Converting from Dog Powered to Electric Mountainboard

[Raja's Dad]

Hello all,
I am one of the few Floridians who own a mountainboard. My German Shepherd Raja and I have had a blast over flat roads with smooth tires reaching speeds of 15-20 mph, but Raja needs help. I would like to add one brushless motor to the front truck so she and I can go longer distances. I have a million questions and so much to learn so I have been searching and searching here and on the hobbyking forum. I use the mbs braking system and would like to use a freewheeling sprocket because it just seems like it would give a smoother ride.
My first question is, can I use a 15 tooth freewheel sprocket on a turnigy sk3 6364 motor? It can be found here.

http://www.thesuperkids.com/elscpigerocl.html

Two issues I see with this are that the motor shaft length may not be long enough to accommodate the sprocket, and that the motor shaft does not have a 10mm collar. Is there an adapter or something for this, or am I way off base in trying to fit this sprocket and motor together?

I have many other questions, I thought it might be good to start with just this one.

 

[Raja's Dad]

I seem to have found an answer to my question here...

http://www.modifiedelectricscooters.com/forum/pop_printer_friendly.asp?TOPIC_ID=1303

There's a pic in there of the same sprocket with a turnigy motor of the same shaft dimensions. It would not have worked with his motor for other reasons, but it did fit without a 10mm collar it appears. More questions on the way I am sure as my project is only in the planning stage.

 

[Raja's Dad]

Can anyone tell me if this is right, if I am going to use a wired thumb throttle with a 150A car esc, I will need a servo tester to make it work? Thanks to anyone in advance.

 

[dirkdiggler]

The sprocket should work. You might have to thread the hole and use a set screw.
If you want to use a thumb throttle you will need to wire in a servo tester. Easy to do. Should be a fun setup.
I had a gas powered mtn board with similar hand controls. It was fun till the chinese welds all broke and the motor never started. Not to mention the chain kept coming off. i modded the hand controls to shorten things up, similar to the MBS brakes.
Good luck

 

[Raja's Dad]

Thanks Dirk. Are you selling any of the mounts like you used? I would love buy one rather than try to use the bulky screwed together aluminum plate and angle bracket I am envisioning.

 

[Raja's Dad]

Did some calculations tonight trying to decide on a motor. Not sure if I have to use 8s with the turnigy sk3 6364, I had planned on using 6s. Also, I wanted to know if I am geared for 25 mph with no weight on the board but my average speed is maybe 15mph, is that going to be much less efficient? I would like to be able to go a little faster than 25, but my average cruising speed won' t be nearly that high. Any input is appreciated.

 

[Raja's Dad]

I guess what I'm asking here is, is there a reason not to choose a motor and gear ratio that give you a top speed much higher than you need? "Much higher" meaning maybe 20mph faster than average cruising speed.

 

[dirkdiggler]

How big is the 72 tooth sprocket? I've used the 55 tooth that is common on razor brand toys. It seems to have a good low end and high end. Of course you can always switch up the pinion gearing. From what I understand most electronics work best on WOT. So you might not want to gear it to go higher than 20mph. the other benefit is you can have the trigger fully depressed the whole time.
I'm still working on getting some mounts made. I am going to try a different shop. My connection isn't working out so well. He did a good job making mine, but it took forever and a day.

 

[Raja's Dad]

Yeah, the 72 tooth sprocket may hit the ground if the tire gets low. I'm gonna do some refiguring before I buy my motor, then I can try to make a mount that works out with the wider freewheel sprocket I want to use. If you get a mount before that, I'm sure I could shift the motor further away from the tire as needed with a little extra aluminum plate. I have to buy a new front truck with brake mounts anyway, I may just upgrade from the ATS trucks to the ones you have. Even if I end up making my own, your style trucks seem better suited to designing a bolt on mount.

 

[Raja's Dad]

Here's what I think I'm going with...

 

[Vapology]

Hey Dirkdiggler,

On your build with one motor 6364, I know that you had put a 55 tooth sprocket on the wheel, but I couldn't find what size motor sprocket you used. Also what battery pack/how many volts did you use?

