I have another question about these DIY lights. I'm going to order the Optronics lights and I'm trying to decide on a battery from batteryspace. What I've read says that overvolting gives a brighter light which is worth the reduced bulb life. Would 13.2 be good or should I go with 14.4? I'm planning to swap out the bulbs and replace with a 20w spot and 15w flood. The 13.2 is a 4.2amp so if I calculated right that would give me about 1 1/2 hrs.