FIRST BUILD: From start to completion - NEED ADVICE

ESK8 Builds
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## The plan

I want to build a reliable longboard that can reach speeds of up to 35-40km/h with a range of 15-20km while keeping the cost as low as possible. I want to be able to cover, if not all, most of my daily commute distance with my eskate without wasting time. That said, my budget at 300€ (≈ $350) is quite low, since I cannot afford anything more expensive. So, I am planning on cutting some corners at least in the beginning (and upgrading those parts later), without compromising quality, functionality and reliability.

## The design

Initially I wanted to connect both the back wheels with the motor, but since that is quite a hassle, adds unnecessary cost (for the extra belts and pulleys) and doesn’t really offer much, I will refrain from doing that and stick to just one back wheel for now. Maybe I will add a second brushless engine later.

A big goal for me is to make the board water resistant. Now, I know that water resistance is a touchy topic when it comes to skateboards and longboards, anything wooden that you want to preserve really, but I want to make sure I build in an extra layer of water protection, at least on the electric side of things. My strategy so far is:

• To separate the parts in two enclosures just in the case one of them is breached, the other will not get wet as well. Even though both enclosures need to be functional for the board to work, making sure one of them is safe is nice. Also, less stress (will explain later).

• Adding a rubber pad underneath each enclosure to reduce vibrations, create an air-tight seal and hopefully keep any water out.

• Adding rubber grommets on the cable holes and covering the exposed wires with heat shrinking tubes and electrical/gorilla tape.

• Spraying all the electrical parts with waterproofing spray in case the circuits get exposed to water.

I want to go with a design somewhat like Boosted Boards’ for two main reasons. It puts less stress to the batteries/ electronics inside, so it ensures they don’t break, get punctured etc. and allows for a more flexible deck (even though mine will not be that flexible from what I gather). The second reason is for better safety, which has been partially explained above.

## The parts

  Mechanical Parts

Most of the mechanical parts I will buy as a ready-made longboard from China since that is quite cheap and will work just fine, at least until I can afford something better: https://goo.gl/kv6Q7L - Aliexpress longboard link The only thing that I will need to change are the wheels and/or bearings. I decided to pick up these: https://goo.gl/DpC4rk - 90mm 78A generic wheels https://goo.gl/BZpa5w - ABEC 11 generic bearings

  Electrical Parts

https://goo.gl/fzbAaF - Turnigy Aerodrive SK3 DC Brushless Motor (1st choice) – 280KV, 1510W https://goo.gl/YJTtH1 - FVT 120A Waterproof Brushless Sensorless ESC

  Extra Parts

I will be picking up some of the following items as well: 3.5mm gold connectors, 4-6min epoxy, electrical tape, ultra-high strength thread locker (TL 609), silicone rubber sheets, various sizes of rubber grommets, heat shrinking tubes (5mm ones), silicone rubber wire.

## The challenges/issues

The parts I have not yet decided on are the following:

  • Still deciding on the BMS

As you can see I am still far from starting to build my eskate, but I am getting there. If you can help me with any of my issues I would be most thankful.

*The thread will be updated when I have news/get a new part/start to build etc.

Thank you!

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##Update 1

  • Ordered the longboard from aliexpress.
  • Ordered some generic 90mm wheels from aliexpress aswell.
  • Currently finishing up on the ebay shopping list (just need to find a BMS)
  • Decided on buying a FVT 120A Waterproof Brushless Sensorless ESC (need opinions on that) from Banggood
  • Decided on buying a remote control/receiver from eBay

Challenges/Issues remaining

  • Still haven’t picked a motor mount, maybe I will buy a piece of aluminum and make a custom one
  • Haven’t yet picked a BMS (any suggestions are welcome)
  • Still looking into how I can make a hv & hc switch

Here’s the link to an excel sheet with all the parts, which I got from @HumanMint’s thread (and modified to suit my needs). Link to the thread here, hope he doesn’t mind me taking his sheet. (If there’s a problem please PM me, I will take it down.)

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I don’t think you will be able to build a board at the specs you want for 300 euros and the ESC you picked (redbrick esc) has very bad brakes I used 2 of those for dual budget build (costed me ~£250) and needed to make custom braked powered by a servo and the speed was about 25-30km/h with a range of 6km (my weight is about 200lb) motor is 280kv 5060 from banggood with 90mm flywheel clones unless you are really light you won’t be able to build it at the specs you want and I think only a few members achieved to make their boards waterproof and only to some extent. Hope this helps.

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I changed the ESC to the FVT 120A one but forgot to edit it on the main post. Sorry, my bad. I think the new one will have better breaks and maybe offer some better control. What battery did you use for that particular build? From my calculations (going for a 5s4p battery) I should be able to hit a top speed of 28-35 km/h and a range of about 10-11km (though I am a bit lighter). Thanks for the advice!

