What would be the safest method to power a laptop (IdeaPad 510 15isk) from a 14.8v battery pack?
Non isolated buck convertors powering something valuable, often had a crowbar circuit on the output. When over voltage occurs, the SCR is turned hard on, and stays on, until the fuse has blown. (if you use a triac it will also crowbar on reversed battery)







simulate this circuit &ndash; Schematic created using CircuitLab

When the switch of a buck convertor fails, the input flows straight through the inductor to the output. If the load will be destroyed by this, then a crowbar (+fuse) is cheap insurance, and very simple to make. 

For example my ebike battery has a usb 5V output, powered by 42V of lithium cells, and a shitty little buck convertor pcb. You bet I added a crowbar, cos I don't trust the regulator.

Transformer coupled power supplies don't have this issue as a fault generally results in no output. 
However most types of power supply are susceptible to the adjustment pot going open circuit, or being fiddled with. A hard crowbar remains cheap insurance if the load is valuable.

FYI, trimpots can fail where the wiper does not contact the track (permanently or momentarily due to shock). They should always be wired with 3 pins used, so that they don't go open circuit when this happens. 







simulate this circuit

This is something to inspect and correct on cheap CN modules. You can always add fixed resistors to limit the max output voltage to something safe.