I have storm on my localisation and have power issue for about 30-40minutes and my acctual UPS can hold only about 20 minutes <- time for safety turn off server.
I have money from patronite from you from previous project and i am plnning to mount bigger UPS which can hold much longer.

Hi,
Anyone can help me with my calculations about UPS?

I am thinking about buyinh 8 AGM battery 65Ah for each, it will give me 520Ah. In addition i will take sine wave inverter 700W constans power.
At this moment I have serwer 350W (plus some router and switch).

My calculation is for 500W (350W with some spare power):
500W on 230V gives about 2,2A from socket on the wall
500W on 12V gives about 42A from UPS and it's about 5,25A per one battery

capacity of batteries is 520Ah divine 42A gives 12,3 hours?
even after include losees (because i know that battery give 80% of its power ect) on about 30% level it's gives 7-8 hours of work for 500W for that kind of UPS.

anybody have any advice about it <- i am not electrician.
it's that correct calculation?

Hi,

why not think about these lithium solar power banks. small form factor and can also charge via 230v plug. no need of solar panels.
i wont mess with these lead batteries anymore.

I talk to my friend who has company with power banks and solar panels.
Now idea is for 16x100Ah 3.2V lifepo4 + BMS <- it will gives about 5kW energii and about 7-8 hours backup work
I am waiting for information for cost of solar panel instalation for my use <- to have green powered server. But this is maybe next year matter, i don't have budget for everythink now.