Lets say i take two leds and i take the negative termina

Whether that works for your controller is unknown.

I would experiment first before committing to it.

The simplest route would be the one you were taking: rearrange the leds mechanically but not electronically. For that, you need to make sure that your leds were indeed parallel. Once confirmed, just parallel the leds in a circular fashion and call it a day: the controller wouldn't see a difference.

 

Whether that works for your controller is unknown.

I would experiment first before committing to it.

The simplest route would be the one you were taking: rearrange the leds mechanically but not electronically. For that, you need to make sure that your leds were indeed parallel. Once confirmed, just parallel the leds in a circular fashion and call it a day: the controller wouldn't see a difference.

I uploaded a diagram of what the leds were soldered on too. Can you look at that and confirm with me that it is indeed parallel. Because at this moment in time IM NOT sure. Remember. The + of the leds are on the positive line and the - is on the negative line. the ONLY place they meet are in the middle. So that then tells me it cant be just parallel right?

 

I already answered this, but dannyf wants to interject, so it's up to him to explain why all 204 LEDs are in parallel.

 

I already answered this, but dannyf wants to interject, so it's up to him to explain why all 204 LEDs are in parallel.

I'm not meaning to make this complicated.
But the thing that is confusing me is the difference of opinion on this.

 

Ok assuming that your LED's are perfectly happy running in series / parallel, the next thing to consider is that the original LED driver is meant to run more led's than what you are building into your ring light?

Then the current level will be to high.

 

Ok assuming that your LED's are perfectly happy running in series / parallel, the next thing to consider is that the original LED driver is meant to run more led's than what you are building into your ring light?

Then the current level will be to high.

i am using all the original leds all 204

 

i am using all the original leds all 204

Then it should be fine.

The point I was (am) trying to make is that I don't want to blindly promote the idea that running LED's in parallel is no-brainer easy.
Obviously there are situations where sufficiently matched LED's can be run this way, but it can also be a nasty pitfall for the unwary.
There are simple LED circuits that are much more tolerant of mismatch, there is complexity hidden within the simplicity of your light design.

Here are my qualifiers:

1) The LED's must be of exactly the same type and closely matched in Vf.
2) The LED's must be mounted in a way to even out the heat loss- so there is minimal uneven heating of the parts.

 

I understand. I'm sure with time i will continue to learn these things. The leds do appear to all be the same. I'm sure the manufacturer has planned that. The heat should not be a problem as they are being spread out evenly. More so then the way the light panel was before.

So i think i'm good to go this time.

 

I have long suspected that the LEDs used in massively parallel configurations for cheap lighting products coming out of China have inbuilt resistors on the die. The first clue is that they appear to maintain reasonably even brightness and don't cascade fail as soon as expected. The second is that they get much hotter and less bright than normal LEDs would.

 

Yeah this did came from china. Fstphoto is the company. I found it on the board.

 

You said nothing about resistors or current limiting, so I say this:
The problem with LEDs is that they are not like light bulbs. They need a resistor to limit their current or they will pop like a fuse.
We need you to show us how any resistors are wired into this circuit, what amount of resistance they have, and what the voltage supply is.

They pop like a fuse in the final death throes - the weakest LED in a series chain will fail short circuit, the lower combined Vf causes the current to rise still further and kill the next weakest..............and so on.

In theory; only one LED popping like a fuse should cut the current. and end of story - a few months ago I tried repairing a TV LED backlight - somehow more than 1 LED in the chain had failed open, and a couple more popped straight after I'd replaced the identified duds.

 

Well so far i have tested every led with a small button battery to make sure i have the polarity correct

I am going with my original plan which is to wire it in parallel. Reason being. The board it's self was wired in parallel. All i'm doing is transferring that around the ring light and doing a parallel type wiring. Then reconnecting it back on to the control board that looks like it has a in built voltage control and other things all in one. On and off and so on. Let's hope this works.

I see half the LEDs in parallel and that group feeding the other half of the LEDs. That makes 102 LEDs in parallel and the current from them feeding another group of 102 LEDs. Two in series and 102 in parallel. That makes the feed voltage from the converter 6.6 volts @ an average of 2.04 amps, and it's obviously pulsed because that's how switching regulators work.

204 LEDs times 0.02 amps is 4.08 amps. You can't get 4 amps out of a AA battery (or 6 of them in series). Maybe that is the current limiting resistance. Any attempt to get 4 amps out of those batteries will cause the voltage to collapse.

Let's run some math and some measurements.
Assuming 3.3v for a white LED. 3.3v x .02A x 204 LEDs = 13.64 watts.
with a 90% efficient switching regulator you need 14.96 watts.
15 watts out of 9 volts uses 1.66 amps.
I just placed 1 ohm across a new alkaline AA battery (Coppertop) and the voltage dropped to 1.3 volts in 2 seconds.
1.16 volts after 10 seconds.
My old Radio Shack battery book shows 0.68 amp hours out of an alkaline AA with a 1 ohm load. They did that in 15 second bursts and took 145 bursts to get to 0.75 volts at the battery terminals. Total: 36.25 minutes. That's down to 1/2 the original voltage to get 0.68 amp hours out of the battery at an average draw of 1&1/8 amp.

