How do I slow down a 24 volt 250 watt scooter motor?

Poppy

Flashaholic
CPF Supporter
Joined
Dec 20, 2012
Messages
7,177
Location
Northern New Jersey
I was gifted a pair of 24 volt Razor scooters for the grandkids.
They are too fast for the kids, and I can for-see injuries in the near future.
Each is powered with two 12v 7ah batteries. There is a electronic controller that varies voltage to the motor from zero to 24 volts.
I thought that I would just use ONE 12v battery and it would go slow enough. The problem is that the electronic controller.
!. requires that both batteries are connected, AND
2. the combined voltage has to be a minimum of 20 volts.

So my first plan will not work.

The razor homepage, states the units that I have will run at 15 MPH for 40 minutes.
It is a 24V 250 watt motor.

I'd like to drop the maximum speed down to half that.

What kind of resistor would I need to get?
OR is there a better way?
 

TEEJ

Flashaholic
Joined
Jan 12, 2012
Messages
7,490
Location
NJ
I was gifted a pair of 24 volt Razor scooters for the grandkids.
They are too fast for the kids, and I can for-see injuries in the near future.
Each is powered with two 12v 7ah batteries. There is a electronic controller that varies voltage to the motor from zero to 24 volts.
I thought that I would just use ONE 12v battery and it would go slow enough. The problem is that the electronic controller.
!. requires that both batteries are connected, AND
2. the combined voltage has to be a minimum of 20 volts.

So my first plan will not work.

The razor homepage, states the units that I have will run at 15 MPH for 40 minutes.
It is a 24V 250 watt motor.

I'd like to drop the maximum speed down to half that.

What kind of resistor would I need to get?
OR is there a better way?

You could re-gear them.

You could use a governor on the throttle control so they can't use the top half.

You could screw a bolt into the handle and slot the hand throttle so they can't twist it all the way to full throttle, etc.

If there's a throttle cable, you could add slack to it never pulls it to wide open, etc.



:D
 
Last edited:

StarHalo

Flashaholic
Joined
Dec 4, 2007
Messages
10,929
Location
California Republic
Pfft, c'mon gramps, let the kids have their fun, that's what the safety gear is for. Most of the Youtube vids of electric scooters are all tricks and how to make the scooter go faster, so it's only a matter of time before they stumble across those. Just be glad they don't have access to a forklift motor..
 

Poppy

Flashaholic
CPF Supporter
Joined
Dec 20, 2012
Messages
7,177
Location
Northern New Jersey
You could re-gear them.

You could use a governor on the throttle control so they can't use the top half.

You could screw a bolt into the handle and slot the hand throttle so they can't twist it all the way to full throttle, etc.

If there's a throttle cable, you could add slack to it never pulls it to wide open, etc.



:D
Thanks TEEJ,
I might be able to make that work, and then as the kids gain skills, I can make the slot longer so that they can get a higher top end.

The advantage of that system, is that they may get more run-time of a full battery charge.

I THINK that if I use a resistor that the battery will work just as hard, and the lost energy will be lost as heat through the resistor, so there would be no prolongation of the run-time. That is something that I'll find out.


Pfft, c'mon gramps, let the kids have their fun, that's what the safety gear is for. Most of the Youtube vids of electric scooters are all tricks and how to make the scooter go faster, so it's only a matter of time before they stumble across those. Just be glad they don't have access to a forklift motor..

LOL... they'll have their days, but at this point they are just getting the hang of balancing on those little 4" wheel Razors.
 

[email protected]

Newly Enlightened
Joined
May 17, 2012
Messages
35
A resistor added to the input of the speed controller shouldn't hurt battery life. If you find the specs of the pot you could get another one and wire it in series. Then set it to a level your comfortable with and as they get more experience you can turn it down (less resistance) to suit. Advantage is you can put it inside somewhere where they can't access it. Kids are too clever these days!

Sent from my GT-I9505 using Tapatalk 2
 

Poppy

Flashaholic
CPF Supporter
Joined
Dec 20, 2012
Messages
7,177
Location
Northern New Jersey
A resistor added to the input of the speed controller shouldn't hurt battery life. If you find the specs of the pot you could get another one and wire it in series. Then set it to a level your comfortable with and as they get more experience you can turn it down (less resistance) to suit. Advantage is you can put it inside somewhere where they can't access it. Kids are too clever these days!

Sent from my GT-I9505 using Tapatalk 2

The wiring diagrams are on this page, I have versions 19 and 20

http://www.monsterscooterparts.com/e300.html

Could you please explain with a little more detail?
Thanks in advance.
 

Poppy

Flashaholic
CPF Supporter
Joined
Dec 20, 2012
Messages
7,177
Location
Northern New Jersey
Darn, it seems that the version 19 has variable speed, whereas the version 20 does not.
in version 19 the green wire from the throttle varies voltage between 0.8 volts and 3.42 volts at wide open throttle.
Version 20 is either zero, or 24 volts.

So I guess I could use some kind of variable resistor in the green wire of the version 19 model?
What kind of values should I look for?

How about the version 20 unit? What should I do about it?
 

Poppy

Flashaholic
CPF Supporter
Joined
Dec 20, 2012
Messages
7,177
Location
Northern New Jersey
I took it to a local electronics shop, and put in a 5K ohm linear taper Potentiometer in that green line, of the version 19 unit, and it works perfectly! :) Yahoo!!!

One child is excited about riding it, the other not so much. I guess I can buy a new controller, and throttle switch, and upgrade the version 20 unit to a variable input, and add the pot modification I did to the first.

Thanks for the idea to limit the input side. :thumbsup:
 

Str8stroke

Flashlight Enthusiast
Joined
Nov 27, 2013
Messages
5,032
Location
On The Black Pearl
See if you can find some UltiFric batteries that fit! That should keep those little boogers from going fast! lol

Seriously, what about dropping it to 12 volts? Rewire the two 12 volt batteries from series to parallel???
 

Norm

Retired Administrator
Joined
Jun 13, 2006
Messages
9,512
Location
Australia
See if you can find some UltiFric batteries that fit! That should keep those little boogers from going fast! lol

Seriously, what about dropping it to 12 volts? Rewire the two 12 volt batteries from series to parallel???

.
I thought that I would just use ONE 12v battery and it would go slow enough. The problem is that the electronic controller.
!. requires that both batteries are connected, AND
2. the combined voltage has to be a minimum of 20 volts.

So my first plan will not work.
 

[email protected]

Newly Enlightened
Joined
Dec 17, 2016
Messages
2
I was gifted a pair of 24 volt Razor scooters for the grandkids.
They are too fast for the kids, and I can for-see injuries in the near future.
Each is powered with two 12v 7ah batteries. There is a electronic controller that varies voltage to the motor from zero to 24 volts.
I thought that I would just use ONE 12v battery and it would go slow enough. The problem is that the electronic controller.
!. requires that both batteries are connected, AND
2. the combined voltage has to be a minimum of 20 volts.

So my first plan will not work.

The razor homepage, states the units that I have will run at 15 MPH for 40 minutes.
It is a 24V 250 watt motor.

I'd like to drop the maximum speed down to half that.

What kind of resistor would I need to get?
OR is there a better way?

You..need..a..programmable..c[email protected]aol.com.....have...to..reboot...my...computer...
 
Top