ELECTRIC SCOOTER PERFORMANCE OPTIONS

INCREASING PERFORMANCE

This article provides some tried and true suggestions and tips for increasing your scooter performance. In some cases there will be a trade off in that higher speeds can cause less torque (acceleration from start). It all depends on how you modify your scooter.

MOTORS AND POWER PERFORMANCE

Motor are available in different wattage sizes and drive types: belt drive or chain drive. The also mount in two different ways: bracket mount where the mounting bracket with four tapped holes is attached to the motor (usually smaller motors 350 watts and under), by band mount where the motor is round and a band is attached to the scooter frame that squeezes the motor to secure it in place inside the band, and using a flange on the drive end of the motor to attach it to the scooter.

Increasing the wattage of a motor can yield higher speeds and acceleration (torque), increased hill or incline climbing ability. Most small motors use belts, but these are not acceptable for larger motors over 400 watts due to the power and torque generated. Using belts would strip the teeth from the drive belt. Chains are more capable for higher wattage motors and most use a #25 or 8mm chain for motors to 1000 watts.

Replacing an existing motor is typically the trend when the new motor can fit the cavity provided for a motor on the scooter. The new motor may require a new control box to furnish the current (amps) necessary to prevent a control box burn out. If the new motor requires more voltage then the entire battery, electrical system, and control box will be replaceed. If the new motor is chain driven then a new rear wheel which has a sprocket will be required along with the drive chain.

Driving a 24 volt motor with 36 volts power from the electrical system (batteries and control box) will yield higher speeds at lower torque (acceleration). The motor can also overheat if used excessively over a period of time and cause windings to short out (motor burn out). Acceleration is slow, but higher speeds are generated.

If you already have a band mounted motor of 400+ watts, 24 volts, then you might want to increase the voltage to 36 volts or even 48 volts with a new control box and higher wattage motor of 750 or 1000 watts. The best motor for the cost available is our 700 watt 36 volt Motor that is controlled by the matched control box. The 750 watt 36 volt Motor is a high quality alternative, too. It is a proven long life motor.

The largest motor for the cost available is our 1000 watt 36 volt Motor that is controlled by our 40 amp 36 volt 1000 watt Control Box or CT-660B9 multi connector 40 amp 36 volt 1000 watt Control Box. The acceleration and torque with high speed output is the best for the cost of any motor on the market, bar none. It requires a 36 volt battery electrical system, but otherwise standard throttle, etc. Motors of 1000 watts and over can cost upwards to $500 for the same quality.

The advantage to using a larger voltage system is that the amperage the motor uses is less and the control box is not subjected to the higher amperage. This makes the batteries last longer between charges. So 48 volts is a great alternative if you have room for four 12 volt 9 ah batteries. Motors can be 500 to 1000 watts controlled by our 48 volt 1000+ watt Control Box or multi connector 50 amp 48 volt 1000+ watt Control Box.

WHEEL SIZE AND DRIVE RATIO PERFORMANCE MODS

Most 8 inch (200 X 50) Rear Wheels are driven by a belt. But we have 8 1/2 inch rear wheels which are chain driven. Replacing the wheel with a chain drive sprocket wheel will also require replacing the motor with a chain drive sprocket motor. Some motors up to 350 watts are also mounted with four tapped holes on a bracket attached to the motor. You can simply replace the motor, rear wheel, and use a chain. We have a 36 volt 360 watt bracket mounted chain drive motor which allows this conversion or build (if you are building a scooter from scratch). It is necessary to have three batteries and a control box that supplies 36 volts to the motor. The result is a scooter capable of near 25 mph speed and good acceleration. See these components: 350 watt 36 volt Control Box, 350 watt 36 volt Motor, bracket mounted, batteries, and 8.5 inch rear wheel.

Sometimes you can mount a new tire on an existing rim. Our Rad2go 10 inch (3.00-4) can be replaced on the rim with the 3.5/4.10-4 tire. This provides a 10% increase in circumference which translates into a 10% increase in speed. See 10 inch tire.

You can also decrease the number of teeth used on the rear sprocket. For example we have 12 1/2 inch rear wheels that are very similar except that one has a 64 tooth sprocket and the other has an 80 tooth sprocket. Obviously the 64 tooth sprocket will translate the power from the motor into more speed - nearly 25% more speed. The acceleration will be reduced, but the top speed increased. Somewhat more difficult is replacing the front 12 tooth sprocket on the motor with a sprocket with more teeth - more difficult since sprockets that fit motor shafts are hard to find. This ratio decrease is a means to achieve more speed.

NEW

MAKING A TURBO SCOOTER

[Note: The information provided in this section is technical and requires a knowledge of electronics to accomplish. The author found a solution to control boxes that restrict current flow which is a "ramp up" feature to prevent hard acceleration. This design does not eliminate the need for a control box. But in addition to the acceleration produced it could prevent a controller burn out due to times of lengthy hill climbing because of a continuous sustained high current flow.]

The idea of the circuit is to be able to apply full battery to the 1000 watt 36 volt motor when you need it for acceleration or climbing a hill that calls for more current than your controller (CT-660B9) can provide. This design prevents the relay from operating if someone pushes the switch when the scooter is stationary (as kids are inclined to do when they see a button).

