New BB drive (retro fit)
- Thread starter Miles
- Start date
Yes, I noticed that. Velovision says a 100 watt touch of assistance, but that site says 200.
100 watts seems far more realistic from a motor under 31 mm in diameter, but I'd be surprised if there's enough for most prospective e-bike buyers. I'd probably get as much power if I engaged the dynamo with the tyre wall and plugged in four D cells.
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100 watts seems far more realistic from a motor under 31 mm in diameter, but I'd be surprised if there's enough for most prospective e-bike buyers. I'd probably get as much power if I engaged the dynamo with the tyre wall and plugged in four D cells.
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Hehe....
It's not at all clear what they mean..
If you look here: Gruber Antrieb - Gruber Assist - Fahrradantriebe » technology it says motor 200W and up to 100W available at the wheel..... Surely, transmission losses aren't 50%?
It's not at all clear what they mean..
If you look here: Gruber Antrieb - Gruber Assist - Fahrradantriebe » technology it says motor 200W and up to 100W available at the wheel..... Surely, transmission losses aren't 50%?
200 watts is wishful thinking I believe. The NiMh 30 volt 4500 mAh battery weighing 1.7 kilos and good for up to 1.5 hours running is a bit of a giveaway, rather meagre, even for that limited gross power. It easily matches a 100 watt gross output though, so about 80 watts at the wheel if they're lucky. Can't see that's worth the cost and complexity. Might as well eat a third shredded wheat.
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........Can't see that's worth the cost and complexity. Might as well eat a third shredded wheat.
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........Hello flecc, it is very possible to get 200 watts from a motor less than 31 mm. I have a brushless motor in one of my rc cars that has a diameter of 20 mm and a length of 33 mm and using a watt meter have measured a power of 150 watts (without really trying!), this is in a motor of over 80% efficiency, so a continuous output of around 120 watts!
In theory (I have not found a road long enough yet) the speed controller can supply a continuous 25 A at 11.1 V. Or 278 watts, giving 222 watts output.
Yes, I understand that Planky, and even more of course. I'm thinking in practical electric bike terms though, quiet running, long range etc.
That makes things look very different of course, cycling down the road sounding like those model's motors, amplified by the frame tubing in that application doesn't appeal.
As I posted in Kraeuterbutter's thread on this motor system, in practical terms some present systems are demonstrably better, and have been as far back as year 2000.
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That makes things look very different of course, cycling down the road sounding like those model's motors, amplified by the frame tubing in that application doesn't appeal.
As I posted in Kraeuterbutter's thread on this motor system, in practical terms some present systems are demonstrably better, and have been as far back as year 2000.
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hi Planky..
other example:
Kontronik FUN 480-55: Fun480 Kontronik Brushless Motoren
Measurements: 28mm diameter, 50mm long
rated: up to 50A continouse (~500Watt continouse)
up to 90A short (~15 seconds, thats are ~1000Watt)
however there is one thing to considere:
on the bike this Gruberassistant have to spin the pedals with
30-90rpms
so: when you look on the video: there is a tiny planetary-gear and a 90° gear bottom
lets say the 90° gear reduces 1:2
and the planetary gear something between 1:7 (one stage) or 1:50 if it is two-staged..
no calculated: 90rpm of the pedals * 2 (from 90° gearing) * 50 (two-stage-planetary-gearbox) --> that are only 9000rpm
now look what your rc-car-motors does spin, or what the Fun480 i mentioned does spin..
they are more in the 30.000 - 60.000rpm region
so: with such a slow spinning motor (9000rpm, maybe even slower if the planetary-gear-reduction is less than 1:50) there becomes power a problem..
with such a small motor (only ~30mm diameter) you can not have much torque.. and - as said - in that design you also don´t want to get power from high rpm...
so i bet this 200Watt are already on the limit...
in the manuel it says, that the seat post can reach over 70°C temp. and you should be carefull so you don´t burn yourself !!
other example: the Flytec Flyer F-Series motor:
in the Flyer were it spins only with ~70rpm like the pedals it has only 250-400Watt
the same motor with higher volts and much more rpm can reach over 20.000Watt
other example:
Kontronik FUN 480-55: Fun480 Kontronik Brushless Motoren
Measurements: 28mm diameter, 50mm long
rated: up to 50A continouse (~500Watt continouse)
up to 90A short (~15 seconds, thats are ~1000Watt)
however there is one thing to considere:
on the bike this Gruberassistant have to spin the pedals with
30-90rpms
so: when you look on the video: there is a tiny planetary-gear and a 90° gear bottom
lets say the 90° gear reduces 1:2
and the planetary gear something between 1:7 (one stage) or 1:50 if it is two-staged..
