Using a phone charger as LED power supply?

Using a phone charger as LED power supply?

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    12
B

biostudent

Well-Known Member
iHearAll said:
12v seems low to wire in series for that many lights.

Ok, so voltages add up in series and current remains constant through each LED.

Currents add up in parallel while voltage remains constant for each string of leds.
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I understand that bit. But I'm not sure what the setup would look like in parallel, how to wire in parallel, or what volts and current to supply. Pretty much, I don't understand the difference between the two or how the circuit is affected. This probably sounds embarrassing from a technical pov; I know this is elementary stuff.

iHearAll said:
Drop a link to the strips your are considering so I can look at the datasheet. Also, I am a degree holding electronics engineer and am studying electrical engineering now. So you can generally trust me . :peace:
(Theyre slightly different degrees Lol, mostly the calculus and differential equations make them different)
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Well I lost the specs sheet with my phone. I requested the supplier to send me a new one. Only thing I have right now is a small excerpt from its cover and some details off the top of my head.
I'll take your word for it or anyone on this forum. I'm certain everybody here knows more than me about circuiry.

iHearAll said:
I recently made a purchase for some very nice and TCL strips from Estonia via ebay. They come with a dimmable ballast for each strip and you get 5 strips for $50. They need to be mounted to 2" u bar. If you want to follow my build let me know and ill leave a link. They are very efficient LEDs @ 154lm/w as claimed by the seller. Who which also has the best deals for citi leds as well...
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Yes. Please share. I'm always willing to learn from others.
My own project is experimental and keeping a tight budget. I think, if I consulted this forum earlier, I could've saved a lot of the hassle.
Thanks for the help.
 

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iHearAll

iHearAll

Well-Known Member
biostudent said:
I understand that bit. But I'm not sure what the setup would look like in parallel, how to wire in parallel, or what volts and current to supply. Pretty much, I don't understand the difference between the two or how the circuit is affected. This probably sounds embarrassing from a technical pov; I know this is elementary stuff.


Well I lost the specs sheet with my phone. I requested the supplier to send me a new one. Only thing I have right now is a small excerpt from its cover and some details off the top of my head.
I'll take your word for it or anyone on this forum. I'm certain everybody here knows more than me about circuiry.


Yes. Please share. I'm always willing to learn from others.
My own project is experimental and keeping a tight budget. I think, if I consulted this forum earlier, I could've saved a lot of the hassle.
Thanks for the help.
Click to expand...
So, it looks like you can cut the strip on the lines labeled 12v. So, they are actually preassebled in parallel 12v circuits. This means you could cut the strip at the lines and reorganize them in series or parallel as you please. Ill sketch a picture for you in a little bit when I get more time. They don't want you to power the entire circuit from one spot it seems. This is because the resistance of the wire itself in the strip would cause dimming towards one end and possibly greater heat in the wire.
 
B

biostudent

Well-Known Member
iHearAll said:
So, it looks like you can cut the strip on the lines labeled 12v. So, they are actually preassebled in parallel 12v circuits. This means you could cut the strip at the lines and reorganize them in series or parallel as you please. Ill sketch a picture for you in a little bit when I get more time. They don't want you to power the entire circuit from one spot it seems. This is because the resistance of the wire itself in the strip would cause dimming towards one end and possibly greater heat in the wire.
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Yes, the strip can be clipped at every 5cm. I requested a 5.4 meter roll (they usually sell in multiples of 5m). In my setup, I required 6x strings, each 900mm. The original plan was to wire in series, but later findings put me in doubt. Parallel might be easier. I just don't know how current/volts will drop/distribute along the circuit. And with multiple diodes in each 900mm string, if I was to wire in parallel, I'm assuming this would be a series-parallel combined circuit? This is where both my knowledge and experience is non-existent.
 
iHearAll

iHearAll

Well-Known Member
biostudent said:
Yes, the strip can be clipped at every 5cm. I requested a 5.4 meter roll (they usually sell in multiples of 5m). In my setup, I required 6x strings, each 900mm. The original plan was to wire in series, but later findings put me in doubt. Parallel might be easier. I just don't know how current/volts will drop/distribute along the circuit. And with multiple diodes in each 900mm string, if I was to wire in parallel, I'm assuming this would be a series-parallel combined circuit? This is where both my knowledge and experience is non-existent.
Click to expand...
ok, so if each segment of your strip is 12v then you can cut at the line and simply add a wire between the positive of one and the negative of the next on those copper pads. then every time you do that you will add 12v to your series circuit. if for instance, you wanted to cut every two segments for less work then the two that are left together will be in parallel and they will share a voltage. The current required would be double but you could have less soldering to do if you did it in some variation of this method. You could leave 3 in a segment, four, five, it does not matter and they will remain only requiring 12v to power that entire length. whatever you do just keep each length you make containing the same number of segments. This is because you want each length to require the same current.


