take a look as there are few threads about this in the caging section maybe? I don't know the first thing about electricity/wiring/etc......so someone please jump in and correct me if I'm wrong but an important thing to keep in mind is whether or not you have an on/off T-stat or a proportional T-stat. I had a Helix on my incubator and hooked it up to an APC ups battery backup (APC 550VA/330 watts). I went to test it, by unplugging the power cord to the UPS and the Helix threw some error codes so I quickly unplugged it and figured that a proportional T-stat was not going to work with this.

Took a look at some older threads and there is some information floating out there about the reasons why proportional T-stats do not work with battery backups or generators. Someone, somewhere may have one working but like I said, I'm not an electrician. Luckily I did have an extra Ranco T-stat which is an on-off type and this seems to work. I test it by unplugging the battery backup and the battery kicks in and the Ranco stays the same......no temp drops and no error codes. For how long?? I'm not sure but I don't think the amount of flexwatt I have in my incubator would suck up the power like a home computer would so I bet it would last awhile.