On another note, Is there a way to post a table in the forum? I'd like to start a new thread called Your Mountain board build specs as a place for folks to show their build specifications and inlcude pictures. I have found that the best way to learn what components a noobie will need is to examine the specs on boards that others have built already. However, the information people post is inconsistent or spread over multiple threads or posts and many key details for building are often left out of posts.
I was thinking a blank table with the following information would be a good place to start, if not a table then just a list like below? Any other critical information you think would be useful to include?
Example:
Motor: Trngy 6374, 170KV
ESC: Hobbyking Trackstar 150a
TX/RX: HK GT-2
Batts: 2x Zippy 5000, 6s 30c
Bec/UBEC: N/A
Low Volt Cutoff: n/a
Amp Meter:
Connections: 10 gauge, 4mm bullets
Trucks: MBS Vector
Mount: CNC, Hand Machined etc.
Wheel Size: 8"
Motor Sprocket: 13 tooth #25
Wheel Sprocket: 55 tooth #25
Motor Sprocket mount: Keyway/D Bore/Threaded etc.
Max Speed: 26mph
Charger:
Notes: Programming the esc to medium start (3) reduced cogging issues
Pics:

Let me know what you think and whether or not folks would take the time to post up their builds. I know as a noob my self, this is the information I want to know, but it is challenging to sift through so many of the threads to find it.

 

[Raja's Dad]

What are most people using for their Emountainboards "ignition"? and where's the best spot for it?
My motor is on its way, ordering a vector truck any day now. Almost ready to make the motor mount.

 

[Raja's Dad]

Made my own version of "the list." I am a newbie too, I just pieced this together from what others are doing.
Here are the parts I am sure of... so far, Let me know if you see anything that won't work, I have only bought the motor and board so far.


Motor: Turngy 6364, 190KV
ESC: Hobby King 150A High performance Brushless Car ESC
TX/RX: n/a
Throttle: Hall type thumb throttle mounted to hand brake and
hardwired to picaxe microcontroller for signal conversion to ESC.
(we'll see if I can make this one happen)
Batts: 2x Turnigy 500mAh, 6s 20c
Bec/UBEC: 6V (built into ESC)
Low Volt Cutoff: ?
Amp Meter: ?
Connections: ?
Trucks: MBS Vector front, MBS ATS rear
Brakes: Stock MBS Atom 95x brakes
Motor Mount: ? (Will be aluminum plate welded together and bolted to Vector truck)
Wheel Size: 7.5" (actual diameter of MBS Roadie 8" tires)
Motor Sprocket: 15 tooth freewheel #25 (for smoother ride, requires mechanical brake)
Wheel Sprocket: anywhere from 55 to 68 tooth #25
Motor Sprocket mount: set screw
Max Speed: ? (don't know what tooth count wheel sprocket yet)
Charger: iCharger 206B 300W 8s Balance/Charger
Notes: ESC will not brake due to freewheel sprocket
Pics:

I am still wondering about the "ignition" question. I'm guessing it's just a switch mounted somewhere close to the ESC that would be on the nose of the board. Is there a clean way to mount it to the hand brake? Any ideas?

Regards,
Aaron

 

[Vapology]

Awesome Raja's dad!

I hope you don't mind that I copied your post over to my "post up your EMB build thread. Thanks for taking the time to put down this information.

Cool set up with the hand break and integrated throttle. Can't wait to see pictures or video once you get to building. I started my own build thread where I hope to keep a step by step journal of my progress. Painfully inane details, but its the level of detail I look for in other builds so hopefully it will be helpful to others starting the process. Didn't realize how tricky mounting the wheel sprocket absolutely centered on the hub, but I'm really pleased with the results.

 

[Raja's Dad]

Thanks, Vapology. I don't mind at all. I only hope that I don't have anything in that list wrong compatibility-wise. I am very new at all of this, but I have been searching these and other forums a lot, trying to piece it all together. I was a little bit obsessed with the mountainboard before the thought of a motor, now it's even worse. I can't help but try and notice all the inane details. I'm just hoping to try and get it all right on the first try without burning anything up... though that's almost never the way it goes. Anyways, I can't wait to have it all done, but until then I will keep posting updates as I go.
I definitely like the thumb throttle idea which should work, but there may be something wrong with putting a switch on the throttle because of the length of the wire running to it... not sure though. Anyone who knows if there is anything wrong with placing the on/ off switch so far far from the other electronics please let me know.

Regards,
Aaron

 

[dirkdiggler]

How are you doing the hall throttle to ESC? I am not familiar with the picaxe, but have done the servo tester and that was easy.
I am using a 14 tooth motor sprocket with 5000mah 6s batteries.

