|I did try this in an outside shed with an old server ups. The test failed. I just wanted sometime power without having to put an extension cord. I didn't exactly have the 48 volts it needed either.|
UPS systems are pretty smart. It may know the load or type of the battery in some sense circuit.
Chargers are slightly different but in some cases they can charge both.
Remember the flooded lead acid offers some dangerous reasons not to use it in a home or business. The acid is on creepy thing. It gets everywhere and crawls out of the battery so you usually keep them in a battery box. Second is the explosive gas (hydrogen) that is present.
Get a UPS that has the ability to offer external batteries and purchase the correct ones. It is not worth you life or home to play with this.
Katy Perry, I'd never treat you badly.