Is it better to have more solar panels or more batteries?

We get this question a lot- is it better to buy more solar panels or more batteries. Our first answer is to always consider a storage tank before batteries. Storage tanks accomplish the end goal of storing a water source above ground, waiting for use. Especially for livestock or irrigation projects, where that water could easily gravity feed into its final destination 24/7, day or night. We think a storage tank always wins out in terms of dollars spent and very little maintenance costs compared to batteries.

More solar panels? You can always expand a solar array by adding more panels. More panels means greater square footage of solar cells exposed to the sun, resulting in higher efficiency and longer runs times into the earlier morning and later evening when very little sun is available. If you’re needing just an hour or two of longer run time, try adding another line of panels. For example, and RPS 400 with four 100W solar panels in 48v would add four more 100W panels in parallel. Now if you already have batteries attached to the system, adding more solar panels will recharge the batteries faster.

More batteries? Maybe you’re running out of power at night, your batteries are drained but there are still more chores that require water around the ranch. In this case, add more batteries and consider adding a few more panels as well. You might be using quite a lot of power during the day and the batteries are unable to charge back up quickly enough for nighttime activities. Adding more batteries adds power storage to your system. Now, adding batteries to a solar water pump won’t automatically bestow 24 hours of consistent pumping time. Usually in a bank of four, 55Ah 12v batteries there’s about 4-6 hours of pumping time stored. Most people use some power in the morning, leave for the day and then return at night. Their power usage is shifted and split around throughout the day.