Can a high capacity gel battery be connected to a computer UPS?

Question

Computers

Hello. Is it possible to connect an AGM battery (traction, not car) with a capacity of 100Ah (intended for inverters) to the Ippon Back Power Pro 500/600. I want to bring out a switch that would allow switching the power supply from an internal battery to an external one, and a port that would allow an external "large" battery to be connected. Do I understand correctly that the characteristics of the UPS (runtime) is determined solely by the capacity of the battery? Based on this, some average operating time for a home computer is calculated (3-5 minutes.) And the load that can be connected is displayed so that the UPS provides the estimated time (I'm a little on the other side, of course, that the load characteristic is first declared, and the battery is selected under it.). At the same time, the internal charger is designed to charge exactly the installed capacity. From this we can conclude that connecting an external battery will be undercharged. Ready for this, half a meter is a charger for AGM. Those. I connect a charged battery to the UPS, and after a power outage and the battery returns a charge, I manually charge it.
Do I understand everything correctly?
And is it necessary to connect the battery through a diode so that it gives off, but does not accept a charge from the UPS charger? Can such a circuit damage the UPS charger?
And will the connection through the diode allow not to disconnect the battery from the UPS when it is charging, or will the diode not affect this at all?
Can an external battery provide a lot of battery life at rated 500/600VA? And is it possible to connect, for example, 1000W, namely, is it safe for the UPS?

Answer 1

you can connect
the battery will be fully charged but slower
for longer work / a slight increase in power will have to add forced cooling

Answer 2

Well, yes, as a UPS, you can safely use a similar https://aky.com.ua/category/gelevye-akkumuljatory/ gel battery, as I do it now, in fact. As they say above, the capacity is not too large - so to complete your work and turn off the device. And longer, then a backup power system is already needed, which is impractical with gel batteries.