The relay is a 12 volt DC high current type. The higher the better, it could draw over 100 amps when first closed depending on the scooter power, voltage and weight. Make sure you use heavy duty wire in all of the high current carrying parts of the circuit.

Circuit diagram The switch shown just to the left of R2 is a momentary push button type. Current is low through here so just about anything will do the job. Mounting it on your handlebars where you can get to it while driving will be the biggest challenge of this project probably. If your scooter is weather proof, you'll need to take care of that for this switch too. [Note: A handlebar grip switch assembly Horn Button can be used. ]

The diodes are all the "fast recovery" type and the one across the relay should be high current too. When running down a hill over your top speed, that diode could conduct several amps as it dumps the excess current being generated by the motor back into the battery (although you will find there's a similar diode in your controller output, either internally in the MOSFETs or externally to prevent voltage kickback from the motor destroying the MOSFETs). The regeneration current will be shared between these two diodes in a ratio that depends on your set up. The real purpose of this diode is to suppress sparks across the relay contacts when the relay opens. Sparks will burn it out in no time if you do nothing to prevent them.

Also make sure all diodes have a reverse voltage rating higher than your battery voltage.

This design assumes a 36 volt system. If yours is different, then R2 must be designed to provide 12 volts to the relay when battery voltage is applied "upstream" of R2. For a 48 volt system R2 would be 3 X R, for 24 volts it would equal R. You'll need to determine the relay coil's resistance "R" either by measurement or specification to calculate R2.

It also assumes your controller delivers the current to the motor's positive lead and the negative is grounded. This is the case for the CT-660B9 controller at least. Some controllers control the negative motor lead and the positive is connected to the battery. In that case, the relay switch contacts should be connected to ground and the motor negative lead. The diode across the relay contacts must then be connected so the anode is grounded and the cathode is on the motor negative lead.

The circuit works by storing the battery voltage in C1. As soon as any throttle is applied, C1 will jump to battery voltage arming the "Turbo" switch. After that, when the turbo switch (to the left of R2 and mounted near a handle grip) is pressed, C1 dumps its energy into the relay closing it. THIS DIRECTLY CONNECTS THE BATTERY TO THE MOTOR SO MAKE SURE YOU'RE READY FOR IT! Mine does wheel stands if I press it when it's going slow.

When the throttle is released, C1 discharges through R3 disabling the push button. You can adjust R3's value to suit but make sure it can handle the power it will dissipate. It could be higher than you think.

Finally, while I offer this design free to anyone who wants to try it, of course I take no responsibility for anything that may happen. ie. no guarantee. However it's working fine on mine and it's simple enough that there's not much to go wrong. I highly recommend having a "kill switch" on any scooter. One that completely removes the battery from the system circuitry and that is accessible while you're driving. Controllers can fail to FULL THROTTLE, it's happened to me. Without a kill switch you're in a runaway condition and that's dangerous! - Submitted by Warren Harding

BATTERIES and CAPACITY IN AMPHOURS

Batteries produce the power. Batteries can be capable of producing so many amperes per hour such that if the scooter electrical system requires a sustained amount of amperage then the batteries should provide that amount or more. Restricting the amount of AH may cause a reduced performance since the batteries cannot produce the amount of AH needed. Batteries are also rated for length of time between charging, the larger the battery the longer it will run your scooter before needed a recharge. Sometimes there is a trade off in that even small cells required for an upgrade can be used to power larger voltage systems due to space requirements for installation of the three cells. The scooter may accelerate a bit slower, but top speed may be the same. Obviously the larger the cells, generally 12 volt 17 ah being the largest, then the better the overall performance and more time in service between recharging. Your own use and requirements will govern your best alternative choices for the batteries you use. 12 volt 12 ah battery cells are the most commonly used for 24 volt and 36 volts in series; but, it is not uncommon to use 12 volt 9 or 10 ah batteries in series for 24, 36, or 48 volt system. And even three 12 volt 5 ah batteries in series will produce 36 volts at 5 ah for powering 36 volt systems where the length of time between charges is not an issue.

RESULTS VARY

There are many factors that can produce differing results. Outside temperature, surface conditions, operating environment, motor windings, battery quality, etc. We have seen customers install 300 watt motors in place of 200 watt motors only to realize an increase in torque and acceleration when they actually wanted extra speed. We have a great article about rewinding motors which sheds light on how to get more speed by reducing the motor windings (something akin to using a 24 volt motor instead of a 36 volt motor). There are many approaches. Manufacturers have spent time to find the proper balance of torque and speed and the combination of motor size, drive gear ratio, batteries used, with the control box choice is not an accident. Scooters are designed with these factors in mind. But many customers are unhappy with their purchases and want improvements. We hope this article will provide you some help in achieving a desired result.

SUMMARY: Electric scooter performance can be increased rather simply. Change the gear ratio so the rear gear is smaller or the motor gear is larger, or increase the size of the rear tire diameter. The motor size can be increased to compensate for loss of torque and acceleration. Bottom line - Performance is a matter of the gear ratio and motor size.

PERFORMANCE TIPS