Battery Faulty and small memory, what can I do?

A

AC Question

Battery Faulty and small memory

My Samsung Galaxy Trend gets really hot in short space of time but I realized it was my battery when I took it out and felt where the heat was coming from. Why would it get so hot so quickly? As well the battery life is short, from 60% it will suddenly jump to 15% and then within seconds its down 2% or 1% it is literally like a count down. Also the I have a 8GB memory card and it keeps saying insufficient space and all I have is some photos and few apps. ( A small game, Facebook, Instagram, WhatsApp and BBM). I have moved the apps to memory card but that doesn't even work it makes my phone lag which is annoying especially when you are trying to use it. Oh and my battery is not swollen.