Hello everyone,
speedyganga : you have to wire your COB in parallel, to avoid voltage division due to serial connexion.
The driver you talk about can both handle constant current and constant voltage output but we actually use it more like a constant current version.
You can adjust output current from 3.3 to 6.7 amps, so if you put 4 vero 29 in parallel, they'll have from 3.3/4 = 825mA to 6.7/4 = 1675mA each (but as the driver can provide 240W max, you'll have more like 1.5 amps max each).
According to bridgelux datasheet and my own measurements -and as COB will impose output voltage- the driver will be asked to deliver from 36.4V to 38V for this range of current (he can actually provide up to 38.5V)
So you can expect from 30W to 60W for each COB, depending on the current adjustement you did on the driver...basically from 120W to 240W (maximum output) of global power for 4 vero 29.
mlabit : a HLG 185H c 1400 can't handle 4 vero 29, as output voltage is limited to 143V.
Depending on environment and current output the more you can provide is 143/4 = 35.75V for each ; this voltage is tipically the one needed @675/700mA.
The driver won't be able to provide more voltage, so the max power will be something like 25W for each COB, when only 3 vero 29 wired in series will provide 50W @ 1400mA under 37V each...
I can tell because I've tried this with 4 vero29 on a HLG 185H 1400A, voltmeter + ampmeter and the current does not even raise 700mA for 143.3V... dimming internal potentiometer has absolutely any effect, the driver is at maximum voltage range and just can't provide more volts... so the COB just can't have more amps !
Wiring 3 vero 29 is OK with this driver and adjustment can be done from 25W to 50W each.
See ya folks !