Say you wanted to divide your entire roll into 4 sections. You would make sure each four lengths contains the same number of segments. Then add a wire at the parts you cut and add up the voltages. 12v * 4 = 48v required now.

you should do this according to the driver you want to use.

this is the correct part?
https://www.alibaba.com/product-detail/Hot-High-Lumen-Ultra-Bright-CRI_60562444073.html

they dont provide a current requirement per segment but a good approximation would be found by the 18W/M value given. The formula for power is volts*amperes= Watts. If, for instance, you cut at every meter, which requires 18w, then you know your voltage is still 12volts for that entire meter. So 18/12 = 1.5 amperes would be required.

your extra .4 meters will make this a little bit tricky to correctly assemble. can you count how many segments are in a meter for me? I want to know the current requirements per segment. I can probably design you an easy to assemble cutting and wiring diagram.

CIMG4616.JPG CIMG4617.JPG
 
B

biostudent

Well-Known Member
iHearAll said:
ok, so if each segment of your strip is 12v then you can cut at the line and simply add a wire between the positive of one and the negative of the next on those copper pads. then every time you do that you will add 12v to your series circuit. if for instance, you wanted to cut every two segments for less work then the two that are left together will be in parallel and they will share a voltage. The current required would be double but you could have less soldering to do if you did it in some variation of this method. You could leave 3 in a segment, four, five, it does not matter and they will remain only requiring 12v to power that entire length. whatever you do just keep each length you make containing the same number of segments. This is because you want each length to require the same current.


Say you wanted to divide your entire roll into 4 sections. You would make sure each four lengths contains the same number of segments. Then add a wire at the parts you cut and add up the voltages. 12v * 4 = 48v required now.

you should do this according to the driver you want to use.

this is the correct part?
https://www.alibaba.com/product-detail/Hot-High-Lumen-Ultra-Bright-CRI_60562444073.html

they dont provide a current requirement per segment but a good approximation would be found by the 18W/M value given. The formula for power is volts*amperes= Watts. If, for instance, you cut at every meter, which requires 18w, then you know your voltage is still 12volts for that entire meter. So 18/12 = 1.5 amperes would be required.

your extra .4 meters will make this a little bit tricky to correctly assemble. can you count how many segments are in a meter for me? I want to know the current requirements per segment. I can probably design you an easy to assemble cutting and wiring diagram.

View attachment 3973541 View attachment 3973542
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So, let me get this straight: if I cut at the cut-line and add a wire, it will become series? If I don't cut, it is parallel? I'm lost here. I thought this entire strip from 0 to 5.4m was in series if uncut.

60 LED's / meter.
20 segments / meter.
3 LED's / segment.

Point to note,
After 10 segments, the cut line seems to be missing and it looks like the 11th segment has been soldered to the 10th. Not sure if I can cut this or unsolder. The same appears at the 20th - 21st segment partition. [pic attached]

1499799617445-2104119750.jpg

But there is a cut line at 90cm where I planned on cutting because I wanted each strip at 90cm in order to fit into my system.
 
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B

biostudent

Well-Known Member
Strip #1: 6000K
IMG-20170706-WA0003.jpg

Strip #2: 3 blue : 1 red
IMG-20170706-WA0002.jpg

The dimensions are off (i.e. not 5000mm). The supplier is the one you posted (Shenzhen Coxo).
 
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iHearAll

iHearAll

Well-Known Member
biostudent said:
So, let me get this straight: if I cut at the cut-line and add a wire, it will become series? If I don't cut, it is parallel? I'm lost here. I thought this entire strip from 0 to 5.4m was in series if uncut.

60 LED's / meter.
20 segments / meter.
3 LED's / segment.

Point to note,
After 10 segments, the cut line seems to be missing and it looks like the 11th segment has been soldered to the 10th. Not sure if I can cut this or unsolder. The same appears at the 20th - 21st segment partition. [pic attached]

View attachment 3976234

But there is a cut line at 90cm where I planned on cutting because I wanted each strip at 90cm in order to fit into my system.
Click to expand...
Ok just make 90cm lengths and power them in parallel at 12v. This will be perfectly safe form he strips. The manufactures warning won't apply to the circuit as soon as you cut the strip.

