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  #21  
Old 07-05-2015, 11:42 AM
Skalabala Skalabala is offline
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If a manufacturer claims 1Kw then rule of thumb is 2Kw with not to much loss, but at 3x 4x the losses stat to get high.
At factory specs a motor will last 10+years
No it was not rewound And there are a lot.
Well I get almost 60Km/h with the "320W" MY1016
I am not trying to be wise or anything Just sharing out of my experience and a lot of other peoples experience that over power is awesome :p
http://endless-sphere.com/forums/vie...57483&start=75

And it is a 36V only controller.
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  #22  
Old 07-05-2015, 08:27 PM
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Sorry you mess things up, or lost me on the way somehow.

longevity and efficiency are two completely different things!
one is measured in % the other in hours...

None is measured in years
as in rougly 90000 hours under load is something that will need intermediate maintenace
(replacement) of bushings, bearings, brushes (where applicable) etc.
even without load that's very hard to achieve outside clean rooms I guess

speed without weight is hard to judge,
but with just 100kg (adult on an E-bike )
... no you don't reach 60km/h (not even close)
(~1850 W mechanical ; best case : 2175W electrical power)
your controller doesn't provide more than 1440 W of electrical power at any given time @ max throttle.
even if it's a 48V controller it'd be 1920 Watts (ELECTRICAL) or roughly 1630 W of mechanical power...
not enough to reach anything like 60km/h (not even 55 km/h)
(free spinning doesn't count, neither does 'downhill' or free fall )

We turn in circles...
and frankly, if you do the math on page one (or even read it thoroughly) you'll see that there is serious cowdung going on in a few endless-sphere threads.

'sid
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  #23  
Old 07-06-2015, 04:52 PM
Skalabala Skalabala is offline
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It is a road bike And I am 60Kg
For sure the controller will do more than 1440W burst
I like the cowdung part hahahaha :p

What I mend by years is that the factory specs are there for longevity and not max power.
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  #24  
Old 07-13-2015, 03:48 AM
cuyler1 cuyler1 is offline
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i look at it another way:food for thought!
all the formulas in the world are old school now. we have microprocessors that are antiquated the day of manufacture. these m/p's are in the speed controllers and can extend volt/amps rendering old formula's with possible updating.
i utilize timer ne555 chips in projects here at home and configure them as power savers/extenders as they will produce short bursts' of controlled v/a's switching on and off to create a home made pwm. i run 14.4 volt drill motor batteries with my boxx to operate 6 volt motors with no do stress upon them.
check out youtubes "liquid coolong a starter motor" for a bike. i am working on that now.
telegraph-telephone-cell phone what next?
steam engine-combustion engine-battery power-solar?
it'll never fly said the barber to the wright brothers!
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  #25  
Old 09-29-2015, 05:21 AM
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Quote:
Originally Posted by cuyler1 View Post
i look at it another way:food for thought!
all the formulas in the world are old school now.


Wow I just read that (don't know how I missed that earlier)
This is the funniest post i read in a while... thank you

Yes, math is sooo oldschool.. your phone has a calculator build in.
I actually know a kid that said something just like that a month back commenting his math class.
That's as smart as saying:
Tear down all powerplants.. who needs them;
we all have electric outlets in our home!


If you -however unlikely that is- meant that as a serious comment, you should ask your teacher for some additional classes

Quote:
Originally Posted by cuyler1 View Post
we have microprocessors that are antiquated the day of manufacture. these m/p's are in the speed controllers and can extend volt/amps rendering old formula's with possible updating.
i utilize timer ne555 chips in projects here at home and configure them as power savers/extenders as they will produce short bursts' of controlled v/a's switching on and off to create a home made pwm.
Again, too funny..
maybe the oldest of all discrete electronics (NE 555 is from the 1970s!)
is new school? it's one of the most common chips in electronic devices,
a microprozessor is the "what if" part
a timerchip is "when then" architecture,
two very very different things.

