Hey all, utter newbie out of his depth here.
I'm thinking about a project to force me to learn more about electronics in general and thought I could use an UPS for my server and workstation (in home use, obviously). To make it more interesting, I wonder if I could combine double-conversion (aka online) UPS and two ATX PSUs by stripping DC-AC circuit from the UPS and primary transformer and rectifier from the PSUs.
Besides learning, motivation for this would be avoiding conversion losses online UPS normally brings while still providing good quality power to the machines. I'm planning to buy a old-ish UPS with depleted batteries which I'd replace with bunch of gelled lead-acid motorcycle batteries in parellel. I don't know make or model of the UPS yet, PSU's to be butchered would be Corsair's AX 850*2.
Bypassing transformers in the UPS and two PSUs would remove the isolation between the three pieces of equipment and it'd essentially be a single battery backed PSU with two 70 amp 12v rails +minor rails. Would PSUs cause interference to one-another? Possibly from switching noise?
I'm not sure what's the voltage after transformer in the PSUs but I'll likely need a regulator. Noise here shouldn't be an issue since PSUs are designed to work on noisy 230v line. If I assume that input to PSUs varies between 14.5v when the system is on-line and then declining to 11.5v as batteries discharge (after which system would issue suspend/shutdown PCs plugged in until power is restored). Current draw would be high tho, up to 140A from input, should I expect to run into problems there?
But most importantly, does this even make any sense? While I'd be doing this to learn, I'd perfer to have a working system in the end. Preferably one that won't fry the PCs connected or worse, be a fire hazard. High current draw makes me a little nervous. 140A is a lot of juice.
I should note that I'm not expecting to hit anything near that 140A on live system, peak draw would hardly go over 70A and median should be around 35A, maybe less. But if I'm using two 850w PSUs (which I have already), designing the system to be able to provide that sounds like the correct choice.
Insight would be appreciated. I realize that this all sounds like I'm oblivious to my ineptitude but I prefer to think I'm simply overreaching