"peak power" - Trek 4300 20" Magic Pie build.
- Thread starter neptronix
- Start date
o00scorpion00o
100 kW
neptronix said:
I had regen set to 2 in the controller, and going down the steep 16% grade was generating a fair few watts so it could only have been adding to the heat.
Putting 3.5 kw in going up was bad enough.
neptronix said:I got the motor up to 120c. Finally, this got the case hot, at 3000-3500w constant! NOW i can start testing the cooling mods
Before you drill it I'd put some oil in and re test!
So by going to a 20" wheel doesn't make much of a difference, it will still get very hot. So I think it proves that What I think is right that it's total watts that matter not necessarily lots of amps.
Your amp draw was about 35 amps compared to my 58 ish amps on 16S LiPo and it still got very hot.
The thing nep about the pie is that it has absolute tonnes of torque in reserve that you are not using, it's just way too much of a slow wind.
Perhaps a faster wind would mean you would get away with far less voltage and the same amps but you would be putting in far less watts making it run more efficient and generating a lot less heat, still outputting the same torque, or is my theory wrong ?
Having said that on 16S using halls and 120%, I got 35 mph in a 26" wheel so It would be quiet reasonable to expect 40-44 mph on 72 volts. I could live with that, but If the pie was wound to do 40 mph on 16S it would still have plenty of torque. The acceleration on 24S and 80 amps was just thrilling, but my 20C Zippy's were not happy at all in 1P.
Nep, what lovely weather you have there, temps so far this May have hardly got above 9-10 Celsius during the day. I'd love to live in a country that had sun and heat.
Regen setting 0 gave me 10 amps in, so approx 700-900 watts.
Anything above setting 0 is extreme overkill on my motor at least. I see how taking many thousands of watts in could have changed things.
I'm not interested in oil cooling at all, You can experiment with that on your own
Slower or faster wind does not mean more efficiency. Play with the crystalyte and 9C motors of various windings in various voltages / amps with the ebikes.ca simulator and you'll get it.
Watts are watts and you can use any ratio of volts / amps to get those watts.
And smaller wheeled DD hubs are always more efficient per watt. They end up generating more power due to their higher RPM. It is like the engine in your car - the faster it spins, the more power it makes. A DD hub in a 26" wheel is like limiting a gasoline motor to 2,000rpm. You need a V8 to get good power. Meanwhile a big RC motor like an astro spinning to 10,000rpm+ will put out 7kW..
This is another reason why our MAC motors put out so much power per their weight.. after the gears and such, it's only a 7-8lb motor that puts out similar power as a 9C, coming in at 14lbs.
http://ebikes.ca/simulator/
P.s. 120% is really hard on controllers and motors. I was shocked at how hot my MAC and 12FET got using 120% on 36v. It loaded the motor and controller so much harder than just running 57v for the same speed.
Weather here is quite good. I did not get around to drilling the hub cover today though.. my bad
Anything above setting 0 is extreme overkill on my motor at least. I see how taking many thousands of watts in could have changed things.
I'm not interested in oil cooling at all, You can experiment with that on your own
Slower or faster wind does not mean more efficiency. Play with the crystalyte and 9C motors of various windings in various voltages / amps with the ebikes.ca simulator and you'll get it.
Watts are watts and you can use any ratio of volts / amps to get those watts.
And smaller wheeled DD hubs are always more efficient per watt. They end up generating more power due to their higher RPM. It is like the engine in your car - the faster it spins, the more power it makes. A DD hub in a 26" wheel is like limiting a gasoline motor to 2,000rpm. You need a V8 to get good power
. Meanwhile a big RC motor like an astro spinning to 10,000rpm+ will put out 7kW..This is another reason why our MAC motors put out so much power per their weight.. after the gears and such, it's only a 7-8lb motor that puts out similar power as a 9C, coming in at 14lbs.
http://ebikes.ca/simulator/
P.s. 120% is really hard on controllers and motors. I was shocked at how hot my MAC and 12FET got using 120% on 36v. It loaded the motor and controller so much harder than just running 57v for the same speed.
