Electric conversion kits

DIscuss anything relating to non-standard cycles and their equipment.
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[XAP]Bob
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Re: Electric conversion kits

Postby [XAP]Bob » 15 Apr 2013, 1:56pm

What are the motors you are talking about? ESC?
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

bobc
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Re: Electric conversion kits

Postby bobc » 15 Apr 2013, 3:18pm

Hi Bob
the motors are brushless DC "outrunner" types intended to drive the props of BIG model aeroplanes. These things are available up to 10kW(!!!) for very reasonable money.
Because they are for radio controlled (RC) model planes, the control interface is a radio control servo interface. ESC is Electronic Speed Controller.
The motor I'm using is probably 1.5 to 2kW but my "bodge board" measures battery current and limits this to about 12A (=300W which is 250W + a bit to compensate for transmission and electrical losses).
My bodge board also has a speedo reed switch input so it can (1) limit speed to 15.6mph and (2) avoid synch loss issues due to grabbing a handful of throttle when going slow. A straightforward ESC based drive is hard to drive but easy to blow up - this should be better on both fronts ;^)

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[XAP]Bob
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Re: Electric conversion kits

Postby [XAP]Bob » 15 Apr 2013, 3:25pm

bobc wrote:Hi Bob
the motors are brushless DC "outrunner" types intended to drive the props of BIG model aeroplanes. These things are available up to 10kW(!!!) for very reasonable money.
Because they are for radio controlled (RC) model planes, the control interface is a radio control servo interface. ESC is Electronic Speed Controller.
The motor I'm using is probably 1.5 to 2kW but my "bodge board" measures battery current and limits this to about 12A (=300W which is 250W + a bit to compensate for transmission and electrical losses).
My bodge board also has a speedo reed switch input so it can (1) limit speed to 15.6mph and (2) avoid synch loss issues due to grabbing a handful of throttle when going slow. A straightforward ESC based drive is hard to drive but easy to blow up - this should be better on both fronts ;^)



I'm REALLY interested in more details. (e.g. links)
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

bobc
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Joined: 5 Apr 2012, 11:59am

Re: Electric conversion kits

Postby bobc » 15 Apr 2013, 3:35pm

OK - trying not to hijack the thread too outrageously -
I get all my RC gear from hobbyking (just google it) look at their big outrunners & speed controllers
here's my bike build blog with some old projects in
http://freespace.virgin.net/bob.carter/mybikes.htm
and the endless sphere link above.
TBH most RC builds use very expensive fancy speed controllers - I'm in quite a minority trying to make RC ESCs work.
Progress on the "bodge board" (a key element of the drivetrain) is going OK
http://endless-sphere.com/forums/viewto ... =2&t=47220
Bob

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[XAP]Bob
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Re: Electric conversion kits

Postby [XAP]Bob » 15 Apr 2013, 3:36pm

Ta - I'll shut up for a while
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Geriatrix
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Re: Electric conversion kits

Postby Geriatrix » 16 Apr 2013, 12:35pm

bobc wrote:I get all my RC gear from hobbyking (just google it) look at their big outrunners & speed controllers

Here are some great e-trike projects that use RC motors but I suspect you already know of them.
http://etrike.wordpress.com/2012/08/08/recumbent-e-trike-projects/
For a successful technology, reality must take precedence over public relations, for nature cannot be fooled - Richard Feynman

Janelle
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Re: Electric conversion kits

Postby Janelle » 22 Apr 2013, 10:32am

Only just catching up with the model plane ideas. Can anyone give a rough idea of the final cost of doing it this way please, just as comparison guide against a quality bike conversion kit? The decent standard kits are way too expensive for me and seem, to an ignorant eye, very expensive for what they contain.

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[XAP]Bob
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Re: Electric conversion kits

Postby [XAP]Bob » 22 Apr 2013, 11:10am

Basically if you have a local freindly workshop this can turn out a full system for ~£1-200, although range will be very limited, then you pay for batteries...
A shortcut has to be a challenge, otherwise it would just be the way. No situation is so dire that panic cannot make it worse.
There are two kinds of people in this world: those can extrapolate from incomplete data.

Geriatrix
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Re: Electric conversion kits

Postby Geriatrix » 22 Apr 2013, 11:52am

[XAP]Bob wrote:Basically if you have a local freindly workshop this can turn out a full system for ~£1-200, although range will be very limited, then you pay for batteries...

The Sunstar will work out at about £1300 including the batteries (depending on the battery you choose) but if you choose this option make sure with the dealer that it will fit your bike. This applies to any option you choose.

