Hello,

Let me begin by saying that I'm not an engineer but DIY electronics enthusiast.

I'm building a custom LED light for my aquarium using the strips.

Length of the aquarium is 1m so I'm going to cut the 5m strip into 5 x 1m and connect them in series/parallel.

My question now is, can I connect the 5 x 1m strips in parallel for increased brightness?

The 5m strip has 300 LEDs and is supposed to draw 1.2A per 5m (12volts). Can I use the same or should I use a power supply with higher amps?

The ultimate goal is to have the best brightness as possible. What do you suggest?

Thank you very much for your help.

PS: I used the search function within the forum as well as Google but couldn't find any answers related to brightness and parallel/series.

Regards,
Carty..

 

hi Carty,
Welcome to AAC.
If the current thru the LED is the same value, the brightness will be the same parallel or serial.
E

 

I tried using 2A, 5A and 8A transformer but got the same brightness. Is it because the strip or circuit is designed to allow only required/limited current?

 

hi C,
The controller in the LED driver will determine the current thru the LED's, it will only draw the current from the 'transformer' as set by the controller.
E

 

As long as the power supply voltage is correct, it does not matter if the power supply has a higher current capability. The LEDs will draw the same current. Think of a 12V plug pack that can supply 1.5 Amps (like a lot of external hard drive supplies). Your LED strip will draw the 1.2Amps with the supply not running at full current capacity. But you can only run one strip.
Now, put the LED strip on a 12V car battery. It will still draw the 1.2Amps but for a car battery, that is a very small load. The battery could easily run a dozen LED strips.
The important thing to remember, get the voltage right. And have the current rating a little higher than you need so the supply is not working flat out.

 

As the string is designed for 12 V ( ? ), I would not suggest raising the V to over 12 V but look for a brighter string.
If the cut marks are every 3 LEDs then we have 100 short strings or only 12 mA / LED. If it were my string then I would raise V to 15 to 20 V using one short string for test.

 

The 5m strip has 300 LEDs and is supposed to draw 1.2A per 5m (12volts).

I would just cut into the strips you want and parallel the strips. Each strip will draw about 240 mA with 5 strips. They will only draw their rated current so placing a supply out there with a higher current capacity will not get you anything. Placing the strips in series will result in a need for a higher voltage supply, for example just two 12 volt strips in Series would require 24 volts. All you need is a 12 volt 2.0 amp supply which should be adequate. You may also want to fuse the LEDs with maybe a 1.5 amp fuse just in case anything goes wrong.

If the brightness with the strips is not adequate I would just look for brighter LEDs.

Ron

 

I think actually, connecting the strips in line is not in "series".
Each LED has its own resistor and so the strips are not connected in series unless you hook the +Ve of one strip to the -Ve of the previous one. If you do that, make sure both strips have the same number of LEDs.

 

Thanks a lot for the assistance. I will connect them in parallel.

Placing the strips in series will result in a need for a higher voltage supply, for example just two 12 volt strips in parallel would require 24 volts. All you need is a 12 volt 2.0 amp supply which should be adequate.

Ron, in the above quote, "two 12 volt strips in parallel would require 24 volts" you meant series instead of parallel?

Regards,
Carty..

 

Thanks a lot for the assistance. I will connect them in parallel.



Ron, in the above quote, "two 12 volt strips in parallel would require 24 volts" you meant series instead of parallel?

Regards,
Carty..

Thanks, I fixed it. Two 12 volt strips in Series would require 24 volts. Can't believe I typed that. I would just cut your strips and connect them in parallel. If the light is low I would just seek brighter LED solution.

Ron

 

I'm glad I figured it out

Thanks for all your help.

Regards,
Carty..

 

Depends on what you have. If they're color changing RGB LED's then they're wired per the RGB drawing below. If they're all white then they're wired per the "White" drawing below. As you can see, the RGB are in parallel in groups of 3. Likely on your strip there's places where you can break the string. You can solder the 0 volt line to the next 0 volt line. Just be sure to solder each 12 volt line so that if you want all red you get all red. (blue or green - so on and so on).

If they're all white then parallel is even easier to connect. Notice that each group of 3 white LED's are in series with a single resistor to control their brightness.

In each situation (RGB or White) the current is controlled by either the controller or the resistor (or a combination of both). As has been explained to you, the string will draw as much current as it is designed to. Whether you have a supply capable of 10 amps or 1,000,000 amps, the strings will only draw what they will draw. The larger supply won't make the lights any brighter. To change the brightness you need to change the voltage. Understand that upping the voltage ups the current. Upping the current means increasing the wattage. Increasing the wattage means having to deal with more heat. If the resistors on the strings are capable of handling 1/8 watt and you get close to 1/8 watt (or exceed) then you can start having burn-out. Even if you don't burn out the resistors, running the LED's at higher current will shorten their life. Too much current and they may last a week. TOO TOO much current and they may last all of a few seconds. OR SHORTER!

Keep in mind, you're concentrating all the light into 1 meter length. 5 times the amount of light to be precise. It may very well be plenty of light. Let's make up some numbers: Suppose 1 meter of LED's produces 1000 lumen. Not a lot. 5 meters of LED's will produce 5000 lumen (over 5 meters). folding the LED strings back and forth so that you have 5 times the LED's in 1 meter means 5000 lumens concentrated into that 1 meter space. I'd go ahead and build the light without modifying any currents or voltages and see what kind of effect you get. If you're happy with the amount of light - great. If not - you can take the next step(s).

It may also be of help if you identify what LED strip you're using.

 

Thanks tony for the detailed drawing and explanation. I will connect them in parallel.