24v to 12v Using Relay

Im wanting to add 2 LED round lights to the back of my deuce bed where the original reflectors are. 24v lights are 40 bucks each and 12v lights are 10 each. I am wanting to use a relay to drop the voltage and I might be totally wrong here but thats why Im asking!

Using this drawing ( but with a 24v relay ) Get 12v from one of my batteries to batt side of relay. Use 24v from the original tail lights to pull in the coil and that should give me 12v out to the light? I already have a box of old relays I could use or I wouldnt even think about this. If I do it this way I would need 3 relays, 1 for both brakes and 1 each side turn correct? Or will 12v even pull in a 24v coil?

Yes that will work.
Remember to fuse the wire coming from the battery.

You could get a pair of 12v lights for each side and wire them in series so you could run them off 24 volts directly.

I got a 24 to 12 volt inverter on E bay for $20 its a 30 amp works great!

How are you wanting to use these lights? Back-up? Night utility lights? Wire them in series (Suprman's idea) or use a convertor (Tigger's idea). Either way is correct.

Thanks! Wanting to use them for stop/turn/tail, just a simple 4" round to flush mount on the bottom of the bed. May just end up getting the 24v lights to keep it simple lol. I have 3 LED light bars for the truck to install as well but they are 9-30v input.

It is a bad idea to tap off of one battery for 12v when they are charged in series.

You will end up will a dead battery or both(the other one will overcharge)/

Search "center tap" for much discussion on drawing off one battery

1985mustanggt50 said:

Thanks! Wanting to use them for stop/turn/tail, just a simple 4" round to flush mount on the bottom of the bed. May just end up getting the 24v lights to keep it simple lol...

Click to expand...

I was kind of lost on your use for the lights...gotcha now. Get the 24 Volt units and keep it simple, best idea yet.

If you plan on using them as STT lamps then you won't be able to put them in series since each lamp will be powered from a different source. Use the KISS principle and get a couple of 24v lamps. That way you don't have to worry about dropping the voltage and you can wire them directly to the existing lamps.