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LED garden lights malfunctioning

Noobster

Oct 28, 2013
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I have quite a few LED garden lights that have stopped working. I have disassembled them and found that when placing a fully charged battery in, they do NOT switch off the LED when in direct sunlight. Hence when it is night time they do not work because the battery is flat.

Could it be the 4 lead black package, code numbered YX805A, or the solar panel / sensor gone bad?
 

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Alec_t

Jul 7, 2015
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The black blob hides a miroprocessor. It's possible (I'm only guessing) that it monitors current produced by the solar panel and only turns on the LED when it detects a reduction in current, which would normally occur at twilight. There is no such reduction if you just insert a fully-charged battery.
 

Noobster

Oct 28, 2013
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Thanks for the reply. But I have tried a partially charged battery with identical response. I think it must be the YX805A black package. I will see if I can source some and report back.
 

Alec_t

Jul 7, 2015
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I think the only way you'll get one of those black blobs is by cannibalizing another garden lamp. Good luck though.
 

dorke

Jun 20, 2015
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These usually are operated (on/off) using a Photosensitive device.
Isn't there one on the unit?
 

Mike Hatch

Mar 29, 2017
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Mar 29, 2017
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I have quite a few LED garden lights that have stopped working. I have disassembled them and found that when placing a fully charged battery in, they do NOT switch off the LED when in direct sunlight. Hence when it is night time they do not work because the battery is flat. Could it be the 4 lead black package, code numbered YX805A, or the solar panel / sensor gone bad?

YX805A is a boost converter and switch, it uses an inductor (100uH), the greenish resistor like component to boost the voltage a bit to feed the diode. The battery is charged whenver the solar cell voltage is greater thna the current battery voltage.

Several things can go wrong -
1) Battery is duff,
2) YX805A is duff, no charging or no boost voltage,
3) The solar cell is not producing an output, it can be anything up to 2V, usually its corroded wiring on the back of it as its the part that gets the weather and the sealing is usually not that good.
4) On-off switch is corroded inside.

QX5252 is another part that does the same as YX805A and is a pin-pin replacement, its a bit more efficient, either are readily available on the web.

Fault finding will require soldering skills, a meter, a scope would be usefull if you have one to see if the boost converter is working. Disconnect the solar cell and see if a fully charged battery will kick it into life, if so its the solar cell. An ordinary AAA would do for testing. The rechargeables in the lights are 1.2V Ni-MH around 300mAh, they can be charged (Constant current) externally at upto 60mA short term or 25-30mA for some hours but don't go over 1.3V. The solar cell will give anything from a few hundred mV low light to over 2V in bright light.

I have fixed all of my colour changing type, changing the inductor from the 100uH fitted to 220uH as I do each one which reduces the battery drain but leaving the LED just as bright. Three have needed the solar cell corroded connections fixing with silver loaded paint and a dob of epoxy when the paint has dried. Several YX805A's have had to be replaced as the leads corroded right off the board, and one LED with the same problem.

Bad manufacture is usually the problem, duff soldering or sealing leading to corrosion. I've never had one where it was just a bad component. Batteries are usually blamed but I'm still on the originals 4 years down the line.

I've uploaded datasheets for the YX805A, QX5252 and the circuit for a Cole & Bright 3 colour garden light, basic circuit for the single colour light like yours is in the QX5252 data sheet.
 

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(*steve*)

¡sǝpodᴉʇuɐ ǝɥʇ ɹɐǝɥd
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Jan 21, 2010
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Batteries are usually blamed but I'm still on the originals 4 years down the line.

You obviously live in a place that doesn't see the sun too often.

The batteries die very quickly in environments where there is lots of bright sun for many hours on end...
 
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