In my earlier blog, yesterday I discussed using a 1 Farad capacitor to hold enough charge to run the flasher for several hours, from dusk to midnight or later. I checked Mouser’s parts and found a 1F 2.5V capacitor from Bussman for about 2 dollars in single unit quantities. Kind of expensive but cheaper in the long run that replacing AA cells. I will have to check some surplus websites and see if I can get some 1 F caps for cheaper.
I found new 1F, 2.5V capacitors for $0.65 each from All Electronics, so I bought some. These are not low ESR capacitors, so they are not made for quick charging and discharging. But with the flasher, the charging and discharging rates are very low, like only 1 mA or less. So they should work okay without a problem.
I have a bag of several dozen red high brightness LEDs in my parts drawer, so I don’t need to buy any LEDs. I may have to use more than four LEDs per capacitor because with four, the charging current may be too low to completely charge the cap before the end of the day. I think with four, the charging rate will be slower than the flasher discharge rate. But that’s okay because the flasher only has to flash from dusk until midnight, which would be at most 6 or 7 hours during winter at this latitude here in Southern Calif. The front of my house faces directly south, so it gets maximum sun exposure the whole year, and the flashers should have no problems charging up full on a sunny day, due to the absence of shadows. If I’m lucky, the 1 F capacitors may not discharge fully during the night, and when there is a cloudy day they may charge up enough to flash during enough of the night.
