PHANTOM XENOBOMBER: 13s6p VTC5A, 210amps peak, dual 6374, dual Focbox, 8.2kW CONTINUOUS build <WORK IN PROGRESS>

Hello everyone, this is my first post and I intend it to be intense!

Let’s start with the parts, Mechanical:

SUM + shipping = 520$


SUM + shipping = 1000$

Other crap:

SUM + shipping = 261$


SUM + shipping = 209$ + ?$

Other crap not directly for the project but bought during it:

SUM + shipping = 450$

FINAL SUM: 1990$ :scream::scream::scream: (or 2440$ with everything included)

Now that this is behind us, (and I will be eating rice and water for the next 3 years) we can start the project!

All the parts are currently shipping so no building quite yet but I have some pictures and schematics about the project. This is the deck, a ridgid composite downhill deck. I’m not a fan of the graphic but the enclosure should cover it up: never-summer-soldier-tm-deck-only

This is my wiring for the complete build, it took me quite a while to sketch but I’m sure it will benefit somebody else around here who isn’t sure how to bypass a BMS or wire other stuff up: 121212 As you can see in this wiring schematic, I am planning on having an exterior voltmeter constantly hooked up to the battery pack. This is because I will be bypassing the BMS for discharge and I want to make sure that I don’t overdischarge my cells. I trust the FOCBOXes for lower voltage limiting while riding but I don’t want to forget it overnight. Secondly, I will have a switch to cut the BMS which should avoid current leakage. I will use a DC 2.1mm plug for charging. To kill the entire system when I am done riding and to use as a sort of key I will simply use an XT90 anti spark connector on the battery positive lead with a loop. Finally (and I haven’t seen this before), I bought a 5v DC DC buck converter with a USB 2.0 plug connected to it to charge outside devices from the skateboard’s battery pack.

I just got home from vacation and this is what awaited me: IMG_6384%20(2)IMG_6386IMG_6389IMG_6388

The cells look amazing, can’t wait to stich them together! The pictures following that one show my current DH setup compared to the new deck (I have since changed the wheels on the DH setup to bigger mach 1 wheels, and cleaned the dirty griptape)

I am thinking of a way to store my boards (I have 4) and this wall stand looks beautifully simple. Will probably be building one in the near future. IMG_6396

Next is the FOCBOX aluminium case bought from @Kug3lis IMG_6443IMG_6447IMG_6444IMG_6448IMG_6446 The case is magnificent, 120% worth the 60 bucks, shipping from Lithuania was quick and trouble free. I really recommand this, it was shipped out in a day or so and I am honoured to have this on my build. Big time credit to @Kug3lis

Next comes the composite case building, before doing anything with composite you need an inverse mould to lay it on. To do that, the most common way is to buy a big chunk of foam (think polystyrene) and shape it up. To do that, the most efficient way is to use a hot wire cutter and run it through the foam. I didn’t have such a tool but I did have a 12V power supply and a drok DC motor controller (not brushless, simple DC + - motor). So I just wired it all up and threw together a wood jig to hold an iron wire up. IMG_6452IMG_6459IMG_6456IMG_6461 As you can see from the first picture, the spring melted and so I was forced to take it out of the loop. I tried building it without a spring but as soon as the wire heats up, it dialates and looses it’s straigness; making it useless. So I had to add a spring once again (last picture). The wire gets nice and hot (glowing red kinda hot) so it will work wonders once I get to shaping the foam.

Next day has passed and I got to work on said foam. Here is the progress: IMG_6481 IMG_6482 On the bottom, a cut made by the homemade hot wire cutter, on the top, a cut made with a knife IMG_6484IMG_6485IMG_6493

So I have cut out the entire board out of styrofoam, I then placed some cells on the enclosure mockup. I used the very last picture up here as a guide to photoshop different cells configurations and see what was the most efficent. Next picture is the result of those 3h of work: Esk8%20enclosure%20planning

This configuration is done all to size (1mm = 4 pixels) on the real styrofoam already cut out, this should give me the most accurate results. The configuration shown is the one I ended up choosing, the only issue I’m facing is that I haven’t received the trucks, motors etc. from torqueboards yet. This means that I don’t know how close I can get to the trucks but I made some guides. The upper one is where the 97mm wheels extend to on the board. The lower one is the truck distance + 133mm from the torqueboards mounting bracket. Hopefuly that will be enough. The positive aspect of this cell configuration is that it will be very easy to weld together because the packs of 6p are always together. It will also be easy to weld the 13s because the cells are back to front snaking down the enclosure. As you can see, I have plenty of space for my 78 cells + FOCBOXes + BMS + switches, voltmeters, etc. I am even considering implementing an integrated charger. I am currently waiting on it from China, will see if it is small enought to take apart and put in the enclosure (13s 2A).

Next aspect of this build is the asthetics. I am usually one to skip over thoses but this time I decided to outdo myself. First of all I had to choose a name for the build and a colour theme to stick to. I ended up choosing: “PHANTOM EXOBOMBER” because I will be bombing on this board. So fast even that I will zip by and be gone in an instant (phantom). But simply calling it bomber was sad because it is way overused in the EV market. The power on this build will be from another universe so that is where the “exo” prefix comes from. The colour theme will be red and black, same as the gear I have bought. I then had to find a “logo” for the build and I found just what I wanted on the interweb. So I ended up printing it, sticking it on the back of my griptape and cutting the griptape patch out. This job took me 2h of non-stop forearm destroying cutting (with a box opener…): IMG_6495IMG_6497IMG_6500IMG_6501

This is all I have done for now but expect this thread to be active since this is just the beggining. If you have any comments, advice or past experiences you’d like to share, please go ahead and enlighten me!


