Reddit reviews BiXPower 12V or 24V Input (Range 10V ~ 30V) to Multi Selectable Output Voltages (12/15/16/18/19/20/24V) Universal DC Power Adapter with 12 Interchangeable Connector Tips - DD90X
We found 2 Reddit comments about BiXPower 12V or 24V Input (Range 10V ~ 30V) to Multi Selectable Output Voltages (12/15/16/18/19/20/24V) Universal DC Power Adapter with 12 Interchangeable Connector Tips - DD90X. Here are the top ones, ranked by their Reddit score.
This DC to DC power converter can accept a very wide range of input voltages: from 10V to 30V. It can be used with 12V or 24V car/truck/boat cigarette lighter.It can output many different voltages at user selection: 12V/15V/16V/18.5V/19.5V/20V/24V. It also has a 5V USB port that can power and charge an iPad or iPhone (USB power cable not included).USB port on power adapter can power and charge iPad/iPhone & many other devices that can be powered and charged from 5V USB port.(USB power cable not included).This power adapter comes with 12 interchangeable connector tips for many popular laptop computers such as Acer, Asus, compaq, Dell, Fujitsu, HP. IBM, Lenovo, Panasonic, Sony and Toshiba and many other brands.
Use a car 12v to selectable output adapter like this:
https://www.amazon.com/BiXPower-Selectable-Universal-Interchangeable-Connector/dp/B00MMUMST2
Check if the maximum wattage and connector matches though (i havent check for this specific adapter).
That's much more efficient then converting 12v dc to 120v ac and back to 19.5v dc.
https://www.amazon.com/BiXPower-Selectable-Universal-Interchangeable-Connector/dp/B00MMUMST2/ref=sr_1_11?ie=UTF8&qid=1524850048&sr=8-11&keywords=12v+to+19v+converter+car
or
https://www.amazon.com/BOLWEO-Universal-Adapter-Automatic-Voltage/dp/B01N1SWXSE/ref=pd_day0_23_2?_encoding=UTF8&pd_rd_i=B01N1SWXSE&pd_rd_r=4G0GZPYTC2ZBFMWPAP6K&pd_rd_w=oi5PT&pd_rd_wg=Y6XTV&psc=1&refRID=4G0GZPYTC2ZBFMWPAP6K
I don't know if I would trust the "Automatic Voltage" products.