12V winch power from DS controller?

[Revolution]

Dave,

Your DVM should read the voltage fine, as long as a motor is attached. The main problem with over volting a winch motor is heat. They are designed to run intermittently. It might work fine it may burn out quickly. You should start with 12-14 volts and increase slowly.

Your controller won't output any more than its rated for. The winch on 12-14 volts won't pull more than it name plate rating.

Depending on your controller brand and model you might not be able to use the remote you have now. You might have to reprogram it also.

What controller do you have?

[Sergio]

My comments and opinions on your questions:

1) Yes, the controller is PWM and You can use a regular DC voltmeter to measure the voltage. The meter will show you the "Average" voltage, which will be proportional to the duty cycle of the of the output signal.
A nominal 12v car system is usually 13.4v when the alternator is running, so anywhere between 12v and 14v should work OK for the controller output voltage.

You will find a lot of confusing information about Voltage and Current relations in a motor, specially since they are often used in a generic statement when they should be very specific.

The reason a motor runs faster when You apply a higher voltage is because of the Back EMF. The Back EMF is a constant specified by the motor manufacturer and it is based on coil design, air gap, etc. It is specified in Volts/RPM or mV/RPM. As a motor spins faster, the Back EMF increases to the point the motor achieves a balance against the input voltage. If the input voltage is higher, the motor can spin faster before the Back EMF reaches that value.

The torque produced by the rotor is directly proportional to the current in the armature windings.


2)Those winch motors run pretty hot, If yours does not have a thermal shutdown, you will need to monitor the temperature just like you would if it was powered by a 12v battery.


3) You had no number 3.


4) You do not want to stall any DC motor.

5) Given your explanation of proposed use, we need a slightly different approach to the design.

A potentiometer will make finding the correct throttle voltage setting easier, but you will need to be very careful that the potentiometer does not get moved after you set it or the controller voltage output could go a lot higher.

I am thinking You will need (2) DPDT switches and a solenoid to accomplish the task. The solenoid is not needed if You keep the winch disconnected from the controller when not in use.

Use this wiring diagram for reference:

http://www.buggiesgonewild.com/attac...car_ds_48v.jpg

I am separating the throttle change over function so 1/2 goes into each switch, this will prevent the winch from receiving +48v if you only flip one of the switches.

Also, fliping both switches (to winch mode) with the key switch ON and the FNR in Forward or Reverse would allow the cart to run at about 1/4 speed. You would need a SPDT solenoid to avoid this scnerario if you want to eliminate this possibility.


The "yellow" wire is the one that was connected to controller #3 terminal.

The "green" wire is the one that was connected to the controller #2 terminal.

The N/O contact of the solenoid is where You tap the "Negative" side of the winch power. The positive goes to B+.

You would adjust the 10k potentiometer until you get 13v or so between M- and B+. You would need to make sure the potentiometer does not move after you set it. You can also measure the resistances and replace the potentiometer with (2) resistors once you get it adjusted.

This is just an idea, suggestions are welcome.

[greg-g]

so your thinking of pulsing a 12 volt motor with 48 volts and because the meter reads an average it will be OK ? this is a brushed motor correct

[808Pants]

Great stuff, Sergio, thanks. Followup questions, of course...

I didn't really get this bit:

Originally Posted by Sergio

....I am separating the throttle change over function so 1/2 goes into each switch, this will prevent the winch from receiving +48v if you only flip one of the switches...

...but it may not matter if I do this using a simplifying variation. I'm thinking that for now, at least, until I get some kind of "proof of concept", I will forgo the solenoid, and instead, as a less-technical safety precaution, I will place the fat power-connector and pigtail such that it's impossible to miss it when getting into the driver's seat, the idea being that I'd have to be a complete moron to try to drive off without first disconnecting the winch power.

With that in mind, extracting what I think are the bare-bones from this part of what you wrote:

Originally Posted by Sergio

....
The "yellow" wire is the one that was connected to controller #3 terminal.

The "green" wire is the one that was connected to the controller #2 terminal.

The N/O contact of the solenoid is where You tap the "Negative" side of the winch power. The positive goes to B+.

You would adjust the 10k potentiometer until you get 13v or so between M- and B+. You would need to make sure the potentiometer does not move after you set it. You can also measure the resistances and replace the potentiometer with (2) resistors once you get it adjusted.

...