Hi @Deckoz, I think it’s important to put your name down here because in school I was always taught to reference my sources otherwise it would be plagiarism. I have to admit, I was very inspired by the master EVO, mainly the 13s madness and the deck inserts, so here goes my attempt at getting a good grade. (and as a side note I value your experience and advice)


Why did you choose to bypass bms discharge?

Just curious, thinking of doing it myself because it will save me a lot of money

Nice Deck, plenty of wheelbase for stability and room for the goods.

Great question! answer is in two parts, firstly it’s that I’m not rich so the first half decent 13s BMS I found that could handle 200 amps discharge (granted most batteries can’t do what mine will) ran around 120$. But the piece of crap I bought ran me 17$ and free shipping. Yay aliexpress! Second part of the answer is space, I am going to try fitting 78 18650s on 1 layer + 2 FOCBOX + all the other crap in the diagram. That means I do not have the necessary space to fit a 200 amps capable BMS with the thickness I am currently planning. But I quite recommend it because it is a lot safer. Skipping the brain of your battery for half it’s work (discharge) means that your brain needs to compensate. That means no foolproof skateboard you lend to your friends and they forget to turn it off and to charge it overnight. This screams overdischarge to my ears and I am terrified to ruin 300$ worth of batteries with one forgetful evening. Plus you need to be aware of unbalanced cells signs (google it) so that you can check it with a multimeter.

I like your pack size. Kinda scared of the 13s tho :slightly_smiling_face:

Guess I’ll go with the safe route then!

I will be running 10s anyway, those bms’s aren’t that expensive

It’s very reassuring to get a positive comment from a guy as experienced as you, especially about the deck. I doubtfully bought it because it is on a crazy discount but it matched all my other expectations. I also quite liked the ridgidity of a composite DH deck and thought I would need all the space in the world for all those cells.

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Ya, I forgot to mention the sale price is a steal!!!

I searched high and low and paid around $180ea. for my decks.

I am bloody terrified of 13s too. Especially because I live on a mountain (at the top) and to go down to the train station I need to kill a good 300 meters of altitude. So every morning with a full battery pack I’m going to be hitting the brakes HARD and it cannot cut out on me because of overvoltage protection (20+% hills cannot cut out). But my 13s mentor (decky) apparently hasn’t experienced those cut outs so I hope he can reassure me about this.

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I’m not sure that the Focbox or any 4.12 Vesc can handle 13s without overheating. Even 12s is pushing it. As for the overcharging while braking, Just don’t fully charge your battery and don’t set the Batt min too high.

A lot of people say that you can really extend the life of your battery by undercharging it as well.

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If I can share my aliexpress knowledge, I know two stores for decents BMS discharge rates, the cheaper one, and the expensive one. Here are the links for both (10s BMS):

Cheaper (80/100/120 amps continuous):

Expensiver (80-200 amps continuous):

I was actually thinking of a bestech bms with e-switch

Have you bought cells from nkon nl or ru? There’s a Big difference outside eu

What is the 18650 charger for? I don’t get It. And just an advice… Ac spot welders are done for. Arduino are the future. Say goodbye to breakers tripping all the time with those. I am sure your build will rock da house.

Lithium ion 20%-80% discharge-charge is the way to go. You go from an average of 300 3V-4.2V per cell cycles before the battery looses 10% of it’s capacity (capacity is in mAh for anyone not sure) and is therefore deemed dead. Up to 1000 cycle if you use 3.2V-4V per cell. So I will make sure to stick to the 80% line. That also lowers the battery total voltage, it doesn’t go up to 54,6V but only up to 52 volts. Since I hear most of the fets and components of the FOCBOX are rated for 60V that should indeed be better.

Now about the overheating part, this really worries me because I am planning on using my 8kW continuous to the fullest. The mountain I live on has a nice 15% average gradient road that is a few kilometers long (5-10 minutes of riding full throttle). I will overheat my FOXBOXes like a trigger happy 12 year old using a machine gun. So I had an idea, do you think it would work cutting out holes in my case and strapping on OVERSIZED heatsinks to the focboxes with the fins outside the case? If the answer is yes, do you know a FOCBOX aluminium case for sale or do I have to diy my own?

Edit: god this community has every thing I need already for sale. @Kug3lis saving the day with his custom dual enertion focbox aluminium case. Fins already included! Have you done any tests at 150 amps continuous (both focboxes) with your finned case?

Hahaha my friend, I live in Switzerland (i.e. the country that benefits from all the european priviledges and doesn’t assume any responsability in the EU’s economy (we have our own bloody currency)). So I pay no VAT and of course ordered it from I just thought I would link the nl site for people in europe.

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18650 charger would be for smaller projects or troubleshooting single cells that are too low on voltage. I don’t have a 4.2V capable charger.

I 100% belive you about the future in arduino spot welders, I just needed too get a hold of a spot welder and decided to get the not too crappy one since it had free shipping. Now would I rather have a battery operated arduino spot welder, yes of course, but for now, that’s all I’ve got.

edit: It’s also quite challenging to build a “battery operated arduino spot welder” without a spot welder to weld that battery together…

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Thanks man. Lol I’ll probably always be known as the 13s guy. This build should be fun.


That’s direct discrimination for Japanese people who eat rice everyday :smiley: