We dry camp a lot. Here's some suggestions from our experience:
Use a stove top percolator for coffee. It takes a little longer but the results are worth it. My wife wants to bring the percolator into the house because she prefers its taste to drip. If you choose to use a stovetop percolator use about one tablespoon coffee per cup and perk at as low a heat setting as possible to maintain a gentle perk. Time it for about a minute per cup. When ready transfer to a thermous carafe.
About charging your battery. The onboard charger in the camper may work just fine, but if you have a WFCO charger (most campers do) it may not deliver the necessary current for an efficient charge. Mine (like many) absolutely will not go into BOOST mode no matter how dead the battery. I have found that using a protable 10 amp charger does a much better job. About one hour of generattor use per day keeps the battery charged.