Say NO in parallel! Because power is related to current, the higher power will continue to flow to the lower power in order to even out the balance. Can he handle it as a child? {(A serial connection is barely possible) It depends on the power of the electrical devices used. According to your two parts, it is acceptable to use electrical appliances less than 10 W. If the wattage of your electrical appliance is higher than any of these, it should not be used. The low wattage part will burn over a long period of time, so remember! ｝
Just equip it with a battery of about 10AH. Since the charging current of a 10W solar battery is less than 1A and the sunshine time per day is no more than 10 hours, you can choose a battery of about 10Ah. As for how many 12V DC bulbs can be powered, it depends on its operating current.(That is, the wattage of the bulb) If you choose a bulb of about 10W, it can be used for about 8 hours. (If you have other powers and multiple lights, you can calculate it yourself)