Hey everyone! I'm looking to set up a solar-powered pump for my small wildlife pond to help with aeration and keep algae growth in check. I've found a pump that operates at 115V and has a maximum power requirement of 142W. My question is, how do I determine the appropriate solar panel size for this? I see panels rated at 20V and I'm unsure if that voltage will be too high for my pump setup. Any guidance on how to estimate the solar panel size and what else I should consider before making a purchase would be greatly appreciated!
3 Answers
You might want to consider using a DC pump instead of the AC one you're looking at. That way, you can skip the inverter completely. If you go with the AC pump, you’ll definitely need an inverter to convert DC to AC. To get a rough estimate of panel size, you can take the maximum power usage and multiply it by 24 hours for a daily usage figure. Typically, you should calculate based on about 5 good hours of sunlight to figure out how many watts you need from panels. So for a 145W load, you'd need around 700W of panel capacity to meet daily needs, plus a battery to power it overnight—starting with one that holds about 3.5kWh sounds good!
If you're looking for a budget-friendly option, check out Vevor. They sell affordable DC solar pumps that generally only need one or two panels in parallel. Choosing an AC pump would mean investing in an inverter and batteries, which can add up.
How much flow do you really need for your pond? I just snagged a 12V pump and paired it with a 100W solar panel from Amazon. No batteries or inverters needed, and it does a great job for my needs! Just keep in mind that the panel is 18V, which is ideal for charging the pump directly. If you want higher flow for something like a hot tub, you might want to consider getting a bilge pump instead!

That sounds like a solid plan! Just make sure to account for potential inefficiencies in your system as well.