Using RC motors on E-bikes [Archive]
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safe
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It's a completely new hub... physically it's massive and just based on looks at this point it seems to be well built and strong. This replaces their old style hubs that used to have a chain going through the axle. This new style shifts using a rotating mechanism next to the sprocket and the axle is completely solid. They include notched washers... but if those are not up to the task I have a welder and can improvise. :wink:Miles said:
One wonders if some of these internet reports are of the "new" hub or their old ones. I'll be surprised if I can break it because it seems at least as strong as a regular freewheel cluster. The old Sturmey Archer hubs were not that great. The Rohloff is so expensive that it's not worth it, but it's clearly the best available.
I'll let everyone know how it works when I get the bike running... (don't hold your breath :lol: )
recumpence
1 GW
OK, question for you guys------------
Can these hubs be run backward? I don't mean reverse pedalling, I mean can you drive the hub (at the spoke flange) and use the attached sprocket as the drive sprocket to drive the rear wheel? I see no reason why not. Look at my intermediate jackshaft (BMX hub). I am using it that way. I drive the hub, and use the freewheel to drive the chain to my rear wheel. If these multi speed hubs can be run this way, they will give a reduction, rather than a gearing increase. That would make them far better suited for our intermediate drive.
Now, assuming we could run the hub that way, we could, then, use a 2 or 3 to one reduction going to the rear wheel. I think we could get away with a few KW run through them if a reduction was used between the hub (used as an intermediate reduction/jackshaft).
Matt
Can these hubs be run backward? I don't mean reverse pedalling, I mean can you drive the hub (at the spoke flange) and use the attached sprocket as the drive sprocket to drive the rear wheel? I see no reason why not. Look at my intermediate jackshaft (BMX hub). I am using it that way. I drive the hub, and use the freewheel to drive the chain to my rear wheel. If these multi speed hubs can be run this way, they will give a reduction, rather than a gearing increase. That would make them far better suited for our intermediate drive.
Now, assuming we could run the hub that way, we could, then, use a 2 or 3 to one reduction going to the rear wheel. I think we could get away with a few KW run through them if a reduction was used between the hub (used as an intermediate reduction/jackshaft).
Matt
johnrobholmes
10 MW
That is a very good idea for a small and very adjustable gearbox. The heft might be a lot, but the end result could sure be worth it.
recumpence
1 GW
It would not work with a coaster brake hub. But, a freewheeling hub may work.
Like I said, you would end up with a reduction rather than an increase and you could drastically reduce the load on the hub by reducing it another maybe 3 to one to the rear wheel.
Any thoughts on wether or not this would work?
Matt
Hey John, I got my caps. I need to call you and ask a tech question. :wink:
The new (repaired) HV110 is working fine with wiring and connector upgrade!
Like I said, you would end up with a reduction rather than an increase and you could drastically reduce the load on the hub by reducing it another maybe 3 to one to the rear wheel.
Any thoughts on wether or not this would work?
Matt
Hey John, I got my caps. I need to call you and ask a tech question. :wink:
The new (repaired) HV110 is working fine with wiring and connector upgrade!
Has anybody looked at trying to adapt an EVO scooter 2 speed transmission?
http://scooter.wikia.com/wiki/Evo_two_speed_transmission
looks like it can take in excess of 5 hp.... accepts over 10k rpm... has a clutch... belts inside and belt to the wheel. Not sure what the ratio is.
Looks interesting to me!
http://scooter.wikia.com/wiki/Evo_two_speed_transmission
looks like it can take in excess of 5 hp.... accepts over 10k rpm... has a clutch... belts inside and belt to the wheel. Not sure what the ratio is.
Looks interesting to me!
Interesting specs on this one:
http://www.neoscooters.com/proddetail.asp?prod=EVO2X
only place I can find one is here:
http://www.neoscooters.com/proddetail.asp?prod=Evo_2_or_2X_Transmission
not cheap ($265)
nice exploded views in these pdfs:
http://www.evopowerboards.com/Site/PDF/Evo%20Parts%20Manual.pdf
http://www.evopowerboards.com/Site/PDF/Evo%20Workshop%20Manual.pdf
http://www.neoscooters.com/proddetail.asp?prod=EVO2X
only place I can find one is here:
http://www.neoscooters.com/proddetail.asp?prod=Evo_2_or_2X_Transmission
not cheap ($265)
nice exploded views in these pdfs:
http://www.evopowerboards.com/Site/PDF/Evo%20Parts%20Manual.pdf
http://www.evopowerboards.com/Site/PDF/Evo%20Workshop%20Manual.pdf
recumpence said:
Good point, Matt.