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You can totally use my list! I just had those different colors and all because the yellow color was the “accessories” of my build, and the red part was for the people who want to try out my build without the accessories and stuff.

Really nice build btw, but one thing that caught my eye, does that wheel pulley really pull your wheel?

I’m no expert whatsoever, I’m doing my first build as well right now, but I thought wheel pulleys are supposed to hook up to the wheels, not from the bore in the middle?

As you see, those little things that pop off the pulley fit right inside the ABEC wheel holes, and you use some hardware and a spacer type of thing in the other side to secure it tight.

image.jpg1000×1000 74.8 KB

The one in your list looks like it mounts on motors with the bore in the middle… unless you are planning to heavily modify it to fit your wheels… Again, another noob here, anybody can correct me here.

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that is indeed a motor pulley mint. i would advise @leftaas to play with this tool a little bit to figure out the gearing he should use. http://toddy616.blogspot.nl/2013/07/electric-skateboard-calculator.html

personally i used 3:1 gearing ratio with a 260KV motor at 8S.

also, the motor you’re planning to use has a 5mm bore. i ordered the exact same one as you but i had to return it bc i couldnt find any pulleys with a 5mm bore. the ERPM would also be higher than the vesc’s limit if you run it at 8S or higher, so i’d recommend this one https://hobbyking.com/en_us/turnigy-aerodrive-sk3-6354-260kv-brushless-outrunner-motor.html it also gives you a bit more torque.

the most ideal setup would be 190KV at 10S but that’s all personal preference.

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Get this esc http://www.ebay.com/itm/302439713065 And two 5s batteries. This way you will have less strain on motor. But chose a motor for less then 200kv. If you’re making your mount, use those genetic trucks. If not, you can but calibers and hobbyking mount.

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I think you might be right… I found this kit online, which looks quite good for the job. I will only need to change the motor pulley since it is the wrong bore diameter (I need a 6mm one) and has too few teeth (I want 15 for a 2.4:1 gearing reduction ratio). The only problem is I don’t know if they will fit my wheels… (The Chinese tend to not give any numbers/technical drawings)

HTB1UxfRiEQIL1JjSZFhq6yDZFXar.jpg800×800 98 KB
What do you think?

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The specifications on their website say that it has a 6mm bore diameter. Are you sure this is the same one? I went with a 15T/36T for a 2.4 gearing reduction ratio. I think it’s ok, might not produce the same torque but I don’t want to climb a lot of steep hills, so I should be fine.

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oops, i meant 6mm! the thing is you’ll need 8mm for most gears/pulleys you can find online.

you don’t need torque for just hills but also for starting from a complete stop. my first (and recently made) board has 8S batteries and260KV motor at 3:1 gearing ratio and starting up from a complete stop is still pretty slow. in hindsight, i wish i had a little more torque. therefore i’d recommend 190KV with 10S batteries.

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the motor pulley he found had a 6mm option so he is good on that part, i agree on everything else you put there though

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@Humanmint @meesie I agree with what you are saying… I wanna try the 280kV motor for now and I will try to push the battery to a 6s4p one… There’s always room for improvement in the future.

Any BMS recommendations?

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Have you done any research???

This thread basically shows you what motor KV and battery S rating fit eachother. If you go too high with your S (voltage,) your ERPM will rise and probably blow up your Vesc. If you go too low with the S, your system won’t have enough power to accelerate you. If you want your board to be reliable and work well i’d advise you to go with one of these setups. 200 kv 10s would be my personal favorite.

170kv - 12s 200kv - 10s 260kv - 8s 340kv - 6s (Copied from @chaka 's thread)

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I don’t see what the problem with my configuration is. If I have a 280kV motor with a 6s4p battery (and considering I have 14 poles or 7 pole pairs), my ERPM comes out to about 49.392-29.400 (with a nominal ERPM of 42.336). Those ranges are well withing the limits. The only problem I will probably have is bad acceleration and maybe having to kick once or twice when starting the motor. I am well aware of those problems, but I am willing to bear them for now.

About the BMS… I found those which limit the continuous amps to 15 (batteries can handle 20 amps continuous, so I will be in the safezone and won’t strain them). I am thinking of creating 4 6s battery modules and connecting them in parallel. So I will have a battery of: 21,6V (nominal), 80A (limited to 60A by the BMS) and 10.000mAh. What do you think? Are there any complications charging the modules together (with a laptop type charger)?

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The setup you suggest is very inefficient. It lacks in voltage so it’ll draw a lot more amps which heats up the (V)ESC more than it should. but you know, do what you want. I’m just giving advice