Key Switch/Voltage Reducer question

[scottyb]

Agreed, the solenoid activation circuit is subject to massive voltage spikes. That's not the kind of supply you want.

Use the battery main supply. These are the only 2 posts which do not connect to another battery. White is positive and is closest to the front of the cart on the passenger side. If you want a switched supply for the relay, go from the keyswitch .

[timbo73]

I have 99 series txt and am attempting to use my stock soleniod with my key switch to power up my voltage reducer. I am having a hard time understanding how to wire this up. I can get the solenoid to close using the 36 volts off the key switch. However, I don't understand how to wire up the two large post of the solenoid to the voltage reducer. Also, do I need to use the resistor and diode that was on the stock solenoid? Anyone have a wiring diagram of this setup?

[JohnnieB]

You need just the diode on the small terminals.
You definitely do not want the resistor installed.

If you've got the solenoid clicking when the key is turned on, you are almost there.

The voltage reducer has two wire that attach to the main terminals of the battery pack.
Pick one or the other and attach it to one of the big terminals on the solenoid.
Attach the other big terminal on solenoid to the battery pack terminal that the wire to the reducer was originally attached to.

The solenoid is simply a switch that has a electromagnetic coil instead of the toggle lever.

[timbo73]

JohnnieB thanks for the quick reply. One more question does the direction of the diode matter?

[JohnnieB]

Yes!!!!!!!!!!!!!!!!!!!!!!!!!!!

The banded end goes to the terminal the the wire from the Keyswitch attaches to.

[timbo73]

I got my voltage reducer working with my stock solenoid using the key switch as the activation circuit. However, with the key in the on position the solenoid opens when switching the F&R lever. I suspect this is because the wire on the "B" post on the switch is connected to the MS2 switch on the F&R switch. Does the F&R switch interrupt the power to the key switch? Can this condition be avoided?

[JohnnieB]

Your suspicion is correct.
Here is a schematic with the solenoid activation circuit highlighted.
As you see, B+ goes to MS-2 on the F/R assembly before it goes to the Keyswitch.
If you re-route the wiring so B+ goes to the Keyswitch before it goes to MS-2, shifting between F and R wouldn't cause the drop-out, however that would mean changing where some wires are connected and maybe running some more wires.

I've never done it, and don't have the same type motor drive (mine's a PDS) so I can't tell you what wires to move where. Sorry.

[Offtwice]

Originally Posted by JohnnieB

You need just the diode on the small terminals.
You definitely do not want the resistor installed.

If you've got the solenoid clicking when the key is turned on, you are almost there.

The voltage reducer has two wire that attach to the main terminals of the battery pack.
Pick one or the other and attach it to one of the big terminals on the solenoid.
Attach the other big terminal on solenoid to the battery pack terminal that the wire to the reducer was originally attached to.

The solenoid is simply a switch that has a electromagnetic coil instead of the toggle lever.

Johnnie - what does the diode do for a contactor? I am using a contactor on my key switch to turn on my voltage reducers too

[JohnnieB]

Originally Posted by Offtwice

Johnnie - what does the diode do for a contactor? I am using a contactor on my key switch to turn on my voltage reducers too

The diode doesn't do anything for the contactor (solenoid), it protects whatever is turning the electromagnet (coil) off.

When the contactor is energized, a strong magnetic field is developed by the coil, closing the contacts.
When the contactor is de-energized, that magnetic field collapses, creating a huge spike of voltage with the opposite polarity of the voltage that created it.
This happens in nano-seconds while the switch turning the coil off is mechanical and moves at a much slower speed, so the voltage spike impinges on the opening switch contacts while they are still in close proximity and may arc across them, shortening their useful lifespan.

The diode is reverse biased when the energizing voltage is applied (Cathode - banded end - is facing the positive voltage) and forward biased when the magnetic field collapses.
Basically, the diode shorts the spike back into the coil where it is dissipated harmlessly.

The contactor will work just fine without the diode, but whatever is turning it off will fail sooner.

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On the other hand, the resistor across the main terminals of contactors used in golf carts and similar applications, protects the contactor's contacts, but should not be used when the contactor is being used to turn something like a voltage reducer on/off.

The controller contains a bunch of filter capacitors whose voltage bleeds off with time and the initial charge current for a capacitor approaches infinity, so without the "Precharge" resistor keeping those capacitors charged, the peak current flow through the contactor's contacts would be huge the moment they close and arcing and melting could occur.

A voltage reducer might have some filter capacitors in it, but no where near the size of those in a speed controller and we want to shut the voltage reducer completely off when the contactor is de-energized.

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Hope this helps.

[MiltonC]

The converter from EZGO I installed on my RXV had 3 wires. Red to + battery pack, Black to - battery pack, and orange to the non-battery side of the solenoid (opposite).

Evidently it is using the switched side of the solenoid (48V) to provide a signal to the converter to operate, but getting the power from the battery pack. After turning off the key, the lights remain on for about 2 minutes then the converter trips off. When turning the key on the lights start once again.

As this is an OEM Converter from EZGO specifically for my RXV I assumed all was well. Do I have someting else to worry about that I am missing?