ROCKSOLAR 0.4 HP 20–40 V Solar DC Brushless Water Transfer Pump Kit
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ROCKSOLAR 0.4 HP 20–40 V Solar DC Brushless Water Transfer Pump Kit
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What it is, and what it is for
ROCKSOLAR 0.4 HP Solar DC Water Transfer Pump Kit
What's included:
- 1 × 0.4 HP 20–40 V DC brushless water transfer pump + external controller
- 1 × Hanersun 445 W full-black bifacial solar panel
- 1 × 10 ft 10 AWG PV cable
- 1 × 2 String Waterproof PV Combiner Box with 32 A 500 V Circuit Breaker and surge protector
- Mounting brackets for solar panel (optional)
- User manuals + warranty card
Included solar panel: Hanersun 445 W full-black bifacial panel. Each panel measures 67.80 × 44.65 × 1.18 in (1,722 × 1,134 × 30 mm) and weighs 51.4 lb (23.3 kg).
Key specs:
- Motor: 0.4 HP DC brushless | Input: 20–40 V DC
- Max flow rate: 8.8 US GPM (at minimum head)
- Maximum head: 98.4 ft
- Outlet: 1 in diameter
- Solar array: 1 × 445 W bifacial panel
Built for: Garden fountains, small ponds, livestock watering, irrigation, remote cabins, small pools, off-grid agricultural applications
Key features:
- Fully automatic solar operation — controller adjusts pump speed to available sunlight, stops and restarts without manual intervention
- Float switch / pressure switch compatible — automates tank fill/shutoff for livestock troughs and storage tanks
- Battery compatible — can be supplemented with a battery for cloudy-day or overnight operation
- DC brushless motor — quiet, efficient, low-maintenance
- Advanced protections: dry-run, overload, overvoltage
How the System Works
The ROCKSOLAR Solar-Powered Water Pump System converts solar energy into a reliable water supply for livestock watering, irrigation, and remote agricultural applications.
The operating sequence is as follows:
- Solar panels convert sunlight into direct current (DC) electricity.
- The solar pump controller continuously monitors the available solar power and adjusts the voltage and current to maximize energy harvest from the solar array.
- The controller supplies optimized DC power to the brushless surface transfer pump, ensuring efficient operation under varying sunlight conditions.
- The pump draws water with its intake pipeline from the well, pond, cistern, stream, river or other approved water source and delivers it through the discharge pipeline.
- Depending on the application:
- Livestock Watering: Water is pumped into a storage tank or watering trough. When an optional float switch is installed, the controller automatically stops the pump once the tank reaches the preset water level and restarts pumping when the water level drops.
- Agricultural Irrigation: Water is supplied to irrigation systems such as drip irrigation, sprinkler systems, soaker hoses, or storage reservoirs for crop, orchard, greenhouse, vineyard, pasture, and garden irrigation. Flow can be controlled using irrigation valves, timers, or storage tanks based on the specific irrigation design.
- During periods of insufficient sunlight, such as early morning, late evening, or heavy cloud cover, the controller automatically reduces pump speed or stops the pump to protect the system and optimize energy use.
- When adequate sunlight returns, the controller automatically restarts the pump without requiring manual intervention.
This intelligent, fully automatic operation minimizes maintenance while providing a dependable and sustainable water supply for livestock, irrigation, and other off-grid agricultural applications.
Flow rates are listed in U.S. gallons per minute (US GPM). Head and distance are in feet (ft); connection sizes are in inches (in). Maximum flow and maximum head are separate ratings and do not occur at the same operating point.
2 components
Each one is a product we sell on its own, so you can read its full listing, and replace or add to it later.
Published before you buy. No email required.
Every number, by component.
The figures the manufacturer publishes. The datasheet above is the reference if the two ever differ.
| Pump Specification | Details |
|---|---|
| Product | ROCKSOLAR 300 W Solar Brushless Transfer Water Pump |
| Motor Type | High-Efficiency Brushless DC Motor (BLDC) |
| Controller | External with MPPT and Protection Features |
| Power | 300 W |
| Voltage | 20-40 V DC (Best at 30-40 V) |
| Max Head | 98.4 ft (30 m) |
| Max Flow Rate | 8.8 US GPM (2.0 m³/h) at minimum head |
| Pump Diameter | 1 in |
| Pump Outlet | 1 in |
| Protections | Dry Run, Overload, Overvoltage, Low Voltage |
| Warranty | 1 Year |
| System Installation Distance | Controller to Motor: Up to 262 ft (80 m) |
| Ingress Protection | IP54 Rated (Pump), IP65 Rated (Controller) |
| Hanersun 445 W Full-Black Bifacial Solar Panel | Details |
|---|---|
| Manufacturer | Hanersun |
| Power Output | 445 W |
| Panel Type | Full-black bifacial, N-type monocrystalline |
| Dimensions (L × W × H) | 67.80 × 44.65 × 1.18 in (1,722 × 1,134 × 30 mm) |
| Weight per Panel | 51.4 lb (23.3 kg) |
| Thickness | 1.18 in (30 mm) |
| Construction | Dual glass, 0.079 in (2 mm) front and rear |
| Junction Box | IP68 |
Before you order.
If yours isn't here, ask an engineer. It costs nothing and it's the step most people skip.
Submersible or transfer pump — which do I need?
A submersible pump goes down the well or into the cistern and pushes water up from below; it is the right choice for any well and for deep tanks. A transfer pump sits beside a pond, creek or tank, lifts water a short height and then pushes it along; it suits surface water and moving water between tanks.
Does it run on cloudy days, or at night?
A DC brushless pump slows down when the light drops and stops when there isn't enough, then restarts on its own when the sun returns. It does not run at night. The usual answer is a storage tank, filled by day and drawn on around the clock. If you need pumping after dark, add a battery, or choose a hybrid AC/DC pump that falls back to the grid or a generator — but only if you actually need that backup, because it costs more and most sites don't.
Do I need a battery?
No. Solar-direct pumping into a tank is the standard design and the cheapest one: the tank is the battery. A battery is worth adding only where water has to move at night or on demand, such as a pressurised house supply with no tank.
What is in a kit that isn't in the pump alone?
A kit adds the solar panels sized for the pump, the PV cable and the combiner box with its breaker and surge protection, so it is ready to wire up. The pump-only listing is for people who already have panels or a battery system to run it from.
How do I know which model to choose?
Two numbers decide it: how far the water has to be lifted, including pressure and pipe friction (the total dynamic head), and how many gallons a day you need. The finder works both out from your well and your use, and picks the model with the right curve. If you are unsure of your well depth or static level, ask us before you order.
Will it stop when the tank is full, or the well runs low?
Yes on both. The controller takes a float switch or pressure switch, so the pump stops when the tank is full and restarts as it drops, and it has dry-run protection that shuts the pump off if the water level in the well falls below the intake.
What if I'm not sure this is the right product?
Ask before you order. Send us what you need to run, or your pool or well figures, and an engineer will confirm the choice — it costs nothing. Or use the finder below, which sizes from what you actually run and shows its reasoning.
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