no calculated: 90rpm of the pedals * 2 (from 90° gearing) * 50 (two-stage-planetary-gearbox) --> that are only 9000rpm
now look what your rc-car-motors does spin, or what the Fun480 i mentioned does spin..
they are more in the 30.000 - 60.000rpm region
so: with such a slow spinning motor (9000rpm, maybe even slower if the planetary-gear-reduction is less than 1:50) there becomes power a problem..
with such a small motor (only ~30mm diameter) you can not have much torque.. and - as said - in that design you also don´t want to get power from high rpm...
so i bet this 200Watt are already on the limit...
in the manuel it says, that the seat post can reach over 70°C temp. and you should be carefull so you don´t burn yourself !!
other example: the Flytec Flyer F-Series motor:
in the Flyer were it spins only with ~70rpm like the pedals it has only 250-400Watt
the same motor with higher volts and much more rpm can reach over 20.000Watt
That's in line with what I've posted previously on this system.
I doubt it gives very much power at the wheel in practice. At best it might just deliver 150 watts at the wheel in ideal circumstances, just about cancelling the extra weight of the system and battery on hills, so no real gain over a normal unpowered bike.
The bottom bracket Panasonic system in it's latest guise is capable of well over 400 watts, delivered through chain drive efficiency, much more practical, though it's power is at present constrained by the software in the interests of very long range.
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hi Flecc...
in the manuel you can see: the batterypack (30V) has an 10A fuse..
so: we know -> there is for sure never more than 300Watt out of the battery
and because you don´t want to fuse the fuse all time, i think you should also stay away from the 300Watt -> so the 200Watt they say for inputpower sounds right..
now: motorefficience + controllereff. --> i guess: 80%
the 3stage gearing (2 planetary gears, 1 90° gear):
lets say 95% each
--> that would be 200Watt inputpower * 0.8 * 0.95 * 0.95 * 0.95 = 137Watt
so lets say 120Watt to have a round value
your naked bike + driver weights 100kg
the electrified bike + battery weights 103kg
i guess the 120Watt should do more than only compensate the addional 3kg of weight
its for sure a big difference on a hill if i have to peddal with 240Watt and iam dead at the top of the hill or i have to carry 3 additional kg, but for that have only to pedal with 125Watt because the other 120Watt come from the motor
i also think that lot more than 100Watt is to danagerouse when the motor is direct connected with the pedals and the pedals spin when the motor is running
i see it this way:
"classic" electric bikes (with front or rear hubs) are ideal for driving to work every day...
you want to arrive there without sweating, for that the motor is running nearly all time, for that you need also a bigger battery
the Gruber-Bikes i would say are sport-toys..
you WANT to sweat when you drive with such a bike..
and you want it to be as light as possible..
but sometimes there are hills which are too steep and than you kick in the motor, and it helps you driving up a 30% hill (which would be - i bet - a problem for most hub-motors around )
or give you the last kick when going with 37km/h onroad and want to reach the 40km/h
for that it also does not need a batter which gives you 35km range...
i would say - because of only 2.2kg weight of motor+battery - that you drive this bike most time without motor..
its only there for the reasons were you need sometimes a little extra-power
and additional 100Watt makes the normal driver to an athlet at the 24% hill
100Watt makes the old woman strong enough so she does not need to downswing the bike and push the bike up the hill..
(also i don´t see this drivetrain (for this price) in the hands of old woman anyway )
in the manuel you can see: the batterypack (30V) has an 10A fuse..
so: we know -> there is for sure never more than 300Watt out of the battery
and because you don´t want to fuse the fuse all time, i think you should also stay away from the 300Watt -> so the 200Watt they say for inputpower sounds right..
now: motorefficience + controllereff. --> i guess: 80%
the 3stage gearing (2 planetary gears, 1 90° gear):
lets say 95% each
--> that would be 200Watt inputpower * 0.8 * 0.95 * 0.95 * 0.95 = 137Watt
so lets say 120Watt to have a round value
your naked bike + driver weights 100kg
the electrified bike + battery weights 103kg
i guess the 120Watt should do more than only compensate the addional 3kg of weight
its for sure a big difference on a hill if i have to peddal with 240Watt and iam dead at the top of the hill or i have to carry 3 additional kg, but for that have only to pedal with 125Watt because the other 120Watt come from the motor
i also think that lot more than 100Watt is to danagerouse when the motor is direct connected with the pedals and the pedals spin when the motor is running
i see it this way:
"classic" electric bikes (with front or rear hubs) are ideal for driving to work every day...
