If coffee is what you want ... an inverter is an expensive way to go not only in original purchase price but also weight and DC to AC inversion wastes a lot of energy.
My Wife uses a pour over filter cone with a thermos. The coffee comes out delicious and is easy to do.
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You simply boil water ... remove it from the heat until it just quits boiling, place the filter cone over the mouth of a thermos bottle and pour the hot water thru the grinds.
Sweet Maries is where we got ours at and the Zojirushi thermos keeps the coffee hot for at least 18 hours.
The advantage in taste is the HOT water ... coffee is best if made at a temp of around 180 - 200 degrees and most home coffee makers can't get that hot.
A simple pour over filter cone and a thermos is a great way to enjoy coffee