1. Description
The IV Curve allows for an estimate of the contribution that the Solar Panel setup makes to the overall power budget.
The curve is a measure of voltage vs current under different conditions. The two main conditions are the amount of solar energy falling on the cells, and temperature. A test unit is used to collect data and points on the curve are recorded by placing different load resistors across the panels and measuring the resulting voltage and current.
The test circuit consists of a switch, a combined voltmeter / ammeter, a choc-strip connector, and a set of discrete resistors. The meters are part of the normal circuit monitoring equipment.
2. Touch Points
A switch directs solar panel output to the test circuit or to the ProStar 15 battery charge controller.
3. Power
This is designed to provide an estimate of the amount of energy the solar cells are capable of providing to the boat. This energy is stored in the house / starter batteries.
This measure can only be an estimate and is dependent on the strength of the solar energy, the time that the panels are illuminated, and the ambient temperature. Further, once the batteries are charged, any power generated after this is 'wasted' though it will maintain full charge if there is a small load.
4. Method
The IV Curve, more accurately; set of curves, are create using the following approach:
5. Links
The IV Curve, more accurately; set of curves, are create using the following approach:
- This is best carried out on a clear day.
- The test circuit switch is initially set to 'On'.
- The combined Voltmeter / Ammeter is switched on.
- The ambient temperature is taken.
- The solar irradiance is measured and noted.
- One of the test resistive loads is connected to their terminals.
- The test circuit switch is briefly set to 'Test' while the Voltage and Current is noted.
- The last two steps are repeated with the remaining resistive loads.
- The temperature, irradiance, voltage and current readings are noted throughout the process.
- The raw data is processed into a set of IV Curves.
5. Links
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