made by mistake. That said, I don't use metal cases, so I am not concerned about a metal surface being less than a mm away from the alum cell in my battery packs. You do you, I will do Me.
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yea cells won't get more than a few degrees above ambient unless you run at 1C or more (which is, if your battery = 280amp hour you need to be pulling 280 amps).
I've tested it in 120F box they stay pretty much ambient temp there too.
At 70-80 max I can get is 87 with zero air flow and in container
42OhmsPA said:
I like these, made in USA. Arrow Home Products 10pc Flex Cutting Mat, White https://a.co/d/eaouxbb

That fish paper is interesting. FR4 seems expensive.
If somethings getting hot enough to affect the cutting boards I have bigger concerns than FR4 sheets.
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fish paper is made for electrical insulation so imo it's good enough...
unless you're offroading with your batteries, then I'd recommend something with better abrasion resistance <__<
 
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In my first pack, I applied the Fish Paper to all sides/bottom of every cell, then put the cells into the cases.
On the next three DIY packs, I just applied the Fish Paper between adjoining cells, one layer between each cell. This seems good enough to me, and as Gotbeans said, totally different for a mobile battery set, where you know there will be vibration/dynamic forces on the cells leading to abrasion concerns. When I look at automotive cells, they don't seem to use FR4 between cells, they use adhesives, and mechanical clamping systems to keep the cells firmly secured.
 
OffGridForGood said:
In my first pack, I applied the Fish Paper to all sides/bottom of every cell, then put the cells into the cases.
On the next three DIY packs, I just applied the Fish Paper between adjoining cells, one layer between each cell. This seems good enough to me, and as Gotbeans said, totally different for a mobile battery set, where you know there will be vibration/dynamic forces on the cells leading to abrasion concerns. When I look at automotive cells, they don't seem to use FR4 between cells, they use adhesives, and mechanical clamping systems to keep the cells firmly secured.
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Got to ask, where in the world have you seen an EV Battery Pack using the square prismatic cells ?
If LFP, most are Pouch Format or like the BYD Blades as well as the CTP packs. A few years back, in China, they used Prismatics for all sorts of things including EV Car/Truck/Bus batteries but not much over the past couple of years unless they are LSV's or Quadcycle types of vehicles.

In any case, battery cells MUST be completely isolated when inside any metal container, that means the bottom & sides, cells must be isolated from each other and pending on bindings used that can be variable. Cell the exterior skin of Prismatic Cells, there is voltage there !

Static Battery Packs are easier to deal with but mobile packs have their special considerations.
 
I see them on Battery Hookup all the time.
I get tempted to buy some, but then the freight and bother of cross-border shipping, concerns over cutting packs apart, then I just buy cells. LOL.

{Edit: and: Why do we call the top quality prismatic cells 'automotive grade' if not used for that purpose? }
 
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I build EV batties for both ebikes and electric motorcycles and what I now mainly use between cells and an outer wrap is Teflon/PTFE sheets which are sold for oven trays and barbecues etc, which we then fasten with wiring loom tape, which in itself works very well, Teflon sheet is cheap around £2-4 for 10x 600x400mm 0.2mm sheets, Its non-electrical conductive, very flame and heat resistant and super strong, this is why we wrap the whole battery pack in it as it will retain the any fire for some time, then the whole pack is covered in heat shrink, which doesn't apply here,

But as some seem to have problems getting other's suggestions here, you can also use normal fibreglass matting, or fibreglass matting from a fire blanket, which is what some still use on DIY batteries.
 
It works fine but don't confuse thermal runaway temperature with an actual fire. PTFE will melt instantly in any fire.
 
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