Modified board

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Bob K
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Well I finally got it back on the road.
After it just about broke my ankle and then my SLA's
died in storage, and life has a habit of taking
a lot of your time....

I put 20 Elite brand 4aH Mimh batteries in it this time.
After I looked at the discharge curves of my old 7aH SLA's
I found I was only getting 4 aH's out of them at anything over
8 amps anyways! I saved about 10 pounds too!

So I get back on the old Rietti and WHOA! These batteries
have a lot more "punch" , they can really deliver the amps!
NICE! So I cruise around really easy just getting back into
the grove of this thing. Alright, I hit the throttle and.....
Snap! Zin-nng goes the motor......
( visualize a broken belt in the street )

Rats! So now I have a belt on special order
( I had no idea how many belt tooth profiles ther are !! )
So I have a little time and I though maybe someone might
like to see some pictures.

Bob K

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Rietti.jpg53.41 KB

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LinkOfHyrule
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Re: Modified board

Nice. How fast does it go?

That looks just like one of the ones I was going to get. But I decided to wait until I get a welder and just make my own.

I JUST was adding even more voltage to my G1. That and a throttle. Then I got interrupted by work. I would have tested it right before, but the throttle plugs didn't match exactly. The prongs are loose, so it will slam on full throttle (with virtually no ramp up) if it's jiggled. Good thing I found out BEFORE I got on it. In any case, it should be good for somewhere between 20-25mph. Which kinda scares me, because at least at 16mph I could run fast enough to pass it. I'm screwed if I eat it now.

I had a belt problem, too. The extra torque I had at 36V stripped the cog :O. I'm gonna have to be careful with the throttle. That and find either a better plastic or metal cog...

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Bob K
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Re: Modified board

Here's anotherE_Skateboard_031.jpg

Bob K
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Re: Modified board

That is my "hands free" throttle control.
It's just an R/C car transmitter and batteries
put into a "cuff" that I just wrap around my fore arm
and it just velcro's on.
I then use my thumb and fore finger to trigger the
throttle and brake.

Bob K
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Re: Modified board

Here's a pic of the motor sans belt.
It's a 24 volt Unite Motors MY- something.
I guess it's about 15 mph.
Lotta torque though.E_Skateboard_021.jpg

LinkOfHyrule
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Re: Modified board

Is it a MY-6812? That's identical to the one I have in my G1. I'd overvolt that sucker if I were you. I just tested at 48V all I can tell you is that it's AWESOME. I haven't tested the speed formally yet, but it's incredible. I thought I had it good at 36V.

I was wrong.

All I have left to do is make the power cable and stuff everything in a backpack. I need to do something about the front wheels, though. I'm destroying them at these speeds. Back seems okay for now.

Also, it didn't strip the cog. The cog is steel. I took a better look at the belt, and it had been destroyed from the slippage I got the one time I rode in the rain. It looked all fuzzy, but you couldn't really tell it was damaged unless you felt the teeth. They just kinda flopped over.

Your throttle is much better than mine. I just hold onto a half twist bike throttle. It works, and I can hold the whole thing if I just want to cruise.

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Bob K
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Re: Modified board

48Volts!
You must be young and bounce better than I do!
Post some pics of the guts of your G-1, I wanna see 'em!

An MY 6812 huh? That sound about right, I'm not sure.
Unite motors USED to have a website that had specs and
graphs. I sure would like to find the specs for this motor....

Your speed controller, is it tethered ( ie cable) ?

Bob K

LinkOfHyrule
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Re: Modified board

It's funny, though. You're so high up you don't realize how fast you're going. But still, 48V is some serious power. I want to force air cool the motor before I take it on any long rides. It should be fine, but I want to be sure; I don't want to have to get a new motor before I make my own board. I'm still waiting on my Watts Up meter to get here so I can find out how much power I'm using.

I've almost eaten crap on the board already. I twisted the throttle a little too hard and it tried to fly out from under me. I'm attached to the board via the backpack, but the power cable can pop out of the socket if it's pulled too hard, so I don't really have to worry about it. I didn't even trip, but I probably looked like an idiot. I know of a few fixes to smooth out the throttle response, so I'll try to do that later.

My cable is tethered. You have no idea how hard it is (maybe you do) to just find a speed controller and wireless throttle. I could only find one place, in Canada, who only had the site up as little more than a store display; there's no way to actually order them.

Like I said earlier, I don't even ride it that often, but at these speeds, I'm destroying the wheels. They've been ground completely flat already. I think they're also wasting a lot of power, as they're noticeably warm after I ride. I don't exactly get the smoothest ride out of these, and at full speed, those ridges in concrete feel like...um...really deep ridges in the concrete? Really, the wheels are my only (and major) complaint at this point. I need to find some better ones. Solid rubber or semi pneumatic would be good, but I can't really find anything that is the right size. They all seem to be made for casters 6 or more inches in diameter, and are much too fat. I wonder if off-road rollerskate tires will work...

