A HID question for the electrically savvy.

brassmonkey001

I should change this
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and this as well...
Now then, if one was to fit HID lamps to ones bike (one for dip and one for main) it seems usual to fit two ballast boxes. Would it not be possible to just use one ballast and connect the dip/main switch between the ballast and the lamp thus saving a bit of space and weight?
 
Good question!!

If I said that the starting voltage for a hot HID bulb was about 20,000 volts, you'd understand why switchgear designed for 12v might not work long, and may not stop the errant voltage from reaching parts it shouldn't eg your fingers!)

Greg
 
brassmonkey001 said:
Fair enough, but the wires from the ballast to the igniter are only very thin. How come they don't melt?

For the same reason that National Grid power transmission lines don't melt.

What makes cables hot is current - the amperage passing through the wire/fuse/bulb filament. But if you double the voltage, the amperage halves for the same energy flow.

In fact HID bulbs normally run at around 100v, but they need a big voltage jolt to start them. But even only 100v means that the current is only around ½ an amp. A normal headlamp bulb is about 4½ amps.

But high voltages require good insulation, hence the reason the switches will be no good.

Greg
 
So the wire is actually at a cooler temperature than a conventional headlamp during normal running, but it's a fancy wire that can cope with a much larger temperature for a second while the bulb fires up?
 
There are normally two sets of wires for the HID bulb (aren't there?) - one to 'fire' it, and one to run it. Am I talking bollox again?
 
littleredrooster said:
There are normally two sets of wires for the HID bulb (aren't there?) - one to 'fire' it, and one to run it. Am I talking bollox again?

I've an HID spotlight - it has the one cable feed to the bulb, but it's the thickness of your finger.
 
Steptoe said:
I've an HID spotlight - it has the one cable feed to the bulb, but it's the thickness of your finger.

Does it have radar tracking, or do you have to spot the planes yourself?
 
The Pilot kit that i got for the bike has two pairs of wires 1) normal that plugs into the normal light plug and goes to the Ballast, 2) the pre-installed cable from the Ballsat to the new bulby thing. The normal 12v from the switch turns on the ballast, when it fires you can hear the crack.

Lyn.
 
The examples I have have three wires between the ballast and the igniter, one of which is an earth and they are 1mm or possibly 1.5mm thick. The two wires from the loom connector to the ballast are thicker, perhaps 2 or 3mm. Both the thick and thin wires run through metal sleeves about 25mm long which I assume is some sort of heat sink to prevent the connector blocks melting.
 
brassmonkey001 said:
How hot does the lamp get in normal use? Is it hotter than a halogen lamp or cooler or much the same?

I've never felt my lamp to see how hot it gets ? :confused:
 
brassmonkey001 said:
How hot does the lamp get in normal use? Is it hotter than a halogen lamp or cooler or much the same?

I have fitted HID to my dip on an 1150 adv, the HID bulb is rated at 30 W
which is just over half the normal Halogen 50 W, so it should run cooler........Greg, please jump in if not correct.

Your earlier question regarding using 1 HID unit to power both lamps.

When changing to main beam the dip beam stays on as well so would have to power 2 lamps, not one.

:beer:
 


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