Do you own a hybrid or stand alone inverter system.
Let's look at stand alone system, that comprises an inverter and bank of battery or batteries.lets use su-kam inverter for example, not that it is best, inverters are similar in operation.
At the back of most inverter you will see two switches or three for example contec.
Switch One UPS and WUPS.
Switch Two, LA and SMF/Tubular.
These switches are not permanently set, just as it has been the case with most installers, for the benefit of owners, if you are having erractic power fluctuations, move your inverter switch to WUPS or Wide UPS, your inverter will accept voltage range from 90 to 260 good for evening period,while on UPS your inverter will not accept voltage less than 170v.
At the other switch LA and SMF/TUB. Most installers move this switch to LA, that's normal charging up to 10amps, this is not good for new battery. So to maximize the life and performance of your new batteries move this switch to SMF/TUB this delivers 15amps fast charging currents, similar to two solar panels. If your battery is getting older than a year or two, your inverter switch stays at LA.
The Su-kam inverter picture attached, May differ from your own.