Came across this when looking for something else:
http://www.lupine.de/web/en/products/lightheads/betty/ Now then, aside from the fact that this is called Betty (there's also a Wilma!), the spec is pretty impressive: it's a 7 LED unit that produces a staggering 1,500 lumens.
- 23W Power LED lamp
- 1500 Lumens
- Advanced Lens Disk 16°
- Frontglass anti-reflection coated
- 23/9/0,25 Watt
- 3D adjustable mount
- LED monitor
- H-mount
- 120 cm ex cable
- Li-Ion rechargeable battery 7.5 Ah,
- Battery charger: charging current 2.5 A , 12 V car adaptor.
- With headband
- 120cm extension-cable
- Colour/headbelt: blue
- Burn time @ 23 W: 3 hours
- Burn time @ 9 W : 7 hours
- Burn time @ 1 W : 44 hours
- Burn time @ 0,25 W: 168 hours (1 week non-stop)
- Charging time: 4 hours
- Weight: 470 g
There is, of course, a price to be paid for this - and that is €865 - or about £815 at today's exchange rate! 😮
I doubt one of these is ever likely to see the inside of a UK mine and furthermore, I suspect it would prove to be a hindrance rather than an asset of used at full power, but all the same it's interesting to see what the world of orienteering (or indeed freeriding bikers) apparently requires!
EDIT: what also caught my eye is the way the price is broken down. The headlamp alone retails at €540 (£510) but the 7.5Ah battery is a surprising €169 (£159). This really doesn't compare well with the Stenlight 5.0Ah battery which retails at £59.99
http://www.excellentstuff.co.uk/StenLight/Lithium-Ion-Battery/c-1-69-71/ . There's also a 15Ah battery for the Betty at €290 (£273), but that's still 50% more expensive than the Sten battery when considered Ah for Ah.
Hello again darkness, my old friend...