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[Designing] Modular Rugged Battery system for esk8

Heya nerds. Fellow nerd here.
I was recently watching one of the Luna Cycle Videos, and it got me thinking. They Pot each battery in a sort of epoxy, making it (in theory) waterproof, and pretty rugged. Introducing countless post-it notes of thought later, my take on rugged batteries for esk8.

So. What we have above is 12 1s4p 21700 packs, to be wired in series, on a Landyatchz Switchblade 40’’. Each individual pack will be potted, feature cell level fusing, and will interface to the main system via an XT-90s. The plan is for them to have a shared BMS, but like the rest of this project, nothing is certain.

So what does this accomplish? Im so glad you asked.

  1. Hot-swappable packs -If a pack goes bad, you can easily swap it out. Furthermore, you can easily change battery configs without too much heartache, Want to go to an 8p setup? If you have the ground clearance, it should be possible.
  2. Flight friendly (ish) - Each 4p pack has an estimated Wh of 67.2, when using Molicell p42a’s. This is well underneath the 100Wh limit that most airlines seem to have set, and since they have XT-90s connectors on the end, they can easily be isolated.
  3. Rugged- Because each pack is potted, it’s inherently waterproof, but also more resistant to vibrations and hits. For more discussion on potting, check out this Endless Sphere thread.

I’d love to hear what you guys have to say, especially in the way of suggestions/ feedback.

As it stands, im going to continue polishing up the design, and then hopefully work to make it printable, and then eventually, scalable. My CAD skills are abhorrent at best, so its taking me some time to learn from my mistakes, but slow and steady wins the race!

Thanks for reading

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@BillGordon

Would be amazing to switch a bad P-group like that. Looking good!

How will they all hook up to the bms but still be removable? What connector do you plan on using for the balance wires?

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If you could make it conform to the deck, and flex, mmmmm.

BMS Cables will just hook to the internal XT90 receptable. Thats the plan anyways

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It already conforms to the deck, but i dont know about Flex. According to @eBoosted, the LY switchblade isnt very flexible, which will help with a 3D printed enclosure. After i start prototyping i think ill get a better idea of what is and isnt possible in terms of the flexibility.
A really good recommendation i’ve gotten already is to print in TPU, to give it some flex and ruggedness

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You cannot potting the battery cell. Can only potting the electronic for protecting from vibrate.

Interesting. Whats the thinking behind that?

I did something!


Now gotta get the exoskeleton done. Proud of this because now it has joints!!

Wish i could use a XT60 instead of XT90, but with 4 cells in parrallel, 45 amps per cell possible, im already pushing it.

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By god im almost there. Im hopeful for this.

Basically, the plan is to have removable 4p packs, which are potted and fused, and connect to the pack via an XT90-s. I got inspired watching the Luna cycle guys, and came up with this.
What this accomplishes is easy battery maintainance, so if a p group goes bad, not only will it fuse out, but you can bypass it using a loopkey and continue riding in limp-mode (eg going from 12s to 11-s)

The potting obviously makes it waterproof, but also gives the advantage of being travel friendly (Wh wise anyways) This is a 12s4p of Molicell p42a on a Landyatctz Witchblade 40’’.

Just got to finalise the design and make it look pretty. But all with good time really.

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Very clever indeed :fire:

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Are you planning to 3d print all of this? And would you kindly make a thread of the process for a build like this? If this works out for you, I’m sold for my next build

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Thats the Plan for now. We’ll see how 3D Printing Holds up.Undoubtedly there’s gonna be issues to iron out through the way, but im excited to see if this works. As soon as I make real progress, there will be a thread!

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I would love to see someone do what HoytSt did with their 10s1P x 3 packs

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I would recommend printing in TPU, it will help a lot both for cushioning and for tolerances.

@Mikenopolis got a link for Hoyt stuff?

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Thats not a bad idea. Some Hard TPu would likely be a nice middle ground for reliability and printability, but if i can get it done i hard plastic that doesnt just crack, i’ll be a happy boy

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This is similar, with the main differences being a shared BMS/ charge circuit, 1s4p packs and plastic casings

If I recall correctly, Ultimaker TPU is like 95A. Very good structure yet enough stretchability and rebound, if you don’t need lot of bridges it is a good starting point. And it resists tearing pretty good too. So maybe you can aim circa this duro :fire:

watch here:

6 Likes