Garden Solar Panel LED light NOT WORKING! - Page 1
Forum section: electronics / beginners

author: MrJoeyJoeJoe
author_rank: Contributor
timestamp: February 24, 2016, 02:24:02 pm
content: Hey guys, I love the EEVblog videos and forum, you guys have helped me out (indirectly) many times in the past!I am an electronics enthusiast, however, a total novice! So I beg for patience...UPDATE:Solution in process! Just waiting for a 3.2v to arrive to conclude this problem!I now have a problem solving a tiny solar powered LED light circuit.From what I've read this is a genius little circuit, as it only uses a 1.2v battery,(to power 3 10mm super bright LEDs) and oscillates the current until it is enough to light the bulbs for a fraction of a second so quickly that we can't see it flashing.It also has no need for an LDR as once the current from the solar panel drops to a certain amount, that is when the oscillation begins.I don't fully understand the circuit but I think that is the gist of it.I have replaced the two transistors, and tested the diode, and eliminated the solar panel, the switch and even LED's to simplify possible errors.With the battery plugged in (the solar panel unconnected) my multimeter only registers 1.2v through the LED terminals. The circuit is not oscillating? (I'm guessing it would need at least 3.6v to power those LEDs?)Would the fact that the solar panel is not plugged in affect this?Any clues to common Garden Lamp problems?Appreciate any feedback, thanksJoe!

author: Audioguru
author_rank: Super Contributor
timestamp: February 24, 2016, 02:53:55 pm
content: Most of my solar garden lights cost only $1.00 and use an IC and an inductor to produce a high enough voltage to light LEDs. Your circuit has no inductor so maybe it needs two 1.2V battery cells to light only 1.8V red LEDs.The first garden lights I purchased are now about 20 years old and look like that. The two transistors do not oscillate, instead they are simply a voltage detector and an on-off switch.I found this schematic and photo of it in Google:

author: alsetalokin4017
author_rank: Super Contributor
timestamp: February 24, 2016, 03:10:40 pm
content: Quote from: MrJoeyJoeJoe on February 24, 2016, 02:24:02 pmThere are many different circuits for these garden lights. Since yours only uses a single 1.2 v rechargeable battery it is not using the circuit in the above post.If you could post clear photos of both sides of the circuit board we can probably figure out the circuit and help you trouble shoot your problem.Yes, not having the photovoltaic panel connected can affect the performance, and also not having the LED connected.What transistors (original and replacements) are in the circuit?It is possible that one of the "resistors" (the very small one) is actually an inductor. Also, what is that black thing at the top of the PC board?

author: Audioguru
author_rank: Super Contributor
timestamp: February 24, 2016, 04:29:34 pm
content: The black thing at the top of the board is a "hole" in the board.The funny hex-shaped symbol of the transistors is for a BC147 or BC157 that I used 50 years ago.

author: MrJoeyJoeJoe
author_rank: Contributor
timestamp: February 24, 2016, 04:54:54 pm
content: Thanks guys for your replies!Thanks to Audioguru's first comment, I checked to make sure it was only 1 battery that was needed...The guy who asked me to fix it had given it with a fully charged 1.2v battery in the only battery slot. But I just checked and imprinted on the plastic it says 3.2v battery...I don't know how many things I've fixed and I still haven't learnt in the diagnosis to rule out the basics!!Sorry for wasting everyone's time, but I'm pretty sure it's going to be that!I've just ordered some 3.2v batteries and will conclude when they get here!!!Thanks/sorry,Joe!

author: Audioguru
author_rank: Super Contributor
timestamp: February 24, 2016, 05:45:32 pm
content: Two of my cheap Chinese solar garden lights failed. They didn't have plastic solar panels that get sunburned, instead they have high quality glass solar panels. But they were not properly sealed so rain got under them and rusted away the bottoms of the solar panels. They lasted about 9 months.I bought 10 of them last year and they are so poorly made that I marked the 5 or 6 that did not work and I took them back to the store for replacement. I bought more and selected ones that did not have my mark because the store simply put the defective ones back for sale.I think their cheap price is for the shipping from China and the solar garden light is free. No, the new AAA size Ni-MH battery cell probably costs more than double the price of the entire solar garden light. Then the store buys them for a few dollars and sells them for only one dollar?

author: MrJoeyJoeJoe
author_rank: Contributor
timestamp: February 24, 2016, 07:00:42 pm
content: Yes the cheap solar lights last very little time and are very poorly made.I can't believe they just put them back on the selves!! I'll have to bear that in mind as I frequent the Chinese Bizarre often!This one however I think cost him at least 20€ which is about 25$, it looks fairly well made, and has 3 powerful Super-bright LEDs which is why he preferred to try and fix it rather than just buy a new one. Luckily I found some special 3.2v batteries for 8€ (2€ each) so I think it's worth it.Thanks a lot for your help man!Joe!

author: Audioguru
author_rank: Super Contributor
timestamp: February 24, 2016, 07:42:12 pm
content: Older cheap Chinese solar garden lights used a Ni-Cad battery cell that rusted away in one month. Maybe it does not rain or there is no dew in China?

author: Gyro
author_rank: Super Contributor
timestamp: February 24, 2016, 08:05:19 pm
content: Oh, it certainly rains!Edit: On the other hand, they're probably not big users of cheap solar garden lights!