Budget RC Build Recipe?

[sharp21]

Hi Gang!

I didn't see an intro forum, but I've been interested in electric vehicles for a long time. I've looked at building a set of bikes for my wife & I with electric assist, but was never impressed with the offerings.

Then I saw some of the RC built bikes!

I've read through a bunch of threads here & seen reference to some low budget builds, but so many of the threads are so long that its hard to sift through them to find what I am looking for.

Can somebody post a budget build recipe with some examples, or a step by step conversion? I realize that the components depend on what kind of commute you have, but I'm just looking for somewhere to start learning & building from. Obviously I want a hot rod, but I'm willing to start with a Pinto

Thanks
S.

 

[def215]

welcome!

like you, when i first started with ebikes, i started with a "pinto." well, i still own it, but its like a pinto with basic bolt-ons...lol.

for simple rc ebike builds, i would look at evtodds work or try to purchase a kepler drive.

here is a thread to one of evtodds recent builds:
http://endless-sphere.com/forums/viewtopic.php?f=28&t=21097

and here is keplers drive system he sells:
http://endless-sphere.com/forums/viewtopic.php?f=31&t=20491

these two are probably some of the best builds ive seen here for being on a budget . there is also the recumpence drive, but i just would have the funds for something like that at the moment yet...lol

 

[Jeremy Harris]

The simplest, and probably most cost effective, way to get an RC motor bike running quickly and easily is to go for something like Kepler's friction drive.

If you are happy to spend a bit more and want a unit that drives through through the chain (a better approach, in my opinion) then take a look at Matt's ('Recumpence') reduction drive. This needs more engineering work, plus, maybe, some mods to your bike, but will undoubtedly give pretty good performance, although it probably doesn't fit the 'budget' requirement.

As far as motors go, there really isn't that much difference between the expensive stuff and the cheap motors, barring the quality of the assembly and bearings. Controllers are a wholly different kettle of fish, though, as cheap RC ones are generally total crap. There are a few exceptions, but it's like looking for a needle in a haystack trying to find a good cheap one. The good quality (albeit pricy) controllers are pretty good, as others here will testify.

If you are technically up to it, then fitting Hall sensors and using an affordable ebike controller is an option worth looking at. These work very well at modest power levels and give good bottom end power.

Jeremy

 

[gwhy!]

Hi And welcome to ES,
If you want to go with a chain drive system but want to help keep the cost down and not going to use a RC esc i.e you fit halls to the motor and use a cheap keywin controller dont worry about having a free wheel on the motor this adds complexity and in my option not worth the effort it also makes sorting out the gearing a little easier ( you can go with a smaller front gear ).

 

[daveo]

Hello,

I'm new here too and was wondering the same thing. The evtodd build sounds interesting but the pictures for the thread have been removed by Flicker and I can't even begin to visualize what he built!

 

[AussieJester]

Keplers friction drive aside...maybe? IMHO though i don't think its really possible to do a
"rc motored" build on the cheap, well....on the cheap and reliable, cheap you can do easily how long it will last
is entirely a different matter, want anything bar a friction setup in non frock config best bet giving the 'rc' components a miss if your
budget doesn' allow for quality escs at least.. I know GWhy will disagree but not everyone has the expertise to fit halls
and make 6fet Infineons work if you're intending to be buying off the shelf components i.e plug and play its going to cost for reliability i guess i should of stated...

KiM

 

[etard]

There seems to be 2 camps when it comes to RC drives now, Friction or Chain drive. Friction drive seems to be more successful with the cheap RC controllers at only 24 volts. I think Todd's latest build came to a grand total under $200. Chain drive has been a little more pricey overall, especially if you want it to freewheel ($80 for a White freewheel ), but builds like Bubba's using wood instead of aluminum can be done for about $500. It's all relative to how cheap you want to be, but if you want a hot rod, I think chain drive is the way to go. There is even a toothed hoop made by.... Golden Eagle I think that could get you a direct drive belt in one stage. Also, I have found countless products used on the RCgroups classifieds section.

 

[sharp21]

Great community here, everyone is real helpful!

I definitely want to go chain drive. I saw the reducer built by Recumpence & was thinking something along the lines of that, but I haven't looked at the other examples yet. While I don't have a cnc I could probably cobble something together out of 1/4" plate.

When I say "cheap" I don't mean scrounging old tv's for transistors cheap. Perhaps the better question would be; What is a build recipe for a more or less plug & play system, that can be upgraded in the future? A good platform to build from, that doesn't require advanced electronics theory?

I saw one bike on here on a MTB frame with 2 motors & motorcycle wheels! I'd love to work my way towards something like that.

I'll check the links you guys provided. Any other helpful links would be appreciated, but I'm finding that there is a lot of tech bandied about here. That is great, but I haven't found a primer to get up to speed on it. Is there a glossary or something that I can find definitions for stuff like ESC & Hall sensors?

