Just wondering . I’ve got a few chunky Anker USB batteries (13000 to 26800milli amp hours) that are useful for keeping phones ands tablets going sans AC or car power. Would it be difficult or impractical to make some inverter type adapter that would output 12V DC from these 5V DC batteries so you could use it for powering notebooks and car accessories?
Search for a 5V DC to 12V DC converter.
You may find something like this…
or this…
That is interesting. It also shows me that best an adapter like that is going to do (700 ma and only for short periods) is way less than most modern notebooks a require for a charging amperage (usually 3 to 5 amps @ 15 to 19VDC ). These portable batteries seem powerful in that they can run phones and tablets for days but when more serious power is required they apparently have their limitations.