# Electrical gurus needed, relay Q's



## joed (Mar 13, 2005)

As long as the trigger voltage matches the coil rating of the relay it won't be a problem. 
The contact rating needs to needs to match the voltage and the current rating of switched power.


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## myz8a4re (May 5, 2020)

Thank you fit the reply Joed. So can I purchase relays with my specific needs? A 12v coil rating and a 48v contact rating or close those specs? I'm just not very knowledgeable about relays... as if you couldn't tell


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## quatsch (Feb 4, 2021)

The contacts need to be able to handle a Motor Load, as opposed to a Resistive Load or a Lamp [tungsten] Load.


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## SW Dweller (Jan 6, 2021)

12 volt trigger/ coil voltage is pretty common. 48v unknown amps is a bit harder.
Be sure to exceed the amp draw of the circuit your switching. If the load at 48 is 5 amps I would be looking for a 10-20 amp set of contacts. Also you need something that is sealed. Golf carts get in the dust and dirt


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## joed (Mar 13, 2005)

The contact rating is the maximum it can handle anything lower is just fine.So the contact rating needs to be the same or higher than the installed load. Higher is better.


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## quatsch (Feb 4, 2021)

Forgot: a DC motor load. 
The arc doesn't extinguish 120 times a second like AC, so DC is harder on the relay contacts.


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## myz8a4re (May 5, 2020)

Great info here, I really do appreciate it. I feel more confident moving forward with the project!


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## raylo32 (Nov 25, 2006)

The other thing you can do is wire up one of these transformers that step down the DC voltage to 12V. Pick the one that takes 48V input and gives 12V output. Then you could use standard 12V parts. I use similar to make a 12V power supply using my Makita 18V batteries for portable inflators and such.

These are apparently made for golf carts so maybe you have similar in there already. I suspect that you would want a 12V circuit for lights and other accessories and not send 48V to them directly. So find your manual and have a look at the electrical schematic.

Amazon.com: BANKEE DC Voltage Regulator Buck Converter DC 48V Step Down to 12V 20A 240W Reducer Power Converter Waterproof Module Transformer for Golf Cart Club Car (48V to 12V 20A) : Electronics


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## myz8a4re (May 5, 2020)

Thanks, I do have a Voltage reducer installed for my accessories but it is wired to turn on with the ignition switch so U don't leave anything draining the batteries, so it wouldn't have power to remotely turn on my ignition using a 12v RFID kit. I'm looking to add security by adding an RFID chip or remote to control the ignition switch. There's definitely more "cool factor" going into this project, lol. But it will add security bypassing the keyed switch. Again I do know there are easier methods to add security to a golf cart.... but what's the fun in that?


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## raylo32 (Nov 25, 2006)

LOL... yes, what fun would that be?? But hey, here's another idea... an easier way to do theft protection would be to hide an Apple AirTag or Tile onboard somewhere. But I like the cool factor of the RFID interlock.


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## myz8a4re (May 5, 2020)

Funny you say that, I have several of those Tile tags laying in my drawer at home. Looks like I'm dropping one in the cart thanks to you. Added security!


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## raylo32 (Nov 25, 2006)

I can see it now when the police locate your stolen golf cart and commence a low speed chase! ;-)



myz8a4re said:


> Funny you say that, I have several of those Tile tags laying in my drawer at home. Looks like I'm dropping one in the cart thanks to you. Added security!


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## Iceberg62 (11 mo ago)

Just curious if you ever came up with a solution for this project? I have a similar question.


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## chandler48 (Jun 5, 2017)

@Iceberg62 welcome to the forums. You may garner more responses by asking your question in a new thread. Sometimes the old one will have specific answers that may not apply to you. We read them all. Fill us in on your problem and we'll go from there.


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## myz8a4re (May 5, 2020)

Iceberg62 said:


> Just curious if you ever came up with a solution for this project? I have a similar question.


I did end up purchasing an RFID kit that was designed for a motorcycle and using a high quality automotive relay to do exactly as I described but it got a bit glitchy in a very short time. You needed to get really close to the reader for it to engage, almost touching it, which was fine though I was hoping for just "close proximity". It ended up needing the key waived several times as it took a few tries to get the ignition to turn on. I like fluid motions with one try that is consistent so I may have been hoping for too much. But for the money spent on the RFID kit I expected it to work this way. I ended up pulling the RFID kit out and installed a remote fob controlled system that was designed for 12v-120v systems, So I knew it would handle the 48v load without any problems. Now I'm using that remote fob that has an on/off button that works flawlessly to date and it is still pretty cool to start the cart this way. The remote system was cheap and is solid as well as taking only a few minutes to install. If your interested in knowing more about what I used, RFID or remote kit, let me know and I will give you more info on them.


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## Iceberg62 (11 mo ago)

I appreciate the response. I started a new thread as I’m trying to do a similar thing with what I’m assuming is probably the same wires key situation that you’re using. I was trying to add an extra layer though. I wanted to use the remoter to open the power to a switch that needs to be pushed. Kind of like the way you unlock a car then push the button. So you understand what I’m trying to accomplish. And that’s why I had the same question about the relay.

i started a new thread here:








Relay size and wiring help for golf cart project.


I'm hoping someone can help me work through this issue. I'm trying to replace my 48v golf cart key switch with a latching push button. The key switch basically connects the 48v battery pack to the solenoid. Can someone walk me through how that would work? Would I need a 48v relay? Can I trigger...




www.diychatroom.com


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## myz8a4re (May 5, 2020)

I'll make my way over to your other thread.


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