battery life and memory

Does live wallpapers drain battery life quicker than regular wallpapers?
And my sd card is messed up. It might be corrupted and/or I might need a new one. I use task manager to save some battery life and it works well but even killing all my apps, I don't have much memory afterwards. Is that cause my phone isn't reading my card? It used to have around 100m after I kill all my apps but now its only around 50