You can have as many 90cm strips as you want. You can even add 10cm strips. Any length really. As long as they remain in parallel to the power supply you don't have to worry. I say his because each segment is labeled for 12v but the manufacturers says to power the entire length you also use 12v, so they're in parallel. Parallel components share the same voltage while the currents add up. Series components share current while the voltages add up.
1499808572605-792626371.jpg
 
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B

biostudent

Well-Known Member
iHearAll said:
Ok just make 90cm lengths and power them in parallel at 12v. This will be perfectly safe form he strips. The manufactures warning won't apply to the circuit as soon as you cut the strip.

You can have as many 90cm strips as you want. You can even add 10cm strips. Any length really. As long as they remain in parallel to the power supply you don't have to worry. I say his because each segment is labeled for 12v but the manufacturers says to power the entire length you also use 12v, so they're in parallel. Parallel components share the same voltage while the currents add up. Series components share current while the voltages add up.
View attachment 3976297
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So, in this diagram, you have 2x strips in parallel. Can I add more strips in parallel, given the supply gives enough amps? i.e. Can I have 6x strips at 900mm in parallel with a 12v x +10a supply?

Also, (this is probably a stupid Q) the supply you linked 12v 20a for example, as with most supplies, it has 3 ports each for + and -. If I was to to supply three different circuits with one supply unit, will the output power (240W) divide into 3, or will each of the three circuits receive 240W independently?
 
iHearAll

iHearAll

Well-Known Member
biostudent said:
So, in this diagram, you have 2x strips in parallel. Can I add more strips in parallel, given the supply gives enough amps? i.e. Can I have 6x strips at 900mm in parallel with a 12v x +10a supply?

Also, (this is probably a stupid Q) the supply you linked 12v 20a for example, as with most supplies, it has 3 ports each for + and -. If I was to to supply three different circuits with one supply unit, will the output power (240W) divide into 3, or will each of the three circuits receive 240W independently?
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Yep you can do that. I think the pics are generic for that item. It may be different in person. But, I would imagine the outputs are all connected internally and they are just separate ports to the same location behind the cover of the supply.
 
B

biostudent

Well-Known Member
iHearAll said:
Yep you can do that. I think the pics are generic for that item. It may be different in person. But, I would imagine the outputs are all connected internally and they are just separate ports to the same location behind the cover of the supply.
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Ok great. So it's safe to use single a 240W supply to power two different 120W circuits?

Also, last thing I forgot to mention, because I have 2 rolls of 5400mm each, one 6000K and the other 3blue:1red, and I want to create two circuits, each having 2700mm 6000K soldered to 2700mm red:blue, is it okay to connect two different LED types in this way in one circuit? They are both rated 12v 97.2W @ 5400mm.
 
iHearAll

iHearAll

Well-Known Member
biostudent said:
Ok great. So it's safe to use single a 240W supply to power two different 120W circuits?

Also, last thing I forgot to mention, because I have 2 rolls of 5400mm each, one 6000K and the other 3blue:1red, and I want to create two circuits, each having 2700mm 6000K soldered to 2700mm red:blue, is it okay to connect two different LED types in this way in one circuit? They are both rated 12v 97.2W @ 5400mm.
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I wouldn't push the supply they hard but it will work. If you want two 120w circuits I would get a supply unit that can handle well over 240w. You'll have a better power transfer and a PSU that stays cooler.

Yea you can add any 12v circuit in parallel with the others. It can be a 12v fan, less, or whatever
 
B

biostudent

Well-Known Member
iHearAll said:
I wouldn't push the supply they hard but it will work. If you want two 120w circuits I would get a supply unit that can handle well over 240w. You'll have a better power transfer and a PSU that stays cooler.
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Well, the single circuit itself is 97.2W. I added 23W extra for supply so it doesn't run at max load.
Thanks for the great help btw. I won't forget.
 
nfhiggs

nfhiggs

Well-Known Member
B

biostudent

Well-Known Member
nfhiggs said:
I would use 14AWG for the A wires and 18AWG for the B wires.
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My build is almost complete. I will post the pics here once completed. Just one more thing I forgot to ask, what gauge to use on the "L, N, ground" terminals that will be plugged into the wall? Is ground necessary?
 
nfhiggs

nfhiggs

Well-Known Member
biostudent said:
My build is almost complete. I will post the pics here once completed. Just one more thing I forgot to ask, what gauge to use on the "L, N, ground" terminals that will be plugged into the wall? Is ground necessary?
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The ground is not needed for operation, but is necessary for safety. Power cord from a computer power supply will be plenty big enough. I got tons of those laying around.
 
B

biostudent

Well-Known Member
Well.. I don't have spare computer ps cords but I might have some regular power extension cords (but they don't have a ground wire i think). Will these work? If not, if I go to a hardware store, is there any specific wire/cord I should be looking for?
 
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