Slow this puppy down...

[jakesnake27]

Originally Posted by bokeasmowl

Put a block of wood behind the go pedal.

Another mechanical approach (and I think someone did it on here once) is to put a large bolt through the go pedal so it sticks out the back and contacts the floor board so it can't go down all the way.

[Budule]

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[fastbasser]

Originally Posted by Budule

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A very reasonable, cost effective alternative IMHO....

[InVision]

I agree the mechanical way will work, but it is just not flexible enough for switching a few times a day. A switch would be nice. Does anyone know the value of the resistor inline for reverse in F-R switch that uses 3 micro switches?

M

[caokgafamily]

Buy your wife a slow golf cart, his and hers.. Ha ha

[InVision]

It will come to that probably. It is quite ironic that series carts seem to jump from 22 mph to 32+ mph with not much in between. I let some air out of the tires and now it has slowed down to 32 mph. Probably could put smaller tires on it also to get to 26 mph.

M

[Sergio]

Lots of mechanical solutions, so let me add an electrical/electronic solution. I don't think a mechanical solution works good in this case because of the requirement of switching speed modes often.

The way to accomplish the task will depend on how the throttle is configured, 2 wire potentiometer mode or 3 wire voltage divider.

The DS throttle circuits where you see the resistor for half-speed is designed to work as a voltage divider (0-5v). The resistor that is added basically reduces the maximum voltage the controller can see when the pedal is at WOT.

If you have a 2 wire potentiometer mode (only 2 wires of the MCOR being used), you need to shift the potentiometer range, that will require a DPDT switch and 2 resistors.

I sketched both for reference, but for simplicity I left off the resistance of the MCOR wiper arm since it is a constant and will not affect calculations. The actual MCOR externally accessible points never go down to 0 ohms, but more like 1k ohm.


2 wire Pot Mode (Using DPDT switch):

Normal Speed:
S1 - 1 is Open so R1 is not connected.
S1 - 2 is Closed so R2 is being by-passed.
The MCOR resistance range is the regular 5.8K-0 ohm range

Reduced Speed:
S1 - 1 is Closed so R1 is in parallel with MCOR
S1 - 2 is Open so R2 is in series with wiper.
Using: R1 = 5.8k ohms, R2 = 2.9k Ohms
The MCOR resistance range is : 5.8K - 2.9K ohms.

The advantage is that You would have a smooth speed change during the entire travel of the Pedal.


3 Wire Voltage Divider Mode (using On-Off switch):

Normal Speed:
S2 is closed so R1 is being by-passed.
MCOR voltage range is 0-5v

Reduced speed:
S2 open so R1 is in series with top of MCOR.
Using: R1 = 5.8k
MCOR voltage range is 0-2.5V

You can probably use 1/4 watt resistors as there is very little current in the throttle circuit.
I also assumed the MCOR being 5.8K, you may need to measure your actual resistance accross the MCOR (White to Purple wires).
R1 = measured MCOR resistance.
R2 = 1/2 measured MCOR resistance.

The other cool thing is that you can flip the switches of the fly since the signal to the controller is never interrupted. If you are at WOT at the reduced speed and flip the switch, that would be like hitting an NOS switch, or the equivalent of going from half-throtle to full throttle.

Have Fun.

[InVision]

Thanks for the in-depth response. I have a series cart so the stock MCOR actual is 6.45K - 1043 ohms across the yellow and green wire. I am not an electrical engineer but I stayed at a Holiday Inn Express. :-) I ordered the wrong switch, single pole oh well. This does seem like a better solution for smooth response. Could it be modified for a DP3T switch so there would be a kill zone also?

Thanks again !!!!!!!!!

M

[Sergio]

The measurement you did is not the resistance across the MCOR. The resistance across the MCOR does not change as the Pedal is depressed.
You need to measure between the Purple to White/Black wires.

I don't like the idea of using the throttle for a kill switch since you would not be able to change speeds without disconnecting the MCOR, which means the cart would have to be off at the time.

I sketched a simple hidden "Start Switch" that would be effective.
You would need a charger relay, 2 diodes and a Reed switch. It costs around $10 shipped from an electronic supplier place like mouser.

When you turn the key switch ON, power only goes to your voltage converter, so You can listen to music of leave the LED lights on. If a child or dog steps on the Pedal, the cart would not move since there is no power to the rest of the system.

You would them move a magnet (hanging from the key chain for example) within proximity of the Reed switch (S1). That would cause the Relay to turn on and the Diode D1 would then latch the relay coil on so you no longer need the magnet.

The system would stay ON until you turn the key switch OFF, causing the system to reset.

The Reed switch can be mounted anywhere behind the dash, so unless you know where it is, You would not know where to place the magnet.

Sorry to get off topic...

[InVision]

Great info !! Don't be sorry. You the Man !! The light bulb is starting to turn on. The resistance between the purple and white black wires is 6.09K ohms. If you push pedal it goes to 5.98K ohms.

Ok I will buy another switch DPDT this time. Would it be possible to post the wire colors where I hook in your throttle switch. (black, yellow, green, etc). Here is my wiring diagram.

Thanks so much !!

M