What are some recommendable brands/products for each application?
The working principle of inverters is the same regardless of application: they convert DC power to AC power. The main operational difference when using inverters in grid-tied and off-grid systems is:-Grid-tied systems feed the output of the PV array directly into the inverter. DC voltage ratings of these inverters may go up to 600 Volts, even in small PV systems.-Off-grid systems must first convert the DC output to a voltage which is suitable for charging batteries, such as 24V or 48V. Any inverter used for this application must be able to operate with smaller input voltages.
Some suitable products for off-grid PV systems are:Radian Series by Outback Power, which offers hybrid operation for stand-alone and grid-tied systems alike.Sunny Island Series by SMA. It can be considered a version of the Sunny Boy for off-grid systems.
With respect to grid-tied systems, some good options are:SMA Sunny Boy string inverterEnphase microinverterSolaredge string inveters with DC optimization