Will only work with 1.5V battery output instead of 1.2V

If the recharageable battery is more than 3 - 4 years old then the battery could be worn out.Rechargeable batteries have a finite number of charge and discharge cycles andwill lose their charge capacity over time, i.e. won't charge to 100% and graduallythe charge reduces until the battery won't charge up at all. OR The batteryshows a 100% charge but when the adapter is disconnected the battery drops offto zero capacity in a very short time. If the battery drops to an unacceptablecharge level then the battery needs to be replaced.

You can't charge the A80 by plugging in a USB cable. The cable is for downloading photos only. Assuming that you are using rechargeable AA batteries, you need to remove the batteries and place them in an external charger to recharge them.

Rechargeable batteries are rated 1,2V while ordinary one's use 1,5V. Thats why.

No. The A80 is not a battery charger. If you want to use rechargeable batteries with the A80, you must recharge them outside the camera using a separate charger.

Hmm... What kind of batteries are you using? Does this happen on the charger power? If so, it definitely needs repair.
If batteries only:
Try using batteries specifically for cameras - they are worth the money.
Try cleaning the battery door with a little 99% pure alcohol and a Q-tip. This can make a BIG difference if it is battery issues.
Rechargeable batteries may not work well. Try cleaning both ends of the batteries with alcohol as above. If the rechargeables are over 3 years old, they may be toast.

try here AA Rechargeable Battery 700mAh NiCd 1 2v or NiCd Rechargeable Cell AA 1 2V 700 mAh Flat Top 1PC or Amazon com SANYO 700AAC NiCd AA 1 2V 700mAh SANP1100 Toys Games you'll know which one you need from the pictures I'm guessing...

So camera doesn't give live view to take picture? and you can view old / stored  pictures OK, is it?
If yes, then it is problem of CCD imager in Canon A80 and this part needs to be replaced.
Canon will repair your A80 free of cost as per announced scheme of CCD imager support.
Click Canon CCD Advisory to know how to get free repair facility.

Hello

Recharging the batteries seemed to solve it. Although I had not received the low battery warnning and this phenomenon had not occurred at other times when the batteries were low, it seems to have fixed the problem.

Thanks.

Have you tried a new set of batteries?