H1-A boost driver with emitters in series. Stock sense resistor is 25mΩ with 75mV sense voltage for 3A output current. Swapping the stock R025 with both R050 plus R100 stacked would net 2.25A output, for example, and an R050 alone is 1.5A which for ≈10V of output that is ≈15W at the emitters.
For those interested check this thread: Buck and Boost Drivers, Testing, Modding, and Discussion (Pic Heavy)
Current newer versions of the H1-A can drive 3S emitters straight out of the box.
Cheers ^:)
P.S.: my current EDC is a heavily modified SK98 with dome shaved XHP50A G4 3500K CRI90+ driven with an H1-A with R100 + R200 sense resistors on top of the stock R025 (4.125A). It's bright. ;-)