Talk To Me About Fuse Blocks And Relays

I've admitted it several times before, I am ignorant about many things, Electricity being at the top of the list. In the past, I had multiple things running straight to the battery for power. This time I told myself that I would do it right. So I started looking into fuse blocks. This is where the problem begins. It's not that I am having trouble finding them online, I am finding too much and I am going into information overload. I don't get what a relay is and why it is necessary or why it isn't part of the fuse block. It's like explaining hard disk partitioning to someone who doesn't understand bit sizes much less file allocation tables.

So my question to you people that are far more experienced than I is this; What should I get? I do not need much. I know my requirements. I will have minimal accessories in the beginning, but I want room to grow a little bit. Here is what I plan on using:
(I only want power to accessories when the bike is running. )
- Cell phone - I will only be using it for music and GPS. I want to have it on a ball mount on the steering stem.
- 12 volt power outlet - just for versatility.

In the future, I would like to add the following:
- Heated grips or maybe heated jacket/gear.
- Dedicated GPS

So it appears at the minimum I will need 4 powered lines. For a fuse block, I am wanting the simplest installation and usage. Try to image Lennie from Of Mice & Men hooking this thing up. Wire(s) to the battery, secure under the seat, then wire to the accessories.

The ones that I have looked at but seem to be either overkill or overly complicated. PDM60 for example. My friend (scguy) bought the PDM60 and appears to have had nothing but trouble with it. Even if it was a perfect solution, it is pretty expensive and requires Windows to program it. I know I will not need that level of control over it. Then there is the "roll your own" Eastern Beaver setups. This looks like the route that mello dude would go. But the installation makes me uncomfortable.

So what do you guys recommend?

 

http://www.fuzeblocks.com/

 

very good product, I have installed 3 of these units

 

First up I'm not an electrician or engineer, but here is my take on moto-electricity. What is a relay and why would you want one? And what size fuse is appropriate?

A relay is a remotely activated magnetic switch that can potentially handle bigger currents than the switchgear on the handlebars or the wire in the loom. A relay is triggered by the lesser circuit and that drives a magnet to close the main circuit for your higher current draw needs. When triggering power is removed, a spring opens the main circuit. You will usually hear a relay"click" when the triggering power is applied/removed, that is the main circuit closing/opening.

As an example of this, the dual headlights on the VFR are controlled by a relay so that the full headlight current does not have to pass through the handlebar switch. That means lighter gauge wires can be used to the handlebars. The starter solenoid (basically a heavy duty relay) is another example of this.

A relay typically has four connections, two for the triggering power, and then an in and out for the main power, plus sometimes a common ground.



I used a relay to power my heated grips and voltmeter so that I can connect both of these directly to the battery, but only have them "live" when the ignition is switched on. For triggering power I use a connection from the live wire feed for the tail lights (which are always on when the ignition is switched on) to one trigger connection on the relay, and then back from the other trigger connection to a ground. When the ignition is turned on, the relay closes the main circuit. For the main circuit I took power from the positive battery terminal through a fuse to one of the relay main terminals, then from the other terminal to the heated grip positive input, then back from the heated grip negative terminal directly to the negative terminal on the battery.

For fuse size, you need to work out what the "normal" current would be. So for example if you had two 60W headlights bulbs on a common 12v circuit, these would draw 120 / 12 = 10 amps. For that application a 15A fuse would be suitable to use (50% more than the normal current).

 

My way.

Cut wire going to power to circuit horn and used it to activate relay to power accessory fuse block that is wired direct to battery with fuse. Wired new horns to new fuse block.

Now turning on key powers up fuse block and makes horns alive on push of conventional horn button. Heavy duty wire to battery prevents frying block for accessories.

Fuse block is mounted under seat next to battery.

Works for me.

Larry

 

Damn... that was one helluva a reply. Thank you for the detailed answer. I'm going to read that over and over until it sinks in.