Because my Red Brick ESC won’t brake the way I would like to, I’ve ordered a boat ESC from Hobbyking. Their support guys have assured me that it will have a forward, neutral and brake function with the GT2 transmitter.
Here’s a link to the one I’ve gone with. It’s coming from Honk Kong so it’ll likely be a couple of weeks before it arrives so stay tuned for testing.
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=19438
Over the weekend I decided that my Hobbyking GT2 transmitter was too bulky, So I purchased a smaller ABS case to put it in, Seeing as all I plan to use on the transmitter is forward and brake, I decided not to integrate the wheel into the new case. I had received some questions as to how this could be done so I thought I would document it here. It’s really very simple. You don’t have to do it the same way I did, mine is very much function over form. Firstly, to take it apart, I removed all screws, then removed the flap which covers the switches. 
Then I gently prized the housing apart from the back as there was a sticker on the front holding it together. 
Next, I unplugged the battery and the small wheel control. 
Before I removed the PCB from the housing, I de-soldered the antenna from the Wi-Fi module. 
After unscrewing the trigger from the housing, it all simply lifts out. I decided to do away with my 8 x AA batteries and go with a LiPo battery. LiPo’s have slightly higher voltage than the AAs do but the regulator will deal with this. 
When fitting the PCB into the ABS housing I bought, the Wi-Fi module was sitting too high so I de-soldered it and then soldered it to go underneath the PCB. If you aren’t confident enough with electronics then don’t do this. 
Here’s the PCB with the Wi-Fi module mounted below.
From there, I just put everything snugly into the new housing, cut the corner the accommodate the trigger, and screwed it all together. It’s much smaller now. I should note that I have fairly large hands so this is quite comfortable for me to hold. Oh, I also cut a small hole in the new ABS housing to accommodate the switches.
Overall, I’m very happy with it. It’s lighter and much better to hold IMO.
My new sealed ceramic bearings have arrived! They feel much smoother to my knackered old ones. I’ll have do some work on my new motor mount this weekend now. I’ll take some photos of my old motor mount to show where I went wrong along with photos of the new mount once it’s all sorted.
I’m just waiting for the car ESC I want to buy to be in stock so I’ll have better brakes and this project will be about done.
My motor started making some serious noise after about 2 weeks of use. The motor didn’t come with a circlip to hold the bearings in and I didn’t notice until the bearings were shot. Not having a clip would have knocked the bearings around.
After toying with the idea of buying an other motor I’ve decided to give the NTM one last razz to see if I can revive it. I’ve ordered some ceramic lightning rubber sealed bearings from Boca Bearings so I’ll see if it still makes some noise with the new bearings.
For anyone following, if I were to do this over again I’d probably have gotten the SK3 245kV motor from HK. On the same topic, although the Red Brick ESC is still serving me well, I haven’t been able to have it brake the way I want it too. Apparently plane ESCs brake differently to car and boat ESCs. Foot braking is doing OK for me for now though although I may look at getting an HV car or boat ESC after I’ve done a bit more research on which ones have good braking for electric vehicles.
Just a quick post with some build notes.
The ESC does get quite hot. I’ve added a fan to hep cool it down. It needs to be a good quality fan though because if it’s cheap and flimsy the plastic may crack due to the vibrations.
The bearings in the NTM motor won’t last long because of the vibrations and debris. They’ll need to be upgraded to ceramic bearings and I would also recommend some kind of shield to stop dust and grit getting into the motor.
Use and ABS case for your batteries. I’ve used an angled one to make it easier going over driveways. I’ve hit trees with RC planes and seen exactly what can happen when a LiPo battery takes a knock to they need to be well protected.
If you make your own motor mount, get a metal pulley for your motor. Mine was mounted so it looked straight to me but it must have been marginally off axis because the belt was putting pressure on the pulley and the outer flange popped off one day and could not be found. I’ve now replaced mine with a metal one.
Again, if making your own motor mount, have it adjustable like the alien mounts. Don’t make the same mistake as me and make your motor mount adjustable at the motor (I’m in the middle of fixing this).
Use loctite for all screws and grub screws. Don’t assume that the factory that made the motor used good stuff. So many motors I’ve used have had rubbish stuff used and screws have come loose.
Don’t put a flat spot on your shaft, drill a shallow hole for the grub screw to grab. I put a flat spot on mine and no matter how tight and what loctite I used it still managed to rotate around. This defies logic but it must be under a fair amount of pressure. That combined with the vibrations must be enough for it to loosen just enough to rotate on the shaft. What then happens is because it’s a steel shaft and an aluminium pulley is they will seize.