 

[Vapology]

Dirk, are you running one motor or two now, I can remember where you are one your most recent board? What kind of ride time are you getting out of it those packs? and how is the power? 10 15 or 20 ah? I'm at that place where I'm about to have to make a decision on what esc to go with. I'm leaning toward the trackstar 200a. I'm gonna run one motor for quite a while (budget constraints you know) and I don't want to lack enough power to get me around town. I live in Knoxville Tennessee and its really hilly. I may start with 6s, but I would like the option to move up to 8s if I want or need.

 

[Raja's Dad]

I noticed someone using a picaxe micocontroller in place of a servo tester while searching on the subject. Some people were saying that certain servo testers would not work with the hall throttle. I think all servo testers may work with a pot throttle. But with the hall throttle, they said you must remove the pot from the servo tester and then solder in a "jumper wire." Did you have to do this Dirk? I may do the servo tester still, it's cheaper, but I wanted to try to do something with a microcontroller for fun I guess. The post I was looking at can be found here:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=12196

 

[dirkdiggler]

Yeah, I wired it up just like Hillhater did in the thread you linked. One jumper wire and I changed out the connector on my throttle to servo style. Very easy.

 

[Raja's Dad]

Well I have the motor, sprockets,#25 chain, master link, vector truck, and 6061 aluminum now to make my mount. I am following Vapology's lead and looking for a local machine shop to cut a keyway into the sprocket, and finish doing everything I can't with mount. I am trying to keep it as simple as possible... 3/16 thick plate bolts to 5/8 thick "hanger clamp" and hanger clamp bolts to threaded hole in the vector truck. I just have to buy the nuts, bolts and lock washers and hopefully I can get a reasonable deal from the machine shop and it won't take forever.

I looked into having an on/off switch on the hand brake/ throttle and decided it was a bad idea. Most people seem to think it is a bad idea to extend those wires at all.

I also am thinking about building some sort of fiberglass battery box to mount underneath the board. I won't be riding it offroad, so I'm not too worried about clearance but I know the fiberglass has to be very strong. I would go for a vacuum molded plastic box, but I don't know how to go about having one made.

 

[dirkdiggler]

If you have the vector trucks I would sell you one of the extra ones I have. Probably $65 or so with shipping.
As to the battery box. Radioshack has them or Ebay has even more options. Search for project box. Here's a link for a few. Just depends on what size you are going for.
http://www.ebay.com/bhp/electronic-project-box?_trksid=p2045573.m2388

 

[Raja's Dad]

Thanks, I couldn't find boxes that size for some reason. I still might go with fiberglass to make it more custom. I already bought the front vector truck. I'll let you know if I decide to replace the back truck too. The Vectors look much nicer than the ATS trucks.

 

[Raja's Dad]

Ok, here's an update. I had a local machine shop do the work for the motor mount I designed which cost double what I wanted it to, $150, but oh well. Here is a pic of the mount which seems like it will work with the MBS Vector truck, only I have to put the truck backward... fail on my part for drawing the cross-section of the truck backward on the aluminum plate. The two sprockets seem that they will line up just fine though. I'm taking out the board later without the motor and the truck put on backward to decide if it will still ride ok. I am hopeful it will since the Vector truck seems almost symmetrical from to back.

I have decided to go with only one 6s 5Ah 20c lipo and Hobbyking's cheapo 6s balancing charger with built in power supply to save money for now. My dog will just have to tow me home if I run out of juice, lol. Also, I guess there are no more trackstar 150A ESC's left at hobbyking and have not been for a while, so I am now going with the cheaper 150A ESC from their site. That will probably have to wait till Christmas, so maybe I will be riding by early 2014??? Patience.......

 

[r3volved]

What the!? I thought I invented dog-boarding! lol

I'm hoping to make to power upgrade my longboard from dog to electric next summer
For now, I dream and live vicariously through ES posts.

Do you do trails with your dog?

How do you hook him up? I've been using a leash connected from a pull harness to a pinch collar. Using the harness side of leash to pull me and the collared side to direct and discipline. Without the collar he'd be pulling me at 30kph across the grass, going after rabbits.

 

[Raja's Dad]

I used to do the same thing, two leashes with one on the choke collar, one on the harness and I was still scared. Raja never learned when to slow down. That is the reason why I bought the mountainboard -- brakes. The brakes on my board can stop us both on a dime even if she keeps pulling, which is great because there are ducks everywhere in my neighborhood. We stay on the road where we can go faster without Raja having to pull too hard and I just use a normal harness and leash.