Solar charge controllers : Buyers guide
If you are looking to go off-grid or wanting to use a hybrid system to produce solar-generated electricity during the day and using a storage solution to provide energy , during an outage or during weather turbulence there is no doubt you will need a solar charge controller the most baisc function is that it Monitors the battery voltage, Opens the circuit Stopping the charging, when the battery voltage rises to a certain level, Prevent the DC electricity flows back to solar panel at night, when solar panels are not generating electricity, electricity can actually flow backwards from the batteries through the solar panels, draining the batteries. It is, however, pertinent to note that use of a controller is recommended for solar chargers that are rated 15 watts and upwards. controller works in such a manner that it maintains the necessary voltage that the batteries need while charging. For example, during days when the sunlight is harsh and thus the solar panels produce more voltage, the solar charge controller regulates overcharging of the batteries.
There are 2 types of solar charge controller:
1: MPPT solar charge controlle
2: PWM solar charge controller
1 – selecting your Voltage
Select a charge controller that is compatible with the system voltage. The standard configurations are 12, 24, and 48 volts. If you are wiring your batteries for 24 volts you need a charge controller that is rated at 24 volts.
Some controllers are voltage specific, meaning that the voltage cannot be changed or substituted. Other more sophisticated controllers include a voltage auto-detect feature, which allows it to be used with different voltage settings.
2 – the capacity of your Current
Chose a charge controller that can handle the maximum output current of the solar panel (or solar array). The maximum possible current that a PV panel can generate is the “short circuit current,” indicated as Isc in the panel’s label or specs sheet.
It’s recommended to include a safety factor for isolated events as well. Take instance that , a solar panel with a LSC of 7.89 amp could potentially generate an extra 25% on a sunny day with very clear snow pack. (light reflected from the snow). This results in a possible maximum of 9.86 amp (7.89 x 1.25 = 9.86 amp). In this case, a 10 amp charge controller would be recommended
PWM solar charge controller
The use of an MPPT solar controller in a solar installation can lead to production gains of up to 30%.
An MPPT solar controller can connect a 24V photovoltaic solar panel to a 12V solar battery, in the same way it allows the use in isolated site of a photovoltaic solar panel intended for resale (often called grid injection panels, they often have 56 or 60 cells).
MPPT controllers are generally more sophisticated. They can adjust the input voltage and current of the PV array to find the optimum operating voltage that will generate the most power at a given moment. (, an MPPT controller will be able to generate more power than a PWM controller during bulk charging.
PWM solar charge controller
PWM charge controller Some modern solar charge controllers use Pulse Width Modulation (PWM) to slowly lower the amount of power applied to the batteries as the batteries get closer and closer to fully charged. This type of controller allows the batteries to be more fully charged with less stress on the battery, extending battery life. It can also keep batteries in a fully charged state (called “float”) indefinitely. PWM has some complexity but lacks some mechanical connections to break
However you must Read carefully the user manual of the selected MPPT solar controller and ask your questions to your supplier or at Diamonds- solar-power – contact if need be