I note all my flight particulars in a notebook in the field than when I get home I fill out my 'proper' log books with the deatails...a spreadsheet.
I say log books in the plural since as well as my main spreadsheet log book I also run a cut-down version which contains the minimum detail on flight hours that the CAA require for PfCO which they can inspect at any time. That does not contain battery info. Just the date, time, location, flight times, and is signed off by me on a monthly basis.
My main log book contains far more detailed info and is not available to the CAA since they don't require such detail:
Date; Time; Make/model of sUAS; Location; Flight time; Max Height (from flight data); Max distance from take-off (from flight data); Satellites count; Video Duration; Number of stills taken; Battery start; Battery end; Battery number; Overall cycles for a particular battery; A notes field (a note of any significant occurrence); Recorded wind speed at ground level; Air temperature; A note about the general weather (sunny/cloudy/dull overcast, etc.); Flights over buildings Yes/No; Flights over water Yes/No
This record goes back 3 years covering every flight I've done since I started this log book. So, for example, I can say exactly how high I flew my aircraft on February 2nd 2015 and how long that flight lasted in the time it takes to load that spreadsheet into my computer's memory.