So the problem with modified APC UPS is that they dont stop charging the batteries when full. I have noticed they keep on charging at lower amps, when actually they should be only float charging at this point.
So I need to design an efficient yet powerful system that would provide at least 1000watts of constant backup for 3-4 hours continuously. It should be able to recharge back to full in same amount of time, meaning theini charger should be powerful enough to put back the energy used in the same amount of time it was used for, 3-4 hours.
I am thinking about using slightly modified (avg 8-10amp charging) 2200va/1980watts APC units and I am thinking of using 3 of them.
This could be the setup:
3 x APC in parallel
4 x 200 amps AGM VRLA batteries like sacred sun or concorde etc
total cost would be around 2 lacs.
Any one got any better solutions, please share.