Switched radio, constant memory with reducer

[Sergio]

They have not made radios with small current "memory wires" in over 10 years... All radios now work similar to the voltage converters with a trigger wire:

A +12v Constant power wire that provides powers for the amp, logic section and maintains the presets, etc...

A +12v ignition/switched "trigger" wire (sometimes small gauge) that tells the radio to power the amp.

I thing the best option is to get a charger relay (under $10) and wire your converter to provide both switched and constant +12v

Get +48v from the pack thru a "long term storage" on/off switch located near the Tow/run switch so you won't forget to turn it off.

That switch will provide power to the +48v input of the converter and the trigger wire if available.


Run The +12v output of the converter to anything that needs constant power (like your radio).

Run another wire from the +12v output of the converter to one side of the charger relay NO switch.

The other side of the relay NO switch provides switched power for lights, horn, turn signal, radio trigger, etc...

The charger relay coil is wired to the key switch so all accessories (including radio, but without losing memory) go off when you turn the key switch off.

Originally Posted by Sergio

there ya go .. this is going in my FWI file

[kraftchick]

Sergio, that is exactly the explanation I was looking for. I'll do some research on the piece you mentioned!

[Sergio]

You are looking for a 48vDC coil relay, 30 amps SPST Normally Open contact.

I normally use the T9AP1D52-48 relays, they are under $5 + Shipping....

You will need .250 quick connects for the contact terminals and .187 quick connects for the coil terminals.

It is always a good idea to use a diode in parallel with the relay coil, cathode or stripped end towards the +48v coming from the key switch.

You can use a 1n4004 diode, less than 10 cents and will protect other sensitive equipment you may have connected to key switch.

[kraftchick]

Sergio, after reviewing further, I've gotten myself confused a little bit. What to you mean by "no switch" when referring to the charger relay. And then at the end mention, wire the charger relay to key switch? What you describe is definitely what my intent is, I just didn't understand each step of the wiring regarding the charger relay....probably because I don't understand a charger relay. Secondly, I did some Googling...what is different from a charger relay than a regular relay? Can you post a link to one that would work? Thanks for everybody's help!

[Sergio]

Bad lighting, but I think a picture will be more explanatory.

The NO is for Normally Open switch.

KSI is the Key Switch Interrupt.

There is no real difference in the relays, in this case I call it a charger relay to refer to a 48v coil relay instead of the regular Bosch type automotive 12v relays.

Also, out of habit I drew the ground symbol, but remember there is no chassis ground in a Golf Cart, all negatives in a ClubCar go back to the controller B- terminal.

[Cart Sports]

The Madjax DC/DC has a constant 12V and Switched 12V signal. It will do exactly what you are looking for.

[Sergio]

The original poster already has a voltage converter,so $5 relay is better than $100+ new converter...

Also, the Madjax has a rating of only 10 chinese amps in the constant voltage output.

While I have never seen the internal diagram, I would suspect very poor voltage regulation at the max current.

You could have problems depending what kind of radio and how much peak power you are using.

[Cart Sports]

Originally Posted by Sergio

The original poster already has a voltage converter,so $5 relay is better than $100+ new converter...

Also, the Madjax has a rating of only 10 chinese amps in the constant voltage output.

While I have never seen the internal diagram, I would suspect very poor voltage regulation at the max current.

You could have problems depending what kind of radio and how much peak power you are using.

We have used them without failure on 20+ carts. I'm not sure what Chinese amps are, but I assume they are similar to normal amperage. Regardless, if you have a head unit that is pulling more than 10amps for a memory signal, you need a new head unit.

[kraftchick]

Original poster here...fortunately my DC/DC converter does have the switching control wire, so I should good to go on parts by just picking up that 48v coil relay. Thanks Sergio!