Don't worry, it gets a lot hotter inside the light during use - outdoor temperatures shouldn't be an issue.when i recived my light in the mail and took it out to hold it it was really hot because its 100 degrees today outside. I hope that dident do any harm to my light.
You might want to take that over to the battery sub-forum here, but my opinion is not high. There is too much variability between suppliers to know what you are actually getting (ultrafire isn't really a defined brand, more a loose standard that is heavily duplicated). There have been plenty of reports of used/pulled laptop batteries finding themselves under ultrafire-branded wrappers. I would recommend sticking with a quality brand name - again, the batteries subforum is a good place to look.Whats everyones opionin on ultrafire 18650 batteries?