Hi guys I'm having a problem with some of these cheap solar garden lights I have and I has hoping someone may be able to help me. I bought them a few months ago but after they came on the first night they just never came back on again. Even when I remove the batteries and recharge them, once I replace them it still doesn't work. I have drawn the PCB for this device below and taken some photos as I'm unsure as to how this works because the IC package has a designation I cannot find any information on at all. Initially I thought it maybe a voltage comparator so it switches between charge and discharge and dawn and dusk but as I cannot check the part labelled "8599B" I have no idea what it is doing. Has anyone come across this kind of circuit before?

Thanks as usual for any help guys

P.S. Batteries in this are 3x 1.2V Ni -MH in parallel configuration and the LEDs are 6x White 5mm also all in parallel.

 

IC1 is a boost converter. I'd bet 'R1' is actually an inductor; not a resistor.

 

IC1 is a boost converter. I'd bet 'R1' is actually an inductor; not a resistor.

Ahhhh thank you. I was thinking for a second why a metal film resistor had only 4 bands on it. I've adjust the circuit diagram accordingly. So if it's a boost converter do you have any advice on where to start looking for problems? I can't seem to find any replacement ICs.

 

So if this is the basic boost converter (thank Wikipedia )



Is the IC in this circuit acting as this switch in the circuit above, based on the input from solar cells? Thing is I'm not entirely sure how this is charging the batteries during the day.

 

I can't be 100% sure from random angle pictures so you will need to sketch out what you see.

Typically the solar panel connects to the battery via a diode. Yours may be a discrete diode, the newest 4 terminal modules I have seen put that diode inside an IC.

The IC I have seen just need an external inductor besides the solar panel, LED, and the battery.

If the lights only work for one night I would suspect the solar panel is either not working or not connected properly.

 

I can't be 100% sure from random angle pictures so you will need to sketch out what you see.

Typically the solar panel connects to the battery via a diode. Yours may be a discrete diode, the newest 4 terminal modules I have seen put that diode inside an IC.

The IC I have seen just need an external inductor besides the solar panel, LED, and the battery.

If the lights only work for one night I would suspect the solar panel is either not working or not connected properly.

Thank you that would explain the missing link between the solar panel and the batteries, so the IC is a charge controller. I've got some HID lights in the garage and just warming them up now to test the voltage from the solar cells. Also thank you for linking that other thread, some very useful information there.

 

Solar panels seem to be working, 1.70V and all are wired in parallel. I don't have any information on the charge controller in this circuit, would it be risky to change it for the one you mentioned in the other post, the QX5252? Or will I have to change the inductor as well depending on the current required?

 

Just tested the caps in the circuit with my DMM @ 2K Ohms, it went up 0.08 and it stayed there, it didn't go back down. IIRC that's a busted cap right? If so could this be the fault and would I need to increase the capacitance to stop it happening again?

 

yx8018 is similar

 

Just a quick follow up on this. I got the replacement LED drivers but when I replaced one it flickered when it was supposed to come on and then died again. I then thought maybe this design was flawed and the capacitor was "designed" to be a smoothing capacitor but, as we discussed, was creating a boost converter that was busting the LED driver which only has an absolute rating of 5V. I replaced the driver, removed the capacitor and it seems to work now. You gotta love the QC they have over there lol.

Anyway thanks for all the help on this guys