what kind of motor?
- Thread starter Fenrir
- Start date
- Status
Hi & 
that depends on how accurate you want to be with it...
to keep the kart moving no more than 150Watts are needed,
the problem is, you need to have some more serious torque to get 200kg moving in the first place
let's just ignore air densitiy, road inclination, rolling resitance and such nasty numbers..
you need to overcome accelerative resistance first,
that should be something in the range of
1.1 * M * a
M is the weight of the kart plus driver and a is the acceleration you want to achieve
So 220kg * 1.5 m/s² that's 330 N for a reasonably accelerated kart.
and that means after the first second you reached 1.5m/s (5.4km/h) and you used 495 Watts to get there.
So minimum motor for a 200kg kart (inkl driver) is 500Watts;
rolling resistance and friction in the drivetrain and all those little things will add up fast enough to reduce the acceleration considerably (maybe close to or even below 1m/s)
1km isn't far at 10km/h its just 6minutes ...
let's double that to 12 minutes and you have two times the range
say you have a 24Volts motor and on average it uses 240 Watts (accelerating and cruising combined)
that's 10 Amps.. for 12 minutes, that is 0.2 hours.. so your batteries can be as little as just 2Ah.
(2 amp for one hour, one amp for 2 hours.. or 10 amps for 12 minutes)
'sid
that depends on how accurate you want to be with it...
to keep the kart moving no more than 150Watts are needed,
the problem is, you need to have some more serious torque to get 200kg moving in the first place
let's just ignore air densitiy, road inclination, rolling resitance and such nasty numbers..
you need to overcome accelerative resistance first,
that should be something in the range of
1.1 * M * a
M is the weight of the kart plus driver and a is the acceleration you want to achieve
So 220kg * 1.5 m/s² that's 330 N for a reasonably accelerated kart.
and that means after the first second you reached 1.5m/s (5.4km/h) and you used 495 Watts to get there.
So minimum motor for a 200kg kart (inkl driver) is 500Watts;
rolling resistance and friction in the drivetrain and all those little things will add up fast enough to reduce the acceleration considerably (maybe close to or even below 1m/s)
1km isn't far at 10km/h its just 6minutes ...
let's double that to 12 minutes and you have two times the range
say you have a 24Volts motor and on average it uses 240 Watts (accelerating and cruising combined)
that's 10 Amps.. for 12 minutes, that is 0.2 hours.. so your batteries can be as little as just 2Ah.
(2 amp for one hour, one amp for 2 hours.. or 10 amps for 12 minutes
)'sid
thanks,
you made it really clear to me.
i'd be using a car battery 74Ah, 680A 12V .
another question i have is : my kart also has to be able to drive backwards , do al motors have te ability to chance their direction by changing the + and - ?
and how can i change the + an - ? is there a special kind of switch ?
i really appreciate your help, thanks
you made it really clear to me.
i'd be using a car battery 74Ah, 680A 12V .
another question i have is : my kart also has to be able to drive backwards , do al motors have te ability to chance their direction by changing the + and - ?
and how can i change the + an - ? is there a special kind of switch ?
i really appreciate your help, thanks
Wait..
the battery is overkill, and depending on the motor you'll end up using, you will need two or three or even four to provide the Voltage you need
(24V, 36V or 48V motors are common)
So 74Ah car battery is not a wise decision
just think about what four of them would weigh
If you want to go cheap, use motorbike batteries..
YB4-LB for example a small gel battery (5Ah 12x7x9 cm and roughly 1.7kg each ~$20)
again twice the cpacity I suggested (four times of what you need) and
four of them are lighter than just ONE car battery with 74Ah (about 16kg at least)
and just slightly more expensive.
Anyways..
yes, all dc motors can run backwards,
except for the few ones you didn't even think about (like a car starter motor)
Yes, there is a switch (it's called contactor)
but it's not what you think it is...
I have the feeling you have a wrong idea of how to build an electric motor driven kart
Forgive me if I'm mistaking..
but if at any point you thought about "resistor" or "potentiometer" to adjust the speed
you are wrong.