I guess it depends on the gear changing mechanism used for a particular hub. I just tried back-driving a Shimano Nexus 8 which I had lying around - for the default gear, it worked fine in reverse. Maybe safe could do the experiment with the Sturmey Archer 8, for us?
BTW, the Sturmey Archer 8 is the only one that has direct-drive on the bottom gear - for the others, it's somewhere near, or above, the middle of the sequence.
Fumesucker
100 W
What sort of gear range is actually needed for an electric motor?
Is there really a need for more than two speeds?
Is there really a need for more than two speeds?
RealPeterPan
10 mW
jnuts said:
Found another one whre to buy the Transmission itself (price is the same):
http://www.extremescooters.biz/evo-r-evo-2-evo-2x-evo-spx.aspx
There are a few dealers on the main page of the scooter:
http://www.evopowerboards.com
If anyone knows more about this thing please let me know.
Thats exactly what I´m searching for.
Need info bout transmission and how much power it can handle (Mars Brushless i.e. )
Regards Sven
Fumesucker said:
It depends on the speed range you want to cover and the available power. The problem, from this point of view, is that most of the available multi-speed hub gears have quite close ratios.
For speeds up to 25 mph, 2 or 3 gears is sufficient for most cases, I would have thought.
Fumesucker
100 W
Miles said:
If you have a freewheel, "pulse and glide" becomes an option to help maximize efficiency. Essentially you only power up in brief bursts at a relatively high (and hopefully more efficient) power level and then coast on your gained kinetic energy for a while. This works quite well in ICE cars with a manual transmission since most ICEs are most efficient at or near full throttle.
Here's an interesting chart I found while looking for information on e-bikes.
For my purposes I need around 1700 watts delivered power for hill climbing.
After a closer look at my bikeE and a little head scratching I think driving the chainring a la Stokemonkey style is going to be the easiest thing for me to accomplish. I don't mind pedaling all the time as long as I don't have to work too hard at it and I have the three speed SRAM hub I can shift under power or while stopped.
Miles said:
Above 2 kW Pout max 2 gears are sufficient up to 40 mph at very moderate span 200%.
Above 1kW Pout max 2 gears are sufficient up to 25 mph at 250% span.
3 gears are needed below 1 kW for very special needs excluding racing purposes ( many gears wanted by safe ).
Along with time cells would be cheaper as well as controllers too, so more power would be available for less money.
From that point of view 2 gears are quite enough even for today 250W cont. power systems which are able to be 100% overpowered easily today.
Tomorrow they could be 300% overpowered to 1kW for the same or even less money. So spending money for extra motor gears is a wasting of money until racing isn't the goal IMHO.
Even if more gears could be useful for some cases today, they become useless tomorrow.
recumpence
1 GW
I have found gears uneeded in my case. I have extremely good efficiency at low wattage (low throttle), yet super high power when needed.
However, gears would be great for use with weaker motors.
Matt
However, gears would be great for use with weaker motors.
Matt
safe
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Miles said:Ah, so you have one of the new ones then do you?
Wow, they're already coming out with an upgrade.
Sounds like the number one problem with the existing model is that people are having trouble getting the gear shifting adjusted properly. The shell looks to be either identical or nearly identical to the version I have which is now (I guess) three years old. It sounds like they are very serious about building a top of the line hub to compete with Rohloff and since these cost about $130 rather than $1300 it seems like a great deal.
Sturmey Archer seems committed to getting it right... (and mine is probably already a big upgrade compared to their really old stuff)
safe
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How Many Gears?
I think people are approaching the problem in the wrong way. The question should not be:
"How many gears?"
...but unstead it should be:
"How much gearing range?"
...because if you have two gears that are essentially the same gear ratio then you've achieved nothing.
Three speeds have a range of 177%.
Five speeds have a range of 225%.
Eight speeds have a range of 305%.
The newest Sturmey Archer has jumped past that to 325%.
The Rohloffs (14 speeds) have a range of 525%.
...my guess is that the minimum range you need is around 200%, but if you have aspirations to hit speeds of 50+ mph you need more like 300%. Keep in mind what you are trying to do... you want to be able to climb the steepest hill at slow speed and also hit your top speed and at ALL TIMES be right in the most powerful and efficient areas of your motors powerband.
And I actually agree with eP somewhat in that it's true that a wide gearing range only really matters when you are getting serious about extending your top speed while using a restricted motor size. You always have the option of using brute force power instead of the gearing option.
I think people are approaching the problem in the wrong way. The question should not be:
"How many gears?"
...but unstead it should be:
"How much gearing range?"
...because if you have two gears that are essentially the same gear ratio then you've achieved nothing.