The suspension is okay, but I have to work kinda hard to not let it wobble. Better tires should help. If not, I can just fit it with heavier springs.

I still haven't put grip tape on the deck. Haven't cut a design out of the fairly generous grip tape sheet they gave me.

Charging is annoying. I don't have a 48V charger. The pack is tapped at 36V for the controller's uchip power source (I think). So I can use my 36V charger there, and I use a 2/4/6A Vector for the fourth.

The board has been disemboweled, to use your metaphor. I had to remove the tiny controller from the deck when I put in a third battery. I never intended to fit four in there. I used mounting and masking tape to hold them together. It was supposed to be temporary, but it works very well. It feels like one solid brick. I'd replace the masking tape with something better, though (perhaps nuclear grade duct tape [I swear, there really is such a thing]). The batteries go in a backpack. They aren't very big (5Ah) so it only weighs about 15lbs. The controller goes next to them. The throttle cable runs out to my hand, and the power runs down to the motor. The power cable needs to be fatter, by the way. It was made out of some power cord I had handy, and gets warm from the amperage draw. It's not really a problem, but it's probably dropping a volt or two. I haven't got the heavy speaker wire I want to use as power cable yet, so it's all I could use.

Interestingly, the backpack setup was originally intended for my upcoming ebike, but it was a simple thing to make work on my board.

Basically, the board is neat, but has its shortcomings. This is why it's really little more than a tide-me-over for my custom board. I was going to wait until I got a welder, but I thought of a few ways to make it without a single weld. But, that's for later.

Oh, and I'll take some pics if I can steal my friend's cell for a while. It has a pretty good camera.

EDIT: I just took a look at the info you posted about your board. Your motor is not the same model of motor as mine, but I think it's still a My-6812. They made several different models of that motor (A, B, C, etc.). If yours is rated to 450 watts, you should be able to go even faster than me (should you want to). In fact, I wouldn't think 30mph would be out of the question...

How well does that suspension work? It looks like it would do a pretty good job.

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Bob K
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Re: Modified board

Yes, it is so easy to sink a bunch of money into these things if one is not
well,prudent.
It sounds like you have pushed the design of the G-1 as far as it can go. Speed wobble
is usually the first sign.
As far as the controller goes, yes, I need more control of the acceleration and
braking "ramps". As it is, my wireless controller is well, in my own hands....
It is proportional, but straight linear.
This is not really very safe, as you have yourself experienced.
My motor is actually an MY-7618 24v 450 watt, so it's pretty torque-y.
Until I get my controller aligarythms dialed in, no more top speed for me.
But, the large wheels and the BMW style suspension is just great.
I just really love the "feel" of this suspension over even Torsion Trucks
which are pretty awsome too. The Torsion Trucks (Exkate) don't ever speed wobble, always solid. The BMW's don't speed wobble, but they do not "self center" either. For my
style of "slice and dice" sidewalk surfing they are great. But, I would choose
Exkate Torsion Trucks for high speed every time, no doubt.
Also, 4 inch diameter off-road skateboard wheels ( soft ) are much better for a powered
skateboard on the street, in my opinion.

Bob K

Bob K
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Re: Modified board

E_Skateboard_034.jpg

Bizarre looking speed controller.
Very ergonomic.
Man machine interface.......

LinkOfHyrule
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Re: Modified board

I was looking at that throttle, too. So unusual. Where did you get it?

As for the G-1, I don't think I've pushed it's limit quite yet. It does feel like it wants to wobble, but it's hard to tell with the way the wheels vibrate. It LOOKS like it wobbling super fast, but it doesn't FEEL like it's actually wobbling. I took another ride to look more closely. The suspension itself I'm sure can take much higher speeds (especially with heavier springs and thick grease), but the wheels are so hard that they make it rattle pretty badly, and their odd (they ground themselves down at an angle) shape just exacerbates the problem.

Wobble seems to be relative, too. When I first got the thing, I had trouble with wobble at 12mph. After a few rides and 12V later (;)), I was completely comfortable at 18mph with no wobble at all.

I agree about the off road wheels. They look much better than the polyurethane ones I have now. Know any good places to get some?

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Bob K
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Re: Modified board

The black part is the throttle trigger from the R/C car transmitter and potentiometer. The grey is just some PVC I whittled out to fit my thumb. Fits like a glove! Quite odd until you have it in your hand, then it feels quite natural. Better than anything else!

As for the off road wheels, just google skateboards, that's what I'd do.

Bob K

feinstaj
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Re: Modified board

I have an Exkate Raptor 3.0. I am planning on modifying it and I am really excited to find this thread!

