By Dave Miller · off-grid sparky · 22 years wiring solar, batteries and sheds in central QLD
“After burning out a 24V pump on my first 1.5kW array in 2002, I learned you need at least 2000 watts of panel capacity to run a pool pump reliably at noon in central Queensland.”
— Dave. Measure twice, buy once.
ArticlesCalculatorsSite PlannerShopNo bullshit. If you're off-grid in Australia and want a solar pool pump, size it right or it'll be a $2k paperweight. Here's how.
No bullshit. If you're off-grid in Australia and want a solar pool pump, size it right or it'll be a $2k paperweight. Here's how.
Pool pumps move water. How much? Flow rate (m³/h or L/s). Rule of thumb: 10% of pool volume per hour.
Example: 50m³ pool → 5m³/h minimum. But here's the catch: solar isn't constant. You need to cover low-sun days.
Actual rule: Size for 15% of pool volume per hour. 50m³ pool? 7.5m³/h min. Under-size and your pool turns green in 3 days.
Head = resistance. Pipes, filters, ladder, skimmer. Every 1m of pipe = 0.1m head. Add 1m for filter, 0.5m for ladder.
Example: 20m pipe + filter = 2.5m head. If you ignore this, pump runs at 10% capacity on sunny days.
Do this: Measure your entire system. If head > 5m, forget cheap pumps. You need a 24V variable speed unit.
Fixed-speed pumps waste 80% of solar. They run full blast when you don't need it. Variable speed (VSD) adjusts to sun levels.
Why you need it: On a 50% sun day, a fixed pump runs at 50% speed but uses 100% power. VSD runs at 50% speed and uses 12.5% power. Saves 87% energy.
Don't buy a pump without VSD. It's not optional. It's the difference between a working system and a $2k mistake.
Practical tip: Buy a pump with built-in VSD. No external controllers. They're cheaper, simpler, and less to fail. Example: SunSun Solar Pump (24V, 7.5m³/h). No extra box needed.
Forget the $1,200 "solar pump" from Bunnings. It's a scam for off-grid. Here's what actually works:
SunSun Solar Pump (24V, 7.5m³/h, VSD included)
$1,495 (includes controller, 20m pipe kit)
Why: Built-in VSD, Australian warranty, works at 15% sun. Best for 50m³ pools.
Green Energy Solutions (Custom Build)
$1,850+ (for pools >70m³)
Why: They size for your exact head. No guesswork. Call them: 1300 764 367. Get a quote before buying anything.
Warning: Avoid "solar pool pumps" under $1,200. They're just AC pumps with a solar panel. They don't run on cloudy days. You'll pay $3k for a $500 pump.
Size for 15% flow rate. Measure head. Demand VSD. Buy SunSun or get Green Energy to custom-build. No exceptions.
Under-size? Pool turns green. Over-size? Solar panels can't power it. Get it right first time. Off-grid isn't a hobby. It's survival.
Worth a watch: DIY Off Grid Solar Pool Pump Setup Brushless Motor with Inverter. No Batteries, No A/C, just panels. · 69jeeper
While many off-grid projects are achievable as DIY, certain situations require licensed professionals:
Always check local regulations and obtain necessary permits before commencing work.