Yes, a 5W solar panel can charge a 12V battery. Then, after doing it, I saw that Google isn’t exactly giving the best answer to this question: Huh? And I decided to write this article to set the record straight. Yes, you can charge a 12V battery with a 5W solar panel. You just need to make sure it’s a 12V solar panel.
Based on the above charge times, we can draw some conclusions: 5W and 10W solar panels are good for slow, trickle charging 12V batteries. They’re a good size solar panel for maintaining a 12V battery’s charge, and will slowly charge it up over the course of weeks — maybe even months depending on the weather and size of the battery.
Make sure to get a 12V 5W solar panel. If it is a lower voltage 5W panel (like 6V or 9V) it won’t work with a 12V charge controller. Make sure your charge controller is compatible with your battery’s chemistry. For example, some charge controllers only work with lead acid batteries. Others work with lead acid and lithium batteries.
According to our solar panel charge time calculator, it takes around 107.3 peak sun hours for a 5W solar panel to fully charge a 50Ah 12V lead acid battery using a PWM charge controller. And here are the estimated charge times for 5 other common solar panel sizes:
80W and 100W solar panels are good for fast charging large 12V and car batteries. If it’s a 50Ah battery, they can fully charge it in around 12 hours or less of direct sunlight. For more help on finding the right size solar panel for your solar charging setup, check out my post on what size solar panel will charge a 12V battery quickly.
Understanding Solar Panel Types: Familiarize yourself with different solar panel types—monocrystalline, polycrystalline, and thin-film—to choose the most efficient option for charging your 12-volt battery based on space, cost, and performance.