LED lights/head/tail lights/running lights DIY kit

[Sergio]

Originally Posted by hawgsalot

Why use a relay if you're coming off the key side to power on the Voltage reducer?

That way the relay contacts and not the key switch is what turns the converter ON/OFF.

There is a large spark created when you turn the converter ON as it immediately chargers its capacitors, the key switch is not designed for the task, You need a fast acting switch like a relay to take the load.

The relay coil only uses about 0.02 amps so it is a lot easier on the key switch.

In your case the diode on the relay coil is not critical (but always recommended) since you are using a mechanical switch to turn the relay on/off.

The relay contacts power the converter directly from the pack and not from the key switch power.

[hotwls13]

Originally Posted by Sergio

That way the relay contacts and not the key switch is what turns the converter ON/OFF.

There is a large spark created when you turn the converter ON as it immediately chargers its capacitors, the key switch is not designed for the task, You need a fast acting switch like a relay to take the load.

The relay coil only uses about 0.02 amps so it is a lot easier on the key switch.

In your case the diode on the relay coil is not critical (but always recommended) since you are using a mechanical switch to turn the relay on/off.

The relay contacts power the converter directly from the pack and not from the key switch power.

Sergio, thoughts on my diagram on post #11?

Can I just use the separate 48v toggle switch to turn the reducer on/off without a relay?

Then run my 12v connections up to a separate 12v toggle switch in the dash to control lights? With a couple in-line fuses along the way?

[Sergio]

You can do it the way you have drawn, the relay is mainly to ensure that everything is turned OFF when the cart is OFF.

[yawood]

Once you get your reducer installed, another accessory that is very useful is a couple of USB ports and maybe a 12V socket (aka cigarette lighter socket). This allows you to charge your phone or run a small inverter etc. The photo shows where I have mounted mine on my Precedent.

[hotwls13]

Alright, just so I'm not rewiring later, I ordered a small 6-fuse fuse box with a negative bus.

Plan to mount it on the drivers side glovebox area (on wall left of dash). I have a small dry-box I may put it in (just to keep everything clean and prevent from coming in contact with).

[hotwls13]

Hope this drawing makes sense. I suck at these diagrams.

Fuse and wire size suggestions would appreciated. I have plenty of 14ga and smaller wire. The inline fuses I purchased use 12ga wire.

Thanks

[Fairtax4me]

Are you using a DPDT switch?
If that's a single pole switch, The way you have it drawn the switch does nothing.
You can put the switch on either positive, or negative side of the reducer.
But having both positive and negative spliced together at the switch makes the switch useless.

It's actually a dead short across the switch if you hook it up the way its drawn. As soon as you flip that switch it's gonna turn into a smoke show.

[hotwls13]

Originally Posted by Fairtax4me

Are you using a DPDT switch?
If that's a single pole switch, The way you have it drawn the switch does nothing.
You can put the switch on either positive, or negative side of the reducer.
But having both positive and negative spliced together at the switch makes the switch useless.

It's actually a dead short across the switch if you hook it up the way its drawn. As soon as you flip that switch it's gonna turn into a smoke show.

Haha!! der! That's why I'm not an electrician. Also, why I ask a ton of questions. Makes perfect sense now that you pointed it out.

So, just wire the switch on the hot+ side to complete the circuit? correct?

And wire guage/fuse size recommendations?

[Fairtax4me]

That's better.
Wire size on the 48v side I would use no smaller than 18ga. 14 will work for everything if that's what you have.
Fuse I'd go for 15amp. Probably wouldn't go above 20 since that's probably the rating for your fuse holder.
With lights on and a USB charger, you'll probably only be pulling 5amps on the 48v side.

[yawood]

Originally Posted by hotwls13

Hope this drawing makes sense. I suck at these diagrams.

Fuse and wire size suggestions would appreciated. I have plenty of 14ga and smaller wire. The inline fuses I purchased use 12ga wire.

Thanks

I thought you were going to use a relay? Just follow my diagram that I posted earlier. That also shows you which wires get connected to which poles of the relay so that you don't get them mixed up. There were two diagrams, one with an additional switch for the reducer (via the relay) and another without the additional switch so that the relay is operated just by the key switch.

It's good that you have a fused box and -ve buss. The +12V from the reducer goes to the common positive of your box. The -12V from the reducer goes to the common -ve of your negative buss. For each accessory, the positive will go from one of the fused terminals and the negative will go from one of the terminals on the buss. Here's a picture of the one I use.

As for the wire gauges, just remember that watts = volts x amps. So if you have a reducer that will output 20A at 12V it is a 240Watt reducer (12 x 20). This means that on the 48V side you will have 240W = 48V x ??amps. The amperage will be 240/48 = 5A (5 x 48 = 240). So the 48V wires will carry a max of 5A and the 12V wires will carry a max of 20A. You should always increase these for safety, say 25A on the 12V side and 10A on the 48V side.

Using the DC Wire Selection chart that I posted earlier (thanks to Sergio) that shows that you need 16AWG for 10 A and 12AWG for 25A. For the fuse, I agree with FairTax4Me and would go with a 15A fuse. The max it should carry is 10A so a 15A fuse will allow it to carry its max but will still give you plenty of protection in case of a short before any wires start melting (which is what a fuse is all about).