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so, a lot of people had suggested a wagner bp1210 h4 80/100watt bulb...and I was out online and ordered a 90w/100watt bulb instead...

well, looks like I blew a fuse...but, wondering if it was because of the bulb or the moron I am...I forgot to put the rubber cover (dust cover - I think it's called) back on the housing. Anyways, need to go run buy some 10amp fuses...i've heard fuses can blow cause wiring can touch housings/etc...thus, i really really need to put that dust cover back on after replacing the fuse!!! arrghhh!!!!

but is 90w 12v bulb too much for our 10amp fuses?? Service manual says not to replace with higher amp fuse...I was thinking of throwing a 15amp on there...but, might now just resign myself to go buy a 80w 12v bulb...

is the calculation someting like 80*12 = 9.6amp draw???

so, 90*12 = 10.8amp draw and overloads???

When i first installed it fired up no problem and I didn't see it blow out or anything like that...was riding today and noticed that light wasn't on...
 

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Running the 80w Wagner bulb and love it. Much better than the SilverStar bulb.

Watts=Volts*Amps for DC circuits, so Amps=Watts/Volts

A 90 watt bulb should not blow a 10 amp fuse unless some other lights are on the circuit or the circuit shorts out on something.
 

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I have been running the Wagner 80/100 also and even on high beam, there is no issue with blowing fuses.

100 watts / 12 volts = 8.3 amps

There are only 4 possible causes.
1 - bad fuse (sometimes they just go out)
2 - short in circuit
3 - you have other lights on the same circuit putting you over the max amps
4 - your battery/alternator are not keeping you at 12 volts

100 watts / 10 volts (low battery) = 10amps (pop!)
 

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I have been running the Wagner 80/100 also and even on high beam, there is no issue with blowing fuses.

100 watts / 12 volts = 8.3 amps

There are only 4 possible causes.
1 - bad fuse (sometimes they just go out)
2 - short in circuit
3 - you have other lights on the same circuit putting you over the max amps
4 - your battery/alternator are not keeping you at 12 volts

100 watts / 10 volts (low battery) = 10amps (pop!)
The amount of current a light bulb draws connected to a DC power source is dependent on the resistance of the device and the voltage applied, not the wattage stamped on the base of the bulb. The resistance of the device doesn't change so that if you apply 12 VDC to a bulb with a resistance of say 1.3 ohms then the current draw will be 9.23 amps. If the voltage is raised by 2 volts to 14 VDC then that same resistance will draw 10.76 amps. If there's a protection device, like a 10 amp fuse, built into the circuit then the chances are greater for that fuse to blow if the voltage is raised. This should not be confused with a motor where pure resistance plays a small part of the total current draw. There, counter EMF also acts as resistance to current flow. If the electric motor isn't, or can't spin, at the designed RPM because the voltage source is a little low then there's a higher rush of current thru the windings. Starter solenoid contacts tend to pit faster due to increased current too.
 

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Service manual says not to replace with higher amp fuse...I was thinking of throwing a 15amp on there...but, might now just resign myself to go buy a 80w 12v bulb...
Fuse have only one function, and that is to protect the wiring. I don't believe you'd really want a fire on your bike.
 

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Fuse have only one function, and that is to protect the wiring. I don't believe you'd really want a fire on your bike.
But (ironically), flames are COOL man! we all paint flame jobs on our gas tanks and get flame cut chrome grills and stuff, imagine going down the road with REAL flames shooting out how badass that would look!:D
 

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But (ironically), flames are COOL man! we all paint flame jobs on our gas tanks and get flame cut chrome grills and stuff, imagine going down the road with REAL flames shooting out how badass that would look!:D
Just remember that you have some personal body parts in very close proximity to that fuel tank that has that wiring bundle just below it.:eek:

Anyway, the only safe way to run more wattage is to use heavier wiring and relays.
 

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the Wagnar 80/100 and the 90/100 have the same hi end amperage, 100 watts. I've been running the Wagnar 80/100 for 2 years. Put the 90/100 in just to see if my bulb had dropped off. Looks about the same but I'll run it for a bit. You must have other problems or draw on the circuit.
 

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The amount of current a light bulb draws connected to a DC power source is dependent on the resistance of the device and the voltage applied, not the wattage stamped on the base of the bulb. The resistance of the device doesn't change so that if you apply 12 VDC to a bulb with a resistance of say 1.3 ohms then the current draw will be 9.23 amps. If the voltage is raised by 2 volts to 14 VDC then that same resistance will draw 10.76 amps. If there's a protection device, like a 10 amp fuse, built into the circuit then the chances are greater for that fuse to blow if the voltage is raised. This should not be confused with a motor where pure resistance plays a small part of the total current draw. There, counter EMF also acts as resistance to current flow. If the electric motor isn't, or can't spin, at the designed RPM because the voltage source is a little low then there's a higher rush of current thru the windings. Starter solenoid contacts tend to pit faster due to increased current too.
First, I admit that I am a mechanical en-guh-neer, not electrical. But I found the electrical calculator at the website below. I do not know what ohms rating is actually listed on the bulb in question per my bike is at home and I'm at work. But this calcuator seems to show that voltage, current, resistance and power all have set direct relationships. So therefore, if you have a 100 watt bulb and a 12 volt supply, you will get 8.3 amps and 1.44 ohms. If you change the ohms, the watts change too. I don't see how you could have a 12v supply, a 100 watt bulb and a 1.3 ohms resistance. Please feel free to bring this poor ape into the light if I my logic is not correct.

electical calculator
 

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First, I admit that I am a mechanical en-guh-neer, not electrical. But I found the electrical calculator at the website below. I do not know what ohms rating is actually listed on the bulb in question per my bike is at home and I'm at work. But this calcuator seems to show that voltage, current, resistance and power all have set direct relationships. So therefore, if you have a 100 watt bulb and a 12 volt supply, you will get 8.3 amps and 1.44 ohms. If you change the ohms, the watts change too. I don't see how you could have a 12v supply, a 100 watt bulb and a 1.3 ohms resistance. Please feel free to bring this poor ape into the light if I my logic is not correct.

electical calculator
Sorry Jeep if my post was confusing. I wasn't considering a fixed wattage when I wrote it, only an example how increasing the voltage (pressure) actually causes the pure resistance device to flow more amperage.
 

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Sorry Jeep if my post was confusing. I wasn't considering a fixed wattage when I wrote it, only an example how increasing the voltage (pressure) actually causes the pure resistance device to flow more amperage.
Oh! Thank God. For a while there, I thought all that time I spent in College Algebra and Basic Electronics was wasted.
 

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Discussion Starter #12
Fuse have only one function, and that is to protect the wiring. I don't believe you'd really want a fire on your bike.
So, i replaced the fuse with spare 10amp (as is originally in there)...and it's now working great, because:

I put the rubber cover back on the wire connector this time! The cover i'm talking about is in the headlight unit. I had originally replaced the bulb and forgot to put the rubber boot back on and it was causing metallic touch/shocks...what a moron!

Thanks for quick responses all and light bulb is awesome!!! easy upgrade and something i highly recommend. :)
 
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