After experiencing three failures within 18 months of a certain model of laptop charger, an alternative method needed to be found. Careful experimentation with a current limited power supply revealed that a constant voltage (the voltage the charger claimed to provide) would charge the laptop. With this in mind, a DC-DC buck-boost converter was found that could supply that voltage at a reasonable amperage.
The DROK converter has been found to be fairly reliable, although it does produce a noticeable whine and slight drop in voltage when the laptop is drawing above 4 amps. Two voltmeter/ammeters would provide the most information about power from the battery and to the laptop. It is probably only nessecary to have a pair of voltmeters (to avoid damaging the laptop or over-discharging the battery).
Similar procedures have been found not to work with Apple laptops, but do not cause damage. This has been tested with certain Sony laptops, but may not work with all models.
This is not tested on most laptops, and requires careful tuning to ensure that the voltage given to the laptop is the correct polarity and voltage. Failure to do so will most likely damage the laptop's battery charger, power supply, and quite possibly other components.