The inductor is definitely going to be the limiting factor, it basically always will be in a compact buck or boost driver. That said, these little drivers aren’t too bad!

Ran some new tests on stock and modded drivers with 4 wire input and output to read voltages at the board this time. My temp numbers aren’t perfect, just a thermocouple held onto the inductor, but decent ballpark. There is also no heatsinking at all, driver is just in open air, no fans.

**H1-A Stock**:

Input 3.58V 1.72A outputs 6.26V 0.94A, 95% efficient

Input 3.27V 6.11A outputs 6.37V 2.82A, 90% efficient, temps hit a bit over 50C after 2 mins.

**H1-A with R100 added**:

Input 3.54V 2.19A outputs 6.30V 1.18A, 96% efficient

Input 3.07V 8.71A outputs 6.48V 3.52A, 85% efficient, temps hit around 75C after 2 mins.

Based on the efficiency drop I think the inductor is saturated, this is probably as high as we want to push with a simple resistor mod. Overall I am very pleased with this H1-A.

**H2-C results below are not accurate due to an unknown malfunction of the driver! New results in later post.**

H2-C is not as good, or resistor moddable. Comes stock with 2 R100 stacked, I added a third R100.

**H2-C stock**:

Input 3.51V 2.62A outputs 12.45V 0.65A, 88% efficient

Input 3.29V 5.45A outputs 12.49V 1.10A, 77% efficiency, temps hit around 65C after 2 minutes.

**H2-C with R100 added**:

Input 3.39V 4.14A outputs 12.46V 0.99A, 88% efficient

High mode showed no change, output current actually went down a tiny bit to 1.06A. Tried lowering the output voltage, still no change. It appears a bit over 1A is the limit without more extensive modifications. I went back to stock resistors so the lower modes stay lower, as they did all move up despite no change on high.

Bigger inductor would probably help, and is certainly possible on both drivers, as the SMD inductor is on top of other components, connected with a large solder blob and jumper wire to the board, it does not sit on the board at all.