Graaand I’m more than happy to disregard it then. Either way, I got a layer of fish paper in there in the last couple of minutes and it’s not hurting it so it’s gonna stay
1 Like
Yep definitely wont hurt.
1 Like
Hey guys, just lookin for some advice. So I have this 12s3p 26650 a123 partially assembled battery pack on a flex pcb and I was just wondering what else I need to do before I stick it in my board. I’ve got a LLT bms on the way already and I’ll solder the connectors soon, but what else do I need? Do I need a giant thing of heatshrink for it?
pics below:
1 Like
Aight people, one of my coming up videos is building my 12s7p p42a battery for my mountainboard. I’m fully aware of how to build these batteries, but what are some things you’d like to see highlighted?
I’m open to any suggestions, I have not even started the writing process for that video yet.
My battery videos do very well so it is safe to say several thousand people will see this, what are the most common things we correct on brick packs?
If you’ve seen my other videos, I am always careful with balance wires and fishpaper. I was thinking for this battery I’d either do fishpaper or use a 3d printed spacer, not sure yet.
5 Likes
It would be smart to put fishpaper between the end cells on each P group. Would also recommend a piece of fiber tape around each group of three
2 Likes
Maybe some In-progress safety measures like what needs to be kept away from each other, what to keep covered up in case of dropped material/stray tools?
1 Like
Hmm, maybe where to weld (not in center of negative), how many welds (5A/weld max, 6 points whenever possible at least even if current wise its not needed) and how pack design can stop nickel limiting current (brick packs are a good example because they use a row design to completely eliminate nickel bottlenecking current, except on the ends)
1 Like
Will definitely incorporate this, great suggestion.
Good idea
Great thing to mention too
Yep will do
2 Likes
General question while im here
Is there a consensus on what to do when shrink-wrapping flexi packs? They kinda aren’t flexible at all anymore after they’re wrapped, and although they can flex a tiny bit i cant help but worry the shrink wrap will apply weird stresses to the pack as it bends, and on some setups where its especially flexy it might cause pretty adverse effects. I’ve cut shrink wrap to introduce some flex back before, but it kinda then starts to make it ineffective.
Anyone got a method for this?
Definitely cannot flex my 10s4p build that I had for a client after wrapping.
Only way around this is to do split wraps, or shrink it, then make incisions.
1 Like
safety, safety, and safety. Spend a small segment to talk about all of the safety features we implement and why they’re important. Electrician packs on esk8 are scary!
5 Likes
It depends on whether I am making a truly flexible pack, or just a “flex tolerant” pack. If it’s truly flexible, then it’s probably going inside a segmented enclosure and the series connections will be a few cm long to bridge the enclosure segments. For those packs, I shrink wrap each segment separately.
If a pack is built all in one continuous segment, then I would never recommend them as “flexible”, instead I would call them “flex tolerant” meaning they won’t break because of the micro-flexing that all skate decks have, but they are not meant to flex fully. Those get one continuous piece of shrink wrap, which yes, makes them pretty stiff.
Can you send pics of what kind of pack you are talking about?
4 Likes
I’ve seen a few references to foam but can’t find any specifics on what to get or where to get it. I have a sheet of this stuff, but I’d prefer to keep it for the underside of the deck because I don’t really want to put in another order just for that and wait for shipping
Are there any keywords that’d make it easier to find locally?
What I’ve been using in the past are a few of these, they seem to have held up well
1 Like
All the foam I’ve used has been from Amazon. Neoprene foam sheet, available in a variety of widths and thicknesses (sheets and strips), either adhesive backed or not.
3 Likes
The reason to why we adding insulators of what type and where. People seem to think it’s between cells when a knolageable person knows it’s between any where that has potential voltage difference.
Advantages and disadvantages of keption tape/fish paper and how to take advantage of the pros.
How power flows throw groups and were so people understand we’re the rails need bulking up
3 Likes
Wiring inductance.
It creates the voltage spikes that can zap an ESC and determines how high a voltage pack can be used with a particular ESC, i.e., how close we can run to an ESC’s voltage rating.
Sure, most people just hope the ESC can handle it. But there are things that can be done when wiring a pack to help reduce the inductance, giving you more of a safety margin when operating an ESC at near its rating.
1 Like
This for example was basically a solid brick after wrapping, its for a pretty stiff deck so in this case i doubt it’d be an issue but a more recent pack for an evolve was a lot longer, would potentially need more flex
2 Likes
Your braid is saturated with solder at the point your bending it meaning that over time small flexing could still cause fatigue and failure.
1 Like
Yea I know what you mean, I think some strands are tinned but the braid is still fully flexible. The far side is kinda being reflective in that picture but its even less tinned than the close side in person
If you want the solder to wick less then using a more powerful iron or bigger tip will keep the heat more localised and reduce wicking.
Also, if your not already then pre-tinning the braid will make connections quicker.
2 Likes