Flashing solar lights timing out after conversion

  • Hi guys... I've been hunting around and hoping that you can give me a solution to my issue! Being christmas, we do a fairly big display at our house (Its a huge thing in Australia!).

    I have some solar lights that have worn out over the years, so when the solar controller gets into pretty bad shape, I just knock up a little voltage converter to drop a 5v power source down to about 3V to power the solar lights, and give them a new life, not to mention that I can also turn them all on and off by the same power switches, rather than hunting for all the individual switches out in the garden lol.

    I'm a little stumped though, because I have a couple of sets of solar stars that flash, and they would cycle in a roughly 2 second on/off pulse on solar, but now that I've converted it to low voltage mains, it becomes a half second on, 3-4 second off cycle now. I'd prefer to keep them to the same cycle if I can, as now they don't really show up very well.

    I have seen some references to the flash being a result of the batteries internal resistance, so I might need to add something to my circuit, but I'm not sure what.... that's where I got stuck.

    The circuit is a really simple LM317 with 2 resistors to drop the incoming 5V down to 3V, which then just feeds into the input side of the original light controller, so essentially it replaces the solar panel and the battery inside the compartment.

    Any tips? 🙂

  • Mod

    I'm no expert but it looks like the circuit got imbalanced with battery missing so there are probably some capacitors that charge and discharge at a different rate making the flashing behave this way. Did you try to put something on battery side to see if you get any change?

  • Thats kind of where I'm stuck, I'm not sure what to put on to help it, whether its just that the power circuit is slightly higher output voltage than it would normally get from a battery pack or whether I need to have something else added in....Creating these circuits (While somewhat simplistic) is a bit of a first for me, so still learning as I go 🙂

  • Mod

    Try with some batteries first, than you could try with a capacitor with a decent capacitance

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