This started with me trying to power 12 V AC LED swimming pool lights - which are always spec’d as AC for historical (and consequently safety certification) reasons - from a hefty 12 V DC leisure battery. While they work fine using 12 V AC, they don't work off the battery.
Most normal “AC” LED lights have a bridge rectifier on the input, so can run from DC. For whatever reason my pool lights can't. I tried up to 17 V DC just in case the lights relied on some peak threshhold detection, without success. There's clearly some AC coupling involved.
These pool lights are too $$$ expensive – and sealed – for me to tear down. There's no marking on the lights identifying them, and my local supplier isn't helping with this.
I could convert 12 V DC to 120/230 V AC using a cheap commercial inverter then transform down again to 12 V AC (or possibly replace the inverter’s output transformer). And this may be the easiest and most cost-effective solution - but it's not ideal.
I have an electronics background and designed stuff many years ago. Intellectual curiosity took hold, and wondered if I could make a simple low voltage 12 V DC to 12 V AC 50/60 Hz PSW converter based on a modern PSW inverter control chip – plus I wouldn’t need such high-voltage components for the power stage and keeping everything LV makes it inherently safer.
As everything is off-grid and solar/battery powered, I'm looking for high-efficiency solutions. And I'd prefer the output to be pure sine wave - at a low (50 to 60 Hz) frequency, as I know the lights will work then. A MSW/square wave output may damage components over time, and as I said, these lights are expensive...
While this started in response to a lighting challenge, it's now a more generic enquiry. I only need a 20 W output, but haven't found any low voltage low power inverters. I was wondering if there are simpler approaches, especially modular ones.
I’ve been looking at single board drivers like Sunyima’s EGS002 module using their EG8010 controller chip. Can anyone share their experience of trying to do something similar?
I've got some good comments below on solutions to power my lights - but still interested in hearing if anyone has used low-cost PSW driver boards...