Ok, thanks
Scott
Fuse Values on a Vintage Speedster.
Al of the fuses are 15 amp except #2 wghich is a 20 amp fuse.
#2 is counting the fuses from left to right.
Also--I installed my fog lights with a 15 amp fuse but am thinking a 20 might be better? If anyone knows. (They seem to work ok with the 15 amp that I used.)
Thanks --Jack
You raise one that I have been putting off. I have a wiring rig and relay but need to tap into the fuse box or a bigger fuse box if I redo it. What is your feeling on tapping into the existing Vintage fuse box instead of wiring in a newer bigger one? The lights have their own "20A" fuse in line.
Fred Adler
San Diego
Fred Adler
San Diego
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Jack-what is the make/model of your fog lights?
Scott
Scott
Jack:
If your fogs are working OK with a 15 ampere fuse in there, why go to something heavier rated? If you have trouble, all the higher rated fuse will do is cook something that you maybe didn't want to cook.
Assuming you have 50 watt bulbs in them, then combined they'll be pulling something like 8-ish amps. Heck, a 10-amp fuse would be what I would put in there!
So with a 15 amp fuse you should be clear for low-voltage excursions and all that happy stuff. If the bulbs are less wattage, even better. They would have to be over 90 watts per bulb to exceed a 15 amp fuse.
What'cha gotta do is look at everything on any particular circuit and total up the wattage (or amperage) of everything on there. If it's in watts, then divide the watts by 12.5 (volts) to get amperes. If it's in amperes, multiply the amps by 12.5 to get watts. Once you have totaled everything on the circuit, then run a fuse that's rated approximately 10% more than the expected load.
So, for your two fog lights and assuming they have 50 watt bulbs, the equation is: (50+50)/12.5= 8amps 8*1.1= 8.8 or 9amps so round up to a 10 amp fuse.
You could do this for the other locations, too: 15 amp fuses across the board on a Speedster sounds convenient, but some of them are overkill and could be decreased. decreasing their rating may mean that they'll pop sooner, but they'll also provide more protection for whatever they're supposed to protect.
gn
P.S. for you REAL Engineers out there: I know this is simplistic and makes the assumption of a constant 12.5 volts when reality says it varies from 11.6 to 13.6 and that might throw the fuse ratings off. To that I say: "THTTPD!!!!!"
http://acme.com/software/thttpd/bill.gif
If your fogs are working OK with a 15 ampere fuse in there, why go to something heavier rated? If you have trouble, all the higher rated fuse will do is cook something that you maybe didn't want to cook.
Assuming you have 50 watt bulbs in them, then combined they'll be pulling something like 8-ish amps. Heck, a 10-amp fuse would be what I would put in there!
So with a 15 amp fuse you should be clear for low-voltage excursions and all that happy stuff. If the bulbs are less wattage, even better. They would have to be over 90 watts per bulb to exceed a 15 amp fuse.
What'cha gotta do is look at everything on any particular circuit and total up the wattage (or amperage) of everything on there. If it's in watts, then divide the watts by 12.5 (volts) to get amperes. If it's in amperes, multiply the amps by 12.5 to get watts. Once you have totaled everything on the circuit, then run a fuse that's rated approximately 10% more than the expected load.
So, for your two fog lights and assuming they have 50 watt bulbs, the equation is: (50+50)/12.5= 8amps 8*1.1= 8.8 or 9amps so round up to a 10 amp fuse.
You could do this for the other locations, too: 15 amp fuses across the board on a Speedster sounds convenient, but some of them are overkill and could be decreased. decreasing their rating may mean that they'll pop sooner, but they'll also provide more protection for whatever they're supposed to protect.
gn
P.S. for you REAL Engineers out there: I know this is simplistic and makes the assumption of a constant 12.5 volts when reality says it varies from 11.6 to 13.6 and that might throw the fuse ratings off. To that I say: "THTTPD!!!!!"
http://acme.com/software/thttpd/bill.gif
Fred--I am the last guy to answer this for you. Gordon could but when it comes to Ohm's law I'm lost--sorry.---Jack
Scott--my new fog lights are Marchals./ They could be reproductions but if they are, they are very good ones. There is the genuine looking Marchal chrome logo on top and the glass has the big "m" molded in.
The chrome is very thick and well-done and the notes inside are in French so who knows. If I had to bet though, I'd say reproduction---same as my Speedster.
The lights are a perfect size in my opinion--not the huge ones I have seen but more in proportion to the small size of the Speedster.
I found mine on ebay for about $150.00
---Jack
The chrome is very thick and well-done and the notes inside are in French so who knows. If I had to bet though, I'd say reproduction---same as my Speedster.
