Hi all,

I am trying to build some underwater lights for my boat. I am using 10 pcs of 3W RGB 6 pin leds in series and i have tested the output. I am currently using a constant current constant voltage driver.


I would like to make a pcb capeable of driving the 10 leds and controling them with PWM from an esp32 or other mcu, but i have some trouble finding a good driver.
I have access to 12V on the boat. I can't find a datasheet but acording to where i bought the leds needs different voltages, and since they are in series i end up with the following requirements.

Red: 700mA @ 28V

Green: 700mA @ 33V

Blue: 700mA @ 33V




Can someone help me find a driver that is capeable of driving the leds and controling them with PWM. If you have made a circuit/project like this feel welcome to link it.

 

Unless the voltages are typos, you may want to look for a solution that requires lower voltage on a boat. Especially if you're going to be in saltwater. From personal experience, if you're salty and you touch a 12v battery, it makes your fingers and hands feel like your tongue feels when you lick a 9v battery, not dangerous but very uncomfortable. I suspect that if you start getting up above 30V and someone salty somehow touches a bare wire, or is swimming near by and there's a short, it's going to be much less than a pleasant experience. I believe even swimming pool lights are limited to 12V for safety.

That said; there are a bazillian off-the-shelf DC PWM voltage controllers for cheap online, including ones that can be controlled via logic if that's a must for you. For safety be sure to use as low a current fuse on the output lines as you can get away with.

 

The buck driver chips used in LED MR11 and MR16 lamps usually have a control pin that can be used for linear or PWM dimming. https://www.ebay.com/itm/321789692730
But it might be easier to just use a resistor to limit current, and PWM them using a logic-level MOSFET driver.

 

I have mixed LEDs and water, albeit in a fresh water pool, but they get very wet every time we get in there.

You can easily get RGB LED strip lights with IP65 (?) water resistant coating. Using those and some silicon sealant to cover the wire connections got me some nice lights. I use an inexpensive controller placed outside the pool in a water resistant box and power this off an isolated 12V power supply.

Note the 12 volt power. Your boat already has lots of 12 volts lying about. Or athwart. The RGB controllers come with remote controls, or just have Alexa find it so you can "set the pool to aqua."