Segmented Carbon Flex Enclosure for Trampa Urban Carver

You’re not afraid of accidentally shorting those connectors? They look awfully close and exposed. Maybe I just don’t fully understand what’s going on here. :confused:

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made one now - its a basic loop key setup:

well, there is SOME thinking in these connectors by now :sweat_smile: first of all: they are enclosed in 1.5mm thick glued shrink tube thats really indestructible and hard to get off. this sits in sugru (partly seen on outside, mostly on the inside), which is an awesome non conducting and quite robust material. so nope, not afraid at all that something just wears out and shorts ultimately.

the rest of safety comes with the layout itself: if you check my picture vs diagram, it doesnt match, because the diagram was a lot easier to draw like this. the key (hah) difference is: left connector in my boards picture is battery “+” connection. right port on my picture is battery “-” charging connection. if these 2 touch, there will indeeed be a lot of smoke and tears. i designed the charging wire to evaporate instead of anything else, so its easy to replace should that ever happen!

you switch on the board by connecting middle (vesc “+”) and left (battery “+”). if middle (vesc “+”) and right (battery charging “-”) touches, nothing happens at all.

if middle (vesc “+”) and left (battery “+”) touches, the board is on.

so either way, nothing bad happens except for when the 2 outer ports touch - which isquite unlikely! you can see, this is different in my awkward diagram, where neighbor mid left shorts the battery. THATS bad design cause it might happen on accident or so. i just drew it like that for simpliciy sake.

hope its more clear now :slight_smile:


Thanks for the detailed response. So elegantly simple. Since you don’t seem to be using a bms, what kind of charger do you use, and how do you avoid overcharging and keep them balanced?

i explained that so many times in so many different threads :laughing:

this thread is a good starting point for charger, nobms & co. it quickly derailed into something else and I think you can stop reading esrly on in the thread. gotta run off to work now :sweat_smile:


Damn, you just HAD to link to the ONE thread I HAVEN’T read on this forum. :stuck_out_tongue_winking_eye: Thanks for that. I would have never found that. /thread derailing

today I made the segmented battery - was a lot of work cause I used 8 nickel strips for each 4P1S pack - 4 strips per serial connections. its a lot more work than just soldering some copper wires ontop of one nickel strip, but it looks cleaner and feels more solid as a pack.

few pictures of the progress:

added cardboard stickers for additional safety @ plus poles

4 layers of nickel strips to account for the max of 80A continuous current

its pretty thick in sum and has a nice solid feel to it

one 1S4P pack with nickel strips extending beyond the pack for the segment connections:

all 10 packs done

since i want to bend the extension of the strips by 90°, I glued adhesive felt sheets on the cells to protect them from the sharp nickel strips

now I started soldering the segment connections with superthick braided copper wire (about 10mm wide, 2mm thick):

did that for all aaaaand done. at the enclosure segments where the braided copper wire is running, Ill dremel some resin out to seat the connections flush with the enclosure base:

finally adding some shrink tube - and I was quite generous - just heated it up and pressed the segments into the enclosure - shrink tube easily gave in where it had to and stiffed up when it cooled down:

waiting for my 2 german vescs & mini remote now - all thats left is adding on/off/charging and 6 phase wire connections to the enclosure. think Ill do that tomorrow! :slight_smile:


This has to be my favorite build right now…you are truly inspiring me to build something similar…so clean and bad ass!

The idea of the flex flat wire is pretty clever. I’m going to borrow it for my urban carver build which I’m planing to work on in a couple of months once I get the funds.

There is going to be a good flexiness on the flat wire part, but how are you going to avoid flexiness on each group of 4 cells in order to avoid the strips from braking? Even though there are 4 nickel strips there’s no guarantee those won’t brake as the board flexes 300 times a day.

an enclosure segment does not really flex, only the flat segment interconnections. thats due to the design of the enclosure! even if the board might flex a little in those segment areas, the enclosure will not. worst case the bending board will lift off the enclosure slighty by applying pressure to the 2 middle cells - but the trampa has tons of camber. some mild pressure will only build up after it bends beyond the “flat” point.

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tiny steps today - Im not in a hurry since my vescs and mini remote are still on their way anyway.

started the day with dremeling the braided copper wire channels into the lower resin areas. you can see very well that in the lower part of the interconnecting segments (beneath the wood blocks that I used to form the segments in the first place), there is quite some resin and also air. got enough room everywhere now for the copper wires :slight_smile:

next I made male/female 5.5mm bullet connector units

which i then shrink tubed with the thickest glue shrink tube I had. you can also see the 5.5mm bullet connector 10AWG loop key. its my first serious dual motor setup, so I went slightly overboard with wire thicknesses and connectors. :stuck_out_tongue:

the idea was to stick out the female part and have a short male connection on the inside of the enclosure to allow swapping components more easily. on my single motor boards, I had VERY little room and most of the stuff was hard soldered. now I got a lot more room to play with and Im using it for some component flexibility.

drilled 9.5mm (!!!) holes into the enclosure which fit the 5.5mm connectors with superthick shrink tube perfectly - can barely move them in an out. fixating with sugru at a later point, since somehow I didnt have any sugru anymore. for the picture the male-female-units are just stuck in there!

at the sides, I got my triple -++ ports for charging and also for on/off with my giant loop key. you can see that I stuck the male-female units far in at the side which fits the arriving braided copper wire perfectly, as its just coming through under the thick shrink tube of the male-female ports.

should be done next weekend I guess :slight_smile:


Very well done whitepony !!

What VESCs are you going to run? BLDC or FOC?

I still don’t get why don’t you use an antispark switch, on a such a beautiful build, the small details always add up, even though the loop key is a clever and reliable solution, an antispark switch looks way nicer in my opinion.

dual german vescs with foc!

after one nearly dead battery i just cant trust antispark switches anymore. cant add LEDs to my builds either, cause its too easy to spot that something is fishy about that board.

i dont think it looks bad anyway! :stuck_out_tongue:

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Hi @whitepony, where do you order your REALLY THICK glued shrinktube? Thanks! Dude :slight_smile:

they arent cheap, but they are extremely durable and just stick to stuff!

How did you actually managed to melt xt90s? At first you made suspicious about vedder’s anti-spark and then basic xt90s. I thought i would like to try something fancier than xt60 loopkey which i have used so far.

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not sure what ever happened to that xt90S. other people reported it got very hot when it wasnt fully plugged in - my guess is that a small resistor (the one that supresses the spark) it the sole connection and the rest didnt really connect. some brought some mysterious polarity into the game which I dont believe up to date.

for me it happened twice with an xt90s - got hot, started melting, game over.

about vedders antispark: i have never used that. so far Ive tried torqueboards antispark which worked fine up to date since more than 2 years. and an alien power system antispark, which I killed TWICE now.

my summary: screw all that crap, go simple!


The only reason to use a full AntiSpark switch is stealth. Other than that a XT90S should work fine - although it seems like people have mixed feelings regarding them. Besides @whitepony I have not heard of a lot of cases that a XT90S has melted. Not inserting it fully might cause obvious problems though.

Okay. Less potential components to fail is the way to go👍🏼

Dang man, that is super clean! I’m beginging a trampa urban carver setup as well but this enclosure is going to change that build setup for sure. What kind of Mph/range are you getting with the dual 6355 and 10s4p?

I really hope I don’t run into the issue of melting an xt90…