The lights are a perfect size in my opinion--not the huge ones I have seen but more in proportion to the small size of the Speedster.
I found mine on ebay for about $150.00
---Jack
Those are the ones I have too and they are good looking. Ohm's law........oh boy. e to the x dy dx, e to the x dx, cosign secant tangent sign, 3.14159, slip stick, slide rule, BTU, hail Purdue. I started doing that stuff and they still taught tubes thanks to the Navy guys learning EE to fix old ships but hell if I remember. Anyway, the fuses may relate more to when the wire load is too much in these non magnetics and melt..........................lower fuses are safer and relays will keep you honest.
Fred Adler
San Diego
Fred Adler
San Diego
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Sorry, Fred...Didn't see your query up there.
Yes, you can tap off of the Vintage fuse panel - find a power lead that is either on all the time or goes off when the key is off - your preference. Pull a fuse here or there and choose a lead that still has power after the fuse is removed and connect there, rather than on the other side of the fuse (which is running other stuff already).
But since your lights are out front and you'll be running a relay for them, you could go right to the battery connector/clamp if it has a provision for an auxiliary connection (usually a 10 ga wire). Then just use an in-line fuse holder and a 10-15 amp fuse and you'll be good to go. I don't use fog light switches on the dash, preferring to simply drive them off of a low-beam connection somewhere and that's it. Whenever low beam is on, so are the fog lights. The signal wire (coming from the low beam connection) is fused by default, so all you need is one on the power lead to the relay for the fogs themselves.
Somewhere on here in the past was a nifty wiring diagram for fog lights, switch and all.....poke around and you'll find it.
No Ohm's law here......just watts, amps and volts. Easy stuff. Little sparks...
gn
Yes, you can tap off of the Vintage fuse panel - find a power lead that is either on all the time or goes off when the key is off - your preference. Pull a fuse here or there and choose a lead that still has power after the fuse is removed and connect there, rather than on the other side of the fuse (which is running other stuff already).
But since your lights are out front and you'll be running a relay for them, you could go right to the battery connector/clamp if it has a provision for an auxiliary connection (usually a 10 ga wire). Then just use an in-line fuse holder and a 10-15 amp fuse and you'll be good to go. I don't use fog light switches on the dash, preferring to simply drive them off of a low-beam connection somewhere and that's it. Whenever low beam is on, so are the fog lights. The signal wire (coming from the low beam connection) is fused by default, so all you need is one on the power lead to the relay for the fogs themselves.
Somewhere on here in the past was a nifty wiring diagram for fog lights, switch and all.....poke around and you'll find it.
No Ohm's law here......just watts, amps and volts. Easy stuff. Little sparks...
gn
You're the man Gordon. Nice and easy. I love it.
Fred Adler
San Diego
Fred Adler
San Diego
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Now Gordon, don't let folks get all confused about Ohm's law being complicated. It's just E=IR. Volts (E = electromotive force) is equal to current (I = I can't rememeber what, but it's in amps) times resistance (in ohms). You can flip it around a bunch of different ways such as I = E/R, etc. Easy peasy.
Yeah, I know all that stuff. On the one and only project where I had a SERIOUS power budget not to exceed, I used "Rhonnie's Law" instead.
What's "Rhonnie Law", you might ask?
Back in 1977, Rhonda (Rhonnie) was a very bright college intern from Cornell who was helping out on our project, an airborne package that did air sampling (Global Atmospheric Sampling Program, or GASP) that we placed in 50 airliners around the World. Rhonnie's job was to make sure we didn't exceed the power budget in our package, so we'd come up with something and yell over to Rhonnie, "Hey! I'm runnin' 3.7 amps in my centrifugal gas analyzer on circuit CL-43. What'cha think?"
"Nope!", Rhonnie would say. Cut it back to 3.57 or you're toast!"
Rhonnie's Law. It was absolute. She was cute.
Now I'm more like; "Who gives a Rat's Pitouti? Run a bigger wire!"
What's "Rhonnie Law", you might ask?
Back in 1977, Rhonda (Rhonnie) was a very bright college intern from Cornell who was helping out on our project, an airborne package that did air sampling (Global Atmospheric Sampling Program, or GASP) that we placed in 50 airliners around the World. Rhonnie's job was to make sure we didn't exceed the power budget in our package, so we'd come up with something and yell over to Rhonnie, "Hey! I'm runnin' 3.7 amps in my centrifugal gas analyzer on circuit CL-43. What'cha think?"
"Nope!", Rhonnie would say. Cut it back to 3.57 or you're toast!"
Rhonnie's Law. It was absolute. She was cute.
Now I'm more like; "Who gives a Rat's Pitouti? Run a bigger wire!"