If you left it charging unattended you may be hosed. (Reconsider editing above). A guy in our club was charging from his truck battery. The battery caught fire, he was off inside the house, and first he knew was when the fire dept showed up. Brand new pickup totaled by the fire. Insurance adjuster read the warnings on lipos, and the insurance sent him a nice letter saying he was negligent and no check. "Failure to follow manufactures specific instructions/warnings as noted in the instructions and packaging".