The standard Varta battery is soldered on the bottom of the motherboard. If you snip out the old battery, leaving the ears, you'll have excellent platform for the new battery, as noted below.
(1) Clean motherboard with electronic board cleaner.
(2) solder "18 inches of insulated wires" to those ears. Red to +, Black to -.
(3) route the wiring, using cable ties as needed, to the front of the power supply cage, near to video slot.
(4) Attach battery. Notch top edge of plastic medicine bottle to allow wires to pass under cap.
(5) Insert battery in medicine bottle, and secure with plastic tie to power supply cage.
I have used this idea with small 3.6v telephone batteries. No more bothersome battery on the motherboard.
