sandall Posted September 3, 2018 Share Posted September 3, 2018 Not strictly core BR business, but seeking illumination. For the last 2 summers we've had a kit consisting of a string of 100 LEDs in parallel across a single 600mAh NiMH battery (charged by a good sized EV panel),looking very pretty from dusk to the wee small hours. A couple of days ago they suddenly switched to coming on about 3 hours after dusk, though still lasting at least 6 hours. Does anyone have any ideas about what might be happening & what (apart from binning the lot) might be done about it ? Link to comment Share on other sites More sharing options...
DrV Posted September 3, 2018 Share Posted September 3, 2018 Have you had a change in the ambient night time lighting? New street lamp, new floodlight on neighbour's house? Has the solar panel moved so that it now points somewhere different? Does it use the solar panel or an independent light sensor to trigger? Link to comment Share on other sites More sharing options...
sandall Posted September 3, 2018 Author Share Posted September 3, 2018 Have you had a change in the ambient night time lighting? New street lamp, new floodlight on neighbour's house? Has the solar panel moved so that it now points somewhere different? Does it use the solar panel or an independent light sensor to trigger?No, no, no, no, no & just the solar panel. I did have to resolder 1 of the LEDs a couple of weeks ago after the local fox caught the string on its way over the fence, but it's been fine since then. The light sensor no longer responds to being covered in daylight, & the whole string now only comes on after several hours of darkness. Link to comment Share on other sites More sharing options...
bigclive Posted September 4, 2018 Share Posted September 4, 2018 That does sound a bit like a common failure mode of the parallel LED strings. Sometimes an LED develops a parallel resistance that can shunt the voltage to the other LEDs intermittently, but then operates normally after it's been powered for a while. But that tends to drain the battery faster than in normal use. If there's no random intermittent dip or flicker then it may not be that. Have you tried re-aiming the solar panel experimentally? Link to comment Share on other sites More sharing options...
sunray Posted September 4, 2018 Share Posted September 4, 2018 Does it use the solar panel or an independent light sensor to trigger? Does it use the solar panel or an independent light sensor to trigger?No, no, no, no, no just the solar panel. The light sensor no longer responds to being covered in daylight, & the whole string now only comes on after several hours of darkness.Make yer mind up sensor or not? It could make a world of difference for our suggestions. Link to comment Share on other sites More sharing options...
sandall Posted September 4, 2018 Author Share Posted September 4, 2018 That does sound a bit like a common failure mode of the parallel LED strings. Sometimes an LED develops a parallel resistance that can shunt the voltage to the other LEDs intermittently, but then operates normally after it's been powered for a while. But that tends to drain the battery faster than in normal use.If there's no random intermittent dip or flicker then it may not be that.Interesting thought - I did notice after fixing the 1 LED that another in the chain had died (perhaps it would have been worth cutting it out of the string at the time ?). I haven't tried substituting a known good battery yet, as it's a bit of a faff to get the panel down. Make yer mind up sensor or not? It could make a world of difference for our suggestions I refer my honourable friend to my previous answer, i.e. there is no separate light sensor to check out, just the one contained within the solar panel !! Link to comment Share on other sites More sharing options...
timsabre Posted September 4, 2018 Share Posted September 4, 2018 Make yer mind up sensor or not? It could make a world of difference for our suggestions I refer my honourable friend to my previous answer, i.e. there is no separate light sensor to check out, just the one contained within the solar panel !!I think he means, is there a light sensor or is it using the voltage from the solar cell to determine the light level... Link to comment Share on other sites More sharing options...
bigclive Posted September 4, 2018 Share Posted September 4, 2018 These days for outdoor use I strongly recommend the strings of lights that are often referred to as copper wire lights. They consist of two enamelled copper wires with surface mount LEDs bridged across them at regular intervals and then dipped in resin to seal them completely. Unlike the traditional wired and sleeved LED strings that often wick water in and corrode at the base of the LED, the copper wire lights are very resilient to water. The absolute best choice of LED outdoor lights is the professional strings with heavy rubber cable and the LEDs and wiring resin-potted in end cups, but they tend to be quite bulky and a lot more expensive than the "disposable" strings. You can get parallel copper wire strings of 100 LEDs on eBay if you search for keywords like 100 copper wire LED string USB. Link to comment Share on other sites More sharing options...
sandall Posted September 4, 2018 Author Share Posted September 4, 2018 I think he means, is there a light sensor or is it using the voltage from the solar cell to determine the light level...Maybe. In my technological ignorance I had assumed that reacting to the voltage from the solar cell is how garden "solar lights" work, as it is presumably cheaper than having a separate built-in light sensor :( Link to comment Share on other sites More sharing options...
timsabre Posted September 4, 2018 Share Posted September 4, 2018 .........or is it using the voltage from the solar cell to determine the light level...In my technological ignorance I had assumed that that is how garden "solar lights" work :( Well sometimes. Or they might have a separate sensor, which I think was what the original question meant. Link to comment Share on other sites More sharing options...
DrV Posted September 4, 2018 Share Posted September 4, 2018 .........or is it using the voltage from the solar cell to determine the light level...In my technological ignorance I had assumed that that is how garden "solar lights" work :( Well sometimes. Or they might have a separate sensor, which I think was what the original question meant.Yes it was. I'm aware that garden lights usually work that way but 40 years of solving problems on the phone has taught me not to assume anything ☺ Link to comment Share on other sites More sharing options...
sunray Posted September 4, 2018 Share Posted September 4, 2018 Well sometimes. Or they might have a separate sensor, which I think was what the original question meant.Indeed, and I find the solar panel only style are far less accurate than those with sensors. Some that have the additional sensor also have a control to allow adjustment of when the lights come on.If you have been making repairs, it not beyond possibility that this has been disturbed. Link to comment Share on other sites More sharing options...
sandall Posted September 4, 2018 Author Share Posted September 4, 2018 Fair enough (I did say I was ignorant about such things!). The unit itself hasn't been moved since May (I'm highly doubtful about its ability to keep out water, so it is well sealed with lots of Gaffer tape). I don't recall any controls, just a battery compartment with slots for 3x AA, but terminals for only one. About a week after I resoldered a wire that was about to fall off one of the LEDs it suddenly changed its switch-on time from around 20.00 to nearer 23.00. Link to comment Share on other sites More sharing options...
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