Alright. I like a challenge. Here is "Ganjineer's dirt cheap not complete shit COB build for a cool 2 hundy".
- CLU048-1212 $13.25 x8= $106.00
- Generic 400w switching power supply $19.11 x1= $19.11
- Generic 600w boost converter $10.92 x1= $10.92
- Cooler Master 12v CPU coolers $6.99 x8= $55.92
- Generic scavenged 12v dc adapter x1= $5
- I find them at goodwill all the time for nearly no cost
- Parts and accessories= $20
- Total: $217
It's not the most elegant, but it'll produce a whole lot of light for very little coin. It'll give you plenty of room to expand and upgrade in the future. I've tested both the boost converter and power supply and they perform as advertised, with around 80-90% efficiency.
You use the power supply and boost converter to power 4 parallel strings of 2 COBs in series (8 COBs in total). You can adjust drive current by adjusting the current and voltage set potentiometers on the boost converter. This will drive them up to 400w if you wish. You use the 12v adapter to power the fans on the CPU coolers