What is a Power Inverter?
When you plug an electrical appliance into a wall outlet, it uses AC (alternating current). However, most off grid solar power systems store power in deep cycle batteries in DC (direct current). The off grid inverter converts the DC power from the battery bank into the AC power that your home appliances use.
What is an Inverter/Charger?
Quite often in an off grid solar power system, the batteries are charged with solar panels. Depending on your system, solar power alone may not be enough to charge the battery bank in the winter, when the days are shorter. In these cases, an AC generator can be used to help keep the battery charged. An inverter/charger would convert the AC power from the generator to charge the DC battery bank. An off grid inverter/charger would be converting the power in both directions, from AC to DC to charge the battery from the AC generator, and converting the DC power from the battery to AC for your appliances. Some inverter/chargers even have the option to remotely start a generator when the batteries’ charge level gets too low.
Another common use for an inverter/charger is in a boat or an RV, where you have an inverter/charger charging the battery bank from shore power or a generator, and the inverter converting the DC power to run your AC loads.
In a hybrid power system, where deep cycle batteries are used as backup power for your house in the event that the grid goes out, the hybrid inverter/charger may use the AC power from the grid when it is up to keep the batteries full and ready to go when the
grid goes down. Some hybrid inverter/chargers, like the Schneider Conext XW+ Inverter and the Outback Power Radian, have two AC inputs for charging the battery bank through its charger, one from the grid and one from a generator. This way, when the grid is up, the grid can keep the batteries topped off, and when the grid is down, a generator can be used as needed to charge the batteries, so the generator doesn’t have to be run the whole time the grid is out. Then, add solar panels to charge the batteries during the day using a solar charge controller, and you can have a powerful hybrid solar solution.
Do I still need a Solar Charge Controller?
We are often asked why a solar charge controller is needed in an off grid solar system if they are using an inverter/charger. The charger in the inverter/charger is an AC charger. It uses an AC source, such as a generator or the grid, to charge the battery bank. If you are using solar panels to charge the battery bank, you need a solar charge controller to manage that. If you are also using an AC source to help out when the sun isn’t providing enough power, you would have both a solar charge controller and an inverter/charger charging the deep cycle battery bank from two sources.
Now you have the uses for inverter/chargers, hybrid inverters, and solar charge controllers. If you have any questions on this topic, feel free to ask in the comments section below.