To select the best photovoltaic system for you, you should take into account your own needs and the area available for panels. Create a list of electric devices you use and check how much power they consume. It is also vital to consider the way you have been using those devices: often, seasonally or, perhaps, sporadically.
Panels with a power of up to 75Wp are a perfect solution when your devices do not consume much power or when you use panels seasonally (e.g. only at weekends).
Bigger and more powerful panels will be better if you have a huge battery (over 5A), lots of available area (e.g. campervan’s roof), if you use your electric devices often or if your equipment consumes lots of energy. If a photovoltaic panel is going to be your only source of energy, you have to keep in mind that one module with a power up to 250Wp can constantly supply the device which consumes no more than 44W/h.
Activesol brand offers panels whose power varies between 9 W and 250W. If you cannot select a standard panel which would suit to the available area you have, you can always order a customized solar panel with the power and dimensions you need. In such a case, you can also choose the color of cells and of the background.