Hi everyone, I'm after some expert advice on some electronics I'm trying to modify. I've got some solar powered lights that are not working. I want to tap into them and use an external power supply as the LEDs within will still be working. Besides this I want to have more control of when they come on and to make sure they all come on together.
Please don't give me any stick. Yes I could buy new ones or alternatives etc but I'm doing this because I enjoy tinkering with electronic stuff.......albeit very much an amateur.
The lights are for use in a block paved drive, hence the reason for wanting them to come on together.
So, I've taken a couple apart and attached a power supply to the rechargeable battery lugs. One started to work and the battery started to store charge so I suspect the solar panels on this one are faulty. The second wouldn't work at all, even when I removed the battery and just attached an external supply.
The up shot, I want to know where is the best place to tap into the circuit with an external power supply and bypass all the internal electronics and just power the LEDs. I can supply a picture or the circuit board if anyone can figure it out?
Cheers
Hi Sourav, thanks for your reply. Can you tell me how to upload/send images.....apologies but I'm new to this :-(
So Sourav, hopefully I've given enough info for you to understand what I want to do. I basically want to bypass all the electronics in each "Brick" (or light) and tap straight into the LEDs inside.
Then is it best to connect multiple "Bricks" in series or parallel with an external power source?
How do I determine the voltage and power requirements for the external power source.
Do I need to connect a resistor before each "Brick" to protect the LEDs and if yes how do I determine the size?
Thank you.
Kindly click the image and attach it in your answer. You can also upload it elsewhere and copy-paste the link.
Sourav, here is a link to the images on Dropbox
www.dropbox.com/sh/3uk03ldnjxndz8r/AADSgjcQtbQZ2CW1pOeJ0mxma?dl=0
Sourav, does it normally take so long for the administrator to approve images. I uploaded the files to Dropbox but the link must have been detected and this also is now queued awaiting approval :-(
Is there another way I can send you the images directly?
Regards
That is a great effort...
The LEDs are 3V/20mA...
Thus if you light up by parallel connection you need 3V DC power adapter and 4*20mA = 80mA
Prefferebly 3V 100mA Adapter. I am not sure if you find this. However, you can make connecting four leds in series.
(+) -------|>|------- -------|>|------- -------|>|------- -------|>|------- (-)
Thus it will need 12V adapter with 20mA of rating. you could cut the trace and join it.
Use 1.2V power adapter or 1.5V across the Battery, Remove the solar panel or cut the panel trace.
This is the best case I would recommend.
Thanks Sourav,
Yes this was my initial plan......to just tap into the battery. However, I have found that some of the units are faulty and even by passing the battery didn't work. Also, relying on the solar panels to switch on the lights means the different units would turn on at slightly different times. So in the end I would prefer to tap directly into the LEDs.
So next issue is that the LEDs are already soldered onto the board in parallel. And actually to save time I only want to remove the sealant from one LED and by soldering two wires onto the soldered connections.
I have a total of may be 14 individual units which means i would need a power supply of 3v and 1.12 Amps (20 x 4 x 14). Correct?
My only real option I have open is to wire the individual units in series or parallel......but in parallel I would need a 32v supply (3 x 14). So I think series is the only way to go.
So if I wire them all in series do I need to add a resistor to protect the LEDs?
Regards,
Sourav,
Do I need to add a resistor to protect the LEDs in each unit and if so how do I calculate it's value?
"My only real option I have open is to wire the individual units in series or parallel......but in parallel I would need a 32v supply (3 x 14). So I think series is the only way to go" - You are wrong. In series you required 32V power supply but in parallel you required 3V 1.12 Amps.
You first light up a single LED and check whether it is working properly or not. You can add up Resistors of 330R in series of each LED.
The connection will be -
(+) --------/\/\/\/\/\/\/-------- ------|>|--------- (-)
330R LED1
(+) --------/\/\/\/\/\/\/-------- ------|>|--------- (-)
330R LED2
and goes on.
Hope this will work.
I’m trying to revive a cheap Lepai LP-2020A+ amplifier that I’m sure I picked up at the Goodwill Outlet. It won’t power on, but if I jump a couple of connections on the relay it will start up. A bit of research has shown that capacitor C15 may be installed backwards, but I can’t find any polarity indications on the board.
I’m trying to revive a cheap Lepai LP-2020A+ amplifier that I’m sure I picked up at the Goodwill Outlet. It won’t power on, but if I jump a couple of connections on the relay it will start up. A bit of research has shown that capacitor C15 may be installed backwards, but I can’t find any polarity indications on the board.
Wildly inconsistent, and apparently missing solder on one of the connections. There were some sloppy bits of solder debris on the board that popped right off as well, although they did not appear to be shorting anything out.
Also of concern is the condition of capacitor C1. It’s not popped, and voltage flows across it, but it looks beat to hell. I’m assuming that it was probably too much heat during assembly:
Sourav Gupta
PermalinkPlease provide the circuit board image.
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Joined February 12, 2018 696Monday at 02:11 PM