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Help Troubleshooting and Modding a Razor Dune Buggy

I've seen this posted a couple of times (at least on the mods) from awhile back but want to ask it fresh.

I'm pretty sure I know the answer to my first question (need new batteries)

I have Razor DB that is 3 years old. It has traveled all over Texas and seen lots of asphalt, sidewalks, dirt, gravel and mud. I've always kept the batteries fairly well topped off but I'm noticing very little quickness when my 60# son hits the throttle. And the charge time diminished really quick. So I'm going to replace the batteries and probably going for 10-12 AH. But I'm noticing it just doesn't roll as freely as it used to. Not in the wheels, it feel more like in the chain or motor. I haven't really dug into it (this weekend's project) but would like some ideas of areas to check out. I don't think it would be the motor unless the bearing is frozen up.

But since I'm replacing the batteries, I figure it's time to move it to 36V.

Where is the best place to put the 3rd battery? 

Would it be better for space concerns to go with a smaller dimension and sacrifice run time, or just make something for it to fit (I have no metal tools but can do wonders with wood)

Do I need to replace the controller (It sounds like for torque I should)

How do I charge the 36V assuming I replace the controller and is the existing charger capable or do I need to replace the charging set up as well.

And outside the batteries (which I can get locally) what part numbers/links to this site would I need assuming new controller, charger and any other items.

Note money is not a huge concern but it's 3 year so I could easily just buy a new one (and probably will get a drifter) plus I don't want to put a lot of time and effort into the project. I'd like to just figure out the 3rd battery placement, crimp a few wires and send my kid kid out at couple of mph faster than before.

Thanks for the help!

You might want to remove the chain from the sprocket to pinpoint which part is causing the drag when rolling the dune buggy by hand.

Overvolting the Razor Dune Buggy's original 24 Volt motor with a 36 Volt battery pack and controller will work and the dune buggy will have quite a bit more power and speed by doing so, however the motor may overheat and burn out if overvolted to 36 Volts depending on how hard it is used. One of our forum members who overvolted the dune buggy motor burned it out after only a few minutes of use.

Most modded Dune Buggies that I have seen have the extra battery mounted above the plastic cover box that goes over the existing batteries, or on the steering column as shown below.


Mounting the third battery on the steering column keeps the center of gravity low and distributes the weight of the batteries more evenly than mounting it on the back of the buggy so it is my preferred location.

Run time is very important to most riders because recharging the batteries takes a long time, so using larger batteries and not sacrificing ride time is what I would recommend.

Like the motor, if the controller is overvolted it will be prone to overheating and burning out. So replacing the controller would be the best thing to do. It will probably help to increase torque as well.

The same charger port can be used and only the original 24 volt charger will need to be replaced with a 36 Volt charger.

If you are overvolting the original 24 Volt 250 Watt motor then a 36 Volt 500 Watt controller such as our item # SPD-36500B would be a good choice.

If you are upgrading the motor to a 36 Volt version then the controller should be Volts and Watts matched to the motor.

For a 36 Volt battery pack with three 12 Volt batteries up to 15Ah a 36 Volt 1.6 Amp battery charger such as our item # CHR-36V1.6A3P is recommended. For 18Ah or 22Ah batteries a 36 Volt 2.5 Amp or 3 Amp charger is recommended.

If you just want to add a third battery and crimp a few wires then modifying the go kart to run on 36 Volts might not be right for you because it requires buying a new battery charger and runs the risk of overheating and burning out of the motor and controller if they are not upgraded to 36 Volts along with the battery pack and charger.

So how would the option of doing 3 batteries, likely 15Ah but (larger/longer is tempting), plus charger and controller replacement. Most of the forums posts I've read don't point to smoking the motor as a huge problem so a risk I'm will to take. I think.

That said, will your controller match the factory holes on the frame or will I be drilling or otherwise finding a place to mount it? (ditto if if down the road I wanted a larger motor)

And if I went to a 36V 500 watt, am I back down to roughly the same speed I'm at now with the 24V 250 watt? Thinking if I burned up the 250 I'd replace it with the proper volt motor. Maybe. But then if that is where I ultimately might wind up larger motor on 3 batteries but at the same speed, I'd be better off just sticking with just 2 new batteries now and forgetting about any top end speed or doing something really extreme which I don't have the tools, time and probably patience to undertake.

And thanks for the response! If I can figure out what I want to do and get a high enough level of comfort to do it, I'll get with you on whatever parts I need to order

Non-original controller mounting holes are in different places than the original controller mounting holes are in, so new mounting holes would need to be drilled. Larger motors have larger mounting brackets so they would also require new holes to mount. I have seen a few Dune Buggy motor upgrade conversions where a larger motor without a mounting base was installed and held on with threaded rods that are bent into a u-shape, so that is also an option.

If the original 24 Volt 250 Watt 2500 RPM motor was replaced with a 36 Volt 500 Watt 2500 RPM motor then the top speed would be exactly the same, however the acceleration rate and hill climbing ability would be doubled. To increase the top speed with a more powerful motor installed, the jackshaft could be removed so the chain goes directly from the motor sprocket to the axle sprocket. This modification would double the top speed of the dune buggy.

That might be something I could look at. I think that means sliding the motor over, correct. And if I replaced with a 36 V 500 W motor, I'd be drilling new holes anyway. I'm trying to envision that after having the cowling off the dune buggy. Mentally it make me thing the wheels would spin in reverse. I would probably need more help than exchanges via this forum to get my head around it though.

Yes you have got it right, after loosening the motor mounting bolts then the motor slides over towards the jackshaft to loosen and remove the chain.

These type of motors can be reversed by switching the positions of the wires between the controller and motor, so if the wheels run in reverse after installing a motor then simply reverse the positions of the wires between the motor and controller to change the direction that the wheels spin. 

Thanks for all the help- I'll have to go out and take a look at the metal to figure out what I'm dealing with. I've got every known power tool possible. For woodworking. About the most I have for metal is a dremel with a diamond blade! So fabrication will be somewhat limited to brute force. But I can put together a wicker pine wood derby car!

Thanks again!

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