since you need to make a chamber, why not use a car cig lighter, (it should be enough power?, maybe 2 i couldn't find data) then it keeps everything at 12V, for your testing,
then after its all working you can use a cordless phone w.charger, charger for your base(gut it, and put in LiPo charger to pins, then put device in phone, attach prongs to each, so you have base charger for your device, that you can lift off when needed)
...if things start tasting like corn, you are burning it too hot...