Hi SparkFun,
I am really interested in the sewable LED ribbons (COM-14136), but I had several questions about them first. I would like them to be as bright as possible so that they could be seen in the daylight. Most videos that I find only have them illuminated in the dark. I saw that powering them off of two coin cells increased their brightness. But I want to make several costumes with them and would rather work with a chargeable lithium pack solution so that I don’t have to keep replacing coin cells. Can you recommend a lipo battery that will give me maximum brightness without burning out the ribbons? How would the brightness of these compare to LilyPad LEDs? Would I be better off sewing in many individual LilyPad LEDs for brightness?
Thanks,
FB
Hello FB.
As far as brightness goes, the LED ribbon is slightly dimmer than Lilypad LEDs just due to the fact that the LEDs in the ribbon are physically smaller.
The ribbon doesn’t have any current limiting resistors built in and because of that, the ribbon mostly is depending on the internal resistance of coin cells to limit current. If you were to attach the ribbon to a Lipo battery, it may very well burn out the LEDs in the ribbon since a Lipo has a much lower internal resistance. You’d need 9 ohm 1 watt series resistor to get the maximum brightness from the LED ribbon and not risk burning them out. (You could probably use an [8 ohm resistor for a bit more brightness at the expense of LED life time.)
Even running on a Lipo, I don’t think these would be very bright in daylight. Even the Lilypad LEDs might not work well in daylight.](Power Resistor Kit - 10W (25 pack) - KIT-13053 - SparkFun Electronics)