I don't want to comment the rest of your post;
and more important YOU wouldn't want me to comment on that

But that's one funny post! (hopefully it's meant as such )

'sid
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  #26  
Old 03-13-2016, 12:09 PM
cuyler1 cuyler1 is offline
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what i posted is meant for humor but with a serious side. i was lucky enough to find a free 3-wheel scooter with a blown circuit board. i ripped all the electrics out and ran the motor numbers and found out it was a semi-truck starter drive unit. i run it forward with an automotive 30 amp relay with 2 micro switches with 2" long levers for activating the relay. the first m/s goes to the relay and out to a 1994 ez go golf cart "lo speed" resistor then to motor. the second m/s goes straight to the motor and all is connected to a single 12vdc 30ah battery. the switch levers are arranged so that my mother(84) has to push out on the levers with her index finger . it starts out slow and then the four barrel kicks in. i found that most people panic and hold on to the throttle tighter when taking out the screen door ,d.r. table and pantry. the finger throttle eliminates this as she applies the "death grip" on the handle bars.
reverse is accomplished with a dpdt switch and another relay and only a"lo speed" resistor.
it'been running inside outside and backand forth to the mailbox for 27 months now and i'm swapping out the first battery at the moment . i thought about this forum and am sharing. enjoy!
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  #27  
Old 04-08-2016, 08:53 AM
cuyler1 cuyler1 is offline
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speaking of 555's today i get a post from all about circuits forum and they have started a whole contortion of projects utilizing the 555 with "new wave" of arduino and raspberry pi projects. also valuable info for todays newbies. yeah i'm 60 and love'd them when they evolved but it shocked me to see this new interest in the old workhorse chip as they parley them as something which just sprang up!
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  #28  
Old 03-24-2018, 11:00 AM
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alfa-wheels alfa-wheels is offline
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Default Gear reduction ratio

A customer of mine bought a 500W 24v 3000 rpm brusless motor for a GoKart with 12 inch wheels.
He has a 6 to 1 gear ratio and says he is not getting enough torque. He says on a bench he can stop the wheel with his hand.
He has 2x 12v 18ah batteries
I think his gear reduction is too low .
But I'd like to know your opinion.
What is a tipical reduction ratio for this motor and size wheel?
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  #29  
Old 03-24-2018, 12:23 PM
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impossible to tell I'm afraid, the motor can be anything from that description,
he can lower the reduction ( if it lacks torque, it is too high, not too low mind you)
but if the kart's too heavy, that wouldn't even suffice tbh.

A 500W motor can have anything from a single Nm up to 5Nm of torque, and with that
one requires five times the gear reduction the other one would need to push the same weight.

That's why a TOY motor (like most RC motors are) is nothing that should be mounted to a vehicle of personal transport to propell said vehicle *gg*

BUT you can wiggle your way into a good ratio:
See what the motor should be capable of.
Keep in mind that motors that are not meant to be used on karts/mini bikes and such are NOT labelled with mechanical output, but with electrical input (and worst that can be the peak value) soo a 500W brushless motor can output at worst no more than maybe 180-220Watts of mechanical power
(which I assume is the case with the motor you're talking about)

And once you know what the motor should be able to do , you know what speed it could reach,
now you just need to work backwards to find the ratio to get from the motor rpm to the wheel rpms to find the gear ratio.

'sid
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  #30  
Old 09-24-2018, 04:17 PM
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Sid thanks for putting this thread together. I will try and go and read it again a couple times.

So disregarding coefficients of drag etc etc..

I have flat roads.
Want to build an electric street motorcycle.
After gas motor removed, stripped of unnecessary parts i will end up with 250kg load including rider. Maybe 275kg
Need to hit 70kmh would like 80kmh if i push it. More speed if a transimission would help.

So 48vdc brush less 6kw motor? 544.50 Eur
Something like this http://www.motiontech.com.au/wp-cont...LDC-030915.pdf

5kw air cooled, 7.5kw water cooled. >10k Hour

Then i also would want 30-60 minutes ride time @~60kmh.....ugh...so much battery power needed. could possibly get away with 25min time. 15 to work with charging station at work. so one way 15-20 min average...

What do you think. more power, less power?

6kw 30 minutes i need 62,500mah if i did the math right....thats a lot of 18650 batteries. 2,600mAh hmm 13s24p carp. $3k for the battery.....ugh...going to cost way to much. i see some for $1k. might be in my range. 2 batteries to get an hour drive.

I dont know crazy i guess. Sid any thoughts on this.


p.s. my other thought was sourcing nissan leaf batteries. 6 of them gives me the 48V with 64Ah. and they go for around $80 on ebay used. so $480? double them to get 120Ah for $1k? might be worth it. they say the leaf batteries are good for 10+ years.

p.p.s. i see people using this one http://kartmasters.fr/shop/en/synchr...-l-48-vdc.html also 48v 6kw motor. Torque 11.9 Nm
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  #31  
Old 09-24-2018, 10:20 PM
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the question you need to ask yourself is this:
do you need 20 minutes @ 80km/h
or do you need 15 mins at 50km/h with a 5min 80km/h top speed?

or more precisely, what do you think your average speed will be on your way to work
(an electric commutor is nice!)

But let's move that to a dedicated thread, shall we?

'sid
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