That's just not the way it works.
You need a controller for the motor.
Small motors like the one we are talking about don't need nothing fancy, a $30 dollar controller will do.
just no RC controller of course, but one off a e-scooter for example.
downside: the ones I can think of do not provide a reverse mode...
So maybe there's some research needed here
Anyways.. please take a look at the forums..
Jim-L-L for example just had his kid's kart converted to a 500W electric drive IIRC.
should be fairly easy to find.
Also there are numerous threads about electric motors, controllers and such,
just take a look at those for a better understanding of the concept.
'sid
the battery is overkill, and depending on the motor you'll end up using, you will need two or three or even four to provide the Voltage you need
(24V, 36V or 48V motors are common)
So 74Ah car battery is not a wise decision
just think about what four of them would weigh
If you want to go cheap, use motorbike batteries..
YB4-LB for example a small gel battery (5Ah 12x7x9 cm and roughly 1.7kg each ~$20)
again twice the cpacity I suggested (four times of what you need) and
four of them are lighter than just ONE car battery with 74Ah (about 16kg at least)
and just slightly more expensive.
Anyways..
yes, all dc motors can run backwards,
except for the few ones you didn't even think about (like a car starter motor)
Yes, there is a switch (it's called contactor)
but it's not what you think it is...
I have the feeling you have a wrong idea of how to build an electric motor driven kart
Forgive me if I'm mistaking..
but if at any point you thought about "resistor" or "potentiometer" to adjust the speed
you are wrong.
That's just not the way it works.
You need a controller for the motor.
Small motors like the one we are talking about don't need nothing fancy, a $30 dollar controller will do.
just no RC controller of course, but one off a e-scooter for example.
downside: the ones I can think of do not provide a reverse mode...
So maybe there's some research needed here
Anyways.. please take a look at the forums..
Jim-L-L for example just had his kid's kart converted to a 500W electric drive IIRC.
should be fairly easy to find.
Also there are numerous threads about electric motors, controllers and such,
just take a look at those for a better understanding of the concept.
'sid
you're right i don't know a lot i'm not that experienced but i try to learn as much as i can
i've been doing some research and i've found these:
http://www.conrad.com/ce/en/product...ntroller-Board-PCB-Component?ref=searchDetail
http://www.conrad.com/ce/en/product...03120-12V-DC-Motor-38RPM-2NM?ref=searchDetail
i think these are compatible and are some i can use.
as far for the car starter motor... i would have to change some things on it no ?
and i don't really get how i can connect the controller to the motor
thanks for all the help
i've been doing some research and i've found these:
http://www.conrad.com/ce/en/product...ntroller-Board-PCB-Component?ref=searchDetail
http://www.conrad.com/ce/en/product...03120-12V-DC-Motor-38RPM-2NM?ref=searchDetail
i think these are compatible and are some i can use.
as far for the car starter motor... i would have to change some things on it no ?
and i don't really get how i can connect the controller to the motor
thanks for all the help
mckutzy
Well-known member
Car starters aren't meant for continuous running, they will cook soon enough.
the controller would work I guess, although I would not recommend it for your application.
what you would want is more something like this:
http://www.amazon.com/ScootsUSA-270...ontroller/dp/B00H4GET00/ref=pd_sim_sbs_auto_2
(depends on the motor you choose in the end)
and for the motor..
the one you linked is pretty much useless for you're needs.
not enough power and the internal gear will most likely not withstand the forces you're going to apply ...
So I recommend something like this:
http://www.amazon.com/Universal-Par...id=1392486766&sr=1-10&keywords=24v+500w+motor
(that's a my1020.. the most common small vehicle DC motor available)
Conrad?? where're you from...
conrad has the SXT 500 scooters, that has the motor, controller and batteries you would want.
basically what I linked above
'sid
what you would want is more something like this:
http://www.amazon.com/ScootsUSA-270...ontroller/dp/B00H4GET00/ref=pd_sim_sbs_auto_2
(depends on the motor you choose in the end)
and for the motor..
the one you linked is pretty much useless for you're needs.
not enough power and the internal gear will most likely not withstand the forces you're going to apply ...
