Battery Inverter
A battery inverter can use the stored energy in a battery, convert it to AC so that connected loads can be powered.
As this is an inverter only, it cannot charge a connected battery with utility grid power. Some other external means of charging will have to be added.
A battery inverter/charger on the other hand, can also charge a connected battery, but not a battery inverter only.
Solar panels cannot directly be connected to a battery inverter.