I think this is a fairly simple question (famous last words...).
I am building a new dynamo light (to run from SP hub dynamo, to replace my long-serving simple but extremely effective 4x XR-E with Ledil SS optics) because none of the lights currently on the market meet what I want (still). Initial requirements are quite simple, to power 2 Luxeon Rebels in series, at 1A, preferably with a standlight (but even that is not that important). The reason for the choice of the 'old' LEDs is that I have a Philips Saferide 80 which will form the basis of the unit (case, optics and LEDs).
Rather than build a driver from scratch, it occurred to me that it might be very simple just to use a driver from an IQ Cyo, which, from research here and on the web, appears to drive a single Cree (XR-G?) at about 1A through the use of a simple courrent doubler. The standlight on the Cyo is pretty good, and appears to be just a 5.5V 1F super cap in parallel with the LED (but hard to confirm this). As far as I can tell, based on limited information, the only mod that would be needed would be to address the problem of a 5.5V cap in parallel with 2 LEDs across which the potential difference will be 6.8-7.0V. Therefore, 2 questions:
1. Is there any obvious problem with the approach described above (does anyone have any knowledge of the Cyo driver circuit)?
2. What is the easiest way to solve the problem of the super cap - simply replace the existing 5.5 1F with two 5.5V 2.2F super caps in series?
I might just go and try it anyway and see what happens (but replacing the Rebels in the Saferide 80 is a bit of pain, having already done it once...).
Thank you.
I am building a new dynamo light (to run from SP hub dynamo, to replace my long-serving simple but extremely effective 4x XR-E with Ledil SS optics) because none of the lights currently on the market meet what I want (still). Initial requirements are quite simple, to power 2 Luxeon Rebels in series, at 1A, preferably with a standlight (but even that is not that important). The reason for the choice of the 'old' LEDs is that I have a Philips Saferide 80 which will form the basis of the unit (case, optics and LEDs).
Rather than build a driver from scratch, it occurred to me that it might be very simple just to use a driver from an IQ Cyo, which, from research here and on the web, appears to drive a single Cree (XR-G?) at about 1A through the use of a simple courrent doubler. The standlight on the Cyo is pretty good, and appears to be just a 5.5V 1F super cap in parallel with the LED (but hard to confirm this). As far as I can tell, based on limited information, the only mod that would be needed would be to address the problem of a 5.5V cap in parallel with 2 LEDs across which the potential difference will be 6.8-7.0V. Therefore, 2 questions:
1. Is there any obvious problem with the approach described above (does anyone have any knowledge of the Cyo driver circuit)?
2. What is the easiest way to solve the problem of the super cap - simply replace the existing 5.5 1F with two 5.5V 2.2F super caps in series?
I might just go and try it anyway and see what happens (but replacing the Rebels in the Saferide 80 is a bit of pain, having already done it once...).
Thank you.