So I recommend something like this:
http://www.amazon.com/Universal-Par...id=1392486766&sr=1-10&keywords=24v+500w+motor
(that's a my1020.. the most common small vehicle DC motor available)
Conrad?? where're you from...
conrad has the SXT 500 scooters, that has the motor, controller and batteries you would want.
basically what I linked above
'sid
so the motor and controller are compatible ?
is the wiring of every controller the same ?
for the backwards driving i've found a H bridge , this also takes care of the braking but is this included in the controller ? can't seem to find it anywhere.
i'm from Belgium, the land of chocolate and beer
thanks
is the wiring of every controller the same ?
for the backwards driving i've found a H bridge , this also takes care of the braking but is this included in the controller ? can't seem to find it anywhere.
i'm from Belgium, the land of chocolate and beer
thanks
had a holiday flat in Knokke for about 15 years.. don't tell me it's the land of beer!
Some of it is likely the worst beer I ever had the mispleasure of tasting..
(well, there was a cheap dark ale from delhaize.. that was okay as a coke replacement)
And GB sold (sells?) Netherlands Hertog Jan, which I actually like.
Anyhooo
BTT shall we
yeah an H-bridge might work,
but to find one that's up for the task isn't trivial I'm afraid.
(I blew 60V 25Amp H bridges with just 24V and 5Amp because I forgot the heatsink)
So it might be easier to find a controller that does provide reverse off the shelf.
the controller I linked matches the motor I linked, yes.. but being from belgium it's not the source (and maybe not even the part) you want
A reason why we suggest adding your location in your profile, for us to know where you are.
I'm pretty sure there are hundreds of bicycle shops in belgium selling cheap (or let's say affordable) parts, you have your coastline pretty much covered in rent-a-bikes offering small electric vehicles for tourists
And yes.. I walked from France to the Netherlands, which isn't very impressive once you tried it yourself.. but it sounds like a big deal
Sorry, bike shops...
yes, I think you should ask if they have something to offer matching your needs.
I'm almost sure they have.
Otherwise there's still chinese offers at ebay (most of them offer free shipping)
so everything's better than getting a part from the U.S. with the nasty shipping fees
'sid
PS IF you are unable to find anything or unsure about a certain part, just ask!
Some of it is likely the worst beer I ever had the mispleasure of tasting..
(well, there was a cheap dark ale from delhaize.. that was okay as a coke replacement
)And GB sold (sells?) Netherlands Hertog Jan, which I actually like.
Anyhooo
BTT shall we
yeah an H-bridge might work,
but to find one that's up for the task isn't trivial I'm afraid.
(I blew 60V 25Amp H bridges with just 24V and 5Amp because I forgot the heatsink
)So it might be easier to find a controller that does provide reverse off the shelf.
the controller I linked matches the motor I linked, yes.. but being from belgium it's not the source (and maybe not even the part) you want
A reason why we suggest adding your location in your profile, for us to know where you are.
I'm pretty sure there are hundreds of bicycle shops in belgium selling cheap (or let's say affordable) parts, you have your coastline pretty much covered in rent-a-bikes offering small electric vehicles for tourists
And yes.. I walked from France to the Netherlands, which isn't very impressive once you tried it yourself.. but it sounds like a big deal
Sorry, bike shops...
yes, I think you should ask if they have something to offer matching your needs.
I'm almost sure they have.
