Yes, they need much more water than desert cacti. They often shed their leaves in autumn/winter but will grow new ones in spring. The less water you give them the sooner the leaves will fall off. It you continue to water them throughout winter at least some leaves may be retained on the plant.
It sounds as if your first plant behaves normally, but the second plant is not well. Have you checked the roots?

To add, I might suggest a different soil mix as well. I use a blend of 50% supersoil, 50% perlite. Here in the hot dry desert that works very well for me. I would probably wait until spring to repot them into new soil.

I water much more often than my normal cacti when they are growing, but not very often in winter when they go deciduous. I grow them all pretty hard outside and they do go dormant when it gets cold (which it hasnt yet here).

I took both pereskia out of the pot, and found the second plant dead with no roots left, I must have overwatered. I had thought all along the problem was not enough water, when it must have been just the opposite.
The other plant still has limp leaves though I repotted in dry soil. So I am basically still at a loss as to how to properly grow a pereskia, and hope the one I have left pulls through. Any suggestions?

Christopher

The leaves on my aculeata are limp too and a few has fallen off, but that is because it is dormant now and I do not water it much. That is why I thought your first plant was ok.
Have you watered it since repotting?

I repotted the surviving pereskia with fresh dry soil but the leaves stayed limp, so I gave it a little water, with no change. I am going to try to force myself to not water it any more until I see some sort of change: I don't want to kill this one too!

Christopher