Something to consider...
I have been asking a similar question. Helmet or bar, best battery life for the wattage, etc. Price is also a considerable concern as I am gearing up in several areas at one time. I came to the conclusion that LED lighting offered the best wattage to battery life for my needs. HID is off the table for my budget, especially when you consider I will need several backup batteries. I like the cateye, but price for multiple backup batts is out of range, and there is no low setting on the tripple shot to get extra life. Double and tripple shot together is our of my budget. I found a smaller LED that I will be testing in early Jan. Basically it is the Cygolite Hi-Flux 100, or rather two of them. This kit consist of a LED single beam run by four C sized batteries. It comes with the bar mount standard, and I will have to pick up the helmet mount from Cygolite direct for about $25. On 4x C off the shelf alkalines, it is supposed to run 25hrs high, and something rediculous on low which will likely only be used in trailside repairs. Their comparisons are supposedly the equivelent of 2w/10w Lo/High. Having tested one light (hi-flux 200) against a bar mounted 10w, it was whiter overall, brighter in the center, with a reduction at the sides in comparison. Subsequent testing with the clip on fresnel lense (supposed to widen the beam) yielded something more consistant with the 10w halogen in terms of coverage and brightness. SO, I guess their claims that the light is the equivilent to a 10w halogen are close enough to say they are correct. Now the plan is to run one system on the bar with the "wide" lense, and a second on the helmet in "spot" pattern. Again, the testing will commence soon, with a brief post to follow. For now this is how I came to that possible solution...
Need:
12+ hours of continuous light output, no charging time available.
Provides:
Claimed 25 hours on 4 alkaline cells on high.
Need:
Reasonable kit that is price as price conscious as possible.
Provedes:
2x hi-flux 100 kits @ $60ea through Bluesky Cycling $120
1x helmet mount kit $25
1x bar mount adaptor (special requirements due to assinine dual control setup) $25
Batteries @ 2x 4 per light plus 4 as backup (12 total). Ni-cad $30
Wall charger so that I am not filling the landfill w/ dead cells $25
Total $225
Need:
Race requirements of backup lighting w/ you at all times
Provides:
Two systems used at same time, redundancy built in as one can get you home.
Other benefits:
Helmet mount for technical courses, looking around corners, down steeps, etc.
Helmet mount for trailside repair.
Bar mount for showing terrain detail and general illumination.
Off the shelf batteries or rechargible batts work in this system.
No winter battery conditioning, buying additional backup batts
Keeps water bottle cage free.
Origional bar mounts can be used for SS, and road bike...no switching required.
If this system proves adequate in testing, or inadequate, I will post it here. Opinions welcomed, but remember the constraints that I am operating under when you post that nothing buy a 13w HID on both bar and helmet will do...