Weather here is quite good. I did not get around to drilling the hub cover today though.. my bad
o00scorpion00o
100 kW
HAha V8's here are as rare as sunshine and heat!
I never had a heat problem with the mac on 120% or the controller. Maybe the climate has a lot to do with it ? The only time I felt the mac really hot was after a long steep hill climb at 30 mph!
I've been thinking about converting a recumbent style bike, something low that 20" wheels don't look daft. Finding one would be very difficult. One with some kind of windsheild would be nice. I'd like the low centre of gravity and less wind resistance and less prone to wheelies.
I never had a heat problem with the mac on 120% or the controller. Maybe the climate has a lot to do with it ? The only time I felt the mac really hot was after a long steep hill climb at 30 mph!
I've been thinking about converting a recumbent style bike, something low that 20" wheels don't look daft. Finding one would be very difficult. One with some kind of windsheild would be nice. I'd like the low centre of gravity and less wind resistance and less prone to wheelies.
I thought about a recumbent too until i rode one.
The 3 wheeled ones were flexy and expensive. Heard that cracking the frames is a frequent thing. They handle great, but i t did not feel sturdy to me at all :|
I am about 240lb and 6 feet tall, so that doesn't help.
Anyway i called up Pat, who is organizing the pike's peak ride this year. He seems uncertain about where ebikes fit into it.. mentioned the thing about optibike slipping a pedal and hitting Josh K last year.. said that eBikes were going to start later, but had their own registration which is yet to be announced, and he'll get back to me.
He asked me what i have.. i said what i have is designed to go 25mph constant.. he said it was fast and seemed unimpressed. I think this guy may be eBike biased.
Not too happy about the uncertainty. I will keep you all updated when i hear back from him.
The 3 wheeled ones were flexy and expensive. Heard that cracking the frames is a frequent thing. They handle great, but i t did not feel sturdy to me at all :|
I am about 240lb and 6 feet tall, so that doesn't help.
Anyway i called up Pat, who is organizing the pike's peak ride this year. He seems uncertain about where ebikes fit into it.. mentioned the thing about optibike slipping a pedal and hitting Josh K last year.. said that eBikes were going to start later, but had their own registration which is yet to be announced, and he'll get back to me.
He asked me what i have.. i said what i have is designed to go 25mph constant.. he said it was fast and seemed unimpressed. I think this guy may be eBike biased.
Not too happy about the uncertainty. I will keep you all updated when i hear back from him.
o00scorpion00o
100 kW
That would be a real pain after all the effort!
A lot of die hard professionals don't like electric bikes and maybe see them as some kind of threat, kind of like some petrol heads hate electric cars!
A lot of die hard professionals don't like electric bikes and maybe see them as some kind of threat, kind of like some petrol heads hate electric cars!
o00scorpion00o said:
Well, the petrol heads can go #!$!#% themselves because they are sore losers and wouldn't know which end of a soldering iron is the hot part. The lycra folks can also go !$@$@ themselves because in their view, bicycling is all about putting on neon hot pants, spending thousands of dollars on a bike, and seeing it as a sport and not an every day mode of transport for the common man.
I'm rather pissed about the whole thing. This area is extremely commuter unfriendly ( no bike lanes, honking and yelling from cars if you ride in the road under 40-50mph ), and caters mainly to the lycra-clad. In Colorado, bicycles are sports equipment and not a form of transport.. unless you live in Boulder, where they actually have bike lanes.
But do you really want to live in a super expensive college town full that leans so far liberal that they make San Francisco look like a republican voter block, i think not :lol:
I'm so done with this state and am moving to Utah ( Salt Lake City area ). They have bike lanes *everywhere*, the bonneville salt flats, and some electric racing is done there already.. whereas we have none here.. very lame !
There is absolutely no reason why ebikes shouldn't compete on Pikes Peak.
Why would a pedalist be threatened? It's a different class. And for the petrol heads - they shouldn't be worried since they have insane energy density. And even so, the sport is all about winning, a new design/motor should be welcomed and praised if it is successful.
