The Nightstar jP is the latest version of the popular range of ranges designed by Applied Innotech in the USA. This version improves on its predecessor through higher rated components and manufacture in Japan rather than China. As a result, it is probably the most durable torch I've ever seen.
Rather than using a rechargeable battery, this torch stores the energy generated when you shake it in a a 1.5 farad ultra-capacitor, made by Panasonic. This is not damaged by being left empty, so you can just shake the torch when you need light, and it can also be charged over 100,000 times, perhaps even a lot more than that! It's also very quick to charge, with one minute of shaking (three minutes if not used for an extended period) giving you up to 10 minutes of effective illumination, and 20 minutes total light duration. The picture below shows the coil through which the magnet passes when you shake the torch:
Efficient LED lighting
The NightStar jP uses a single 15 lumen 0.1 Watt LED - so that's 150 lumens/watt, which is an exceptionally high efficiency - see some examples of other light sources here for comparison.
Magnetic recoil buffers
At each end of the torch is a fixed magnet oriented to repel the moving magnet. Providing you don't shake the torch too hard, this means the moving magnet never makes physical contact with the ends of its tube, eliminating any wear and tear that could be caused by vibration. The picture below shows the moving magnet suspended above the buffer magnet:
Waterproof design using magnetic reed switch
A reed switch is used to turn the torch on and off - the switch on the exterior simply moves a magnet that activates the reed switch. This means there is no hole in the torch casing for the switch or wires, allowing it to be waterproof to a depth of 60m. It also floats! Here's a labelled picture showing the components, though they're only just visible through the casing:
Uses for the NightStar jP
- Emergency preparedness
- Backpacking and hiking
- Boating - it is waterproof and floats pointing upwards.
- Durable and waterproof construction (OK to 60m/200ft depth)
- No battery or bulb replacement ever needed
- Floats pointing upwards
- Polycarbonate housing, which is impact, chemical and temperature resistant
- Manufactured in Japan, with stringent quality control procedures
- Illumination range: 50-ft (15m), beam size:12-ft (3.6m)
- Lumen output: 15 lumens
- Led power: 0.10 watts
- Charging time: 30 seconds
- Light duration: 15 min
- Waterproof to: 60m (200ft)
- Corrosion proof: motor oil, diesel fuel, salt water, mild acids
- Impact strength: withstands 1.5m (5ft) drops
- Storage temp: -40C to +70C
- Ultracapacitor cycle life: 100,000 charges
- Led life: 50,000 hours
- Size: length: 25.5cm (10"), diameter: 5cm (2")
- Weight: 308 grams (11oz)
- Warranty 5 years
- One minute shaking at two-three shakes per second will charge the capacitor fully. A longer period shaking is only needed if the torch has been left unused for a long period of time.
- If you can hear the moving magnet hitting the buffer magnets, you are shaking it too hard - it should rebound without touching them.
- Because ultra-capacitors work in a different way to batteries, the torch will not store a charge for months, though it is OK for a week or two - it is best to shake it before using it each time. Unlike batteries, ultra-capacitors are not damaged by being left discharged.
- The voltage from an ultra-capacitor reduces as the charge is used, which means the light reduces gradually as you use it. For best light output under continuous operation, shake the torch again for a short time every 5-10 minutes. You CAN shake it while it is turned on.
- The above means the performance may seem lower than torches that use batteries, but the advantage is the durability - this torch comes with a 5 year warranty, and only has one moving part!
I'm afraid I've stopped selling torches now, due to being busy with other work, but you can buy them direct from the manufacturer at www.havelight.com or perhaps ask them about being a local distributor if there's not one in your country already.