Replacing Gel battery in RCT inverter with lithium

Is it worth replacing the gel battery in my RCT T 1000 inverter with a lithium ion phosphate battery given that the area we’re in has lots of load shedding and power outages?
We got the inverter to run the router, alarm back up battery, pc laptop etc.
We can’t afford to keep replacing the battery which runs down and lasts only 20 mins now after 4 months.

Yes it will be worth it, you should however ensure the lithium battery gets properly charged, even more so if you go for a bigger battery.
Usually typical UPS’s have a very small battery charging circuit on board.

Welcome Jengo.

You would need to make sure the lifepo4 batt you buy, drop-in replacement (?), can be charged using the “100AH deep cycle VRLA gel battery” charger.

Assuming I have Googled the right model.

When the inverter has charged the batteries measure the voltage of the batteries. With that info we can determine if a drop in replacement battery will work…