Otherwise there's still chinese offers at ebay (most of them offer free shipping)
so everything's better than getting a part from the U.S. with the nasty shipping fees
'sid
PS IF you are unable to find anything or unsure about a certain part, just ask!
for a top speed of 10km/h all you need is 500 Watt, yes.
if you want big wheels you need to increase the first number (1.1) just assume it's a tenth of the wheel diameter in inches for a guess
(it's really not, but it's nearly impossible to do correctly.. so a rough estimation must do)
if you want to accelerate a little quicker increase the last number..
example:
12 in wheels 2 m/s²
1.2 * 200kg * 2m/s² = 480 N
first second: 480N * 2m/s = 960 Watt
15 in wheels @1.5m/s² : 675 Watt, @2 m/s²: 1200 Watt
20 in wheels @1.5m/s² : 900 Watt, @2 m/s²: 1600 Watt
if you think about the take off torque as your point of measurement.
But if you want to take the speed as a measurement,
and even include a serious road inclination of 5° (that's almost 9%)
F = m * g * sin alpha
gravitational force = 9.81m/s²
maximum road inclination alpha = 5°
F = 200 * 9.81 * sin(5) = 171
So you need 171 N to move the Kart up a 5° inclination.
To move uphill at 2.8m/s (~10 km/h) that'll result in
Pm = 171 N * 2.8m/s = 475 Watts mechanical power
and we're back at the 500W motor, even up a hill.
let's cross check where you end up with 1500W, shall we?
top speed: 1500W / 171N = 8.77 m/s (31,5 km/h)
acceleration: ~2.6m/s² (11 in wheels) that's 9.4 km/h in one second after you hit the throttle.
of course you can get a bigger motor,
but for the 10km/h you were asking for it's just not needed.
'sid
if you want big wheels you need to increase the first number (1.1) just assume it's a tenth of the wheel diameter in inches for a guess
(it's really not, but it's nearly impossible to do correctly.. so a rough estimation must do)
if you want to accelerate a little quicker increase the last number..
example:
12 in wheels 2 m/s²
1.2 * 200kg * 2m/s² = 480 N
first second: 480N * 2m/s = 960 Watt
15 in wheels @1.5m/s² : 675 Watt, @2 m/s²: 1200 Watt
20 in wheels @1.5m/s² : 900 Watt, @2 m/s²: 1600 Watt
if you think about the take off torque as your point of measurement.
But if you want to take the speed as a measurement,
and even include a serious road inclination of 5° (that's almost 9%)
F = m * g * sin alpha
gravitational force = 9.81m/s²
maximum road inclination alpha = 5°
F = 200 * 9.81 * sin(5) = 171
So you need 171 N to move the Kart up a 5° inclination.
To move uphill at 2.8m/s (~10 km/h) that'll result in
Pm = 171 N * 2.8m/s = 475 Watts mechanical power
and we're back at the 500W motor, even up a hill.
let's cross check where you end up with 1500W, shall we?
top speed: 1500W / 171N = 8.77 m/s (31,5 km/h)
acceleration: ~2.6m/s² (11 in wheels) that's 9.4 km/h in one second after you hit the throttle.
of course you can get a bigger motor,
but for the 10km/h you were asking for it's just not needed.
'sid
ok so i can use the 500W motor, get a speed of 10 km/h and climb of 10% if i understand you correctly
i don't really understand how you can control the speed with the controller , i know what PMW is but do you have to attach a turning button to the controller?
thanks
i don't really understand how you can control the speed with the controller , i know what PMW is but do you have to attach a turning button to the controller?
thanks
8.7% yes.. on small (11 or 12" wheels).
PWM but yes, of course you have a throttle somewhere.
A pedal on a kart or a twist throttle on a bike or scooter;
sometimes even thumb throttles.
Most controllers require a hall effect type of throttle,
some take whatever you apply, and others (very few) require a potentiometer style setup.
AS soon as you narrowed in on a controller you can check what kind of throttle it needs and find it (chinese sellers for example are capable of selling sets incl a throttle if you just ask them) as are most other sellers, but specialised ones often carry just one type (pedal OR twist/thumb)
'sid
PWM but yes, of course you have a throttle somewhere.
A pedal on a kart or a twist throttle on a bike or scooter;
sometimes even thumb throttles.
Most controllers require a hall effect type of throttle,
some take whatever you apply, and others (very few) require a potentiometer style setup.
