Blowing fuses on added circuit ?

[whitestroke]

The PO installed these auxillery running lights(see link).  They were tapped in to the Blue headlight wire in the headlight bucket.  The 10amp. headlight fuse blew.  I looked up this problem and saw in shoptalk I needed to add a new headlight circuit with relay, or risk burning up the starter switch.  
I added the new circuit and have the auxillery running lights and headlight on this new circuit.  The new circuit has a 15amp. fuse and it has blown twice.
Do I increase fuse to 20amps. ?
Are H.F. fuses p.o.s. ?
I'm not sure what size fuse to run.

http://www.cruisercustomizing.com/kuryakyn-small-halogen-silver-bullets-w-38-in-16-hollow-mounting-bolt-pair-clear-lens/part/KY-2305

[Michvalk]

First thing I would do , is go over the wiring to make double sure there are no pinched wires, or cuts in the wiring. Did you use a wiring diagram from the board to follow? Make sure you have all the wiring correct. I am not sure of the requirements for fuze size for those lights. Maybe someone familiar with these lights will chime in, but, I would think 15 amps would run them. That's why I suggest going over the install again, just to make sure. 

[whitestroke]

P.S.
Fuse hasn't blown the last 2 days of riding. ...

[Blackduck]

Depends on what wattage the lights are. Watts divided by voltage will give you amperage.
IE, 100 watts divided by 12 volts = 8.33 amps  ( 100 W / 13.5 V= 7.41V)
Added another amp to the total to allow for any loss in wiring etc and you will have the minimum fuse size required.
So if your lights are 100 W you would need around a 20 amp fuse (2 x 100= 17.66 amps plus 1 = 18.6 Amps minimum)
Remember you need a good earth/ground return as this can cause the same sort of problems.
Personally for driving lights I run a ground wire back to the battery
Cheers Steve

[Gryphon Rider]

60W headlight 20Wx2 Aux lights = 100W
100W / 12V = 8.3A
8.3A x 1.2 = 10A fuse

If you're repeatedly blowing 15A fuses, something is wrong.

[whitestroke]

If the headlight is 60/55w is that 60+55 with highbeam on.   

[Gryphon Rider]

On a dual filament headlight bulb, only one filament is supposed to be hot at a time.  Because dimmer switches are make-before-break, it is possible to hold the switch in a position between high and low and have both filaments lit, but I'm sure that isn't good for the life of the bulb.

[whitestroke]

On a dual filament headlight bulb, only one filament is supposed to be hot at a time.  Because dimmer switches are make-before-break, it is possible to hold the switch in a position between high and low and have both filaments lit, but I'm sure that isn't good for the life of the bulb.

OR THE FUSE

[whitestroke]

The only ground wire I ran was from the relay to the Headlight bucket ground screw.
Is this enough?
There is the original ground wire also.