DIY Stealthy Longboard Build Log (Integrated batteries)

[sami]

i would be keen but im all the way over in Aus mate they look sweet!

 

[longhairedboy]

That's pretty awesome $650 for a CNC! How well does that thing work for cutting aluminum parts?

They seem to cope quite fine, obviously not as good as a dedicated CNC mill but it's perfect for hobby use

Here's a video of one:
[youtube]KVmf_dac8gY[/youtube]

This is beautiful, and its perfect for my limited space.

 

[bandaro]

Tips for cutting aluminium using a router (Learned them the hard way):
- Don't go beyond 0.4mm depth of cut
- Always use carbide bits, routers are less rigid so we have to remove less material per rotation causing the tools to heat up faster
- Have a can of WD-40 on stand-by and spray the workpiece every pass or two, try not to spray on the tool as it can shatter due to thermal shock
- Always mount your workpiece securely, the stiffer the better.
A safe start would be .2mm depth of cut, 10K RPM and 900mm/min surface speed.

I would agree that when cutting ally, slow it right down. That being said, provided the machine can handle the forces, the speed is determined by the cutter used. It's all a ratio of speed, pressure, chip rate and a bunch of maths if you want to work it out.

But an easier way is to experiment, and listen to how the bit is going. For reference, I was cutting a mount today out of aluminium, with 2.5mm depth, 500mm/min feed, 18000rpm spindle, 300mm/min plunge with a 6.35mm up spiral cutter and it was humming like a bird. I find up spirals are much better, and cutting deeper and slower is more reliable than shallow and fast. Sat next to it with a bottle of wd40 and sprayed it down for each pass, just ahead of the cutter or as it needed.

Should also mention I cut the size of the aluminium out of some mdf and wedges the piece in there to help fasten it. Fastening is important. Any vibrations put extra stress onto the bit.

 

[Marcin]

I can also recommend the MDF piece, it soaks up some vibrations the router creates, I've found it more reliable than mounting metal on metal

 

[dirkdiggler]

Sleziak -
I'm interested in how you did your esc hack. There have been a few guys on here that talk about it, but you are the first that seems to have done it or posted it. Will you post a thread on it? Guess you need to get the brakes working first. I think that people that had issues with the boat esc would lose braking ability on hard stops and then it would no longer work. Must be something with the motor shorting that caused that. Interesting to use regen to fix that issue.

 

[Marcin]

Sleziak -
I'm interested in how you did your esc hack. There have been a few guys on here that talk about it, but you are the first that seems to have done it or posted it. Will you post a thread on it? Guess you need to get the brakes working first. I think that people that had issues with the boat esc would lose braking ability on hard stops and then it would no longer work. Must be something with the motor shorting that caused that. Interesting to use regen to fix that issue.

Thank you for expressing your interest in my ESC
I will post a detailed thread as soon as I finish writing the firmware, which will be in a few days

So far I've been tuning the start-up timings and power for the best possible start
Here's a video of the motor spinning up without load, it reacts almost exactly the same when riding

[youtube]XunBfNAlfYw[/youtube]

Here's another video of it starting under "fake" load 26V, the random bumps are caused by my power supply maxing out at 10A

[youtube]2sigRGV0Cho[/youtube]



Regards

 

[dirkdiggler]

Thanks. I've still got a YEP heli esc that I could never figure out how to program as I didn't buy the programming box. It would be a nice way to go if we could load a custom eboard firmware on to some of these cheaper mass produced escs. I'd like to give the Vedder esc a go, but it needs to be a bit more consumer friendly for me.
How's the 5065 motor working for you? Haven't seen many use that motor anymore. I have one on a board and it is just a bit lacking on the big hills, but works well on the flats.

 

[Marcin]

Thanks. I've still got a YEP heli esc that I could never figure out how to program as I didn't buy the programming box. It would be a nice way to go if we could load a custom eboard firmware on to some of these cheaper mass produced escs. I'd like to give the Vedder esc a go, but it needs to be a bit more consumer friendly for me.
How's the 5065 motor working for you? Haven't seen many use that motor anymore. I have one on a board and it is just a bit lacking on the big hills, but works well on the flats.

It has been a blast for me, not a single hill it couldn't conquer. That's probably due to my weight (60kg) but it was a perfect match on 12x36 setup

Regards

 

[torqueboards]

Dual 5065 works great. A single is slightly lacking unless you gear it heavily although I'm also using 5065 200kv motors.

 

[Marcin]

Keep in mind that most of you use a 50xx <1600 watt version, the motor I'm using is capable of outputting 2000+ watts, it's the longest and torquiest of the 50xx series. It's too long to fit two of them on one truck

 

[sl33py]

Super cool Sleziak! Look forward to seeing the process for your firmware!