you want to arrive there without sweating, for that the motor is running nearly all time, for that you need also a bigger battery
the Gruber-Bikes i would say are sport-toys..
you WANT to sweat when you drive with such a bike..
and you want it to be as light as possible..
but sometimes there are hills which are too steep and than you kick in the motor, and it helps you driving up a 30% hill (which would be - i bet - a problem for most hub-motors around
)or give you the last kick when going with 37km/h onroad and want to reach the 40km/h
for that it also does not need a batter which gives you 35km range...
i would say - because of only 2.2kg weight of motor+battery - that you drive this bike most time without motor..
its only there for the reasons were you need sometimes a little extra-power
and additional 100Watt makes the normal driver to an athlet at the 24% hill
100Watt makes the old woman strong enough so she does not need to downswing the bike and push the bike up the hill..
(also i don´t see this drivetrain (for this price) in the hands of old woman anyway
)@flecc:
i don´t know if you know this already:
John Tetz Low Weight, Low Power E – ASSIST Recumbent Trike
but this is, how i want to be my bike...
the problem with all that small motors -> they spin fast -> they need gearing -> they are not quiet at all ;(
you know my SRam Sparc....
i want(ed) to use it, because its very light (2.5kg including the 5gear-sram-hub)
if you remember, i also wanted to use it with an small battery.. (something less than 1kg)
for that i would have been able - because of the freewheelunit - to drive it most time without motor, and only use it when i need more power..
that was the idea..
downside: this F...ing thing has such a weak, cheap plastic-motor-housing inside: when going offroad with that, it would break at the first jump ;(
so my idea is not to have a bike with 72v and 16Ah battery to go to moon and back with one batteryload
but a small, lightweight thing which is as light as possible (ideal: so light, that i don´t feel it) and i would only use it when i need extra power, not all time
i don´t know if you know this already:
John Tetz Low Weight, Low Power E – ASSIST Recumbent Trike
but this is, how i want to be my bike...
the problem with all that small motors -> they spin fast -> they need gearing -> they are not quiet at all ;(
you know my SRam Sparc....
i want(ed) to use it, because its very light (2.5kg including the 5gear-sram-hub)
if you remember, i also wanted to use it with an small battery.. (something less than 1kg)
for that i would have been able - because of the freewheelunit - to drive it most time without motor, and only use it when i need more power..
that was the idea..
downside: this F...ing thing has such a weak, cheap plastic-motor-housing inside: when going offroad with that, it would break at the first jump ;(
so my idea is not to have a bike with 72v and 16Ah battery to go to moon and back with one batteryload
but a small, lightweight thing which is as light as possible (ideal: so light, that i don´t feel it) and i would only use it when i need extra power, not all time
Yes of course, I wasn't being precise, but from experience of many bike motors I know that even a light folding bike of 18 kilos with 180 watts peak is very weak, and the steeper the hills, the more it shows.
The Panasonic system I mentioned in the stripped Lafree Twist model weighing under 20 kilos is regarded as a low power system with it's 390 watts peak and high efficiency chain drive, so 120 watts is very low powered indeed. I wouldn't want to pay money for such a system able to add so little power.
As purely a source of added power that light weight is very welcome, but I'm not confident you'd feel much power when riding over rough ground or uphill.
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The Panasonic system I mentioned in the stripped Lafree Twist model weighing under 20 kilos is regarded as a low power system with it's 390 watts peak and high efficiency chain drive, so 120 watts is very low powered indeed. I wouldn't want to pay money for such a system able to add so little power.
As purely a source of added power that light weight is very welcome, but I'm not confident you'd feel much power when riding over rough ground or uphill.
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yes..
for THAT price they want for the set (~2000 Euro !!)
i think there are few people to buy this..
than there is the downside with the noise it makes...
i think when i go up to our castle (the rout i like most):
which bike would you recommend?
(there is a 31% hill, just to mention )
i think this 100Watt+ would help me to make this hill a lot easier
i wonder how much watts from an 500Watt Hub-motor would come to the wheels at 31% steep hill
for THAT price they want for the set (~2000 Euro !!)
i think there are few people to buy this..
than there is the downside with the noise it makes...
i think when i go up to our castle (the rout i like most):
which bike would you recommend?
(there is a 31% hill, just to mention
)i think this 100Watt+ would help me to make this hill a lot easier
i wonder how much watts from an 500Watt Hub-motor would come to the wheels at 31% steep hill
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Another way of looking at it is: How much faster will the electric-assist enable me to go, up this hill.....?
