Inverter Run Time Calculator

An inverter allows for a use of electricity from the battery to the appliance. Furthermore, the runtime of the inverter will allow the appliance to operate during a power outage. In order to determine the runtime of the inverter, it is important to understand the relation of the loads of the appliance, the chemistry of the battery, and the voltage of the system.

Should you not understand the relationship of these three factors, it is possible that there will not be enough electricity to power the appliances. One of the factors to consider in calculating how long an inverter will run an appliance is the capacity of the battery. The rated capacity of the battery cannot be used.

How to Calculate Inverter Run Time and Choose the Right Battery

Instead, you should calculate the capacity that the battery can use. Lead-acid batteries only have fifty percent of the battery capacity available before the voltage of the battery drop. Furthermore, lead-acid batteries do not provide there full capacity if the battery is at a cold temperature.

In contrast, lithium batteries can provide ninety percent of their rated capacity, and they are more efficient than lead-acid batteries. Additionally, the capacity of lithium batteries declines at lower temperatures, as well. Another factor to consider is the inverter itself.

The inverter convert the DC power from the battery to the AC power required by the appliance. However, the inverter also draws electricity itself when it is turned on, which is referred to as the idle draw of the inverter. Small inverters will have a lower idle draw than large inverters.

Furthermore, the higher the idle draw of an inverter, the more shorter the runtime of that inverter. Inverters are most efficient at fifty percent of their maximum load. Furthermore, when the inverter is at a very low load or at a very high load, efficiency decline.

Additionally, many appliance will have a surge capacity. For instance, refrigerators and sump pumps require high amounts of electricity to start. If the inverter does not have enough surge capacity to handle the appliances, the inverter will “trip” and stop providing power.

The duty cycle for an appliance will also have an impact on the length of time that the battery will last. Appliances like refrigerators will not be constantly running. Instead, the refrigerator will only be running for a percentage of the time.

Thus, the appliance will use less energy. It is important to understand the difference between the connected load and the surge load of the appliances. The connected load is the total amount of electricity that all of the appliances use when they are running.

The surge load is the amount of electricity that the appliances use when they are starting. The voltage of the battery will also impact the efficiency of the system. Systems that use twenty-four volt batteries will be more efficient than those that use twelve volt batteries.

This is due to the fact that twenty-four volt batteries will require less current to provide the same amount of power to the inverter as twelve volt batteries. Furthermore, low amounts of current create less heat in the system than high amounts of current. Thus, less cables will be needed.

Forty-eight volt systems will be the most efficient for larger loads of appliances, as they require even less current than twenty-four volt systems to supply the same amount of power. Finally, not all battery chemistry are the same. Flooded lead-acid batteries are relatively inexpensive, but they do require maintenance.

AGM batteries are considered to be much cleaner than flooded batteries, and are, therefore, appropriate for indoor applications. Lastly, lithium iron phosphate batteries are best for daily use, as they retain their voltage throughout deep discharge. Each type of battery can have different use in an inverter system based off the needs of the users.

Common mistakes with inverters include overdrawing the system; that is, providing more power to the system than the inverter is designed to handle. Furthermore, some do not account for the idle draw of the inverter. It is important to measure the load of all of the appliances to be used, and to provide a buffer of ten to twenty percent of the power of the system.

This will ensure that the voltage does not drop to a level that will drain the battery to quick, and ensure that the battery does not deteriorate quickly. Finally, it is important to ensure that there is some means of recharging the batteries, as the batteries will need to be recharged after they are used to power the appliances during a power outage.