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KidsWheels
Electrical, Battery & Switch help
User avatar
By gameboy
#28697
posted by: nikg
490 Posts
Posted - 07/13/2007 : 08:30:08
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I hooked up a separate brake pedal to my daughter's jeep, but my younger son rides it and doesn't really get the concept of separate brakes yet. Here's what I did

"GAS PEDAL"---center tab gets + from batteries
---normally closed tab not connected
---normally open tab goes to normally closed tab on "brake pedal"

"BRAKE PEDAL"----center tab gets connected to red switch
----normally closed tab gets wire from gas pedal
----normally open tab gets orange wire that was originally the brakes on single pedal setup. I did add a 5w 0.2 ohm resistor to this circuit to soften the braking effect.

So I disconnect the brake wire from the brake pedal and connect it to where it originally was on the gas pedal and----everything heated up real quick. The resistor and wires got extremely hot, so much that I couldn't touch them.

What's going on? Is the resistor causing the problem? I thought with no resistor the wires should have gotten even hotter, but I never had a problem before. Of course I did change two things at once (two pedals plus new resistor)
I want the vehicle to be safe, so I need help. Right now I am back to the original separate brake pedal, but I'm wondering if the brakes are applied for a long time that the wires will get really hot. I guess I need to test that and get some feedback from you guys.
Thanks
User avatar
By gameboy
#28698
posted by: swhenrik
4067 Posts
Posted - 07/13/2007 : 09:02:23
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A little hard to follow, but I see a couple possible issues...

In the stock harnesss, the battery does NOT go to the center tab on the throttle pedal, it goes to the normally open tab. The motor wires go to the center tab. The normally closed tab gets the brake wire.

Stock, the battery is connected to nothing when the pedal is released. The motors switch between being connected to the resistor when released and to the battery when pressed.

What you did when you connected the orange wire to the throttle pedal like you did, when the throttle is released, the batteries get connected to the resistor. And the motors are connected to nothing. I assume it built heat pretty fast, just sitting there.

But this should only be a problem when you connect the resistor to the throttle pedal. With the new setup, you said "center tab gets connected to red switch" What is the "red switch?" High/low or f/r switches? If I'm understanding it right, it should work. The heat issue might be because of the new resistor, or it might be normal? The orange wire is semi small, I assume to partially act as a resistor, and maybe it normally gets hot.

Here's a diagram that should work..... The dashed orange wire is optional, as is the brake on/off switch. That switch, when "on" would make it brake when the throttle is released, good for panic situations for younger ones. The switch, when "off", doesn't brake when the throttle is released, good for more experienced drivers.

No combination exists that will connect the batteries to the resistor. Also, pushing both pedals (sometimes happens when panicking) will apply the brakes.
Image
User avatar
By gameboy
#28699
posted by: nikg
490 Posts
Posted - 07/14/2007 : 03:51:41
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You read my mind. That switch to enable the separate brake or not is exactly what I was going to do next. How many amps does it need to carry?

I believe the center connected to the motors and the battery going to normally open tab will fix the problem. Seems clear as a bell now. Aometimes you need someone else to tell you the right thing and then you go "duh" to yourself.

Thanks
User avatar
By gameboy
#28700
posted by: Grant
1820 Posts
Posted - 07/14/2007 : 18:13:42


I put in a switch to turn auto braking on and off in my sons Gaucho but it was never used so I didn’t bother with it in his Speed Rider and Off Road Rebel.

The setup I used was quite different to the one above. I used a self contained 15amp pedal for the brakes that activated a 60amp relay. The circuit that switches the relay also turns on the brake lights.
I also put the brake before the accelerator pedal for convenience and to cut down on the length of wire required in an effort to reduce voltage loss.

http://www.youtube.com/GauchoDrift" onclick="window.open(this.href);return false;
User avatar
By gameboy
#28701
posted by: swhenrik
4067 Posts
Posted - 07/14/2007 : 20:59:15
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I love those "duh" moments. Well I must love them, I have enough of them a day myself!

Grant... you had a switch to turn auto braking on and off, AND a seperate brake pedal?

The braking switch current.... an issue of some debate. My opinion, the motors (when braking) send every bit as much power to the resistor, as the batteries send to the motor. It could be more, except that the plastic tires slip so easily. Running 30 amp switches everywhere else? I'd run a 30 amp switch there too.

The other school of thought is that the braking is such short term that you can get by with severely overloading the switch.

Now you know, you'll have to decide what "you" feel safe with.
User avatar
By gameboy
#28702
posted by: Grant
1820 Posts
Posted - 07/14/2007 : 22:00:55
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I installed a separate brake pedal on the gaucho that was always in operation and an additional switch under the hood that would allow you to enable or disable auto braking off on the accelerator pedal. I also installed a 'handbrake' that allowed you to apply the brakes via a button on the dash so you can park it on inclines etc.

As for the current from the motors when braking, you have to remember that the braking resistors are generally a single 10Watt resistor (or 2 in some cases). If anything is going to overheat and burn out, it will be this.
User avatar
By gameboy
#28703
posted by: nikg
490 Posts
Posted - 07/16/2007 : 18:33:52
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The switch I want to use is rated at 7A and 125V. I think this should be sufficient.

Another thing to consider is that this switch will be static when the power/current/"shorted motor juice" is running through it. By that I mean that the switch will be in one position or another during braking, but won't actually get switched on and off itself. I'm no expert, but this leads me to believe that this will help with the overall power handling of the switch. No sparks or arcs inside while power is goingt hrough it.

Thanks guys
Pines

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