My first mod is to change the lead acid 24V setup to LiFePO4 24V to reduce weight. The Chinese one I found on Ebay for $250 comes with its own BCU and charger. Anyone know any reason why this wouldn't work? The motor is 250W.

This is a first for me in terms of doing an electronic project so any tips would be great!

Thanks!

LinkOfHyrule
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Re: Modified board

Ah, I believe you are thinking of Ping's batteries? A 250W motor's controller should be limited to 15A, so the batteries will handle that fine.

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feinstaj
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Re: Modified board

Yes! Any info on Ping or his batteries? He seems to be helpful enough in our correspondence.

I have to take apart the box that holds the battery meter, power cord socket and power switch. I'm guessing there's a battery control unit in there, too. I figure I might be able to get rid of that assembly and save weight since Ping's battery has a BCU attached. I would just need to put a power switch in line and have a plug in for Ping's battery to charge. Was also thinking of wiring in this thing to keep track of my battery performance but I wonder about weight:
http://www.rc-electronics-usa.com/motorized-bicycles/electric-bike-meter.html

Thanks for any help and advice. My main goal is to make he board as light as possible so it is easy to pick up an carry when I get where I'm going.

LinkOfHyrule
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Re: Modified board

Here's a link to a thread on Endless-Sphere. It contains more info than you could possibly want on these batteries.

http://endless-sphere.com/forums/viewtopic.php?f=14&t=2931&start=0

The short of it is this: The batteries are of unknown origin. Some suspect they are Cheer Ocean packs. They are rated for 1C. 2C max continuous. 3C max momentary. Something like that, anyway. They hold very close to their rated capacity. Jury is out on their cycle life, but those who have run them through 75+ cycles have seen no appreciable decrease in capacity.

Ping is generally regarded as the most reliable of the sellers. Anna and NewJourney seem to have disappeared. There's a new seller who sells for cheaper than Ping even, though I don't know if anyone has bought from him/her yet.

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Bob K
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Re: Modified board

Well, I just got off of my board after a full
circuit run.
Nice!
It is the best set up I have yet run!
I can now say, by way of experience,
that 4 amp/hour Elite NimH out perform
7 amp/hour lead acid gel cell batteries.
More amps, more voltage and more USABLE capacity.

ie: more speed, more "punch", and more range.

And less than 1/2 the weight. ( OK, a smidgen less than 1/2)

While they are twice the cost of gel cells, they are still cheaper
because gel cells will not hold up to 20 amp service.
7 amp/hour Gell cells die at 20 amp service. They only give less than 1/2
of their rated capacity and they give 1/4 the rated charge cycles
at 20 amp service. ( if that)

I paid for what I got,
I got what I paid for.

Bob K

Bob K
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Re: Modified board

I forgot to add,

Dimension Engineering's ,
SyRen 25A regenerative motor driver

is a sweet controller in the 1/2 Kw range.
( I don't own one,yet)

Check it out.

Bob K

RussInSd
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Re: Modified board

I have a Exkate X-24 that I want to convert to LiFePO4 batteries. How did your conversion go? Are there any tips you can give me that will help me with this project? I am also looking at the Ping batteries. Can I just swap out the stock SLA batteries or is there other things that I need to do? My board has a 24 volt, 750w motor and the stock batteries are 24 volts, 18 amp hour. I am a complete novice when it comes to these sort of things? Any help that you can provide will be much appreciated.

feinstaj
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Re: Modified board

Well, my lead acid batteries on the Raptor 3.0 finally died, so I am revisiting this project. I ordered a 24V 12Ah LiFePO4 battery from Ping. The original batteries were rated at 16Ah, so I am nervous that the board may be underpowered. Most things I read say the ratings are artificially high for the lead batteries, so I am hopeful. The only LifePO4 battery I could find that would fit the original compartment was this one. Only Ping makes a battery at 70mm tall. Everyone else is 75mm. The battery should arrive in a week or so. I will post pics of the conversion here.

bmxr123
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Re: Modified board

So i have been lurking for a bit and figured i would reply to this thread because i am at a total loss and you guys seem to know your stuff.

First let it be known that i have scoured the internet for answers and haven't found any insight or help on this matter, and it seems rather simple.

So i just changed the batteries in my exkate raptor 3.0(they were completely dead)..I also, of course, changed the battery in my wireless "remote". The board lights up, and the remote sounds and lights up. The wheel spins with what is obviously 24 volts of power, but it cuts in and out..Power to the board is intermittent at best..I actually tried it just now and its not doing anything!..I have read the procedure on how to link the remote with the controller box and i "think" i did it right and still...nothing...

This is discouraging..Any help or insight will be greatly appreciative. let it be known that i can solder/work on electronics but i feel as though i need some kinda guidance before just cracking things open!

I guess i will begin inspecting the internals of the controller and remote for damage?

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