I'll just say that every time i see you "60kg" i chuckle - lucky light guy! I remember being young and thin once... I'm now 2 of you! Helps being 6'8" (2m). Still a lot of weight to haul around.

I'm a huge fan of re-use of a mass produced ESC w/ some custom firmware like this. Thanks for sharing your project! I'm also hoping to get Vedder's as it's just so smooth and polished once configured for your individual motor! Good to have options! I'll do both!!!

Nice work.

 

[torqueboards]

Keep in mind that most of you use a 50xx <1600 watt version, the motor I'm using is capable of outputting 2000+ watts, it's the longest and torquiest of the 50xx series. It's too long to fit two of them on one truck

I think most of us use 2200watts and 2400watts.

 

[Marcin]

Keep in mind that most of you use a 50xx <1600 watt version, the motor I'm using is capable of outputting 2000+ watts, it's the longest and torquiest of the 50xx series. It's too long to fit two of them on one truck

I think most of us use 2200watts and 2400watts.

I see, I might be wrong then

I have another exciting story to tell; The ESC has shown it's magic smoke an hour ago...

While I was testing the brakes at 4A current limited supply, the speedcontroller suddenly went *poof*. My desk filled with smoke and a quite familiar smell: Burnt ICs. There was even a flame for a brief second.
At that moment I thought *oh no* and started inspecting the damage, the weird thing was that the Mosfets all seemed to be fine. I then proceeded to disassemble the two layer ESC stumbling upon a burned linear regulator IC.
After a quick search on google I unfortunately was not able to find a replacement for that particular IC or anything compatible with it. After a quick thought, I started wondering what this 6v regulator has to do with the rest of the circuitry, it's job should only be to power the receiver through the 3 pin cable, there is a dedicated 5V linear regulator that powers the electronics on the board.

After unsoldering that particular chip, having high hopes I turned on the ESC: *Beep Beep*, it works! But not for too long ..
I looked over at my power supply, the ESC was pulling 4A (The limit) without doing anything. After quickly disconnecting everything I went on and checked every single Mosfet, they all appeared to be fine and in-spec. I checked nearly every larger component on the PCB and could not find any issues what-so-ever, there clearly was high resistance on the battery input line but I didn't know where it came from.
Being out of ideas I've noticed that there is a marked "middle line" between the BEC and the rest of the PCB. As a last resort I've cut the entire BEC section off, powered the ESC and started laughing; It's fine now

After connecting my receiver, mapping a damaged output pin to another pin it all ran perfectly once again. I am not powering the receiver from the built in 5V linear regulator.

I wonder what happened and why the BEC that wasn't used burned when I applied brakes. The positive and negative wire were far away from each other so a short was out of question. My theory is is that the braking motor generated too much voltage for the BEC to handle, resulting in the light show

I'm going to replace the default caps to higher capacity ones, just in case.

Morale of this story: Uhm.... How to shed weight and save space 101

 

[2wayspeaker]

Man that must have been frustrating looking for something like that. Once four years ago I had a custom pid controller that never responded how it should so after 2 days of looking I did the same thing, I cut off a non essential circuit I built alongside it. Suddenly it worked. So annoying, still not shure why the side circuit was the problem.

Crazy build so far, this has custom everything, board trucks esc software. Very impressive

 

[Marcin]

Man that must have been frustrating looking for something like that. Once four years ago I had a custom pid controller that never responded how it should so after 2 days of looking I did the same thing, I cut off a non essential circuit I built alongside it. Suddenly it worked. So annoying, still not shure why the side circuit was the problem.

Crazy build so far, this has custom everything, board trucks esc software. Very impressive

Indeed, I got a bit upset thinking that £50 went down the train.
It's nice to have a fellow Belgian around here!

Groetjes

 

[Marcin]

Change of plans again!

In order to keep my costs low I've decided to coat the deck (and permanently seal the batteries) with glass fiber
My plan is to coat both sides with 12 layers of 200gsm glass fiber, hopefully giving my deck enough rigidity

I've ordered the required resin and glass fiber today which will arrive somewhere this week

I'll keep you posted

 

[okp]

hey Marcin, great. You gave me an idea. I am going to change my plan and go the Kevlar stealth way

 

[stuartstardust]

Hello

As for the controller, DX has a OK wireless Wii nunchuck clone (label on Wireless PC: MAR105P121306) for less than15 EUR. I have it working with an arduino nano for the ESC, that might be a nice easy start for your controller setup. Can mail you the arduino code if needed..

