DIY Stealthy Longboard Build Log (Integrated batteries)

[Marcin]

Hi! As a new member I feel like I should introduce myself first;
My name is Marcin, 21 and I live in London, UK. I have a huge passion for all kinds of DIY projects ranging from CNC routers and 3D printers to various electronic bits and bobs. Quite recently I have set my mind to make myself an electric way of transportation, and after some quick research I have decided to do it in style! I always loved skateboarding, and having seen some kickstarter longboard projects I have decided to build my own.

Build goals:
- Stealthy, non intrusive look. I want to hide as much as possible within the deck itself, more on that later
- ~30KM range. This is a huge requirement for me, If I manage to travel +- 20km daily on the longboard it will save me £10.20 on daily public transport. Added bonus here is that I only weigh 58Kg
- Small, reliable remote controller powered by an Arduino Nano with a 2.4ghz module and perhaps built-in screen for voltage / distance monitoring
- To have a lot of fun!

BoM (Part list)
- 42"x9.5" Deck http://www.ebay.co.uk/itm/361211929333?var=630567784894
- 18 5000MaH LiPo cells that will be integrated within the deck itself http://www.hobbyking.com/hobbyking/..._1S_20C_Lipoly_Single_Cell_EU_Warehouse_.html
- Turnigy Aerodrive SK3 - 275kv http://www.hobbyking.com/hobbyking/..._Brushless_Outrunner_Motor_UK_Warehouse_.html
- Turnigy Aquastar 120A ESC http://www.hobbyking.com/hobbyking/...led_ESC_w_Programming_Card_UK_Warehouse_.html

The idea behind this longboard is to make it look as sleek as possible, therefore I have chosen to create 18 pockets in the deck to fit the individual LiPo cells, covering them with a large 1mm thick aluminum sheet that will be anodized black upon project completion. I am planning to anodize the trucks, motor mount and the bottom sheeting cover in black, for a stealthy look

While I am still waiting for most of the parts to arrive, I have started soldering the ESC and the motor making sure that the joints won't break as it seems to be quite common with DIY boards ending up with fried motors/speed controllers




Here's a picture of my CNC router that I will use to make quite a few custom aluminum parts for this project:



Stay tuned for more ^.^

 

[Marcin]

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[sami]

onboard for this. waiting for my CNC to arrive (stuck in customs) good luck and keep the updates coming mate

just noticed you chose a watercooled boat ESC.. you may want to change that to a car ESC for braking and running without the need for water cooling.

 

[Marcin]

Thanks Sami, good luck with the CNC!

I am going to modify this ESC quite a bit to make it bolt-on to my deck making the aluminium sheet act as a giant heat-sink. Apart from that, this ESC does have a brake, we'll see how that goes

Cheers

 

[beto_pty]

regarding the brake... check the manual... the 80 amp version of this esc included brake but it was a typo... hope yours isnt

 

[sami]

sounds good Sleziak, looking forward to seeing it come together.

 

[Marcin]

@Beto, it does have a brake, I've tested it. It does seem a bit harsh, not sure how it will translate into stopping a 60kg object but the worst case scenario would be writing a custom firmware for it and integrate the remote receiver to the ESC, omitting the arduino.

Upon taking the ESC apart, it contains an Atmel microchip which is very common in terms of speed controllers, I'd need to port an existing opensource project, and make sure that I don't let the magic smoke out haha

Regards

 

[Marcin]

The board has arrived today! After a short cruise I have disassembled it and started carving out the battery slot, quite pleased about the result.

I will now start adding support struts in between the batteries before I make the bottom aluminium panel

 

[torqueboards]

Sweet setup!

 

[777arc]

My turnigy trackstar gen II has brakes, but they are unusable because sometimes they brake too suddenly and it can get dangerous. VESC brakes work great

 

[Freshair]

The board has arrived today! After a short cruise I have disassembled it and started carving out the battery slot, quite pleased about the result.

I will now start adding support struts in between the batteries before I make the bottom aluminium panel

Nice work Sleziak! Definitely following your build!

 

[sl33py]

Looks like a cool project! Definitely will follow. Best of luck!

 

[Ohbse]

Very cool, great idea with routing out for each cell. Keep it up!

 

[Marcin]

Thanks for following guys!