S.

 

[Hillhater]

Is there a glossary or something that I can find definitions for stuff like ESC & Hall sensors?

S.

try this for a start..
http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=11162

 

[AussieJester]

What is a build recipe for a more or less plug & play system, that can be upgraded in the future? A good platform to build from, that doesn't require advanced electronics theory?

Top quality components such as Astro 3220 motor, recumpence single stage reduction drive, Castle Creations HV160, Magura throttle and interface (BEC and servo tester kit) and min 6 Turnigy//Zippy 22v 5ah lipos (44v 15ah) will come in just over 1000 dollars U.S
This is just for the drive train/basic electrics...can add to that real time monitoring in the form of WattsUP, Turnigy Meter or Cycle Analyst Then you need chargers for the lipos and possibly some form of battery management, i would say in the vicinity of 1500 would get you a good quality rc setup ready to roll...can obviously cut corners with all of the above and get the price down, reliability may suffer.

KiM

 

[gwhy!]

Here is a thread on adding Hall sensors to outrunners http://endless-sphere.com/forums/viewtopic.php?f=30&t=15686
For the motor I use this one $60
http://www.hobbycity.com/hobbycity/...TGY_AerodriveXp_SK_Series_63-74_170Kv_/_3250W
A non moddified keywin/e-crazy man controller is around $22 ( Highly modded add around $30 )
A basic throttle $6
Jack shaft/pulleys/Bearings/wire/connectors/chain and sprockets $100, The Jack shaft can be made with basic tools.

option 1 : freewheel trials crank arms and good quality freewheel $100 ( needed if you want to run through the bikes gears )
option 2 : two freewheels on the back wheel ( resonable quality freewheel $20 ) A better option in my opinion. ( single speed but would need the controller modded so you do not have to peddle if you dont want to)

Defo get a wattsup meter $25

Some basic knowlage of soldering and a bit of time. Then your good to go

 

[sharp21]

Wow!

I've been reading through the friction build logs all night! I think that is exactly what I am looking for, for a first build. My wife would like just a little extra oomph to help on the hills & they seem to fit the bill nicely.

I like how they are lightweight, compact & easily adjustable. If I cut my teeth on a few of these then maybe I'll move on to a geared unit.

Couple of questions, to make sure I've got it right:

A friction drive can be run either with the motor directly on the tire, but that makes pedaling harder. Does it offer a regen effect?

Otherwise you either need a mechanism to lift it off the tire, or a roller that freewheels? Where would you get a freewheel like that?

Kudos to the fellas here that have gone into production on this type of unit! Great work
S.

 

[spinningmagnets]

The Kepler-drives (and Drifters clone) use the spinning motor shell as the roller. The motor is held a fraction of an inch away from the tire (no contact) to keep the pedaling easy. The torque of the motor starting, flings the motor outward so that it grabs the tire and pulls itself into the tire automatically. When you de-energize the motor, the tire pushes the motor off.

In Todds drive, the motor and roller are separate, and the roller MUST be touching the tire. But, it has built-in one-way freewheeling roller-clutch bearings that roll in one direction, but grab when the motor powers them in the other direction. This allows for it to have almost no resistance when you are just pedaling.

Later, Todd added a sliding mount to the roller, and because of the curve of the tire outer diameter, the roller now barely touches when off, and automatically gets pulled deeper into the tread when power is applied. This allows for the "off power" to be even easier to pedal, and for the "power on" to have even more grip.

If you are a handy builder, Todd has two EV-Warrior rollers (with the built-in one-way clutch-bearing) for sale. I hope to be building the complete drives in a couple months, but don't wait for me, I can't guarantee anything right now. Look here:

http://endless-sphere.com/forums/viewtopic.php?f=28&t=14403

 

[sharp21]

I've been thinking on this & have come up with a design idea.

It'll be a friction style roller drive, with the roller being a chain driven bicycle hub. That'll take care of the freewheeling aspect.

What kind of motor do I need to run in order to attach a sprocket onto the shaft, to drive the chain?

S.

 

[spinningmagnets]

Most of the 63mm diameter RC-motors have a 10mm shaft diameter. The 50mm motors seem to mostly have 8mm shafts. SDP-SI makes sleeves to fatten those shaft diameters up to 1/2"

http://www.endless-sphere.com/forums/viewtopic.php?f=28&t=7192&start=30#p311888

I think an RC motor with a bike hub as a roller would have very high RPMs on the roller, so perhaps a chain might be noisy. You 'may' be able to find a #219 cog that takes a 10mm shaft, #219 chain has smaller links than standard bicycle chain, and you could attach a #219 sprocket alongside the bike-hub freewheel.

