Hello, May I ask if these lamps/incandescent lamp can be used in homes if there is ever a power shortage? In the Philippines, the 12 volt-type of it was rated as 5 watts so it won't produce much heat and it won't pull the battery down fast. So is it okay to use? Once again, in the Philippines the rates of these bulbs are 12 volts and 5 watts. In others, it's 24 volts but I don't know the wattage rating of it. Thank you.