Yep totally makes sense. People don’t know how much time goes into making quality content either lol
Each video I do is probably 20 hours of work at least, and I work full time
It might be worth the time to have a go-to resource of battery building vids, as a combination of my production quality, logical processes, and our knowledge here.
Hold my beer.
I have been summoned.
See you all on the other side. 
I am concerned lol
You want to draw 20A from one cell? Welcome to sag city. Also 20A through 7 or 8mm 0.2 nickel will get faily warm, but should be barely ok still.
20A from a P42A is fine, won’t sag too horribly. It can even do 30
I’d say your audience is people like myself who know how to build a board but unsure how a battery is really put together & thought behind it and would just like to watch and never attempt.
ouch (not mine)
exactly because of that we usually ask.
for reference:
I second this. There’s a difference between overbuilding, and OVERbuilding. Going a bit past the minimum requirement is great. But exceeding it by enough that you make extra trouble for yourself, is not so great. 8AWG is massively too much overkill for a 2p, 40A max battery, and will be a pain in your ass to boot.
Oh I see. Hmm 
so if all my p groups seem fine and are sitting at the correct voltage, does that mean I didn’t blow through the negative terminal?
I have seen a few people’s welds around the edges and I assumed it was something to do with leverage, but that makes more sense. Should have asked 
I’ve built a couple batteries using cell holders and I haven’t had any issues welding to the center on those builds, but that’s probably just luck.
scribbling notes
Do yall think that putting tape on top of fish paper compromises the abrasion resistance of the fishpaper?
My thinking is this:
If you have something you want to insulate, a layer of adhesive backed fish paper, and a layer of tape over that (kapton, fiber tape, whatever) then a cross-section of the stack of materials would look like this:
Tape
Tape’s adhesive
Fishpaper
Fishpaper’s adhesive
Thing you are trying to insulate
Lets imagine a scenario where the battery got packed in an enclosure carelessly and there is something pressing on this stack of materials while the esk8 (or whatever PEV) is under heavy vibration.
Assuming the tape on top is kapton or fiber tape, then it’s not abrasion resistant. So that gets worn through. Then what’s next in the stack? The tape’s adhesive. That gums up between whatever is pressing on the pack and the fishpaper, making the fishpaper no longer a smooth, low friction, robust surface. Rather it becomes a gummed up, torn up mess, and then it gets abraded through as well. And as soon as a small puncture is made through the fish paper, the fish paper’s own adhesive starts to work against it as well, speeding up the process. Then all that gets worn through and you have a short circuit.
Yall think this could be possible? I really hope not, because I almost always cover fishpaper with kapton tape to hold it down, since the adhesive backing on every fishpaper I have used likes to let go pretty quickly after it’s applied.
Lol it feels like over thinking to me, but the adhesive on kapton tape is so thin that I highly doubt it would have noticeable affects
Maybe Gaffer’s tape or fabric tape could
I typically hold mine together with fiber tape, which is also pretty thin and decently abrasion resistant
The exact likelihood of a weld on the negative pole center isn’t known, at least not to me.
In fact, I’m fairly certain that the majority of cheaper manufacturer packs don’t bother to note that at all.
If I have a weld stray a bit too close to center, then I usually stare at it in mild panic and anxiety, and make sure to not do that again. These days I’ve gotten decent at avoid it, but it’s also important to note that one mistake does not an automatic failure make.
Bad batteries are usually a product of several bad things that add up to an unsafe situation.
Usually… I think.
I would tend to think this too, also, how it is installed into the device matters too. There’s a big difference between just tossing a battery into an enclosure, and carefully adding foam padding on contact surfaces to prevent vibrations
Cries in 40 welds per cell
I also don’t believe that the smooth surface of the fish paper does much for its abrasion resistance. If an abrasive surface contacts it, it’ll bite regardless of the texture.
It’s how sandpaper will scratch a perfectly finished surface anyway. The material isn’t hard enough to cause a skid.
If you’ve got paper, and you have to tape it, I’m sure it’s fine.
Right, it’s more of its vibration dampening, thickness, and texture.
Vs if you leave a cell vibrating around in your enclosure, that plastic skin is gone.
Ask my lipos in my first build 
I’m not talking about abrasion from a sandpaper-like surface. I don’t know that any of the materials commonly used in our PEV batteries would hold up to something like that.
I’m talking about the abrasion that happens when you combine pressure and vibrations over a long period of time, even if the two things contacting are comparatively smooth surfaces. (Which, in my view, is the kind of abrasion we are talking about when discussing vibrations and abrasion in PEV’s.)
On my buddy’s first ebike build he didnt properly suspend his battery in his frame bag, so it was partially resting on the frame of the bike. The frame was painted completely smooth. The battery was in a nylon frame bag. The battery was wrapped up in several layers of fiber tape and fish paper. Still, after less than 500 miles of riding the paint on the frame was worn through to bare metal, the frame bag had a hole worn in it, and fiber tape/fishpaper on the battery was worn through, all the way down to the bare metal of the cell.
All that stuff is pretty smooth and pretty tough, but vibrations dont give a shit. They will tear through anything, given enough time. Luckily he caught that before it became a catastrophe, but it definitely taught him (and me) to respect vibrations and abrasion.
I’m just wondering if the fiber tape kept the fishpaper from doing it’s job. The hole that got worn through was pretty gummy around the edges where each layer was pulled back. I wonder if the tape, as it started to break down, caused the fishpaper to tear up little fibers along with it, similarly to how fishpaper (or any paper) tears apart when you stick tape to it and then pull up the tape.
I think you should switch to a different strain 
Sure ya do. Anything mounted inside of an eBoosted enclosure. HEYOOOOO!!!
I’m kidding.
Anyway:
The issue, I think, that carries forward with this line of thinking, is that one can’t reasonably quantify or even qualify any of these scenarious or the variables contained therein.
That is to say:
What kind of miles were these? There are some rides of 10 miles that can do the damage of my 300 miles because I ride like a loser. It’s hard, if not impossible to guage ride quality when trying to figure vibration. Also,
This creates a situation where a very heavy load is resting on a very small contact point, which likely is also subject to comparatively large vibrations and movements between the surfaces. That pressure point itself is something to note, since I don’t thinks it’s entirely represenative of what would go on inside an eskate enclosure.
And neither does physics and the sample sizes of really poorly built batteries and electric skateboards that are still on the road.
This is also something to keep in mind. Service life, the common occurrence of product boredom and the upgrade cycle, rampant consumerism, etc. It’s likely why most of the boards either of us will contribute to will likely never reach anything like a failure test of longevity.
I highly doubt that’s the case.
I’m certainly no material scientist, however I’m having a hard time thinking of a mechanism by which an extra layer of a relatvely robust material would cause the material under it to fail more quickly than it would if it were bare inside an enclosure.
The surface area of a battery inside an enclosure is something important to consider, especially if it’s covered still, in something like a shrink wrap, and then cushioned inside the setup with some kind of foam for spacing or something like that.
This is something that one could make some tests for, however I’d be skeptical of the practical nature of the tests and their likelihood of being similar enough to what could happen in an actual eskate setup.
But who’s to say?
