Aux power box & relay advice needed

[STFlips]

So I wanted to neaten up the accessory wiring on STella and bought an Eastern Beaver fuse box. I should have made a better plan into what I was trying to do as now I'm looking at the wiring diagram, that's a bit of a horror show following that baby! Too many coloured lines, should have broken it up on several pages, but I digress. And now I realize I did not order enough materials for the job, specifically a relay for the switched inputs, spade connectors and some damn wire too! I"m thinking a 40 amp automotive relay and some 10ga wire from the local CT store will do it as I don't want to wait another 8 weeks for EB and Canada Post to deliver.
Any comments or best location advice? I see some mount the box in the tail, put the relay in there too? Thanks guys, I value your opinions.

 

[Andrew Shadow]

Without knowing what capacity fuse box you purchased, just make sure that the relay and the wiring to it from the battery and from it to the fuse box, exceeds the rated capacity of the fuse box. Install an in-line fuse between the battery and the relay, as close to the battery as possible, of a capacity that does not exceed the rated capacity of the wire that you are using.

In the tail is the best place as it will stay dry and is easy to access if you need to do so. I mounted my relay close to the battery because it was a pre-made harness and that is where the length of wire would allow. It doesn't really matter where the relay is- wherever you feel is most convenient. Regardless of where you put it, keep the in-line fuse as close to the battery as possible to protect the wiring.

 

[Andrew Shadow]

By the way- @GGely is just down the road from you. In the chance that you aren't aware, he makes motorcycle wiring harnesses as a business. If you need any help, he will be able to get you sorted with parts and making up any harness that you might need to get the job done.

 

[SMSW]

Go to the Eastern Beaver website > PC8 & 50 amp relay kits. You will see a picture of what you need. You can follow the colors of the wire - left side of the picture shows the 3 leads to the PC8, one of the reds is switched by the relay, one red is hot all the time, and the black is negative/ground. The hot all the time red powers two fuses in the PC8, the relay is triggered by something like a running light (on whenever the ignition is on) and gives you your 6 switched fuses in the box. GGely can make up what you need.

 

[STFlips]

Thanks all, I forgot about GGely, I'll contact him

 

[rjs987]

Personally I think 10ga wire is too big for what you want. Much harder to work with also. Maybe 12ga for the primary power TO the fuse block and all grounds, then 16ga or 18ga for accessories. This isn't house wiring so the same specs don't apply exactly. LED lights don't need more than 18ga. Be sure to use stranded wire.

Any discount auto parts store will have a multitude of colors to choose from. I usually get a spool of every color and go from there. They also have better spade connectors (quick disconnects) and a much bigger variety than Walmart. I keep a bin on a shelf in my garage cabinet with wire spools, spade connectors, and other wire supplies.

I came across this chart a long time ago and it agrees with everything I've read from reliable sources for automotive wiring (same applies to motorcycle wiring). Remember that length of run is the total round trip distance from the battery pos terminal -> accessory -> ground. The main supply wires to the fuse block must be sized for total amps. Each accessory circuit only needs to be sized for the amps used by that accessory. I use 12ga to my Eastern Beaver fuse block, 14 ga for my Stebel air horn (needs 20 amp fuse), and 18ga for my heated gear (no more than 3 amps if even close to that) and LED light bar (likely no more than 1.5 amp at most). Distances on a bike are really not all that far. Slightly more than the length of the bike for the longest run since your battery is nearly in the center... unless you have a single run that goes to the front, then all the way to the rear and then back. Never had issues with following this chart even on my Gold Wing that had a massive load of incandescent lighting all over the rear end and sides.

 

[STFlips]

Good chart, thanks I'll print that & stick it in the manual

 

[Larry Fine]

I would NOT go by that chart. It only addresses voltage drop, but current requires cross-sectional area of conductor, regardless of how short it is. A 30 amp load requires 10 gauge wire at any voltage.

Follow the 20' column at least; the 25' column is even better. 30 amps will overheat 18 gauge wire even if it's only 3 inches long. Overheating wire damages the insulation and leads to electrical fires.

Voltage drop is dependent on only two things: load current and wire resistance; the circuit voltage is irrelevant. However, a given voltage drop at 12 volts is ten times as detrimental as it is at 120 volts.

You first size a wire to suit the load, and then choose a fuse to protect that wire.

 

[STFlips]

OK scrap the chart & go with the load, got it. The Beaver has 50amp rated relay to use with it, but as so far I will only connect a GPS and USB port, and use an unswitched contact for trickle charger, was thinking a 40 Amp rated auto relay, fuse the supply at 30 amp with 12 ga wire. If in the future I need more A's then I could upgrade supply side accordingly.

 

[SMSW]

OK scrap the chart & go with the load, got it.

Lets see if I can post another chart. @Larry Fine is right about loads. And go heavier with the wire - should you add a high load accessory later, you will need the capacity. A 30 amp fuse gets #10 wire. A 40 gets #8. What kind of high load accessory? Heated clothing, maybe coupled with heated grips.
Here goes...As he said, Eureka! Btw, brown is #6awg. The two colums at left are for voltage drop, a 10% drop and a 3%drop.

 

[GGely]

Thanks all, I forgot about GGely, I'll contact him

Sniff... no, don’t worry about me, I’ll be alright. I’ll be back, I have to go to my self esteem class..

By the way- @GGely is just down the road from you. In the chance that you aren't aware, he makes motorcycle wiring harnesses as a business. If you need any help, he will be able to get you sorted with parts and making up any harness that you might need to get the job done.

Thanks Andrew!

 

[Sunday Rider]

I have the Eastern Beaver Centech 2 aux fuse box located under the headlight. I used Velcro so I can quickly pull it down if needed. I have the GPS on always hot slot. I also run aux lights, aux fuel pump and horn from there. The aux fuse box harness provided by Eastern Beaver is hooked to battery with relay and trigger wire from aux outlet at main fuse box. I’ve run this set up for a few years now.

 

[st11ray]

I have the Eastern Beaver Centech 2 aux fuse box located under the headlight. I used Velcro so I can quickly pull it down if needed. I have the GPS on always hot slot. I also run aux lights, aux fuel pump and horn from there. The aux fuse box harness provided by Eastern Beaver is hooked to battery with relay and trigger wire from aux outlet at main fuse box. I’ve run this set up for a few years now.

I don't believe easternbeaver makes the Centech? He makes a wiring harness and relay for the Centech but his fuse box is the PC8.

 

[Sunday Rider]

I don't believe easternbeaver makes the Centech? He makes a wiring harness and relay for the Centech but his fuse box is the PC8.

You are right, the Centech 2 was provided as part of his package way back when I purchased it from him. His wiring harness fit perfectly. I guess that was expected since he used to own an ST1100.