The Trampa / VESC battery systems

You can use the pack to power the lights of your Christmas tree.

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oh boy looks like I’ll be getting one. Fancy a beta tester in the summer heat of aus?

another idea, would be if you would be able to make the software install-able on the DieBieMS. I’d love yall forever if that was the case

What is compressing the cells to the contacts? Foam?

Top plate screws to the bottom plate with long standoffs. The tabs on the top plate appear to be a compliant mechanism that uses spring tension to keep good contact.

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Looks like the top plate is cut to flex and add compression. Maybe it’s just the compression of the pcb fiberglass? Seems simple and fiberglass doesn’t compression set much I don’t think.

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Thats what I was getting at, yeah.

@Trampa correct me if I’m wrong, but it looks like the very top piece is not a PCB, its metal. Which would provide the spring tension to the PCB below it with the contacts.

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If a solid piece of metal be a big short. My bet is on a pcb.

Agreed…IMO it’s bare FR4/G10 or an equivalent, thick enough to provide the desired pressure and not crack or delaminate over time.

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I guess you used leaded solder and had no fuse in the power cables. We can burn the Fuse without de- soldering.

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Indeed no fuse is the main wiring, worst case :nerd_face: hard short. Solder does not really matter. Just wanted to make you aware that there are types who like to jump ^^. But the correct ones don’t, we did discover that the correct ones who fail safely as intended tend to be fast acting fuses.

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Our packs suck so much heat away, that soldering and machine assembly needed lots of testing and design tweaks to get thing to the point that we are confident with larger batch quality. It’s all those details that consume time in R&D. You would need a lot of current to create enough heat to de-solder the fuses in our packs.

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:sweat_smile: Yes shorting the full pack will create those currents, and a failed ESC will create this short. The sizing of the main big fuse and the cell fuses is very very “critical”. I am giving everyone free advise on areas to explore where potential pitfalls may be (which have cost us some time to discover), because we stumbled upon them there is a big chance you will or have been as well.

Please note that I am not trying to corrective or be a smartass, its just that, we build this, we produced this and I am helping us all in maybe early on pointing towards areas which might be worth exploring. Also now that we have shared these ideas others will start building solutions like this as well, this experience will help them build a safer solution.

Long story short: On hard shorts with no or wrongly sized main fuse compared to cell fuse -> fuses will jump of the PCB ( when using slow fuses ). And with fast fuses, a short will result in burned cell fuses instead of a burned main fuse. Finding the right cell fuse with the main fuse where the main fuse blows before the cell fuse blows ( on a short ), is a very very challenging process. Multiple kiloamps will flow with corresponding heat generations even trough the fuses have spec’s lower, fuses are slow in general since they are based on heating.

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Does look like metal, probably aluminum, behind the pcb and machined to add compression. One day someone will take it apart for more pics.

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I would love to see a 4-8P NESE form factor kit like this, then you could leave the cells in the packs for flying or whatever and still have easy replacing.

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Yes, that is what I was describing lol

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I liked it more in my mind with just the pcb. Simpler

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Yeah I agree that would be nice. That would probably need more screws to apply the proper pressure though. With the metal piece one screw can provide the pressure for a whole p-group.

Could do a fatter pcb. More layers. I think the fiberglass pcb could work well for compression.

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How does the cells handle the compression over time since the bottom tab has no soft padding around it, feels as if the cell could get indented over time. Especially on the boards this type is meant for.

Great to see more innovation in this area :slightly_smiling_face::+1:

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They can handle up to 70KG

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