I bought a couple of 80mm diameter LED Angel Eyes on eBay for AU$7.75 from this seller. These LED light rings are designed to accessorise car head lights. The inside diameter should be large enough to go around the barrel of my Makita edge trimmer spindle.
But I found the inside diameter was a little under the advertised 65mm. A little sanding and it fit nicely over my spindle. The lights rings also appear to be manufactured in several nested sizes. There are support tabs which can be seen in the above picture. These were also sanded off.
The light ring is driven from an adjustable DC-DC converter. They light up at just over 6V and reach full brightness at 12V. I am really happy with the result.
No more shining a torch into the enclosure. The effect is better with your eyes. The high dynamic range the light produces is hard to photograph.