I went ahead and started wiring the batteries. LiPo cells are known to be hard to solder because they have aluminium terminals, setting my soldering iron to 450 degrees C, applying liquid flux and soldering the point as fast as possible seems to have resulted in the strongest joints. I've also folded the terminals in two, locking the wire in the fold before soldering

Mess



A little bit of cable management later ...


Regards

 

[Freshair]

Looking good.

So aside from having an aluminum sheet covering the bottom, how else are you planning on securing these cells?

 

[Marcin]

@Freshair;
There will be double sided mounting foam on both sides, similar to this but thinner: http://hobbyking.com/hobbyking/stor...oam_double_sided_tape_10x5inch_4mm_thick.html
Each row of batteries will also be separated by either a 3D printed plastic or CNC cut wooden support, so if they ever slide for whatever reason, no damage will be caused

Regards

 

[CSN]

How many wood ply's are left under the battery pockets?

 

[Marcin]

@CSN 3 out of 9

Regards

 

[Freshair]

You are tempting me to do a variation of this with my upcoming project!

How will you charge your batteries, are you incorporating a bms into your system?

 

[Marcin]

@Freshair
A BMS would be a dream, but I am lacking space for anything more. I'll have a discrete connector on the underside of the board bringing out 3 cells per pin (6 in total) , which I will charge using a LiPo balancer. I am slightly concerned about having 3 cells in series x 6, might cause balance issues but time will tell. Regards

 

[sami]

nice work man and good progress so quickly! keep up the good work

 

[Marcin]

Today my 1mm thick sheet of aluminium arrived, so I've started working on the bottom panel.
After a quick assembly I have realized that due to the curved shape of the sheet, the deck is more sturdy than it was originally, so I have decided to skip the supports in the battery slot.

Drawing a rough guideline to be cut using my grinder


10 minutes later ...


Adding protective padding to the battery terminals to keep the wires from moving and cover the exposed terminals


20 minutes of filing later ..


I am now ready to shape the edges of the sheet to match the shape of the deck, however I am not really liking the result so far. I might've rushed this process a bit...

If anyone knows an (easy) way to straighten the edges of this without adding more screws, please let me know




Regards, Marcin

 

[sl33py]

what about re-cutting the sheet to only cover the batteries? having it captured under the trucks will add rigidity (possibly your intent), but will add weight and make accessing the batteries a lot more difficult!

Just cutting to cover the section of the deck you have batteries in, would help re-do your edges, and make access later easier!

Not sure how difficult it is to re-cut, or if you are trying to minimize flex w/ this as reinfocement. I'd be worried a bit about weight and would try to minimize w/ less aluminum. Possibly add a layer of CF to stiffen w/o as much weight?

GL and awesome project!!

 

[sl33py]

not sure how well that aluminum will "mold", but what about adding your cut out section of wood back to the deck (so you don't press/damage lipos) and adding pressure to form it better to the deck? Worried this would take tons of weight and more likely to damage the deck w/ it being reduced strength with the cutout.

I think you might need to hammer it on a form and slowly add the angle to form to the deck flush. An art (if you've ever seen a body shop guy do with steel for a replacement).

GL!

 

[bandaro]

I am now ready to shape the edges of the sheet to match the shape of the deck, however I am not really liking the result so far. I might've rushed this process a bit...

If anyone knows an (easy) way to straighten the edges of this without adding more screws, please let me know

Thats not good...

But I assume you are meaning for the curve in the deck, because screwing a flat sheet of alu onto it will result in a "springy" feel every time you move your foot. That's not good.

So, the only ways I see are to either get 2 glue lines on it by pressing it onto the deck curvature in a vac bag with a layer of fibreglass or something on each side, or to roll it through a sheet metal roller. Rolling is simpler, lighter and cheaper but only if you have a roller. You can do the vac bag method for less than 5 euro plus the glass and resin costs. Use a pvc vinyl from a hardware store, some regular, 50mm clear packing tape to make the "bag" and then an old fridge compressor for the vacuum. You could try clamping and bending the alu, but this will only ever get it close.

That being said, if it is a tub concave or anything other than a straight radial, a roller won't do it either. Not properly anyway. Any chance of getting a 1.5mm veneer and glassing both sides of it in a bag onto the deck? this would probably be the best option.

Let me know if you want more details on the options, I make longboards regularly for a living.