Why would a pedalist be threatened? It's a different class. And for the petrol heads - they shouldn't be worried since they have insane energy density. And even so, the sport is all about winning, a new design/motor should be welcomed and praised if it is successful.
auraslip said:
+1!!!
But you missed a big one, auraslip
http://www.wolfgang-menn.de/obreepos.htm
What is racing then, if the sport cannot evolve and change over time?
If some people at the top want to pick and choose what's possible?
I built this bike as something that can be pedaled AND be high power with just a cheap hub motor.
Low budget, high simplicity, high power, and still a bike - not something you hit the throttle on and stop pedaling.
Yeah i can run this at 1000w, but with all us at the same power, it will then be a contest of who can stare at everyone's sweaty lycra butt for the longest. 15 miles per hour on 1000w constant. Sounds like a blast.
This build is being dismantled now. I've been dicked by the guys organizing the pike's peak build and it looks about 99% possible that eBikes won't be allowed to go up the mountain. This, just 2 months before the race. Thanks, Pat!
If you want this motor, now you have a chance to buy it, fully decked out:
http://endless-sphere.com/forums/viewtopic.php?f=9&t=40061
I will focus on chain driven setups for my high powered affairs from now on.
If you want this motor, now you have a chance to buy it, fully decked out:
http://endless-sphere.com/forums/viewtopic.php?f=9&t=40061
I will focus on chain driven setups for my high powered affairs from now on.
JohnC
10 W
neptronix said:
That really sucks, Nep. The “Dirty Thirty” is parted out.
Enjoyed following the thread though, thanksJohnC said:neptronix said:
That really sucks, Nep. The “Dirty Thirty” is parted out.
Dirty thirty, hahaha!!! I should have called it that
I'm glad someone got something out of this. Looks like a lot of people are running magic pies all the sudden. Hm, wonder why :lol:
This bike will be reborn though, later on!! It will get a heart transplant of a 2kW rated MAC motor. I have a feeling it will be a little faster than the pie, but i can actually run it in a 24" wheel, which will be nice.. If it isn't faster, then i'm going straight to the eTek size motenergy motor.
This addiction never ends.
gensem
100 kW
2kw rated mac? meaning it can take 4kw? or its just the same design with a new rating?
gensem said:
It's rated for 1500w - 2000w continuous by MAC.. The stator is said to be notably bigger than what comes in the BMC/MAC hubs, but i'm not sure by how much yet.
The 1500W BMC ( 4lbs lighter, so obviously less magnet/copper ) Apparently died at 6kW for one member on here. Who knows what the bigger motor can handle.... that's why i bought two of them, hehe.
http://endless-sphere.com/forums/viewtopic.php?f=28&t=39299
veloman said:
It's am industrial lawnmower motor, there is a thread or two on it on ES, search for '2kw mac' and '2000w mac', you'll find them.
I have not recieved a reason, Just a shitty attitude from the organizer when i called him up and asked how ebikes should register, then he said he'd get back to me next week.. it's been a month now.. i emailed him, called him 4 times, left a voice mail, even called up everyone i could who participated in the race last year and was told that it really sounds like he's not going to allow ebikes up the hill this year.
So, given that we are a month and a half away from the race, i am taking this as a 'no'.
Oh well, sold the bits off, and will be putting together something much more powerful
John Bozi
100 kW
auraslip said:Building wheels requires one tool: a spoke wrench.
Cutting down pedals and re-tapping them requires a hack saw, a drill, and pedal taps.
It seems to me you're hitting a wall that you keep trying to go around but you can't! Eventually you're going to need to get some tools and get your hands dirty.
Have you had any problems with breaking or cracking the cranks when the hole is on a thinner part of the arm? I look at my shimanos and they about half the width away from where they originally tappered.
John Bozi
100 kW
auraslip said:Building wheels requires one tool: a spoke wrench.
Cutting down pedals and re-tapping them requires a hack saw, a drill, and pedal taps.
It seems to me you're hitting a wall that you keep trying to go around but you can't! Eventually you're going to need to get some tools and get your hands dirty.
can anyone suggest cheap unfluted cranks? I need to chop and shorten mine but there so fluted thin.