I have a razor dune buggy that i would like to get 15 to 20mph with. i have read days and days of forums. i am still very confused. i would like to spend under $200 + batteries. some minor changes like a new charging port and voltage meter I think i could wire up if i had to do a 36 volt setup but i am hoping i could stay at 24. is that possible? If some one could tell me what parts to buy i would be very grateful. My son is only about 65lbs so weight is not a problem. thanks
The Dune Buggy could stay at 24 Volts and the top speed could be doubled by removing the jackshaft and running a single chain from the motor to the axle. This would only require repositioning the motor over a little and installing a longer chain. This might put a heavy load on the original 350 Watt motor though because of the amount of air resistance that the Dune Buggy will encounter at 18 MPH. The original motor might be able to handle it, or it might not, depending on riding conditions. If the original motor can not handle the increase in gear ratio that bypassing the jackshaft will create then a larger 24 Volt 500 Watt motor and controller could be installed in place of the original 350 Watt motor and controller.
Another popular way to modify the Razor Dune Buggy to have more top speed is to increase the battery pack, controller, and battery charger from 24 Volts to 36 Volts and leave the motor, chains, and sprockets alone, which it sounds like you have read about in some of the forums. This 24 Volt to 36 Volt modification will increase the RPM and horsepower of the original 24 Volt 350 Watt motor which will result in a 50% increase in top speed, however that only brings the top speed up to around 12.5 MPH which is under your target top speed range.
There are several options for achieving your goal. If it was my Dune Buggy, and was used on primarily flat ground, then I would start with non-destructively removing the jackshaft (so it can be used again if desired), moving the motor over until its sprocket is aligned with the axle sprocket, and then installing a single chain from the motor sprocket to the axle sprocket. Then I would run the Dune Buggy under normal conditions and see how it does. If the original motor and or speed controller overheat and stops working then I would upgrade them from 350 Watts to 500 Watts. If the Dune Buggy will be used to go off-road, in sand, or up hills then I would start off with installing a 500 Watt motor and controller right from the get go just to be on the safe side.
The 24 Volt to 36 Volt battery pack and controller conversion does not really increase the top speed by that much, so I would only choose that option if I wanted a 4.5 MPH increase in top speed, faster acceleration, better hill climbing ability, or sand driving power.
Depending on what you want to do, I can recommend parts for the project. Just let me know which option sounds best to you and I will be glad to make parts recommendations for the project.
If the original 24 Volt motor was run on 36 Volts the Dune Buggy would go 12.5 MPH with the original gearing. This top speed could be increased by changing the gearing to a higher ratio.
I have not seen the Dune Buggy modification using dolly wheels yet. Larger wheels or a higher gear ratio would both provide results in the same direction. The best outcome of changing the gear ratio or increasing the wheel size is to see what the resulting top speed is and make sure it is the top speed you want, and also that it is compatible with the motor which is being used and the riding conditions. Top speed calculations can be performed using our online gear ratio calculator at this link: http://www.electricscooterparts.com/motorwheelgearratio.html
I am not sure if using a 24 Volt 900 Watt motor and controller would save money over upgrading to a 36 Volt battery, controller, and charger. Since the 900 Watt motor is face mount, a custom fabricated motor mount would need to be made in order to bolt it to the Dune Buggy frames bottom plate which could run up the total if you need to have a welding shop make it. If you can make the motor mount yourself then it should not cost too much though.
A 24V 900W motor and controller will provide more horsepower and torque than a 24V 500W motor and controller, so the gear ratio can be made higher for more top end speed. If upgrading to a 900 Watt motor I recommend replacing all of the wiring from the batteries to the controller with heavier gauge wire, such as 10 gauge, to handle the higher Amp draw that the 900 Watt motor will pull.
Most Razor controllers are rated for larger motors than they are paired with. Razor does this for reliability since the controller is usually the weak link in the electrical system.
The original Dune Buggy controller is rated at 30 Amps which is the correct controller Amp rating for a 500 Watt motor, so the original controller can be used with a 500 Watt motor.
i found this motor, what do you think of that? $45 is very cost effective. 5380 rpm at 24 volts sound crazy.
they sell sprockets for it too and motor mounts if i need one.
A motor running at 1000 Watts should have just enough power to move the Dune Buggy at around 28 MPH on flat ground.
got a 500 watt 24 volt motor this week. installed without the jack shaft as we discussed and was successful in hitting the 15mph i was looking for. problem is now the cart has no torque. i was hoping to not have to go all the way with a new controller 3 batts, charger, throttle but i guess that is the only solution?
Its hard to say if installing a different 24 Volt speed controller would provide more torque or not. Some brands of 500 Watt motors have a lot of torque while other brands do not, so its hard to know whether the motor or the speed controller is limiting the torque. Most 500 Watt motors paired with a 500 Watt speed controller have a lot of torque when geared for a 15 MPH top speed though.
if i was to get a 36 volt 1000 watt controller and try it with 24 volts would that work the same a 24 volt controller? just thinking about if a new 24 volt controller doesn't work then i would have to buy a 36 volt. this way it might cost a little more at first but it would be future proof.
Most 36 Volt controllers have a low Voltage cutoff feature that turns the controller off when the battery pack Voltage reaches or drops under 31 Volts, so they will not work with a 24 Volt battery pack.
However we have one controller that works with battery packs between 24 and 60 Volts which is our item # SPD-601000A. This controller is factory rated for 700 Watts at 24 through 36 Volts, and 1000 Watts at 48 through 60 Volts. It is under rated by the factory though and our tests have shown that it puts out a lot more power than it is rated for. When running at 48 Volts we got a reading of 50 Amps out of it which is 2400 Watts.
It is available on our 24, 36, 48, and 60 Volt controller pages at this link: http://www.electricscooterparts.com/speedcontrollers.html