Hi folks,
[ Newbie, first posting. If I miss something, please let me know. ]
I have a Shimano DH-3N72 dynamo on my bike at the moment. It's driving a B&M IQ Fly Senso Plus headlight and B&M DToplight XS Plus taillight.
Everything works great except that I'm jealous of friends who use P7 700-900lm flashlights from DealExtreme. Hence I'm wondering if I can build a dynamo headlight that will compete.
For the bike riding during which I need the brightest light, I am going 15-20mph. At that speed, I imagine the dynamo should be able to put out quite a bit of power. From data on this site, it seems that I can get 6W at 15mph:
http://www.pilom.com/BicycleElectronics/HubDynamo.htm
From other postings here, it seems the dynamo produces 0.5A with voltage varying according to speed. From the manufacturer specs, the P7 seems to want up to 2.8A. Should I build a step-down transformer on the AC side, prior to rectifier input, to get a higher current?
What is the minimal and most efficient circuitry to protect the LED?
All in all, is this whole project worth doing?
Thanks and regards,
Ihab
[ Newbie, first posting. If I miss something, please let me know. ]
I have a Shimano DH-3N72 dynamo on my bike at the moment. It's driving a B&M IQ Fly Senso Plus headlight and B&M DToplight XS Plus taillight.
Everything works great except that I'm jealous of friends who use P7 700-900lm flashlights from DealExtreme. Hence I'm wondering if I can build a dynamo headlight that will compete.
For the bike riding during which I need the brightest light, I am going 15-20mph. At that speed, I imagine the dynamo should be able to put out quite a bit of power. From data on this site, it seems that I can get 6W at 15mph:
http://www.pilom.com/BicycleElectronics/HubDynamo.htm
From other postings here, it seems the dynamo produces 0.5A with voltage varying according to speed. From the manufacturer specs, the P7 seems to want up to 2.8A. Should I build a step-down transformer on the AC side, prior to rectifier input, to get a higher current?
What is the minimal and most efficient circuitry to protect the LED?
All in all, is this whole project worth doing?
Thanks and regards,
Ihab