It's necessary that you get a solar controller if it's more than 5 watts that your panels put out because it'll improve the charge quality. Just remember to get one that handles your wattage, then you'll be fine. It's not necessary to buy tons of solar panels just so you'll be able to fully charge that batteries that you use. You just need to do is determine the necessaary amount of power you want and don't forget to use the proper amount of batteries and solar panels. You don't want the annoyance when getting an inverter by wrestling over a "true" or "modified" sine wave unit, just go ahead and decide if using the modified sine wave device will work.
Have you considered fabricating a solar panel from different parts? You will find that you'll get a kick out of making something that will save you money. At any rate, if you construct a solar system that helps with your power needs, then you will find that you will be saving all sorts of money while saving the environment. If you are eager to obtain a 12v solar panel, hopefully this post will help you to never be stuck without a light at night again.