Backup Options for Solar Pumps – Sizing Batteries and AC Backup Power
If you are a solar pump installer, you know how important backup options are for your customers. The sun is great, and it’s always there in one form or another, but cloudy weather or applications that require nighttime pumping are a reality. At WORKHORSE we do our best to tailor solutions for you, not the other way around, which means we’re very open to discussing how best to work around the limitations of solar power.
Let’s first chat through options for batteries. Our Narrow Series is fully compatible with either a 24V or 48V battery bank. The PSC 100 controller has an optional battery mode that when fully charged can allow for a couple of hours of extra run time. The caveat here is that a full charge is not a guarantee if the pump has been running constantly throughout the day. Batteries also need to be stored out of the elements, and the pump’s performance will be similar to a 500W solar array. Some tips we recommend are using 48V battery banks over 24V battery banks whenever possible, ensuring your batteries are deep-cycle AGM/GEL, and understanding that if you’re not getting the runtime you’re looking for you may need to increase the number of 48V battery banks (in parallel) and/or solar panels on your system.
Figure 1: Solar Panel Wiring 24V battery bank vs 48V battery bank
So batteries are one option; they have their pros and cons and are useful in an assortment of cases. For our Solar+AC Series though we recommend backing up with grid power or a generator whenever possible. These 4-inch and 6-inch pumps have higher-powered motors and can accept both solar and 110V or 220V AC power, so you can avoid the cost and complexity of larger battery systems by simply connecting a generator or grid power to supplement direct solar operation. Our PSC300 controller features dedicated power inputs for both DC and AC, and it can be set to automatically switch between these inputs, always prioritizing solar. Our Narrow Series and Direct Drive Series pumps can also be powered by 110V AC power sources using external converters or auto switchers that WORKHORSE can supply. Our pumps are designed to run continuously, so if they need to be powered outside of the limits of the sun, we have solutions.
Figure 2: PSC300 AC Wiring Inputs
One other backup option that isn’t always considered but is incredibly helpful for solar pump applications: gravity-fed systems. In this application, water is pumped throughout the day to a high-volume storage tank. That storage tank is located at an elevation differential relative to the point of use. When water is called for outside daylight hours, the solar pump won’t run, but the storage tank can continue to supply water. In this scenario (using the value 1 PSI = 2.31’ TDH) you’d need to know the necessary PSI and ensure your elevation difference meets that. You’d also need to pair our WORKHORSE pump with a tank float or water level sensor, which are included in many of our kits. This option doesn’t always work for folks, but it often is the simplest way to ensure a high volume of water can be stored. This is especially helpful in regions of the U.S. where tropical or winter storms can occasionally limit pumping over multiple days, so don’t hesitate to consider this option for your clients.
Figure 3: Backup Storage Tank
If you’re looking for U.S.-based solar pump manufacturers who know what they’re talking about and won’t hang you out to dry with support issues, you can reach out to us at 916-623-4621 or through email at support@workhorsepumps.com. Whether you’re thinking about getting into the solar pump installation business, or you have a history with solar pump systems but are looking for alternative options, we’d love to chat for a bit. We’ve made our name off of human-to-human contact, and we’re looking to grow with you. Our business model doesn’t rely on one sale and then never wanting to hear from you again, we want to hear how products are doing and how we can help your future needs. Hopefully, we can make that work for you today!
