The amount of solar power you need to charge your battery depends on a few factors: the size of your battery, its voltage, and the time it takes you to use up the energy stored in it.
For example, if you have a 30Ah battery with a 12V rating and a 100W solar panel, you can use this equation to determine how long it will take for your battery to charge:
30Ah / 12V = 2.5 hours
So if we assume that you are using up all of the energy in your 30Ah battery (i.e., not storing any of it), then it would take approximately 2.5 hours for your solar panel to recharge it fully. This is assuming that there are no losses due to wiring or inefficiencies in your solar controller.
However, this equation doesn’t account for other factors like shade and weather conditions; depending on where you live and what time of year it is, there may be days when there isn’t enough sunlight available for charging purposes!