Battery Backup vs UPS

[ghosty]

Hi All,

I have a Prusa i3 X pro, with a 15amp power supply, it is under rated for the printer. I need to get a new supply that can handle the load, the 15amp is fine for PLA, but as soon as it comes to heating the bed to 110 for ABS......I gave up today after 35 minutes and it was only 107 degree's

So I am thinking, I have 20 (37 amp) Deepcycle batteries in the shed, is it feasible to hook 4 of these to the printer directly as the power source and then just us the 15amp supply as a charger (or buy a dedicated charger). I would not be limited by current supply as the 4 total close to 150 amps, at its current supply that would be around 8-10 hours of uninterrupted supply perfect for those long prints.
Questions ? the batteries float at 13.8vdc, most chargers charge at 14.1 v DC (assuming I buy a proper Ctech or the like) Is this to high a voltage to put into the printer controller, Would I need a voltage regulator? Under load with no charger (AC fail condition) the batteries would drop to 12.4v dc (and then sit there for hours) pretty quickly if my camp fridge is anything to go by.

Alternatively, do I spend $40 on a new 20 amp or 30 amp power supply and buy a UPS from the local retail store that would set me back $200 aprox and would provide probably some were in the order of 20 minutes backup.

My printer is run by Octopi, I cut the STL in S3D and then pass it to Raspberry Pi to do the rest, so there is no extra load of a pc to consider the Pi draws 1amp an hour max at 5vdc.

I am thinking the battery method but am not upto speed on what the variable voltages may do.
Any hints / thoughts.

[CompoundCarl]

You can get cheap 20 and 30A power supplies on ebay that are only $25 or so. I would just do that instead of manually trying to wire up all those batteries...