AS soon as you narrowed in on a controller you can check what kind of throttle it needs and find it (chinese sellers for example are capable of selling sets incl a throttle if you just ask them) as are most other sellers, but specialised ones often carry just one type (pedal OR twist/thumb)
'sid
are these two compatible ?
http://www.ebay.com/itm/500-W-24V-D...er-bike-go-kart-minibike-MY1020-/151232108134
http://www.ebay.com/itm/Reversible-...tor-Controller-PWM-Control-500W-/281209902550
the specifications say the max A for the controller is 20amps but the operating A for the motor is 26.7 amps ?
http://www.ebay.com/itm/500-W-24V-D...er-bike-go-kart-minibike-MY1020-/151232108134
http://www.ebay.com/itm/Reversible-...tor-Controller-PWM-Control-500W-/281209902550
the specifications say the max A for the controller is 20amps but the operating A for the motor is 26.7 amps ?
Nope..
that's a motor for EV (electric vehicles)
so it's rating is based on it's mechanical power output (500W)
it draws up to 27Amps @ 24V (650W)
the controller can provide a maximum of 20 Amps no matter what Voltage,
at 24V that's 480W max!
Do yourself a favour and specifically search for a EV motor controller!
Even though you might find a motor controller that is up for the task somewhere else,
you might end up with a failure and if it's just because of humidity...
As you can see with this controller for example:
http://www.ebay.com/itm/24v-500watt...508?pt=LH_DefaultDomain_0&hash=item461add3d64
a 24V 500W controller for EV is generally rated at 30Amps
to provide enough electrical power, to produce 500W mechanical power
try to find a Yiyun YK31C for example, unitemotors (the manufacturer of the my1020 motor) makes and recommends them for the 24V 500W motor you mentioned.
there's a relais you can use to add reverse to the controller (or any other controller you choose)
JQX-38F 1KW 24V DC 40A
http://www.ebay.com/itm/JQX-38F-DC-...615?pt=LH_DefaultDomain_0&hash=item35c382d757
just in case you have a controller without reverse
'sid
that's a motor for EV (electric vehicles)
so it's rating is based on it's mechanical power output (500W)
it draws up to 27Amps @ 24V (650W)
the controller can provide a maximum of 20 Amps no matter what Voltage,
at 24V that's 480W max!
Do yourself a favour and specifically search for a EV motor controller!
Even though you might find a motor controller that is up for the task somewhere else,
you might end up with a failure and if it's just because of humidity...
As you can see with this controller for example:
http://www.ebay.com/itm/24v-500watt...508?pt=LH_DefaultDomain_0&hash=item461add3d64
a 24V 500W controller for EV is generally rated at 30Amps
to provide enough electrical power, to produce 500W mechanical power
try to find a Yiyun YK31C for example, unitemotors (the manufacturer of the my1020 motor) makes and recommends them for the 24V 500W motor you mentioned.
there's a relais you can use to add reverse to the controller (or any other controller you choose)
JQX-38F 1KW 24V DC 40A
http://www.ebay.com/itm/JQX-38F-DC-...615?pt=LH_DefaultDomain_0&hash=item35c382d757
just in case you have a controller without reverse
'sid
so these should work ?
http://www.ebay.com/itm/500-W-24V-D...er-bike-go-kart-minibike-MY1020-/151232108134
http://www.ebay.com/itm/12-40V-100A...750?pt=LH_DefaultDomain_0&hash=item20dfef9476
maybe i can use this controller ? i really like the fact i can chance the speed by tuning a button .
as for the reverse , i'm i don't really know how to make the circuit with the relay . maybe i can make a H bridge ?
http://www.youtube.com/watch?v=j7NsbUg5I98
thanks
http://www.ebay.com/itm/500-W-24V-D...er-bike-go-kart-minibike-MY1020-/151232108134
http://www.ebay.com/itm/12-40V-100A...750?pt=LH_DefaultDomain_0&hash=item20dfef9476
maybe i can use this controller ? i really like the fact i can chance the speed by tuning a button .
as for the reverse , i'm i don't really know how to make the circuit with the relay . maybe i can make a H bridge ?
http://www.youtube.com/watch?v=j7NsbUg5I98
thanks
30-40 Amp amp transistors... just saying....
