The VC4plus
It can charge 4 18650s no problem but the limitation is the maximum charge rate for each of the 4 slots, 1A rate per cell for 4 cells, 2A rate for 2 cells, and 3A for a single cell. A 1A charge rate is more than acceptable. The charge rate is automatically selected for each cell based on its internal resistance measurement, which it can selectively display. Optionally you can manually select a maximum charge rate for all four slots (3A, 2A, 1A, 500mA, or 250mA for very small cells).
Optimal charge rates are based on the fraction of a cells rated capacity as a multiplier: 0.5C for normal charge or 1C for rapid charging, where C is the cells capacity. For example, an 18650 with 3000mAh capacity, normal charge is 0.5C (where C=3000) so 1500(mA) which is 1.5A. So either 1A or 2A is perfectly fine.
1C for fast charge=3000mA=3A for fast charge.
Generally, slower charge rates are beneficial for cell longevity in retaining capacity after many use cycles. Always best to round down to a lower charge rate.
The main thing is the intelligent charge circuit in the VC4 can be trusted so you just have to pop the cells in and wait for the LEDs to turn green, while watching the display for the technical details if you want to know.
I looked at the Wurkkos HD15s and they don't specify cell size, only using their onboard USB C charging. It's either an 18650 or 14500 but I'm guessing 18650. Both will work perfectly in the VC4.
Finally, yes the F56 will offer greater overall runtime than the stock Acebeam cell without sacrificing maximum output. It's also half the price of an Acebeam branded 5000 cell.
Glad this helps!