Use a switch. I see a lot of people just using connectors to plug and unplug their longboard. Personally, I don’t think a deans connector has a strong enough hold and an XT90 is tough to get off quickly. If you’re longboarding to work or the shops the last thing you want to have to do is waste time wrestling with a stiff connector. Just flicking an off switch is so handy.
Use a low voltage alarm. WIth LiPo batteries, you don’t want them dropping much below 3.3V/cell. If you drain a LiPo below 3V/cell they can become unstable and most chargers won’t charge them. Low voltage alarms can be purchased for around $2 on eBay so it’s not much cost for a lot of protection.
I’m just doing a bit more work on my motor mount, will post a heap of photos once I’ve sorted it out.
I was out flying with a couple of mates over the weekend and my mate Brent wanted to film a bit of my longboard in action with GoPro attached to his tricopter. It goes pretty well up hills, going up hill in this video I was at about half throttle.
More info to follow…
So most of my parts arrived. Just waiting for my pulleys and belts to arrive from the U.S.A. now.
I picked up the accessory kit because I had heard of others having issues with the pulley on the motor slipping. This will give me the option of mounting the pulley on the back of the motor should I have any issues with slipping.
I’ll start work on getting the electronics set-up, batteries/ESC/Receiver mounted on the board and work on my motor mount while I’m waiting.
While I’m waiting for my electronic parts to arrive, I decided to light up my longboard just for fun.
http://www.youtube.com/watch?v=R-MUCEImNqY
I finally got around to making an order at HokkyKing. Here’s what I have on the way to me:
HobbyKing HK-010 Wattmeter & Voltage Analyzer
Hobby King GT-2 2.4Ghz 2Ch Tx & Rx
HobbyKing Red Brick 125A ESC
NTM Prop Drive 50-60 270KV / 2400W
NTM Prop Drive 50 Series Accessory Pack
2 x ZIPPY Flightmax 5000mAh 2S1P 20C (AUS Warehouse)
Nylon XT90 Connectors Male/Female (5 pairs)
I already have a 5000mAh 30C 3S pack so with these three in series that’ll effectively give me a 7S battery.
Having multiple battery options also will help with my goal of being able to contain it to 200 watts in order to be road legal here in Australia (hence the watt meter). I’m hoping I can get there using 2 x 2S in parrallel. I would need to setup the motor to only draw 27 amps so It’ll definitely be a challenge. When I’m off public roads though, I’ll go the full 7S!
More to follow…
I’ve always wanted an E-Longboard and I’ve finally decided to give it a red hot crack. Inspired by http://howtomakeanelectricskateboard.wordpress.com/ I’ve decided to document my journey.
To start with, I’ve picked up a Vault Pintail 46″from http://www.skateboardexpress.com.au/
I went for the 46″ because I figure the longer wheelbase would give me more stability.
I’ve been building RC planes for a while now so I’m comfortable with the electronics. I’m yet to order all the parts just yet although I’ve already picked out my parts. I’ll be going with a 270kV NTM 2400W motor and I’ll gear it with a 16 tooth on the motor and either a 30 or 40 tooth on the wheel depending on which I prefer. I’m assuming that the 40 will be better, I mostly ordered the 30 in case I want to shoot for a higher top speed. I have ordered the pulleys/belt but they’re coming from the https://sdp-si.com/ and I’m in Australia so it’ll likely be a couple of weeks before they arrive.
I’ll get a Red Brick 125A ESC. I know the guy who was my inspiration fried his, but I have a watt meter and I don’t see how it can blow unless it’s drawing too much current. Considering the max current of the motor is 90A If it’s drawing enough to blow the ESC I’ll be very concerned about the longevity of the motor in this setup. I’ll also modify mine and mount a fan to the heat sink and remove some of the heat shrink so it will cool more efficiently. I’ve been using Red Bricks for a while and I’m a big fan of them.
Battery wise, I’ll be using one 4S 5000mah and one 3S 5000mah in series to effectively be one 7S battery. This will give me maximum voltage without having to shell out for a high voltage ESC. I want to use this to commute to work which is 8km so I’m hoping this’ll give me sufficient range. If not I’ll just double-up the batteries.
One of my goals is also to come up with a setup that will make it under the magic 200 watt legal limit for Australia in case the Police drive by and notice my board is powered. I’m not sure how this’ll pan out but I’ll see what I can do.
Stay tuned…
DIY Electric Longboard 