Hi all :wave: New to CPF...
Well, i'm preparing a dynamo bike light with standlight, ultracapacitors based. Two SSC P4 for direct drive, and a yellow and some red 5mm for standlight. In the past i modded some chinese multi 5mm white led lights for dynamo and standlight use with great success. These modded light used the simplest electronic possible, the whites direct driven in AC, back to back, and a few yellows powered by a diode bridge in parallel with a ultracapacitor stack and the current regulated by resistors. Simple and quite efficient.
For the model i'm preparing i have the idea to connect the yellow power led and the parallel stack of reds in series. But in this case 2 volts (yellow) + 1,8 volts (reds) = 3,8 volts, in a few minutes the voltage of the ultracaps falls bellow this, resulting in a unusable energy. If i connect the yellow and the reds in parallel the current supplied by the ultracaps is twice resulting in poor autonomy. The best solution, i think, is to use a driver (maybe this? http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3151 ) which regulates when the Vin>Vout and boosts when Vin<Vout. Here are my concerns:
- It is possible with this driver to cover a so wide variation of input voltage?
- Is ready the driver, as is, to power on as it receives energy (take in mind is dynamo powered). If not, hackable?
- If the above concerns are possible, what about modes? it should be capable of remember previous mode and power on in that mode when receives energy?
- The above driver, i think, is not really a constant current device, instead of constant voltage, so if possible to hack in a manner which modes are disabled, can be adjusted to +/-3,8v needed by the leds in series and deliver "only" +/-80mA (for a equilibrium between brightness and autonomy)?
Thanks very much. If you are interested in, here: http://www.foromtb.com/showthread.php?t=220616&page=38 and next pages, is my past project with chinese multi 5mm led dynamo powered (In spanish, sorry).
Well, i'm preparing a dynamo bike light with standlight, ultracapacitors based. Two SSC P4 for direct drive, and a yellow and some red 5mm for standlight. In the past i modded some chinese multi 5mm white led lights for dynamo and standlight use with great success. These modded light used the simplest electronic possible, the whites direct driven in AC, back to back, and a few yellows powered by a diode bridge in parallel with a ultracapacitor stack and the current regulated by resistors. Simple and quite efficient.
For the model i'm preparing i have the idea to connect the yellow power led and the parallel stack of reds in series. But in this case 2 volts (yellow) + 1,8 volts (reds) = 3,8 volts, in a few minutes the voltage of the ultracaps falls bellow this, resulting in a unusable energy. If i connect the yellow and the reds in parallel the current supplied by the ultracaps is twice resulting in poor autonomy. The best solution, i think, is to use a driver (maybe this? http://www.kaidomain.com/WEBUI/ProductDetail.aspx?TranID=3151 ) which regulates when the Vin>Vout and boosts when Vin<Vout. Here are my concerns:
- It is possible with this driver to cover a so wide variation of input voltage?
- Is ready the driver, as is, to power on as it receives energy (take in mind is dynamo powered). If not, hackable?
- If the above concerns are possible, what about modes? it should be capable of remember previous mode and power on in that mode when receives energy?
- The above driver, i think, is not really a constant current device, instead of constant voltage, so if possible to hack in a manner which modes are disabled, can be adjusted to +/-3,8v needed by the leds in series and deliver "only" +/-80mA (for a equilibrium between brightness and autonomy)?
Thanks very much. If you are interested in, here: http://www.foromtb.com/showthread.php?t=220616&page=38 and next pages, is my past project with chinese multi 5mm led dynamo powered (In spanish, sorry).
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, but i use the dynamo to charge a Li-ion pack, so i can run on batteries(about 8 hrs on a 4.4Ah/14.4V 
