matching cobs to drivers? CLUO4j-1818c9

190w is at ~3.2A, you probably want to run them at 1.6A or less for efficacy and heat and longevity. 1.6 * 54v = 86.4W per cob with 54V constant voltage driver. 4x86.4 = ~350W. 54V constant voltage.. or a Constant current driver that can handle 216V or more. -- HLG-320H-54A or B to run them up near this value.. .or if you run them at 60W each, a HLG-240H-54A or B (B -- needs a pentiometer to dim it, but can dim it further, type A will be ~50% dimmable on board) The type A's will also go higher than they say. e.g. check out "Report" for the 240 which says 4.45A max for the 240W rating, but it actually goes up to 4.86. If the amps are cranked, it's 4.86*54 = 262.4Watts, not 240. -- 262 /4 = 65.5W each the 320 - ~357Watts, and can run it at the full ~86.4W. on a 15a circut you can run ~12A safely. 12/1.6 = 7.5.. an 8-cob fixture (or 2 4-cob) would be pushing it on a cv driver.. you'd need to run it in a a series and higher volts. 20A is safe at ~15A... google for these values and do the same math to more precise limits.