xX bigmike Xx

I have a 92 civic with a 95 b18c1 gsr swap and well ill go to crank my car it will crank up for about 2 or 3 seconds then die out I've been told its just the battery and I've replaced 4 of them so far and it keeps doing it the car doesn't get driven alot either i will get a battery put on it drive it on the weekends get ready to drive it the following weekend and it cranks up and dies out and it does the whole process over and over. i thought it was my alarm system draining the battery but i cut it off put a new battery on it and it did it again im so confused as to why it does this hope someone knows.