●Rison Solar Water Pumping System Working Instruction
To be able to make proper selections on PV module and battery for solar water pumping system, we need to know how this system running. Thru the operating process, solar panels convert sunlight to electrical energy which is passed to the solar pump controller.
The solar controller stabilizes the voltage and output power to drive the pump motor. If backup batteries (optional) are installed in the system, then the pump controller can also charge them. The stored power can be used during the evening or when the sunlight is not adequate to drive the pump.
Sensors are also connected to the controller and can be used to protect the pump from running dry as well as to automatically stop the pump working when the tank is full.
●Selecting Proper Battery Sets for Rison Solar Water Pumping System
The number of PV panels should be enlarging if you need to install the battery in the system. The extra PV panels are required to charge the batteries while the pump working.
The cheapest option is to try and fill an elevated header tank or if you have no elevation locate the tank near a utility power supply so you can pump water from the tank using a mains powered pump.
You must use deep cycle batteries not car batteries. Deep cycle batteries are designed to take much lower continual discharges than regular car batteries. Deep cycle batteries normally have an “amp hour” rating shown as AH, for instance 100AH.
Rison Solar Water Pumping System Diagram with Battery Connected.
●Battery Calculation for Rison Pumps
Please note even with a deep cycle battery discharging it to allow level will shorten its life, this is why we use 60% as discharge level.
Current drawn by the pump = pump power divided by the voltage.
E.g. : In the case of a 12 volt 300 watt pump.
300 watts divided by 12 volts = 25 amps
100 AH divided 25 amps x 0.6 = 2.4 hours of backup with the battery being discharged to 60%.
E.g. : In the case of a 24 volt 300 watt pump.
300 watts divided by 24 = 12.5 amps.
2 x 100AH 12volt batteries in series = 100 AH at 24 volts.
100AH divided by 12.5 amps x 0.6 = 4.8 hours of backup
Batteries in parallel, add the AH, voltage stays the same.
Batteries in series, add the voltage, AH stays the same.
Question. I want to have backup for 8 hours with a 300 watt 24 volt pump, how many AH do I need?
Re : 300 watts divided by 24 volts = 12.5 amps.
8 hours divided 0.6 x 12.5 amps = 166AH (2 x 166 AH 12volt batteries in series)
Battery Selection Examples are recommendations only, the actual battery sets can be varied depending on the pump size, operation hours, weather conditions, etc...
Pleaase contact Rison team for the optimum solution for your solar water pumping system.