I'm going camping for a weekend (not really, I'm going to a 24 hour running event and will have a tent to sleep in if I stop....). I have lots of tasty nutritious vegan food that I can make with boiling water but.....no kettle. What's my best option? I want to boil half a litre of water reasonably quickly (it takes time out of the race) and very simply (it's likely I'll be tired and not up for complex things). I will have my car nearby so one option is a 12V kettle but apparently they are about 18 mins. Anything simple that's a lot quicker for reasonable money?