Three speeds have a range of 177%. Five speeds have a range of 225%. Eight speeds have a range of 305%.The newest Sturmey Archer has jumped past that to 325%.
The Rohloffs (14 speeds) have a range of 525%....my guess is that the minimum range you need is around 200%, but if you have aspirations to hit speeds of 50+ mph you need more like 300%. Keep in mind what you are trying to do... you want to be able to climb the steepest hill at slow speed and also hit your top speed and at ALL TIMES be right in the most powerful and efficient areas of your motors powerband.
And I actually agree with eP somewhat in that it's true that a wide gearing range only really matters when you are getting serious about extending your top speed while using a restricted motor size. You always have the option of using brute force power instead of the gearing option.
Fumesucker
100 W
safe said:
I guess I phrased my question poorly, I actually meant something closer to "what gear range".
I was assuming that people would realize that I meant the gears would be chosen for optimal utilization of the motor power/efficiency curve. I'm thinking somewhere around a three or four to one difference between high and low speed in a two speed box would suffice.
I for one don't want to go 50 mph, the occasional ten to twenty second burst to 35 or so should prove more than adequate for my riding situation (going over bridges on a busy road with no room at all for anything other than cars and lots of glass and other debris on the sides).
safe
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This ought to give an idea of what's out there... the wider the range the better
because it just gives you more freedom. Closer gear choices also allows
for more precision in selecting the gear that most perfectly matches conditions.
More is generally better. Less gearing simply means you suffer with lowered
efficiency, but the motor will still work... just not as well.
If 15 mph makes the motor happy in first gear,
then 30 mph makes the motor happy in a gear 200% higher.
If 15 mph makes the motor happy in first gear,
then 45 mph makes the motor happy in a gear 300% higher.
If 10 mph makes the motor happy in first gear,
then 52.6 mph makes the motor happy in a gear 526% higher.
Happy motors are cool. 8)
because it just gives you more freedom. Closer gear choices also allows
for more precision in selecting the gear that most perfectly matches conditions.
More is generally better. Less gearing simply means you suffer with lowered
efficiency, but the motor will still work... just not as well.
If 15 mph makes the motor happy in first gear,then 30 mph makes the motor happy in a gear 200% higher.
If 15 mph makes the motor happy in first gear,then 45 mph makes the motor happy in a gear 300% higher.
If 10 mph makes the motor happy in first gear,then 52.6 mph makes the motor happy in a gear 526% higher.
Happy motors are cool. 8)
safe said:Happy motors are cool. 8)
And a cool motor is a happy motor! lol.
Nice chart there, now if we just add a price comparison, lol.
On a more serious note, in a different forum the internal hubs were talked about briefly. With space permitting I was thinking it would be great to have the motor drive the direct drive on the right hand side, and have a freewheel right next to it for the pedal power. That way you don't have to worry about flipping the unit around and wondering if it will hold up or work properly.
Kyle
recumpence
1 GW
That would not work for what I was talking about.
The reason for flipping it to the left side is go get a gearing reduction. Driving the right side would give a gearing increase because you would be driving the unit from the sprocket side whereas driving the hub housing and using the sprocket as the driven portion would give a reduction rather than an increase.
Oh, I wonder what this would do to the efficiency? After all, the unit would be spinning 3 times faster than typical pedalling, plus the fact that E-bikes typically run faster top speed than pedalling only.
Matt
The reason for flipping it to the left side is go get a gearing reduction. Driving the right side would give a gearing increase because you would be driving the unit from the sprocket side whereas driving the hub housing and using the sprocket as the driven portion would give a reduction rather than an increase.
Oh, I wonder what this would do to the efficiency? After all, the unit would be spinning 3 times faster than typical pedalling, plus the fact that E-bikes typically run faster top speed than pedalling only.
Matt
Hello
i am trying to figure up if it possible to use RC ESC and motor to electrify my bicycle.
i would like to use commercial ESC with commercial 500 watt motor.
i need also pedaling abbility.
question is - do commercial ESC can handle flywheel / freewheel .
i mean what happends if i will pedal or go down hill in speed greater than throttle command.
i know there is 'no brake' option , does it applies on zero throttle only or on all thottle range ?
thanks , Dany
i am trying to figure up if it possible to use RC ESC and motor to electrify my bicycle.
i would like to use commercial ESC with commercial 500 watt motor.
i need also pedaling abbility.
question is - do commercial ESC can handle flywheel / freewheel .
i mean what happends if i will pedal or go down hill in speed greater than throttle command.
i know there is 'no brake' option , does it applies on zero throttle only or on all thottle range ?
thanks , Dany
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