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HID Lamp Without Auxiliary 12V Battery
Submitted by Mik on Tue, 07/21/2009 - 02:38
Here is a compilation of several posts about the Vectux HID light:
I bought a set of 2 HID lamps and ballasts for cars, because they contained the same kind of parts as this motorbike kit: MOTORBIKE 12V H4 H/L BIXENON HID KIT 35W 6000K . The content of this ebay link might of course change - be careful.
The seller sold me a motorbike HID harness separately for another AU$25.-
That cost not that much more than the motorbike kit and I got a spare ballast and spare globe that way!
I could rig up another motorbike harness, it should be easy because I know what the original harness looks like.
See: http://visforvoltage.org/forum/3747-vectux-part-3-vectrix-retampi#comment-23081 for the original posting.
This HID lamp is the type which uses an electro-magnet to move the plasma arc into a slightly different position when "High Beam" is turned on.
(There seem to be other types that have a 35W Halogen globe for low beam; those only turn on the HID lamp when High beam is switched on).
On the bench it turns out that the HID lamp consumes 3.6A continuously at 12V on low beam, and 4.5A continuously at 12V on high beam.
The maximum amperage at startup which I have seen was 8.8A, but most of the time it seems to be around 7A.
This current then rapidly reduces (over about 7 sec) to 5.8A, and then continues to fall more slowly until the stable 3.6A or 4.5A are reached.
5.8A is the theoretical current draw of the Vectux headlights when both high and low beam are on at the same time. The stock electronics permit this current draw while the scooter is rolling, but not during standing still. The "steady state" current draw of the HID lamp is therefore less than the maximum allowable continuous current draw.
The potential problems are:
- the higher than usual current at startup might confuse the electronics and cause error messages and/or malfunctions.
- the light might be blinding to other road users.
- the current of 4.6A continuous on high beam might cause more heat than the plastic lamp housing can tolerate without being cooled by wind. The original Vectux electronics will turn off the low beam if both beams are activated and if the scooter stops moving for more than a few seconds; it so prevents this problem.
In other words, the lamp housing might melt.
The current draw for just one "Halogen filament" should be about 35W/12V = 2.9A.
I have not measured it.
The continuous current draw of the HID lamp on low beam is therefore 20% higher than what the Vectux electronics allow during standstill. I believe that about 10% of this HID current is used in the "ballast", producing heat there, and that low beam HID would therefore not cause the plastic lens to melt.
I am not so sure if the current on HID high beam will be safe for the plastic parts, though. This current is 65% higher than the 2.9A usually permitted.
If 10% of that gets used (and turned into heat) in the ballast, then that might mean a 39% increase of heat output inside the reflector lamp housing.
The 0.9A difference between high and low beam is probably what the electromagnet uses, and I do not yet understand if that gets turned into heat or not.
How much these heat output values are reduced by the increased luminous efficiency/efficacy/whateveracy is too hard to calculate (for me, anyways) and might be better addressed by real world testing with a thermometer, comparing the temperature with a HID lamp and with the original Halogen lamp whilst standing still for prolonged periods.
The likely disaster scenario:
You plug in your scooter to recharge at home in the garage, and find much later that you had left the key in the "ON" position and your headlamp has melted.....
(During charging the light is off, but once charging has finished the lamp comes on if the key is in the "ON" position.)
Here is a video of the reduction in current draw during startup:
I think these sentences in Wikipedia explain what happens there:
"This tube is filled with both gas and metal salts. The gas facilitates the arc's initial strike. Once the arc is started, it heats and evaporates the metal salts forming a plasma, which greatly increases the intensity of light produced by the arc and reduces its power consumption."
See http://visforvoltage.org/forum/3747-vectux-part-3-vectrix-retampi#comment-22934 for the original posting.
The HID lamp works in the Vectux, but the lamp telltale keeps blinking.
Temperature measurement of the front of the headlamp with IR thermometer:
Temperature maximum in 19.5°C ambient temperature after about 30min standing still with OEM low beam on in garage: 47°C. About 40°C just after OEM light was turned off.
Temperature maximum in 17.5°C ambient temperature after 20min with HID on Low beam: 55°C; On High beam: 58°C.
The risk of heat damage to the lamp is therefore quite real - particularly in summer.
The beam of the HID lamp was way too high, but can be adjusted by screwing the 4mm hex pins at the back of the lamp housing in or out.
The light is much brighter than the OEM 35W lamp, even if used with both filaments on together.
Below is a video of three test drives on a private property, first with the OEM globe, then with unadjusted HID lamp and finally with height adjusted OEM lamp.
The camera is not really up to recording the dim reflection of a single headlight, but the stark difference can be seen quite well nevertheless:
See: http://visforvoltage.org/forum/3747-vectux-part-3-vectrix-retampi#comment-22989 for the original post.