I have an idea for a project as I can't find anything that fits my needs currently.
The idea is the following, I would like to create a circuit where I could power 12 x 5w 940nm infrared LEDs, be dimmable and powered off of 2 x 18650 batteries.
Things to consider:
I don't require the ability to charge the batteries whilst in the device they will be charged separately.
4 of the LEDs will be on by default but the other 2 sets of 4 I can choose to turn on and off via a inline switch.
The dim function should affect all of the LEDs so I won't have to have multiple dimmers to control each group of 4.
On paper this seems like it should be a reasonably simple circuit where I can decide to power each group of 12 LEDs with a single driver but I'm really not sure what the right approach would be for this.
I'm really interested in hearing peoples thoughts as the more I think about it the more I cannot decide or figure out what the right solution would be.
If it's helpful I can post the specs of the LEDs on here?
High power LEDs and drivers are available from several suppliers.
I use AliExpress. The 3W IR LEDs and Meanwell drivers work good. They do glow red about as bright as a dim standard red LED when fully bright. https://www.aliexpress.us/
If in the US, LEDSupply is good. I use them both.
Are you sure the batteries can supply 60 Watts? Or how long it will last at 60W?
High-power LEDs are normally driven by a switch-mode special constant current driver ("controlled current" for dimming). That's NOT an easy thing to build yourself.
Some LED drivers can be controlled/dimmed with PWM. Some work with 5V PWM but the "industrial standard" is 10V PWM (or 0-10V variable DC) so depending on the driver you may need to add a transistor "booster" with and a 10V power source.
When multiple LEDs can be driven/controlled/dimmed together they can be wired in series and powered from one driver, but you need more voltage available.
Otherwise, you need multiple constant-current drivers for each LED or each group of series LEDs.
Hi mate, I will be using samsung 18650's. Battery life wise I have a similar product I bought which has lasted about 8 hours with a combination of dimming the LEDs down and depending on the situation not using all 12 at once and only using 4 by switching the other 8 off.
Hi mate, I'm certain the batteries can handle the power required as I own a light that does this already but it costs about $300 which is why I am looking to build my own one.
Bear in mind that not all the LEDs are being used at full power all the time, I vary the brightness and number of LEDs being used dependent on the situation and amount of light needed.
With regards to your comment:
"High-power LEDs are normally driven by a switch-mode special constant current driver ("controlled current" for dimming). That's NOT an easy thing to build yourself."
I am happy to buy a driver rather then build my own as I know there are boards already out there I'm just trying to identify which boards to use.
Do you know of any boards that allow for 0-10v PWM control that could also drive the LEDs or would these have to be separate pieces? I've had a look online and I think they may need to be separate pieces as I am struggling to find it all on a single board.
Also I had a feeling heat sinks would be needed for the LEDs as they can get a bit warm.