My experience is that choosing the right dealer is just as important as choosing the right technology because they will provide the technical support when or if something goes wrong. I made the mistake of buying my BionX conversion kit through Evans. When things went wrong it was very difficult to get support because it was way out of Evans expertise and they were simply not interested. Make sure you buy your kit from a dealer that specialises in electric bikes.
For a successful technology, reality must take precedence over public relations, for nature cannot be fooled - Richard Feynman

bobc
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Re: Electric conversion kits

Postby bobc » 22 Apr 2013, 9:51pm

All true - reasons to do a "radio control" build - cheap, potentially good performance, enjoy the buildup process. Reasons not to - you need access to a workshop + the necessary skills, you are running a prototype (likely to need a fair amount of work to make reliable), there's nowhere to go if it damages you or your bike (or an innocent bystander) in some way, & if you have an incident you may have to prove or demonstrate its legality.
The lithium polymer batteries have fantastic performance but do have a reputation for going up in a fireball. This reputation is probably undeserved with modern batteries (I have tried and failed to make one go up) but it's always in the back of one's mind and certainly used to happen a few years ago. Range - put as many batteries on as you like, with the lithiums more battery = more range, unlike SLAs where more battery = too much weight... It would not be unreasonable to sling enough batteries onto a bike to go 100 miles; my old mountain bike runaround (now electrified) would probably do over 30miles with its 4 off 2" x 2" x 5" batteries

4wils
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Re: Electric conversion kits

Postby 4wils » 22 Apr 2013, 10:06pm

All this talk of DIY is very tempting to a self confessed DIY addict, however, I'm interested in order to help the family ride together when we tour. For that I need something reliable with good range (not that I'm suggesting the home builds aren't, just that I'm not sure about my own skills in this department). I'm leaning towards the Sunstar kit. Every indication is that it can't be fitted with double or triple chainrings, this concerns me as I would not want my wife left without power if the battery runs out and without the option of a smaller gear in order to spin easily. On the Sunstar site their gallery appears to show a Hase Kettwiesel with a double chainring fitted to the Sunstar. I will be fitting it to a Kettwiesel.
Does anyone have any experience of fitting more than one chainring?
How loud is the motor, say in comparison with a Rolhoff in its noisy gear?
The Electric Bike Shop in Cambridge were very helpful over the phone and are going to look in to it, I just wondered if anyone on here had any experience.

Geriatrix
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Re: Electric conversion kits

Postby Geriatrix » 23 Apr 2013, 10:30am

4wils wrote:Every indication is that it can't be fitted with double or triple chainrings, this concerns me as I would not want my wife left without power if the battery runs out and without the option of a smaller gear in order to spin easily. On the Sunstar site their gallery appears to show a Hase Kettwiesel with a double chainring fitted to the Sunstar. I will be fitting it to a Kettwiesel.
Does anyone have any experience of fitting more than one chainring?

All their blurb says no front dérailleur which as you pointed out contradicts some of their PR photo's. The best would be to get an opinion from The Electric Bike Shop. A solution to the chainring problem would be to use the SRAM Dual drive on the rear wheel but that would mean replacing whatever you currently have. If went to that expense I would probably also consider the DaVinci drive as an option, which apparently works well with e-bikes.

There is a review of the Sunstar here which comments on the motor noise.
For a successful technology, reality must take precedence over public relations, for nature cannot be fooled - Richard Feynman

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squeaker
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Re: Electric conversion kits

Postby squeaker » 23 Apr 2013, 12:42pm

Geriatrix wrote:There is a review of the Sunstar here which comments on the motor noise.
And shows it fitted to a bike with a double chainring :roll:
"42"

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RickH
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Re: Electric conversion kits

Postby RickH » 23 Apr 2013, 5:00pm

squeaker wrote:
Geriatrix wrote:There is a review of the Sunstar here which comments on the motor noise.
And shows it fitted to a bike with a double chainring :roll:

Although the outer chainring appears to be purely ornamental - its on a hub gear bike & there is no front changer or tensioner to allow you to actually use the big chainring! :?

Having said that it should be possible to use a front mech as it shouldn't foul on the gubbins (to use a technical term :wink: ) inside the inner ring.

byegad
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Re: Electric conversion kits

Postby byegad » 24 Apr 2013, 8:33am

Some of these motors produce more power than you can legally use on road. Remember anything over the limits power wise, or capable of exceeding 15mph qualifies your trike as a motor vehicle which then needs to meet Construction and Use limits, and be taxed and insured. The rider will need the appropriate driving licence.
"I thought of that while riding my bike." -Albert Einstein, on the Theory of Relativity

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