For your 31% hill adding 100 watts of assist to 400 watts of pedal power means your speed goes from, roughly, 3.7 mph to 4.6 mph...
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no, iam not thinking of adding speed..
speed:needed Power is not linear...
so: when going 30% faster on a partikular section my riding-time for the whole course will maybe 10% faster, but i would need 50% more energy..
you know what i mean ? (values just from my mind, no real facts)
i would more see it this way:
instead of 400Watt going up the hill ending with an crayfish-red head,
i would go up with same speed and only have to put 300Watt...
or other: on a hill were i have not enough power for my own, this additional 100Watt can safe it and i can make it
or: instead of 250Watt i will not be able to hold long, will stress me much, i need only 120Watt which is much more in a region i can pedal long..
at the same section i will end it in good condition, turn of the motor and can continou to drive with much more power in my legs left than without that little help
Johns motor has even less power ( John Tetz Low Weight, Low Power E – ASSIST Recumbent Trike ) and it seems that he nevertheless likes it
(of course: if you build something buy yourself, its even superb when 99% of all other people testing it would say: crap)
speed:needed Power is not linear...
so: when going 30% faster on a partikular section my riding-time for the whole course will maybe 10% faster, but i would need 50% more energy..
you know what i mean ? (values just from my mind, no real facts)
i would more see it this way:
instead of 400Watt going up the hill ending with an crayfish-red head,
i would go up with same speed and only have to put 300Watt...
or other: on a hill were i have not enough power for my own, this additional 100Watt can safe it and i can make it
or: instead of 250Watt i will not be able to hold long, will stress me much, i need only 120Watt which is much more in a region i can pedal long..
at the same section i will end it in good condition, turn of the motor and can continou to drive with much more power in my legs left than without that little help
Johns motor has even less power ( John Tetz Low Weight, Low Power E – ASSIST Recumbent Trike ) and it seems that he nevertheless likes it
(of course: if you build something buy yourself, its even superb when 99% of all other people testing it would say: crap)
Yes, you could go up at the same speed, for less effort, with 100 watts of assist - or you could simply drop a gear and go up at less than 1 mph slower, without all the hassle of motors and batteries Note I didn't even factor in the extra weight of the power-assist system.... [Just playing devil's advocate here, folks...]
Note I didn't even factor in the extra weight of the power-assist system.... [Just playing devil's advocate here, folks...]just found on the gruber-webpage in a review:
first colume: without gruberass, the once in brackets () are with gruber ass.
drivetime: 1:33:04h (1:15:33h including a pause for battery-change)
average speed: 19.9km/h (24.4km/h)
used energy for the biker: 906kcal (737 kcal)
pulsrate average: 139pulses/min (121p/min)
so: there seems to be a difference what this little 100Watt can do
(oh: this was driven in Tyrol, maybe you know, there are some hills
Wörgl - Rendlbrücke - Kirchbichl - Angath - Angerberg (Baumgarten) - Mariastein - Angerberg (Embach - Edwald - Pfaring) - Breitenbach (Glatzham - Kleinsöll - Dorf - Ramsau - Bichl - Dorf) - Kundl - B171 - Wörgl
)
english:
first colume: without gruberass, the once in brackets () are with gruber ass.
drivetime: 1:33:04h (1:15:33h including a pause for battery-change)
average speed: 19.9km/h (24.4km/h)
used energy for the biker: 906kcal (737 kcal)
pulsrate average: 139pulses/min (121p/min)
so: there seems to be a difference what this little 100Watt can do
(oh: this was driven in Tyrol, maybe you know, there are some hills
Wörgl - Rendlbrücke - Kirchbichl - Angath - Angerberg (Baumgarten) - Mariastein - Angerberg (Embach - Edwald - Pfaring) - Breitenbach (Glatzham - Kleinsöll - Dorf - Ramsau - Bichl - Dorf) - Kundl - B171 - Wörgl
)
You can get up almost any hill with moderate effort and appropriate gearing. The increase in speed facilitated by the power-assist (at these low speeds) is directly proportional to the power added at the wheel (minus that needed to lift the extra weight, of course). So, small amounts of power-assist make very small speed increases possible on steep hills....
question is (for me) just for interest:
which bike (lets say hub-driven) can you use for 30% hills (without burning) ?
is there any ?
and: does the same bike go well at speeds over 30km/h as well ?
which bike (lets say hub-driven) can you use for 30% hills (without burning) ?
is there any ?
and: does the same bike go well at speeds over 30km/h as well ?
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