Also a turning knob is not a wise decision;
think about it this way:
200kg kart running a 10km/h because someone turned a knob
while standing next to that thing (and not sitting in it)
You want that in your backyard.. running towards your car, or worse your kid?
I know it's just 10 km/h so you might catch up eventually... or not
So self returning throttle is a must I'd say.
If you don't like pedals, go for a thumb throttle or twist throttle.
And yes, the controller will work..
but paying 70 bucks for a controller uncased, uncooled,
that does the exact same thing as a $20 cased, passive cooled controller for you?
*shrugs*
wiring the relais is way easier than building a proper H-bridge (and cheaper.. mind the transistors).
Mount the power output from the controller to 2 & 5 (+ & -)
Mount the + line of your motor to 1 & 6 (bridged)
the - line of the motor to 3 & 4 (also bridged)
add a switch to A and B
just like on the attached image.. (that's a YK31C controller providing the blue and yellow leads btw)
'sid
Also a turning knob is not a wise decision;
think about it this way:
200kg kart running a 10km/h because someone turned a knob
while standing next to that thing (and not sitting in it)
You want that in your backyard.. running towards your car, or worse your kid?
I know it's just 10 km/h so you might catch up eventually... or not
So self returning throttle is a must I'd say.
If you don't like pedals, go for a thumb throttle or twist throttle.
And yes, the controller will work..
but paying 70 bucks for a controller uncased, uncooled,
that does the exact same thing as a $20 cased, passive cooled controller for you?
*shrugs*
wiring the relais is way easier than building a proper H-bridge (and cheaper.. mind the transistors).
Mount the power output from the controller to 2 & 5 (+ & -)
Mount the + line of your motor to 1 & 6 (bridged)
the - line of the motor to 3 & 4 (also bridged)
add a switch to A and B
just like on the attached image.. (that's a YK31C controller providing the blue and yellow leads btw
)'sid
Attachments
-
contr_relayfaname.jpg -
schaltplan-relay_jqx-38f_36V+faname.jpg
http://www.amazon.com/Universal-Par...&keywords=24v 500w motor&tag=viglink129979-20
i understand, so this one should be better then ?
http://www.ebay.com/itm/YIYUN-Elect...Cycling_Parts_Accessories&hash=item1e8397d326
and the throttle :
the controller says 4V throttle so can i use this one ?
http://www.ebay.com/itm/12V-24V-36V...969?pt=LH_DefaultDomain_0&hash=item19d7414f41
relay:
http://www.ebay.com/itm/JQX-38F-DC-...615?pt=LH_DefaultDomain_0&hash=item35c382d757
these should all be compatible ?
thanks
i understand, so this one should be better then ?
http://www.ebay.com/itm/YIYUN-Elect...Cycling_Parts_Accessories&hash=item1e8397d326
and the throttle :
the controller says 4V throttle so can i use this one ?
http://www.ebay.com/itm/12V-24V-36V...969?pt=LH_DefaultDomain_0&hash=item19d7414f41
relay:
http://www.ebay.com/itm/JQX-38F-DC-...615?pt=LH_DefaultDomain_0&hash=item35c382d757
these should all be compatible ?
thanks
correct;
except the controller, which is the correct model but for a differently rated motor
you need a 24V 500W of course.
well a 24V 1000W will do too, but not the 36V version.
So that's the one:
http://www.ebay.com/itm/E-Scooter-S...=DE_Sport_Elektro_Scooter&hash=item2588a83916
'sid
except the controller, which is the correct model but for a differently rated motor
you need a 24V 500W of course.
well a 24V 1000W will do too, but not the 36V version.
So that's the one:
http://www.ebay.com/itm/E-Scooter-S...=DE_Sport_Elektro_Scooter&hash=item2588a83916
'sid
- Status