In order to best estimate which kit you need, simply add up the wattage of all the lights or appliances that will be running off the kit, and round UP to our nearest kit wattage. For example, say you want to light 4 lamps, each at 7 Watts, and for 8 hours a day. This gives a total of 28 Watts. From here, simply choose a kit capable of providing 28 Watts or more.