JR ... a lot has been written about this. Do a search for "solar candle" Tell the search engine (above right) to "match all words" of the
solar candle search.
Wherever I talked about
solar candle, I usually talked about
dry camping.
Also could search for "jump-its" or "jump-it" We've used them ... and talked about them ... for years about extending dry camping stays.
The trick is conservation and minimalization ... but also years of practice and trial-and-error (lots of errors). You have to figure out what works for you.
I know that a lot of people don't believe that my wife and I camp as much as we do ... or that we do as much dry camping as we do ... or that we do as much winter camping as we do.
To me, that's the real trick, however ... and that's to go camping as often as you can.
None of this stuff is rocket science. And luckily, most of your mistakes wouldn't be fatal ones (although that cliff incident in Nova Scotia sure was close!)
After you do some reading about "solar candles" and "jump-its," come back here and post specific questions.