1.125v (average) times 1.125A (average) times .604 hours = 0.765 watt hours per battery.
0.765 watt hours times 6 batteries = 4.587 watt hours.
4.587 w-h/15 watts = 18.35 minutes.
That's a pretty short video.

I can imagine a switching regulator working in the range of 9 volts to 4.5 volts, but at the same time, the necessary current draw will double to 3.3 amps, which the batteries can't do. Summary: you can't get 18 minutes out of this machine with the batteries they recommend.

Now, back to the 102 LEDs in parallel: You can't do that with a random batch of LEDs. Somebody is going to hog the current. Therefore, these LEDs must be matched sets. You can do that if you're sorting a million LEDs. The best advice I can give you is to keep your wiring nice and neat. Try to use equal lengths of wire. Use fairly fat wire. 10 gauge is the mathematically correct size, but you'll never get that to work unless you're using the wire for the mechanical support for the LEDs. (That's not a bad idea!)

Place two LEDs in series for every circuit and make lots of parallel circuits. If it takes 14 inches of feed wire to get to the farthest group, use 14 inches for every group and make little coils to use up the extra length.

So it goes: two points where the power wires arrive from the regulator. A bunch of long red wires which are equal to each other. A bunch of long black wires which are equal to each other. A bunch of groups with 2 LEDs in series. Connect each group with a red and a black.

The only other way is to redesign this with some resistance in series with each pair in series. I think 102 resistors of about 33 ohms. I also think AA batteries are a miserable power supply. You need something like a 9 volt wall wart good for at least 1&2/3 amps.

I feel like your recommendation is my best bet. After re reading this. I think ill do as you said and make that.

For every two leds connected in series connect that in parallel. The only problem i am facing with that is how to connect that back to the controller. Just connect normally with the positive and - wires? Plus i don't need anything else besides wiring it up like you said?

Thanks.

 

For every two leds connected in series connect that in parallel.

Why would you do that? If your controller is a voltage driver for one led, it wouldn't drive two leds in serial.

If you want to go down that path, experiment before committing to it. I don't think you are gaining anything by doing it.

Your original plan is sound, and the simplest, as long as you confirm that the original wiring is parallel. All this noise and thereotical has added nothing but confusion.

 

Can you post an extreme close-up of one LED?

 

Well so far i have tested every led with a small button battery to make sure i have the polarity correct

I am going with my original plan which is to wire it in parallel. Reason being. The board it's self was wired in parallel. All i'm doing is transferring that around the ring light and doing a parallel type wiring. Then reconnecting it back on to the control board that looks like it has a in built voltage control and other things all in one. On and off and so on. Let's hope this works.

If they're white LEDs - you probably mean a lithium coin cell, most button cells are around 1.5V and won't light a white LED. Many keyfobs use a coin cell with no current limiting resistor - they start off bright and fall off quickly, and they don't do the LED any good!

 

the cell is 3v Ian.

Can you post an
extreme close-up of one LED?

Sure man give me a sec

Why would you do that? If your controller is a voltage driver for one led, it wouldn't drive two leds in serial.

If you want to go down that path, experiment before committing to it. I don't think you are gaining anything by doing it.

Your original plan is sound, and the simplest, as long as you confirm that the original wiring is parallel. All this noise and thereotical has added nothing but confusion.

You are right. My original plan is very simple. Yeah it is making it confusing.

Can you post an extreme close-up of one LED?

Ok to save time i'm using a led that LOOKS SIMILAR
The only difference is the right leg is much closer and the top of the left leg is YELLOw and over all the led is ever so slightly wider

bumb

 

Similar doesn't help on this case. I was hoping to see evidence of an internal resistor. Sorry.

 

Similar doesn't help on this case. I was hoping to see evidence of an internal resistor. Sorry.

i have checked my self. It looks Exactly like that led above.

Similar doesn't help on this case. I was hoping to see evidence of an internal resistor. Sorry.

Just being sure. How would you tell if a led had a inbuilt resistor?

 

i have checked my self. It looks Exactly like that led above.




Just being sure. How would you tell if a led had a inbuilt resistor?

Run it from about 12V with a resistor calculated to limit current to about 20mA.

Measure the LED terminal voltage. Each colour has a specific Vf that you can look up in the datasheets - subtract that from the measured terminal voltage and calculate the internal resistance.

20mA is a good generic value for the type pictured earlier - you'd probably have to up that a bit for testing power LEDs.

 

i went ahead and ran the leds off the wall and they all work. I plugged in a laptop powersupply to the controller and played with the power nob and they can go reallly low in brightness and really high if i crank it up but i did not go all the way just to be safe as i have yet to wire in all the leds.

is that a good sign? i was scared i might blow it up when i turned it on but it worked perfectly so far.