Also, i like that you have hacked an ESC, very nice indeed!

FYI:

My plan is to coat both sides with 12 layers of 200gsm glass fiber, hopefully giving my deck enough rigidity

That seems a bit over the top to me, but just my 2 cents. If i remember correctly, i once made a boat(4 person), and there we used 3 * 450 g/m2 for the outside hull..! I will try to verify tomorrow...

/KR

 

[bandaro]

.....
My plan is to coat both sides with 12 layers of 200gsm glass fiber, hopefully giving my deck enough rigidity .....

As in, top and bottom with 12 layers of 200 gsm glass? This would be far, far too much. Depending on the weave of the fibre, I would go 2-4 on the bottom, and maybe 1 on the top, unless there is something very unexpected about your build... For reference, I will run a 9 ply board without glass or a 7 ply with 400 gsm uni glass both as downhill stiff rides. So I'm hoping that should have read "1-2 layers of ..."?

How were you planning on pressing the glass? Will be nice having the complete deck sealed up, until the batteries die in a year or three.

 

[Marcin]

@stuartstardust

I'm already using an arduino and a 2.4ghz module, I wanted something different that just a nunchuck. I'll be printing an enclosure for my remote soon

@bandaro, stuartstardust
You guys are probably right. I have no clue how thick fiberglass is or how much I need to use. I'll try to build up layers until I feel like it will be structurally strong enough. I am however certrain that it will be fiberglass. Option B would be to get a new deck and make a fiberglass battery enclosure for it that's still low profile. I'm currently contacting some longboard shops and asking around for b-stock decks

In terms for pressing; I am going to use a vacuum bag since I don't have any access to a press

Regards

 

[sl33py]

Great build so far and look forward to your glass steps. I'd love to glass in some cutouts like this in a deck as well, but being a lot heavier than most i'm hesitant. So continuing to follow your progress!

GL!

 

[stuartstardust]

OK, just to update on the fiber use if needed..

I called my old boss yesterday, and he said they used 350 g/m2 outside and 200 g/m2 inside for the hull on their 23" racing hull with a 10 mm core(sandwich construction).
He suggested 400 g/m2 on both sides.. or 600 g/m2 and it would handle almost everything except for a tank.. Just some input..

Which vacuum device can be used? (Have never worked with vacuum and fiber, only hand laid fiber.. )

Also can you let us know the ESC chip version?

/KR

 

[bandaro]

In terms for pressing; I am going to use a vacuum bag since I don't have any access to a press

Probably the best way anyway unless you have the exact mould the board was made from; bags are great because they are very universal.

Which vacuum device can be used? (Have never worked with vacuum and fiber, only hand laid fiber.. )

Any. You can't get too much pressure from a vacuum, they max out at around 15psi, where as I press my stuff at 45psi. The autospace engineering manufacturers have sweet autoclaves that do over 100... The most ghetto vacuum press I have used is a regular freezer bag and an old fridge compressor. Worked a treat for the small object I was prototyping, however a pvc plastic is better as these are airtight and reusable, unlike freezer bags. Hand laying fibre leaves a lot more weight in there than you need (in terms of resin), but does the job.

 

[2wayspeaker]

A vacuum bag is easy to use. But get real vacuum bagging materials. If you try to use those vacuumbags that are made to store clothes from Aldi/Lidl, heads up: they don't seal. And if theyy do not seal you have to leave your vacuum cleaner on until it burns up.

Best bet: Real bagging materials and a real vacuum pump, a valve to seal the vacuum and some way to drain the excess resin.

@Bandaro: Thank you for the offer, I'll certainly take you up on that, right now is examination time. So expect that PM or build thread at the end of July.

 

[Marcin]

I'm back with some progress!

Lets head right into it: Because my previous routed deck was too thin and eventually cracked, I have decided to reduce the amount of batteries from 18 to 12 (10A 6S). It's a compromise I had to make to have a stealthy longboard that is structurally strong.
I have contacted some UK longboard companies asking if they have any B-stock decks in stock for a cheaper price. Mindless Longboards and skateboardexpress.com replied. The Dervish deck was £30 and the Mindless deck + talisman trucks were £80 (Both heavily discounted)


View attachment 4

I chose the mindless deck for my electric project, dervish was way too flexible for this. It is however an amazing deck for general commuting, it doesn't weight anything! #

Step 1 was to make a precision pocket in the deck to house the batteries, I've used my CNC router to make the following pocket:

It took 12 minutes to do this.

Result:


Next up will be soldering everything together, add a balance and ESC connector followed by fiber-glassing the bottom of the deck

Kind regards, Marcin