... I'm thinking I will incorporate your connections above, but via just one DPDT switch.
One set of contacts would join/unjoin keyswitch-blue and Controller terminal #1.
The other set would join/unjoin Controller terminals #2 & #3, with that 10K pot inserted in series, mounted somewhere under the seat, probably.

Worries:
1) For my version (or yours?) to use for winch power, the keyswitch has to be on, right? Thus, when set up for winching, if my cat bumps the FNR switch to either F or R, the cart would drive off? (that might be good Youtube material, but it would make me reconsider my aversion to adding more components like the solenoid you'd shown...)

2) Pot wattage: could a little multiturn potentiometer be used, eg the kind that requires a tiny screwdriver to turn, and takes a lot of turns to change much? I'm thinking they're inherently 'bump-resistant.' I think I may have some nut-lockable types in my junkbox, too, but that's assuming they're in the right range.

Thanks much for thinking/writing about this. I will get to rewiring & dry-run testing as soon as it seems like this is resolved.

--Dave

[808Pants]

omitted quote

[808Pants]

Originally Posted by greg-g

so your thinking of pulsing a 12 volt motor with 48 volts and because the meter reads an average it will be OK ? this is a brushed motor correct

I plead ignorance. Does PWM work only with brushless motors?

[Sergio]

There is always a possibility or arcing when running a brushed DC motor above the rated voltage, but since You would only be driving it at 25% duty cycle and the PWM frequency of those controllers is usually around 16KHz, I think there is enough impedance in the motor coils to absorb the ripple.

What I did miss entirely when I read it the first time is that You are using a wireless remote. If that remote is being also powered by the 12v PWM output of the controller, that is not going to work.

Electronic devices will not be that tolerant to the voltage spikes.

Also, the resistor in series with the throttle would only work if you were in the cart to press the pedal. At rest (pedal up) the yellow wire is at 0v, so adding additional resistors in series would not help.

[808Pants]

Sergio,

Good point about the remote power. Right now it is parasitic, so the PWM would indeed mess that up. I will have to augment with a 12V battery like an alarm-system gel-cel, but that's manageable - I can keep it charged with a little PV panel.

On the winch/no-winch switching, I guess if I really understood the accel and interlock-switch functions I could stop asking confirming questions. Thus, I have to ask more about "...the resistor in series with the throttle would only work if you were in the cart to press the pedal. At rest (pedal up) the yellow wire is at 0v, so adding additional resistors in series would not help..."

See attached pdf. First two pages are my attempts to confirm intent of your DPDT sketch. Third is my simplified single-DPDT alternative, this time crudely sketched into the picto-schematic for the whole cart. I thought I'd taken your suggested "winch on" switch configuration, and consolidated that into just the one switch, but maybe I missed something?

Mahalo - Dave

[808Pants]

Not to hijack my own post, but a technically-unrelated question on this application arises. To get my cart to the hillside location where I'd make the winch-power connection, I have to go up a steep weedy slope. From a brief check, it seems like the cart keeps traction going at least partway up that slope (dry conditions.) But envisioning that I could at some point lose traction and hit the brakes - and knowing that this cart has only rear-wheel brakes - how likely is it that I might end up at the mercy of friction and gravity, sliding backwards downslope, regardless that my rear wheels are locked up?

Obviously I've never done any off-path driving, so I have no experience to judge.

--Dave

[Sergio]

You have the correct understanding for my switch arrangement.

Your simplified one will not work because of the throttle signal. Some information may help explain:

Early club cars used a 2 wire throttle device called Multi-Step potentiometer in a "Vglide" body. Those devices produced a 0-5KΩ resistance to the controller.

Later versions used a 3-wire throttle device, either a multi-step potentiometer, a continuously variable potentiometer or an MCOR.

All of those devices produced a variable voltage of 0-5v (approximately) to the controller.

Only after market controllers used those devices as a 5kΩ-0 rheostat.

Your throttle has 3 wires:

White/Black = +5v
Yellow = Wiper
Purple = Negative (B-)

So in order to change the throttle input, You need to switch 2 different wires (assumes the low side of the add-on potentiometer is already connected to [B-]):

The White/Black wire that carries +5v to the throttle and the Yellow wire that is connected to the wiper.

The only way to use your idea is to have the resistor in series with the "Purple" wire, but there would be a possibility of pressing the pedal and the voltage at the controller B+ to M- would go up.