Solar modules produce DC voltage, and their power output varies considerably depending on weather conditions. A solar regulator or solar MPPT charge controller manages these variable to charge a battery bank safely, efficiently and without damaging the batteries. Solar controllers regulate different charging stages automatically and ensure your batteries are fully charged regularly.
Solar inverters are what you see often on side of house walls for grid-connected solar systems. They take the DC voltage and convert it straight to AC for use in the home or sent to the grid. These inverters can also be used on off-grid systems, typically when the solar array becomes large and using ELV wiring becomes problematic and/or costly.
Solar panels vary in output wattage and amperage and can be connected in different combinations of series and parallel (increasing the voltage or amperage). The Victron MPPT calculator is an excellent tool to check your solar panel configuration matches the Solar controller you are purchasing. You can find the Victron MPPT calculator here.
Solar Regulators
The most basic of solar controllers, with limited power capacities, functionality, and features. Solar regulators are the worst performer when it comes to maximising your solar generation into charging batteries. They don't include 'maximum power point tracking' which calculates the maximum amount of power that can be generated through the Amps and Voltage the solar module is generating. It will really only take the solar module voltage and amps and put straight into the battery. Ok, for small, basic solar setups that don't mind non-optimal performance.
MPPT Solar Charge Controllers
MPPT (Maximum Power Point Tracking) Charge Controllers maximise and regulate DC power from the solar array for the charging the battery bank. Unlike solar regulators, MPPT controllers are more effective and efficient at turning your solar generation into stored power in your battery bank. As described above, they pick the optimal point on the solar IV Curve (Maybe google if that term is over your head) to get more usable kWh out of the same solar array. MPPT controllers usually include more features when it comes to programmability, user interfaces and much larger capacities, solar MPPT is our recommendation for your solar array. You can find our range of Victron Solar Charger Controllers here.
An example of a DC-Coupled off-grid system setup using a compatible solar MPPT Charge controller.
Solar Inverters
The solar MPPT inverter (Maximum Power Point Tracking) converts DC electricity from solar panels into appliance friendly 240V AC electricity to either directly power loads, or to charge batteries via the separate compatible inverter/charger unit. This is the same technology/type of unit that is used on standard home grid-connected solar systems. Some solar inverters can work in an off-grid system by adjusting parameters (Designed/Approved by the manufacturer). Note, these units must be installed by a licensed electrician as the input and output voltages are in the LV class.
An example of an AC Coupled off-grid system setup using a compatible solar inverter.
