Tell us about yourself!
Very nicely done, indeed!
Are you going to make your design available on-line? Ever think of making a complete parts list available with suggested sources?
I'm a bit confused. I have a Cyber UPS also and have replaced the battery once. You are should two 12v batteries is series giving 26.2 volts, but as I remember the UPS's stock battery was a lead-acid 12v battery. Why are you feeding the UPS 26v ?