Matt made some 1/2" shaft-to-freewheel adapters a while back, Staton-inc carries 5/8" shaft to sprocket adapters (you wouldn't need one for a 5/8" shaft, but the staton site would show you what Matts 1/2"s look like). Theres gotta be several ways to do what you want, but no single way stands out to me right now as a definitive option.

Best of luck...

 

[etard]

I'm not seeing the advantage to using a bike hub to spin the tire, unless you are going to use gears on the cassette and a derrailluer to change gearing of the roller, that MIGHT make it worth it, but I don't think you need 7-9 gears for a roller, maybe 3 gears tops. Which brings us back to using a 3 speed SRAM internal gear hub, but then again, not sure the 3 speed is up to the task of spinning at 3000-5000 rpm, or you could experince a huge loss in efficiency at those speeds.

If you wanted to stick to chain drive, Ggoodrum sells an adapter that will allow you to bolt a drive sprocket onto your 3 speed hub and still pop a freewheel on for pedal assist, allowing you to use the 3 speeds in the hub for motor gearing.

If you go friction, the cheapest way is either EVTodd's or Kepler style, I don't think adding an extra stage to friction drive is gonna make it any cheaper.

 

[def215]

not sure the 3 speed is up to the task of spinning at 3000-5000 rpm, or you could experince a huge loss in efficiency at those speeds.

If you wanted to stick to chain drive, Ggoodrum sells an adapter that will allow you to bolt a drive sprocket onto your 3 speed hub and still pop a freewheel on for pedal assist, allowing you to use the 3 speeds in the hub for motor gearing.

If you go friction, the cheapest way is either EVTodd's or Kepler style, I don't think adding an extra stage to friction drive is gonna make it any cheaper.

aww man, thats what my next build was gonna be based around, the friction drive RC setup incorporating the 3-speed hub.

that just shattered my dreams apart. but i still want to try it as a one-off build. seems interesting enough.

 

[sharp21]

I wouldn't be adding the hub for gearing, just as a pre-built off the shelf method for incorporating a freewheel. That way it can stay engaged with the tire all the time. The chain drive seems to be a natural extension of that... Hadn't considered chain noise though.

I'll check out that 3 speed adapter, as that sounds like exactly what I was thinking about for a higher powered build!

For this first one I want to keep it simple but have it be able to switch easily between bikes for hill assist.

Def215, keep going on that. It looks great!

S.

 

[Kepler]

Keeping the roller engaged all the time even with a free wheel will introduce unwanted drag. The actual tension required to drive against the tire is quite high especially when you start to push some decent power through the system. This is why most of the latest batch of friction drives use torque activated variable pressure systems. This could easily be used with a hub and free wheel roller setup.

 

[recumpence]

RC stuff is a little fiddly to use for the uninnitiated. However, it is light weight and efficient. So, the tradeoffs are worth it for many people. I will say the easiest way is friction drive with a modest power system. That saves lots of money and time. However, for big power, a chain drive might be the way to go.

There is a big push lately to refine friction drive to its essence. This is a great place to start because you can get your feet wet in RC equipment and E-bikes in general. You can always move up form there later.

Welcome!

Matt

 

[sharp21]

Thanks guys!

Matt it was your recumbent build that led me here. I am going to do like you say & start real simple with a friction drive.

Keppler I've been through your builds & they are fantastic! I like your latest build (I'm slowly reading through the 30+ page thread) but am leaning more towards one of the seat post to motor to wheel builds, or something comparatively simple.

With a freewheeling roller, how much drag are we talking? It'll be going on my heavy beach cruiser so I'm not too worried about system weight. I could probably build it out of 1/4" steel plate & not notice the extra weight!

S.

 

[sharp21]

I checked out that adapter for the 3 speed hub. When installed it allows you to have a single speed off your crank, then 3 speeds off the motor? Has anyone here built one like that? That sounds like the ideal setup for a chain driven build.
S.

 

[AussieJester]

I checked out that adapter for the 3 speed hub. When installed it allows you to have a single speed off your crank, then 3 speeds off the motor? Has anyone here built one like that? That sounds like the ideal setup for a chain driven build.
S.

If your referring to internally geared 3 speed hubs they aren't upto the torque of moderate to high powered setups, the teeth break off the gears

KiM

 

[sharp21]

Roger that. So would it be used instead to keep the hub gears for regular cycling & the single sprocket for electric?
S.

 

[AussieJester]

Roger that. So would it be used instead to keep the hub gears for regular cycling & the single sprocket for electric?
S.

Bingo! :wink: Recumpence sells an adapter that mounts on disk brak holes, this allows you to mount a sprocket that is driven by the motor
as well as retain the rotor, the right side of the hub as you suggested remains there for manual pedal, is actually exactly how the drivetrain
is to be setup on my latest build


KiM